Forum

LiPo batteries

Please can I get some advice on LiPo batteries. I intend to buy a 3300-5000mAh battery to run an offshore power boat model. I will be taking the battery with me to Hungary to use on my local river which I have found is ok as hand luggage properly protected from short circuit. My problem is that at present, I only go there three time a year so the battery would remain unused for 4 months at a time. If I leave the battery with a safety charge, will it last for four months unused or will it fall below the critical voltage. If it is felt that it will not hold the charge, I will have to carry it with me forward and back. Thanks.😊

6 years ago by MouldBuilder

Forum

All hooked up, nowt happens...

Hi All I use the Hobbyking car ESC's HK-45A, HK-60A SL and HK-100A which all use the same program card(HK PROG-CARD). I use the same setup for all my boat, only changing the battery setting for the 2s, 3S and 4S Lipo. 1 Cutoff Voltage for 3S=10.2 and 4S=13.6 2 Start Power Percent=5% 3 Advance Timing=4 4 Run Mode=2 5 Brake Force=1 6 Drag Brake Force=1 7 Neutral Range=1 8 initial Brake Force=1 9 Reverse Force=1 It works for me. Canabus

5 years ago by canabus

Response

Internal wiring & bottom skins

Hi Rob, the Police Launch is coming along nicely. I see that you have long leads from the battery to the ESC. The general rule is that these leads should be kept as short as possible to minimize voltage spikes caused by the fast switching currents and the inductance of the leads. Brushless ESC's have large capacitors, often visible at the end to absorb the transients. You may well get away with it but the life of the ESC could be reduced. Hope your Xmas goes well, Alan

5 years ago by ukengineman

Forum

Proximity (Hall effect) sensor wiring

I do not know how much knowledge of electronics your friend has but I need to point out that a hall effect sensor is not like a relay. While they do act like a switch ( sort of) they need to be powered and have a hall effect voltage to switch. This would mean in the use intended there would be a current drain on the sensor and if the power supply ( battery?) voltage fell to far it would not function. The effect you want could be replaced by a reed relay cheap and simple to use. However reed relays can only pass low currents so would need to be cascaded with a higher rated relay before switching the main battery supply on and off. https://www.ebay.co.uk/itm/10-Pcs-2-5X14mm-3-Pin-4W-Glass-Reed-Relay-Magnetic-Switches-N-O-N-C-SPDT/372165424048?hash=item56a6c9b3b0:g:vgAAAOSwJtdaL2~p:rk:53:pf:0 these reed relays have both normally open and normally closed contacts and at a couple of quid for 10 worth buying so he can experiment.

5 years ago by Haverlock

Forum

fuse holder

Hi all thank you all for advice and comments , I have had a good look at all the suggestion and decided to go for the 3m scotch suitcase type and I will let you know if they are ok. now I have a question for all when choosing motors should you chose a voltage rating equal to the of the battery or higher then the voltage of the battery

5 years ago by teejay

Response

HMS BRAVE BORDERER

Rowen, here are a couple of things that may be of use to you (and others). The battery alarm will save you worrying about running out of steam as they can be set to beep at varying voltages to warn you of low battery, just put one on each batt balance lead and when one goes off (when an individual cell drops below the set voltage) it means start heading back. These can be picked up on Ebay for a few dollars. I use them on my planes as well and are audable from around 100m (these twin horns are the best) Secondly, re your ESC switches, these electronic switches (AliExpress) are great for this sort of thing (as long as you have enough aux switches on TX ) You can link them with a Y cable to work together or use them independantly for anything, (lights, pumps etc, - they can be operated by TX rotary switches as well) The ESC and 2000kv motor (HK) are the ones I am using in my ASR model and will work smoothly down to a crawl, the purple 1980 kv seems to have superseded these but I think they will be as good. The props are from Ali Express and are resin and available in L and R hand, are only a few bucks and perform perfectly while looking quite scale(ish). I painted them with an acrylic bronze which seems to have stayed on pretty well. Model weighs 2.8kg and will run at more than 10mph flat out with this set-up (using the 26mm L+R) props) which is silly speed and that's with 2x 2s 2200mah lipos (which will last till you get sick of it and still have 60% left) I was just looking at your Daman set-up and noticed the wiring method from the batts to the ESCs. You might want to make your batt to ESC connections direct to your ESCs (as per original ESC lead length)as your capacitors may get a thrashing (spikes) due to the extra length/ resistance you have there. There is a general rule that you don't lengthen the batt to ESC wiring without adding a 220mf capacitor of same voltage as the ESC for every 4"of extra wire length (ESC to motor - not so much). Might want to check this out in case you fry your ESCs You probably have thought of this but thought I'd mention it, 'just in case' Might help with your modulation as well. Have chucked in a vid of the HSL manouvering (first trials so wasn't perfect) and also the MTB (brushed) which I have just converted to a twin system (was twin but single Electronize unit) plus a sound unit. You may know that you can use as many RECs (bound to the same TX) for various purposes on the same boat (have run 2 boats together from the same TX) Might get you round the mixed brushless/ brushed problem with a bit of thought. Have you thought of changing your old HK silver 6DF TX to twin throttles, it's a piece of cake(as is the TGY 6x), just remove the aileron/rudder centering spring and make a friction plate as per throttle stick, and use the elevator channel as your other throttle. Set your ESCs and you can then use a twin system giving you perfect control. Saves a lot of hassle.

6 years ago by jbkiwi

Forum

All hooked up, nowt happens...

Hi Martin, maybe! Maybe not! You might be lucky. Check the RX with just a servo plugged in somewhere. Then try setting up the ESC according to the instructions I sent. Basically all you have to do is tell it what type of battery you are using. Then it sets the correct 'Cut Off' voltage. BTW: since this is a 'One way only' ESC before you switch the system on make sure the throttle stick is pulled right back. Otherwise the motor will start up straight away. Mind yer fingas!! 😡 Also check that the throttle channel is not reversed at the TX - like most Futaba sets for some crazy reason - or again the motor will start up with the throttle pulled back. PDF: as Steve says; click on the Icon, then on [Download] in the top left corner. Windows should then offer you the choice of 'Open' or 'Save'. Click 'Save' and Windows will ask where you want to put the file. Cheers, Doug 😎

6 years ago by RNinMunich

Forum

All hooked up, nowt happens...

Hi Martin, Looks like this one XXD HW30A 30A Brushless Motor ESC For Airplane Quadcopter Which means it ain't got no backuds! But I don't suppose that bothers you. Attached is the manual as pdf. Before you can run the ESC you have to program the type of battery; LiPo or NiMH. The ESC then sets the correct cut off voltage to protect the battery from deep discharge. See second page of pdf file for instructions. The ESC has a 5V 2A BEC. if you use a separate RX battery you MUST disconnect the small red wire from the RX plug! Bon chance, Cheers, Doug 😎

6 years ago by RNinMunich

Forum

RC....mixers? And other unknowns..

