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>> Home > Tags > battery power

battery power
gas power
portland model power boat association
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power boat
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12 volt motors to esc,s by Dave M Fleet Admiral!   Posted: 9 days ago
Doug I do believe the FR15 uses the BEC to provide a 4.2v supply to the PIC chip. If you don't switch on the ESC it won't work. Just seen Sonars post so seems all is OK Dave

Wiring in a rx, an ESC and a battery (pack) by Haverlock Admiral   Posted: 12 days ago
first take a deep breath and calm down its not rocket science. Question does your ESC have a battery eliminator ? if so take away the dry batteries to use in something else. Now your nicads connect to the POWER side of the esc. make sure you have the correct polarity. The servo plug from the ESC plugs into your receiver whichever is your throttle channel. If you have a modern set then you can put it on the wrong way round with no worries since positive is the centre post. The output of the ESC connect to your motor. If its a brushed motor no need to worry about polarity for now. With your ESC there should be some setup instructions if there are none ...... Usually its connect and switch on receiver then switch transmitter on with throttle full listen for beeps then go to low throttle. Switch receiver off. When you switch on in future make sure transmitter is switched on FIRST ok having gotten this far it only remains to check the direction of rotation of the motor. Take off the prop ( saves fingers) and put a piece of masking tale around end of prop shaft. Switch on transmitter switch on receiver and try the throttle. If the motor spins in correct direction fine if not Brushed motor swap the motor leads over Brushless motor swap any 2 of the 3 motor leads over. Job done have a cuppa then decide to sort out the rudder.

What type of wire? by RNinMunich Fleet Admiral!   Posted: 20 days ago
Hi Nick, Servos & signal leads For these I use the twisted cable, pic 1. Especially if I need to extend a servo cable. Twisting the wires together helps to reduce interference. The interference current induced in one wire is suppressed by the wire next to it 😊 This is the principle used in high quality phone and LAN cables. Of course you can twist wires together yourself if you want. Clamp one end in the vice, the other ends in your hand-drill and away you go. Drive batter - ESC - motor- Rules of thumb For these I use cable from the motor trade. Make sure it is rated to handle the motor current you expect under normal running AND NOT LESS THAN THE STALL CURRENT OR THE BATTERY MAX CURRENT RATING! I don't do hi speed racers so the hefty 300A stuff doesn't interest me. If you do then use the car battery cable size. Cross section of the copper wires ca 25 to 35square mm. Pic 2. For medium power, < 15 to 20A like most of my scale ships the 'standard' car cable with about 2.5 to 4mm square is enough. Pic 3. Above all: don't forget to fit a fuse (quick blow) in each motor supply lead, Rating less than the max stall current that you expect and/or just under the max current rating of the cable. In the drive battery lead put a fuse (not quick blow!) rating to match the total max load you expect under 'normal' running; i.e.just above your total load but always less than the max discharge rate of the battery (esp. for LiPos!) or the wire mac rating. The quick blow fuses on the motors will blow first if a motor stalls, still leaving you with some power & control. Esp in twin shaft boats, you can limp home on one engine 👍 On singles, time to take your socks off and join the ducks! 😉 Odds and ends - low power So called signal cable or test-lead cable from hobby electronic shops with conductor cross section area of 0.75 mm square is enough. It copes with an Amp or 2 with no problem. General, make sure all connections are clean and tight, use gold plated connectors for all hi current wires, batt, ESC, motors. Hope this helps a bit. Cheers Doug 😎

Bluebird K7 by BOATSHED Commander   Posted: 21 days ago
I see that's a battery charger. I was thinking about a 12v power supply box I have. Can this be done from any lipo battery charger. I don't want to kill my one by doing something that it wouldn't like. It's an Elysium LX60B.

Tamco Tx/Rx by Dave M Fleet Admiral!   Posted: 23 days ago
Hi NickW Sorry I should have explained better. I suspect you may have accidentally reversed the battery plus and minus connections. Doug has already suggested this and if you did this to the rx the internal BEC would have been destroyed which may account for the smoke. It may also have damaged (melted) the battery lead so check this also. You can buy leads to convert the two pin battery connectors to three pins which will not allow wrong connection. Even if you plug in the wrong way round with 3 pins no damage will be done, just the rx won't have power until you fit the plug the correct way. If your boat works ok with the original rx then the ESC should be ok and it is just the rx that is broken. You may be a newbie but believe me I and many others have all made the same mistake, sometimes more than once, so you are certainly not alone in that respect. Dave

HMS Erebus by Dave M Fleet Admiral!   Posted: 30 days ago
Hi Gdaynorm That should be OK. The speed controller in the picture is marked made in China and their rating of 128 amps seems very optimistic. That said we have looked at all the components and the only remaining possible cause, assuming the motors and ESC are not faulty, is the prop sizes and pitch. If they are causing a too heavy load on the motor then the current will be excessive and your new battery is certainly capable of providing lots of power. I do believe the ESC was cutting out due the overheating. As others have said you cannot always rely on Chinese ESC quoted ratings, and in my experience they seem to have missed out a decimal point. You have several options: 1. make a reduction unit between each motor and prop so the load on the motor is reduced. 2. fit smaller props 3. measure the stall current of each motor using a watt-meter and buy two speed controllers with double this current capacity. Initially I would experiment with option 2 to prove the props are the cause of the problem. You can then decide if you wan't to try another option. Option 3 will result in shorter sailing times. Davwe

Battery problems by Dave M Fleet Admiral!   Posted: 1 month ago
Hi Allan If you had water cooling and it was provided by your pump then it would seem the prop was far to coarse a pitch for you fast motor and very powerful battery which was quite capable of delivering well over 200 amps through the 160 amp ESC. Your comment re the power delivered rather confirms this, and holding a model at full speed to test is only possible for about 5-10 secs max. You need to get a much smaller and less coarse pitch 3 blade prop plus a wattmeter to measure the current to make sure you are no where near the max ESC current. Personal experience suggests this should be less than half the rated Max so say 70 amps for your ESC. Testing should be brief