Ok... Currently trying to build a Itaieri Schnellboot, ...but am questioning if what little I think I know to be correct/ workable... I have amassed the following : 3- Hobbyking ST3007 1100KV brushless motors each direct drive to 32mm plastic props.... (2 right hand drive and 1 left hand drive props... swapped over leads on on motor to get it to run as yet untested the left hand prop) 3- Turnigy nano tech 3s 3000mh 25-50C Lipo ( Have got a balance charger and board , flame proof charge bag , check/ alarm units, and will check and charge them await the only local help I have in RC / lips battery a helicopter flyer who has no experience with RC boats ) I just read the post on WTail mixer and wonder if I need that or if my current unkowning idea to just connect all 3 ESC ‘s together to one channel on the radio , again was give Eflite Blade SR HP6DSM 2.4GHz to try out ,Will this unit work or do I need something else , currently will/ can use all 6 channels but would / could use more if I had them ... last time I had anything to do with RC was a a kid/ teen and back then you had ground radios and flight radios and the two should not be mixed .. Ok please advise , how far off am I or am I still within range of keeping it simple ? Thanks All Bill

6 years ago by BW3

Forum

Voltage increasing via regulator

A somewhat confused question if I may say so Eric!😲 You can't 'regulate up' only down. The regulator's job is to produce a constant lower voltage from a range of higher voltages. I often use one to produce 5V for the RX and servos from a 12V SLA drive battery. A little 3 legged device (type LM7805) which looks just like the power FETs in a high current ESC. My version of a UBEC! 😉 What is this 'regulator' you have? Type number? Manufacturer? Photo? To get 12V from 7.2V you would need to use a Voltage converter (also known as an inverter). This works by converting the DC input from the battery to an AC voltage which can then be increased using a transformer. More elegant (and expensive!) versions use a transistor oscillator and amplifier. This uses hi-power transistors instead of the transformer. The AC output of the transformer (or amplifier) is then rectified back to DC. All this is very inefficient which is why it is normally only used for very light currents, where the losses are not so significant, and when there is no other alternative, not often the case! You can't beat the physics and you will never get the same power out that you put in. This leads to a basic design question:- What is the total current consumption of the load? I.e. the motors. A simple example:- Let's say that at 7.2V the motors draw 10Amps total, i.e. 72W (or VAmps). Assuming a utopian 100% efficiency at 12V this would equate to 6A. Due to the three stages of conversion; DC to AC, transformation / amplification of AC to 12V, AC back to DC, you'll probably be lucky to get an efficiency of around 60% to 70%. Thus if you stick 720W in you'll get around 430 to 504W out. Not much of a gain is it!🤔 Your battery would be exhausted in about 2/3 the time it is now 😡 If your motors draw more than 10A the problem just gets worse. So what is it you really want to do? If you just want to up the volts to your motors stick a 12V SLA or an 11.1V LiPo (3S) in and hope that you don't cook your motors! Frankly I don't really know why you're bothering, tugs aren't sprinters! If you want more pulling power with the existing setup try experimenting with prop sizes and pitch. Will probably achieve much more than fiddlin' about with voltage converters. BTW: All this assumes that the RX has it's own separate 5V battery supply or from a BEC in the ESC. Some clarification needed from your side. Cheers, Doug 😎

6 years ago by RNinMunich

Forum

Mtronics and Lipo's

The TIO has a safety low cut-off for LIPO batteries whereas the Viper 15 does not have this facility. if you are confident in not running down your LIPO battery to below a 'safe limit' then you should be OK to just use the ordinary Viper.

6 years ago by ads90

Forum

motor sizeing

Hi Jim I used a Hobbyking D3548/4 1100kv , a car ESC (hk60A-SL)(electric fan on top for cooling), program card(HK PROG-CARD) and a 40mm 2blade prop(test out the one on the boat first). Battery a 3s 5800mah 30C Lipo. This is in my Sea Commander and gives a good turn of speed with a long run time. ESC set up:- 1 Cutoff Voltage for 3S=10.2 and 4S=13.6 2 Start Power Percent=5% 3 Advance Timing=4 4 Run Mode=2 5 Brake Force=1 6 Drag Brake Force=1 7 Neutral Range=1 8 initial Brake Force=1 9 Reverse Force=1 Canabus

6 years ago by canabus

Forum

1.5v AA Li-Fe/Li-ion/Li-po batteries

OK, found some! https://www.ebay.com/itm/8pcs-JUGEE-3000mWh-1-5V-rechargeable-Lithium-li-ion-AA-battery-li-polymer/153101323059?hash=item23a58ccb33:g:hRwAAOSw44BYZ9Lo Interesting that they all quote mWh instead of mAh! I.e. energy instead of capacity! Power being V x I (Amps) divide the mWh rating by the nominal voltage to get an approximation of the capacity in mAh. Saves integrating across the varying voltage during a discharge cycle, i.e.'On Load' 😉 Thus these 3000mWh cells seem to have a capacity of around 1800mAh. Which is considerably less than the typical 2500mAh of an alkaline or NiMh AA cell. Also, to produce the output voltage of 1.5V from 3.7V Lithium chemistry the cells have an internal voltage regulator, which also must consume some power, albeit miniscule. Something else which can go wrong🤔 Summary; yer pays yer money and takes yer choice! Seem rather expensive to me for what they deliver. Depends what you want to use them for. Might be useful in my Sony camera but I wouldn't use them for any high current load in a model. OK perhaps for LED lighting circuits which only need a few tens of mA. Here a list of battery types, sizes and chemistries for reference. https://www.wikiwand.com/en/List_of_battery_sizes#/overview Cheers, Doug 😎

6 years ago by RNinMunich

Forum

Mahogany in Scale

Neither can I Martin! "The transmitter used two vacuum tubes wired as a multi-vibrator with a tank circuit to constrain emissions to somewhere near the 27 M/cs band (same as MHz, but that name came later). With not a crystal in sight, transmitter frequency drift and drain was a problem, so careful tuning just prior to short flights was the order of the day." http://www.modelenginenews.org/cardfile/ed_radios.html#3 Cheers, Doug 😎

6 years ago by RNinMunich

Forum

Graupner Jumbo 540 motors

Doug, The 6volt battery is currently an NiMh battery not an SLA. The problem was that according to Mtroniks the minimum voltage to the ESC to adequately run the BEC connection is 6volts. That is why I was getting erratic control when the was 5.6 volts. The action speed controller will work 2-12 volts and I am going to use a separate receiver battery as suggested by Dave Milbourn just to make sure. Regards Will

6 years ago by Will-I-Am

Forum

Graupner Jumbo 540 motors

I think it would be worth the risk of running the DC Motors at 7.2v (NiMh) or second choise 7.4v (Lipo) and get rid of the 6v lead acid battery. The chance of damaging the motor is limited, the battery packs will be lighter than an equivalent lead acid, but will need to by a charger as well. Always put a fuse in line rated 5 amps below that of the ESC. Or buy two higher voltage motor? only £6.99 each plus P&P link copy and paste into browser address:- https://howesmodels.co.uk/product/graupner-speed-600-8-4v-motor/

6 years ago by CB90

Forum

Cheap motor for a quick fit, but what prop gents?...

Mornin' (😲) Martin., First off; the Hornet ain't mine, wish it was 🤔 I had a look on the Lesro Models site to get an idea of what the prop would have to shove! Was surprised to see it is my hull with a different lid! The current kit is 80 quid BTW. To the motor / ESC; Yeah, you could use an 11.1V LiPo on that motor. BUT your ESCs probably are not LiPo SAFE! Which means that they won't have an automatic shut off or slow down function for when the battery is getting near it's Suicide voltage; roughly anything below 3.0V. Some say 2.7 but I don't risk that. So you would have to be cautious on the first runs and frequently check the remaining volts to learn how long you can run before you risk damaging the LiPo. If you can squash it in how about a 12V 10 cell NiMh? That should give you a good turn of speed with the 35mil prop. Bit heavy though🤔 I use an 11.1V LiPo in my Sea Scout with a 1000kV brushless. i.e. ca 11.100 rpm full bore, and that lifts her snout quite well as you have seen. Hope you find the motor, you seem to make a habit of 'mislaying' motors! Have you found the Supermarine yet? Apropos Supermarine; I've just been asked to renovate one 😉 Looking forward to that so I can see it's coil construction first hand. Will help me refine the mod instructions for you.😉 ESCs; mail me any printing on them and photos and maybe I can identify them and their capabilities. The switch makes me think maybe they do have BEC! The leads don't go nowhere cos it's only there to switch on the ESC / BEC. in my experience only ESCs with BEC have such a switch. Easy way to find out; set up an RX with a servo, plug the ESC lead into the RX, stick a battery on the ESC WITHOUT motor, switch on the TX and the ESC (move the switch to the end where two wires are connected) and see if the servo responds to the TX or any LEDs flash on the RX. Or just measure the volts across the red and black wires on the RX plug! If the ESC has a heat sink I don't think you need worry too much about current capability. Use your natty new Wattmeter to measure the current drawn by the motor as you run it slowly up to full speed. 😉 Don't think you need worry about volts either; all but the teeny weeny ones (like the fingernail size 3.7V ESCs I just bought for my Plastic Magic ships with only a 1S LiPo supply) can normally handle at least 12V, it's current that usually kills 'em😡 Sorry; Your electro-boards are still here, haven't been too mobile lately🤔 So I ordered some prepaid DHL labels (arriving Thursday) and will then get them to collect your parcel from me. Will email when they're finally underway. Cheers, Doug 😎

6 years ago by RNinMunich

Forum

LiPo batteries

Hi Pete, Do you have a Battery Capacity Checker? Like in the pics? Open circuit voltage is NOT a reliable indication of the battery's charge state😲 As you can see in the pics my two bats, 1 LiPo one NiMh, both show voltages above the nominal value. But the capacity / charge state less than half!! Be warned! Believe I did suggest to you to note the capacities before you left Hungary last time. Whatever - Have Fun😉 Cheers, Doug

6 years ago by RNinMunich

Forum

Martin's Taycol Conversion Boards

OK, in chronological order😉 No! The Wattmeter has to be spliced into the cable between source (i.e. battery) and the load, ESC and motor. As shown in example 1 in the instruction extract above. BTW 1: if your Wattmeter comes with instructions in Chinese Unwinese (Misstoodifold in the under number 29s😁) then use the above. Despite it's name it's primary use to us is to tell us the current the motor draws so we can select appropriate fuses. it will also tell you the mAh you've taken out of the battery, or put in when on charge. As far as I'm concerned the actual Watt measurement is relatively useless, except perhaps for 'Bragging Rights' 😁 Speccing the ESC should be done by checking the motor current specs and adding a good margin for safety. if no specs available use the Wattmeter to tell you the current drawn at full voltage from a DC source. if possible under load in the bath. Hang on tight😲 That only works for BRUSHED motors of course! Then use an ESC capable of twice the measured current. BTW 2; if you want to use your 27 / 40Mhz TXs you will definitely need the suppression capacitors on the motors, despite the partial damping effect of the rectifier, to reduce interference to your own radio. Fuses; I'll put 15s in to be on the safe side. if the Wattmeter / Ammeter measurements indicate less than 10A max then change fuses to10A and use a 20A ESC so it has some reserve. Or is operating within it's true capacity😉 Cheers, Doug 😎

6 years ago by RNinMunich

Forum

Which battery?

I tend to use LiPo's but they can be temperamental and need the correct charger. They are smaller and lighter than NiMH and give you a much greater output. NiMH are similar in size to LiPo but are heavier and will not have the same sort of power available. Lead acid are the easiest to use in terms of charging but are much heavier and larger then the other 2 types but tend to be cheaper. Lead acid are a good option if you need the ballast or are not limited on physical size. Cost is also a consideration a good quality charger can be an hefty investment but will serve you well and if you buy the correct type will charge/discharge any battery type that you have. I have heard horror stories about LiPo's bursting into flames, which my son did with his RC car. this was down to him not understanding this type of battery. I have not had good results in terms of endurance with NiMh but Lipo's if correctly selected will last much longer, a word of warning here though, they will stop working suddenly with no indication like running slow etc so if using LiPo's you will, need an alarm on each battery. Lead acid is much easier to in terms of Voltage either 6 or 12v with real problems when connecting them in series or parallel for use or charging, a little harder with the other two types but not impossible. This has probably confused you even more but I am sure you will come the correct battery. I have to confess I have an interest in this build as I intend it to be my next project👍

6 years ago by marlina2

Forum

LED Tug Mast Navigation Lights

Hi Pete, JFF I built a little 'breadboard' (now where's my peanut butter!?😁) to test your LED lighting configurations. Theory and calculation is fine but there's nowt like an acid test😉 Pics attached of the results (Christmas tree😊). Difficult to capture the colours due to the very bright white LEDs🤔 Will play with the resistors to bring up the yellows and dampen the whites a bit. The 3 yellows at the bottom are the deck and cabin lights. The 4 rows at the top are the mast lights, red and green self explanatory! Applied (battery) voltage is shown on the meter top left, current drawn in mA on the meter to the right. The circuits work fine from 6.0V upwards. Current drain is approx- 110mA @ 7.8V (fully charged 6 cell NiMh) 103mA @ 7.5V (probable voltage after running a little while) 90mA @ 7.2V (nominal NiMh . it will flatten out at approx this voltage after running a while - until it suddenly collapses at the end!) 75mA @ 6.6V (voltage of FLAT 6 cell NiMh battery) 60mA @ 6.0V curiosity! Below this some LEDs switch off. Brightness is noticeably reduced. I think we can increase some resistors to reduce the current drawn without reducing the lighting effect😊 More info soon, I'm still experimenting, then I'll start modding my own tug😊 Cheers, Doug 😎

6 years ago by RNinMunich

Forum

What transmitter , receiver

The flysky fsi6/tgy i6 upgrades to ten channels for the price of a of Data cable at £3.00 from hobbyking and a 10 channel telemetry rx £15.00 some sensers at £7.00 so it monitors main and RPM which is very useful especially the voltage . RPM handy for prop choosing I have done my tx and now all I have to do is figure out what to do with the other channels better to many than not enough Good set and expansion at low cost 👍

6 years ago by catman

Forum

LED Tug Mast Navigation Lights

Evenin' Pete, first instalment coming shortly in pdf format. A table, based on your excellent sketches of what you want to do, showing control element on the TX, function, number of LEDs in the cct or ccts, resistor(s) needed, current consumed, for various s. Example attached as jpg pic. Based on your measurements I am assuming that the searchlight is a 3V high brightness LED and all the others are 2V LEDs, and nominal current 20mA. This means that with a nominal 7.2V supply (Vs) for some circuits with 3 or 4 LEDs two parallel ccts will be needed. All will shortly be revealed 😉 I have optimised the resistors so that a) the LEDs don't fry when the batt is fully charged, 8V, b) that the LEDs can still turn on when the batt voltage dips to the 7.2V nominal. c) Only 2 or 3 values will be needed. Now have to convert my Excel file to pdf. Will follow this up with wiring suggestions, including the little Distribution Board with the resistors. I've tried to combine the lights you want logically considering how they would be used on the real ship. Stay tuned! Cheers, Doug 😎 BTW; the mods and resistors suggested in the table mean that the existing SMD resistors on the ccts board must be shorted / replaced with wire. Your wrapping wire (stripped of course!) will be ideal for this😉 Hope you have a small soldering bit!

6 years ago by RNinMunich

Forum

LED Tug Mast Navigation Lights

Hi Pete, since you are in the US try here, the OTHER RS😉:- https://www.radioshack.com/pages/search-results?findify_limit=24&findify_q=wrapping%20wire Personally I prefer stranded wire as it is more flexible and less prone to break if you often have to remove and remake connections, like when you take the cabin off! it's slightly thicker so it's more a question of 'Will it fit?' https://www.radioshack.com/products/22-gauge-hookup-wire-3-pack-25-feet-red-black-green Some model shops have (or used to!) a really thin stranded wire, as used for tiny 'rice grain' bulbs'. 2nd question: I assume your tug has an 800mAh NiMh battery like mine did. Correct me if I'm wrong, I don't know the new models. I propose to change mine for a 2200mAh NiMh. Can't use LiPo cos the Brushed ESC isn't LiPo safe; i.e. with built in cut off if the battery falls to 3.0V per cell - lowest safe LiPo discharge voltage. 3rd Question - changing motors; I've often wondered that!😲 Up to now I don't see any reason to. Maybe those guys want to enter Towing Competitions!? I don't. Also some folks are just not happy unless they are tinkering and 'improving' 😉 I might try to quieten the gearbox down a bit though 🤔 Teflon grease perhaps!? Cheers, Doug 😎

6 years ago by RNinMunich

Forum

Longer run time

Your question does not have simple answers have you used a watt meter to see the current your motor is drawing at full throttle? With any installation its a good idea to do that test since its a good way to match motor and prop. LiPo batteries have a better current delivery than lead acid BUT you do need to be careful about end voltages so as not to damage the battery. Many ESC have a voltage cut off built in to protect LiPo batteries it may be your hitting that limit with your lead acid battery. The simplest solution to your problem is to look at the Amp/hour rating of your existing battery and get something with a higher rating. Going LiPo can give a much higher rating with a LOT less weight. The downside being the need for a special charger and the need to be careful about storage and end point voltages. As to putting 2 batteries in series to get a higher voltage yes you can BUT increasing the voltage to a brushless motor requires you match the prop to the new voltage running on the existing prop will probably cook the motor. How hot is your brushless running now? Outrunners generally can swing a bigger prop than inrunners.

6 years ago by Haverlock

Forum

Longer run time

I am using 1 12v lead acid battery in my sea queen with a brushless motor. It’s only giving me about 15 minutes on the water. The boat will get up and go for a few minutes but after that I can have the throttle wide open but the speed has gone. Can I link more than 1 battery together to give me a greater voltage which I believe a brushless motor can cope with. If so which batteries should I use and should I wire in series or parallel? I await your thoughts Thanks

6 years ago by randhbarker

Forum

LED Tug Mast Navigation Lights

Hi Pete, many thanks, good work 👍 Just one question; What was the ? GF about to drag me out to the Shopping Mall 🤔 so more this evening. Cheers, Doug 😎

6 years ago by RNinMunich

Forum

Spektrum, new, useless...

At the risk of sounding as though I work for the company the Taranis also has telemetry. One can monitor in the model via the transmitter. There are a load of other options including variometer and airspeed. https://www.t9hobbysport.com/rc-gear/frsky-smart-port-sensors However on the downside I do have to say its not the simplest beast to master since its so flexible you have to set EVERYTHING up. From the get go you have to decide which function is on which stick and where it is in the sequence to the receiver. Then things get complicated.

6 years ago by Haverlock

Blog

M.V. TEAKWOOD

Water trials have been delayed by trying to resolve the challenges with my HMS Brave Borderer project drivetrain. As those efforts have been halted, waiting for new components, decided to complete the Teakwood water trails. First battery trails used 8 x 1.2 Ni-Mh cells is series, giving 9.6 volts. This was unsuccessful as the battery life was only minutes. Lesson from this is not to buy cheap Ni-Mh cells from an Oriental source. Tried 2 x 7.4 Ni-Mh packs is series giving 14.8 volts. Vessel was far too fast and throttle control poorly modulated. Was thinking of fitting a voltage reducer with this battery layout so could adjust the top speed. Have done this before and it works well. When searching in my box of bits found a voltage step up increaser. Never used this before so rewired the Ni-Mh packs to parallel and adjusted the output voltage to 10 volts to see how it worked. Result is a nicely performing model with an usable top speed potential for emergency, Duration of the first run comfortable exceeded 1 ½ hours, which am satisfied with. The cells are positioned around mid hull to supplement the fitted ballast. From the pictures the model has all the grace and style of the original vessel and sails well. In conclusion, a successful project that justifies the many hours spent in building and refining the model

6 years ago by Rowen

Forum

Charging NiMhs, one for Doug?...

Evenin' Martin, Oh dear oh dear oh dear! 😲 There is some good advice above, but maybe not optimally expressed for use by a Luddite! Sorry guys but this might be a relatively long post to separate the wheat from the chaff, explode a few myths and resolve this little conundrum of Martin's! One thing at a time! NUMBER1. THE RADIO- Dear Martin: Whatever possessed a self confessed Luddite and Scrooge like you to spring a large chunk of your hard earned pension on one of the most expensive and complex RC sets on the market in the first place???? I bought a Spektrum DX6 on impulse a few years ago while strolling around Conrad here in Munich. I've regretted it ever since. in retrospect it was way too expensive >600€, and complex. it is intended for the Fly Boys, as unfortunately most sets are these days. I have still not successfully programmed it to do what I want to do, instead of what it is pre-programmed to do for helis and fixed wing aircraft. Not even with it's own Spektrum RX, let alone a 'foreign' RX like Orange. So I have not yet risked it in a model. Definitely NOT my Catalina. Since then I have bought a Turnigy I6. Which does the same as the Spektrum, works fine with my Orange RX with giro for the Catalina😉, cost only 69€ (is now available for around 33 quid😡) and within a few hours I had it programmed and tested to do all I want in my destroyer and Sea Scout.👍 In short: the Spektrum is way way way Overkill for your yacht or Fire Float or similar, where you will only ever want rudder and sail servo / winch or rudder and speed control. So flog the Spektrum and get a nice simple (and cheap😉) 2 or 4 channel set. I can't imagine you ever wanting to start building special effects into your models so 2 (max 4) channels is all you will probably ever need. Stick your Spektrum on eBay, maybe you'll get at least a 100 quid for it. If you still want to go 2.4Gig get yourself a Turnigy i6 set with RX, 6 ch but cheap enough and I can help you directly with binding and programming from experience - I have a good English manual with no Chenglish gobbledygook. If not and you still have a working 27 or 40MHz FM set (40 would be better) use that. Where you sail, all alone, who's going to bother you or be bothered? BTW: Yes the Spektrum TX IS DSM2 and DSX compatible BUT you have to tell it what you want to use!!! Frankly I think trying that with a non-Spektrum RX is risky - especially first time out and for a novice Luddite😉 NUMBER 2. THE NiMh BATTERY- Voltage is not a reliable indication of battery charge / remaining capacity. After use a battery will recover slightly when at rest and the open terminal (off load) voltage will rise, often to the nominal voltage or slightly above. This is NO indicator of remaining charge as when a load is applied the voltage will drop again rapidly, the higher the current drawn the faster the voltage drops. if it goes below 1.0V per cell the battery will be permanently damaged and never regain it's original capacity. Haverlock is dead right about batteries losing charge when not used or regularly recharged. An NiMh batt loses charge at the rate of about 1% per day so after 3 months or so you can send it to the great recycling depot in the sky and buy a new one. Periodic cycling, discharge / charge prevents / minimises this - see care hints I posted above. And yes, NiMh do have that irritating Memory effect🤔 albeit not so pronounced as with NiCads. Lipos apparently not, but I ain't seen any evidence yet - the jury is still out! Sooo - ignore the 6.37V and run the batt through a discharge and full charge cycle. if your new NiMh batt has not yet been cycled and charged I would bet that it's present capacity is about 45%. See example below (and in attached pic) of one of my new 4.8V (nom) NiMh RX batts. NUMBER 3. THE CAPACITY CHECKER - "Glorified voltmeter" ? Where did the 6.37V reading come from if not from your 'new toy'? If it is showing volts it should also be showing capacity in %age. If you received the wrong thing it's not the "bloody electrics" but the bloody nit who packed and sent it that's at fault. Before you send it back check the below😉 Send me a photo of the Checker you have and with your battery plugged in so I can see what's happening on the display. Otherwise we are all poking about in the dark (Are we back to Jules and his friend Sandy😉😲) The link I sent you was for a checker exactly the same as mine except for the labelling! As you can see in my photo, properly connected it shows the terminal voltage and the remaining capacity (charge level) of the battery pack. Forget the Nixx (=2 Ni possibilities) display, that just means 'It ain't a LiXX' (3 Li- pissibolities). Attached photo shows a brand new 4 cell NiMh RX pack 4.8V (Nominal) connected to one of my Checkers. As you can see the voltage shown is 5.19V, according to the popular 'folklore' that would seem to indicate FULL charge. Unfortunately not🤔 Capacity indication is 45% which is normal for brand new batteries in storage and transit. Explanation thereof - see above! RE: " if it can do LiPos, why not the relatively simpler NiMhs?" a) the LiPo pack has a different chemistry and construction which requires different input circuitry on the checker, b) LiPos need balancing and are fitted with Balancer Plugs which connect to the multipin connectors on the checker. Each pin connects to one cell of the LiPo so that they can be monitored individually. LiPo chargers use this to balance the cells to within 0.01V (100mV) or less by adjusting the charge / discharge currents to each cell. The checkers use this to show you the individual cell voltages and charge states. A big difference, i.e.lower V and capacity, indicates cells with faults, e.g. higher internal resistance, or a discharged pack which needs charging and balancing. NiMh packs don't usually have this facility to measure individual cells. They are thus connected to a separate input on the checker which can then only show total pack terminal voltage and capacity. BTW: if you can get it passed 'THE Management' store your battery packs in the fridge😲 The 'coolth' slows down the rate of self discharge, which is a function of the battery internal resistance, which reduces slightly with reduced temperature😉 Enough for now, back to stripping my PTB for it's Midlife Refit! Cheers, Doug 😎 PS Martin: Just saw your post about another RX. Why the hell not buy a Spektrum designed Rx guaranteed to work with their TX? Or better still; flog the Spektrum and get a nice simple Turnigy set as above, also recommended by Ron, albeit the 9 ch version. All this frigging about with 'claimed compatible' bits and pieces just wastes money and time, fogs the issue and don't prove nutt'n!

6 years ago by RNinMunich

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Charging NiMhs, one for Doug?...

Mornin' Martin, my PTB problems will take a while to sort but I was anticipating a complete refit anyway. Soooo --- Basically Ron's right about the charger👍 Press 'Batt Type' and then 'Dec' a few times until 'PROGRAM SELECT NiMh BATT (pic one) appears in the display. Press 'Enter' and pic two should appear. Press 'Dec' so that 'NiMH CHARGE Aut' appears in display. Seems the default current is set to 0.6A in this mode. Leave it at that. If not 0.6A use the INC/DEC button to adjust it to that. Press 'Start/Enter' for more than 3 seconds and away it'll go. Charge time depends on the capacity of the battery. Rule is Capacity (C) in Ah/Charge current (I)x1.4 hours. Example; a 2Ah (2000mAh) at 0.6A would need (2/0.6)x1.4 = 4.66r hours, or about 280 minutes. The charger should stop at the right time automatically. BUT: check the capacity of your new battery with your new toy first! If it has residual capacity significantly greater than about 30% and voltage of more than 1.1V it should be fully discharged down to 1.0V minimum first. There is a function in the charger to do this. Then charge it as above with the Auto mode at 0.6A. This is to help prevent the so called memory effect. Extract from imax manual page 9- "Some rechargeable batteries have a memory effect. if they are partly used and recharged before the whole charge is accomplished, they remember this and will only use that part of their capacity next time. This is a 'memory effect' it is said that NiCd and NiMH batteries are suffering from memory effect. NiCd has more memory effect than NiMH." Don't get too charged up😉 I envy you listening to 'The Navy Lark' 😲 A Sunday afternoon delight back then. Before or after 'Desert island Discs'? HMS Troutbridge, Capt. Poby "HENRY are you wearing odd socks?" - "No my love", Number One Sub Lieutenant (Leslie) Philips "Cor! Who threw that?", CPO (Bill) Pertwee, and "Bridge? Staaarboard Lookout Able an' when am I gonna be Leadin' Seaman Goldsteen (?) 'ere. I jus' thought you might like to know that we're 'eadin straight for the Admiral's Barge an' maybe you'd like to change course or summat"! Luvly stuff 😁 Cheers and good night from Munich, Doug 😎 PS: Well meant Haverlock but I wouldn't recommend fast charging for any battery chemistry, MAX 1A charge current for any battery, except perhaps a car battery but then Max 5A. it reduces the useful lifetime of the battery. Fast charge rates are more or less a marketing gimmick, it just means you CAN charge at higher rates without the battery exploding. Of course the manufacturers are very happy if you do do it and then have to buy new batteries more frequently because you've reduced their capacity and shortened their life. Most especially a brand new battery should NEVER be Fast charged. To get maximum life and capacity out of a new battery it should actually run through about 10 discharge / charge cycles to condition it for maximum output and minimum memory effect. Martin: check the label or packaging of your battery for 'Standard' and 'Fast' charge current! PPS: a fully charged 5 cell NiMh can be significantly above 6.0V. Up to ~6.5V, which is why I warned Martin to check the specs of his RX and any ESC. Some are rated for 5V only and go pop at 6V. That's why I only use 4 cell NiMh packs for my external RX supply. 1.2V per cell is only the nominal rating of an NiMh cell, fully or over charged they can go up to nearly 1.28V per cell.

6 years ago by RNinMunich

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Charging NiMhs, one for Doug?...

Doug, Gawd bless yer , Guv'nor, I knew you'd come through with the advice on electrical stuff. My Dad would be ashamed of me as that was his game, but I could never raise interest and therefore retain any knowledge he ever imparted to me about it. A wall wart is what I've seen those little plug in the wall chargers that do 4 AAs or AAAs and charge up overnight described as, mainly by overseas chaps. They do, however become alarmingly warm sometimes, but do a good job for my camera and my wee digital radio, so I can always catch the Goons or the Navy Lark on BBC 4 Extra, or some good new music on Guy Garvey's programme on 6Music. So they work, but I have a pack, now, pre soldered, of 5 cells. My Orange Rx and servos are happy with 6Volts or so their blurb says. I'll look up a battery condition meter and get one. I just ordered a Multimeter to just do volts. Always a good adjunct to a household anyway. I have my Dad's two Avometers in their original leather cases, but can no longer get the high voltage batteries they contain. Found a miniature Avo in a smaller leather case, but don't know how to use it. I hope you can get some sense out of the words and music for the imax B6 charger. Off to eat myself (eat myself?) Eats, shoots and leaves Martin

6 years ago by Westquay

Forum

Charging NiMhs, one for Doug?...

Hi Martin, 1. What the blue blazes is a wall wart? 🤔 2. You can't do any harm to the RC gear with an under charged battery👍 But if you use it before charging it you may drive it below it's damage threshold of 1.1V per cell if you use it too much in that state. A word of warning: some RXs and ESCs don't like more than 6.0V (e.g. Action electronics/Component Shop) and a fully charged NiMh can be more than that so check the specs of your RX and ESC first! 3. Get yourself a simple battery capacity checker, see attached pics of the two I have. As you can see, they all look the same except for plastic colour and brand name. They only cost few quid and save a lot of ruined batteries and cost/heartache😉 Available from HobbyKing etc etc. They can check voltage and capacity. For LiPos they check individual cells. For NiCad or NiMh it just checks total voltage and capacity as most NiMh don't have external connections to individual cells like the LiPos do for balancing the cells. As I still have some hi power NiMh drive batteries, for ESCs that are not LiPo safe, I made a simple JR/Tamiya adaptor to connect to the monitor. In my pics you can see the % charge / capacity display. Some show only around 46% cos they are 'as delivered' with a storage charge only. Before use they need fully charging. 4. Re Charger: Just downloaded the manual - I'll get back to you on that when I've read it. Now it's 'Eat'n time' 😁 Cheers, Doug 😎

6 years ago by RNinMunich

Forum

What Li-po?

Hi Yngvegr, basically I agree with Flack👍 But if you want to go step by step and test it with the 540s first (will give you a Datum to compare with brushless at a later stage) then- Brushed have no problem with LiPos, or any other battery chemistry for that matter😉 For the voltage anything from 6 to 12V is fine for the 540. I have two 540s in my 135cm destroyer and she ran just fine on a 6VSLA, with a relay to switch a second one in series for 'All Ahead Emergency'! Higher capacity brings not only more sailing time but also more weight! Suggest you weigh the existing batteries and check the waterline and trim in the 'domestic test tank' before you buy the biggest batts you can find😉 If you do go LiPo don't forget to buy an appropriate charger and a Capacity Tester as well!!! Whatever you do, have fun doing it, cheers Doug 😎

6 years ago by RNinMunich

Response

H.M.S BRAVE BORDERER

Evenin' Rowen, So far so good, nice job👍 Let me go through your comments one by one😉 1) "Moved the battery towards the stern and, at speed, the forefoot lifts slightly clear of the water. The plane is now almost flat. The battery is not well positioned when near the bow." Battery in the bow is almost always bad news🤔 too much weight forward of the CoG or natural balance point when planing. 2) "The 2S battery used was a 4000mAh 30C; suspect this battery does not have the capacity to operate the model. Every motor will run up smoothly until a second one is operated. The first motor then “stutters” and a fuse might blow, this could be indicative of a power surge. Any comments from the electronic experts among the group would be appreciated." First the battery: you may be right. Especially with 3 x4500 kV motors Since you are using 3 ESCs how about feeding each one from a slightly smaller (lower weight) battery? Precondition of course is that all three are equally charged to the same voltage and capacity AND have the same (or very very similar) internal resistance! Complicates the issue of course and motors with a lower kV rating and one power source may well be the better solution😉 Second the 'stutter': How and when did you switch in the second motor? If the first was still at 'Full Ahead', i.e. 'Pedal to the metal!, I might expect the to dip and then recover with the sudden additional load and a sharp rise in total current drawn. But no particular excuse for a sudden current rise in the first motor ! Where was the fuse that blew? I suspect in the primary supply lead from the single battery🤓 since with brushless motors you can't fit individual fuse in their supply leads like you can with a brushed motor. BUT you can to the ESCs feeding them!!! You can't get a power surge from a battery, not like a surge on the mains network due to lightning etc! But you can get a voltage dip and recovery if you suddenly present it with an additional load😲 3) "The 3S battery was 10,500mAh and 40C; with this battery all three motors can be run at full speed together and fuses do not blow. it was also very heavy at 1700g, holding the model down." All run up together to full speed or 'switched in' as described above? There's a big difference between a gradual increasing of load on a power source and a sudden step increase! 4) "The motors are 4500 kV. On refection, think a slower motor around, perhaps 2000 kV would have been a better choice." I did think at the outset that 3 x 4500kV was perhaps a little ambitious😲 2000 - 2500 sounds much better, and more controllable👍 Then you could also get good performance results with a single battery of capacity lower and weight 👍 The function of the third (centre) motor for 'action speed' would also be more pronounced👍 5) "Would concur with comments by others that a simple single or two bladed propeller layout for this model is probably best - that is unless you want to capture the true scale layout. The centre propeller seems to have little effect on overall performance, (see above re 4500kV motors- Doug😉) although it will power the model quite nicely when operating by itself. Have had several suggestions about how best to use the centre propeller. Will think about them and decide later how to do this when I start to finish the model." As a 'Scale Purist' (as far as my skills and tools allow!) personally I would frown on the use of 2 blade props, much less only a single prop. Do that in a fictitious power boat if you will, but for 'Brave Borderer' ? 😡 Do her justice please😉 Many three screw (😲) boats (including the full size originals of this era) only used the third motor for additional manoeuvring speed in action situations. My personal experience of FACs (Fast Attack Craft) and FPBs (Fast Patrol Boats) over the last three decades shows me that the three screw configuration has been largely dropped, especially since the introduction of much more powerful engines such as improved diesels and gas turbines. Many use a combination of diesel, for cruising, and gas turbine for 'action speed', so called CODAG, COmbined Diesel And Gas turbine. 6) "The 2 blade Hi – speed propellers both increased performance and current draw. The model is more than fast enough with the original scale layout." As I believe the 2 blade props were of larger diameter (and perhaps also of larger pitch) than the 3 bladers the higher current draw is a logical conclusion! Stick with the scale config! 👍👍👍 7) "Will purchase a lighter, 3 S battery as that seems the best choice for performance and weight." 👍 but don't overdo it to the other extreme by reducing weight and therefore capacity too much😲 You want a decent sailing time don't you? 8) "Testing using the bare hull with a minimum of detail worked well. For a models with a complex power train, this is a good approach as access to the internals can be gained easily. Nothing worse that finishing a boat carefully just to find the performance disappointing. Then having to to rip it apart to make major modifications or adjustments!" Heartily agree 👍👍👍 Bon chance mon ami😊

6 years ago by RNinMunich

Forum

Radio in a yacht

most 6V sail winches will work fine on 4.8 volts. if you NEED 6V then things get way more interesting. Check to see what voltage your receiver can handle ( some have built in BECs some not). in the event your radio needs nominal 5V ( 4.8) and sail winch 6V then you need a 6V power supply and a BEC to power the receiver. However some sail winches have a built in BEC so you can power your radio via the winch. ( BEC= battery eliminator circuit in effect a voltage regulator )

6 years ago by Haverlock

Forum

LiPo batteries

Hi all, Lithium-Ion and Li-Po batteries do not take kindly to being stored long term fully charged. When they are new they will do it but after 2 to 3 years of intermittant use, can start to swell a bit and that is where the dangers start. When you give these cells the final run of the season and they show a charge in the the 3.3 to 3.5 (or so) volts per cell then they can be stored relatively safely. (This is called a holding or factory charge) Re start them with a balanced charge before you next use them. Do not constantly fast charge them as thi could induce swelling of the pack earlier. The old Ammo box is a good idea, any strong metal box will do but store them where it does not get very hot or very cold and ideally not in the house. Lipo cells are accepted as hand luggage by most airlines and a holding charge is recommended when flying, so remember to take a small 12v DC balance charger or 'Intelligent' charger with you to other countries, you will always be sure of a power supply, like a car battery even where the mains voltage is different. Small black plug-in cell monitors are readily available from places like Component shop and are a good guide to cell condition. One is these is quite essential as we use these cells more and more. Cheers, hope this helps. Ron.

6 years ago by ronrees

Blog

H.M.S. BRAVE BORDERER

Once the rudder, propeller and shafts were installed, the position of the motors could be established. A light aluminium bracket to hold all three was fabricated and bonded to the hull. Due to the high speed capability of the brushless motors, particular attention was paid to alignment. Also kept to the shortest prop. shafts that could be fitted to avoid whipping. Although the motor type might change, whatever is best will require a sound electrical installation as the current requirements for each brushless motor could reach 50 Amps. Wired each motor and ESC separately with its own dedicated fuse to give the maximum system protection. There is an extra fuse section allocated for auxiliary circuits, such as a cooling water pump and lights. Will try the original planned layout of 3 x 2835 motors with 30mm propellers and a 2S Li-Po battery first. Am hoping the reduced voltage will also make these motors more tractable. For the test program the three ESCs will be each controlled from an individual Rx channel. Once the final layout is determined, a more sophisticated and flexible control system can be installed. To minimize ballast, particularly around the stern, the battery will be housed as far into the bow as possible. After the test runs the final battery type, size and location can be established. To assess performance, hope to try both 2 and 3S Li-Po batteries. Planning to reduce heat build up by fitting cooling water jackets to the motors, these are easiest to instal at this stage so the wiring or mounts are not disturbed in the future. Have not decided the layout for the water circuit yet, but this easily can be added later. All that is needed now is the ice to melt off our local lakes so tests can commence.

6 years ago by Rowen

Forum

Aerokits Patrol Torpedo Boat

PS: Attached is the user manual for a typical Quickrun Car brushless ESC. Par 3 shows how to program it using the TX. Para 5 shows a table of the options available and the presets marked with black background! I used the programmer to set the Running Mode to Mode 3, i.e. No Brake between forward and reverse! the programmer is also useful for setting other parameters; esp number of battery cells and Low Voltage cut off. Hope this helps to know what to expect😉 Cheers Doug 😎

6 years ago by RNinMunich

Forum

Aerokits Patrol Torpedo Boat

Hi MB, can only say what I have which works and I ain't set the house on fire yet 😉 Not surprisingly for someone living in Munich both mine are from German companies! Robbe Power peak Uni 7 and Graupner Unimat 14. There are later versions of both around nowadays but you can still find these on Amazon / Ebay etc. Both of them have automated programmes for various Lithium types, NiMH / NiCad (not recommended these days!) and SLAs. Robbe is now defunct and their Marine stuff taken over by Graupner and marketed as RoMarin! Pics also show the Balancer Adaptor Boards, necessary to connect the balancer cable of the battery. This ensures that each cell is equally charged 😊 I also included in the pics the little battery Capacity Testers I use. They cost around a tenner and are very useful for checking the capacity before a run or charging, as well as the voltage and capacity of each cell, which gives an indication of the battery condition. I found some duff cells with the tester in a few batteries I'd only just bought 😡 When looking for / buying a charger look also for a LiPo Safe bag to charge them in. E.g. LiPo Guard. Charger may cost 50 quid upwards depending on how many charging outlets you want and how many Bells & Whistles. But I get on well with these two 😉 I like the Robbe version cos I can charge two LiPos at the same time. Also in the pics are a few of the charging cables I made up with gold 4mm bullet plugs for the charger end and Tamiya and BEC (for my Plastic magic stuff!) at the batt end. Such adaptor cables are also available 'ready made' but I just like fiddlin' 😊 Hope this helps, Cheers Doug 😎 Nearly forgot! Can't say for sure what current your motor will draw cos I don't know all the other details, but a 40" boat will need some shove! So I wouldn't go below the 5000mAH if you want a half decent run time. A 40" boat can carry a bit of weight! And batt power is more useful than pure ballast 😉 Recommend a little Wattmeter to check the max current draw - see last pic. Basic theory! A fully charged 5000mAh (or 5AH) batt can theoretically deliver 5A for one hour, or 10A for half an hour and so on! Say your set up draws 20A with the 'pedal to the metal' then a 5000mAH batt will 'theoretically' last 15 minutes. Theoretically cos other factors are in play; initial charge state, temperature, internal resistance of the cells, cable losses etc. The latter is why I only use gold connectors! The higher the batt capacity the higher the price and weight. So suggest you start with the 5000 and see how (long) it goes. Then check the weights of higher capacity batts (and the bank account / management approval😉) Bon chance mon ami!

6 years ago by RNinMunich

Forum

Aerokits Patrol Torpedo Boat

Hello. I hope I can get a little help with battery choice. I have been reading the comments above and elsewhere on the site, and have decided to go along the LiPo route. I purchased the Turnigy 3648 1450kv brushless motor along with the Hobbyking brushless car ESC 100A w/reverse. I have done a little research on this battery but still do not know the exact battery I should be looking for. Please can you help with the following: What voltage should I be looking for. To have a reasonable useage period, can you advise on a suitable mAh rating. Please can you recommend a charger. Should I have a charge alarm. Should I have a monitor for cell voltage. Are there any other accessories I should have. Thanks in advance. Peter.😊

6 years ago by MouldBuilder

Forum

Aerokits Patrol Torpedo Boat

Hi MouldBuilder I use the Hobbyking Turnigy IA6 which is the same as the Banggood Flysky I6 2.4G 6 channel sets. You can set up 20 different models of the one transmitter. I have both and are great units. I was scarce of this Lipo stuff years ago, but, a good balance charger with a safety bag you will be OK. A battery alarm is a cheap handy little unit or add a sensor unit into the boat so you can monitor the at the transmitter. Check out you tube about the radio. Canabus

6 years ago by canabus

Response

Dumas 1203 Coast Guard Lifeboat (RNLI Waveney conversion)

Hi I have the Billings version as does a fellow club modeller. initially I used two 300 motors with a 12v 1.3amp battery placed in the rear cabin space. Good for about 4 mins then died. I now use two brushless 28xx size 30 amp ESC and an 11.1v Lipo 2.1 amp. My friend has a similar set up. Gives about 30 mins and exceptional speed. The lipo sits where the SLA was. I can understand your concerns about the lack of warning on your Mtronic but you can source battery alarms that will emit a loud noise when the cell voltage gets below the set voltage. Providing you are paying attention you will hear and bring the boat home. The running time will be similar on each occasion so you could also use a stop watch (on your phone). I have tried NiMhs but they lack the power and are nearly as heavy as the SLA.

6 years ago by Dave M

Forum

Too Powerful Brushless ?

Hi Doug Brushless motors may be similar to AC motors in construction but they are powered by pulsed sequential DC so there is no AC involved. I do agree Watt metres are the best way to make sure the motor, battery and ESC max values are never exceeded. I agree the spec sheets are very useful but are specific to the type of motor and original supplier, and many are for companies no longer trading. I do sometimes have difficulty in interpreting some of the info supplied but the nominal working voltage, max power are usually OK. The stall current is useful to decide on the wire and fuse size as well as choosing a suitable ESC. At the end of the day if the set up is getting too hot you are probably working over the specs and if water cooling doesn't help you need to adjust the prop and / or .

6 years ago by Dave M

Forum

Too Powerful Brushless ?

"The max current is the Max Watts divided by the ." Hmmm! Dave, I=P/V works fine for DC and static resistances but it gets much more complex in a dynamic system like an AC motor, which is all a Brushless is. Don't want to get into rms and power factor and co here so I agree the wattmeter is the way to go to find out what's really happening. Normally (at least here, not so sure with China!!) the max power output is quoted at nominal voltage and max efficiency. If you (can!) trace the motors back to the original manufacturer they publish performance graphs showing efficiency, power vs current and volts. But who does that? Except nuts like me😉 According to the DC formula the ECO 600 would draw 131A at 11 Volts or 97A at nominal 14.8V. The real 'Black art' is then to work out what power you want/need for how much thrust, acceleration and top speed for a given boat and hull type🤔 Best way is to ask those who've 'Been there, done that'. That's why I appreciated very much Canabus' advice when I was looking for a brushless for my Sea Scout upgrade👍 Happy sailing all - Whatever pushes your boat! Doug

6 years ago by RNinMunich

Forum

Too Powerful Brushless ?

Hi Graham and Haig The max current is the Max Watts divided by the . Most motors reach their max efficiency at much lower value, typically about 77%. You need to take care when interpreting the data especially when the description has been translated from a foreign language. The Eco range of motors were developed for model boats and in general were high tork, low revving and low current. They were also designed to work at lower voltages so that would explain the lower Wattage. I would only use the nominal voltage, Kv and max Watts figures. The amps appears to be the stall current but I am guessing. Also we don't know the voltage at which the stall current was measured. Providing you don't exceed the rated voltage and wattage your motor should be OK. I suspect running much above half the rated wattage may require some water cooling. There are many Wattmeters available that will measure the wattage, amps etc at reasonable prices and if you connect in line with your battery and ESC whilst holding the model in the water you will have a good indication of the max current / watts at full bore. This should be ideally about half the max rating (watts & amps) for both the motor and ESC. https://www.componentshop.co.uk/150a-watt-meter-and-power-analyser.html Reducing the prop size will reduce the load.

6 years ago by Dave M

Forum

LiPo Battery Monitor

Hi Bill Doug has shown a battery checker and alarm. You can get battery checkers see https://www.componentshop.co.uk/led-battery-status-indicator-for-2s-to-4s-7-4-14-8v.html. If you are going down the LiPo route I suggest you make sure the ESC you buy has a built in circuit which reduces the current should the battery volts drop below the set voltage (3.3v is common). In my experience the alarms although they work well are not loud enough to be heard, if your model is not near, and they do not cut or reduce the current, leaving your battery at risk of over discharging. Good luck with your model

6 years ago by Dave M

Forum

LiPo Battery Monitor

Hi Andy There are many variations on the market but they all work basically the same way. Most modern Lipo ( and all Lithium based batteries) come with a small white plug with multiple contacts as well as the main power plug, usually connected to some heavy duty wires. The plug is connected to the battery negative at one end and then each pin is connected to the negative on the next battery etc. This allows the individual cell voltages to be measured. The monitors do this automatically when connected to the plug the correct way, if it doesn't light up it's probably the wrong way round. in my experience the monitor connector is not marked so you may need to try different combinations to find the correct way. You will not damage anything if you get it wrong. When correctly connected the monitor will display each cell voltage then the total voltage. This usually repeats after a few secs until you disconnect If you have a charger they have a selection of different size sockets for the number of pins and can only be inserted the correct way. You will need the manual that came with the charger to select the correct screen to display the values, but most can be found if you Google. Glad to hear you have a monitor, LiPos can be damaged if not kept balanced, or discharged below 3v ( some are higher, usually the high power versions) Hope his helps

6 years ago by Dave M

Forum

46'' Firefloat What Motor/Battery

Hi John, you might now be scratching your head, and wishing you have not asked the original question! This seems to be a common issue, as the boating community is light years behind the other disciplines, rc cars, planes helis and so on, its probably due to the facts general boating doesnt really need the later generation technology, the average boater age is probably higher than the other disciplines so budgeting might be an issue, and there is less younger blood in the clubs to explain the lipo/brushless etc. We see posts with a load of numbers, specs, warnings etc, its enough to put people off. Im a big fan of brushless/lipo/ 2.4 etc, been doing it for years, its cheaper and more efficient (once you have the basics) but for the average guy, who just wants to spend an easy afternoon at the local lake gently cruising around, brushed motors, nimhs batteries, even lead acid, will do the job👍 Your 4 foot ply boat, once painted, with fittings, will be heavy, I know, I own one. Those 600 motors are not big enough, they are better suited to the smaller 3 foot boat, then, pushing them with a 6v lead acid, just cant do it. The battery will be screaming HELP!! I started 15 years back exactly the same, 600 motor, 6v battery, massive 50mm prop, I knew no better and took advise from people who didnt know what they were talking about😡, remember those gold hi tech speed controllers!! I had one, it melted, literally melted on the first use😭 Get 700 size motors, they will need to be water cooled, as mentioned by jarvo, the nominal voltage or below isnt good enough, power them at the max voltage. Brushed means you can use one apropriate esc, look out for electronize (are they still in existance?) or mtroniks, preferably use nimhs batteries over lead acid with a high mah. If after all this you want to venture into lipos and brushless motors, go to a club, spot a boat that is similar in size to yours, if you like the performance talk to the owner and gain experience and knowledge that way, it will save money, lost time and a lot of disappointment, I have been there so feel your pain. I say I would never go back to brushed motors and none lipo batteries, but I always want silly speed, not runtime, after 15 minutes Ive had enough and am bored. Rambling over! My 4 foot boat is twin brushless and uses 4 lipo 5000mah cells per motor, it will do 25mph for 15 mins, then I go home😁 Message is, you can get a "reasonable" performance from brushed motors, with the correct batteries, right props, but weight is the enemy. Looks lie you are at Biddulph, get onto Dave M a moderator on here, and arrange to go over to see the crewe and district boys on one of their sailing days, take your boat with you, they will help👍

6 years ago by pmdevlin

Blog

MV TEAKWOOD

Before the funnel could be installed wanted to fit a working radar scanner, navigation lights and the batteries. Decided to use sub C NIMH batteries in plastic holders, they should have the target endurance and provide some ballast. Fitted two sets of 4 cells, one at the forward end of the superstructure and the other at the rear, both at keel level. These were inserted into wooden battery trays to hold them in place. A dry test run showed a full speed motor run time well exceeding the hour target, so will try on water. Also took the opportunity to fit the Rx and then adjust the rudder before finishing off the wiring. Both the navigation lights (LEDs) and the radar scanner work. The radar is driven by a servo with the potentiometer removed and a magnetic drive shaft run up through the superstructure from below the deck. The motor requires about 9 volts to run at what would seem to be something approximating to scale speed; fitted a voltage reducer to allow the lights and the radar to work on less than 6 volts. The mast lights are to be installed in a separate circuit after the masts are added. As I get more into the detail it is evident the GA drawing and the photographs of the vessel in service differ. Fortunately the component locations seem consistent, although the equipment is not. This most apparent in the hold ventilators. The GA shows the standard cowl vents, but the photographs show a mixture between an vertically squeezed oval vent (which am advised is more typically German) and ventilator columns with cylindrical caps. The column style vents with cylindrical caps were easily made from two different sizes of styrene tube with the cap tops made from styrene offcuts. The squeezed oval style vents were more difficult. Broke them down into the major parts of the cylindrical vertical tube and, from a larger tube cut a small ring and filed one end to straddle the tube once it had been squeezed oval. Glued it into place whilst restrained in a small hand vice. Once set, removed and sanded the the two to give a smooth transition, closing the rear aperture off with styrene offcuts. Then resorted to wood filler, filed down to give a smooth, oval vent.

6 years ago by Rowen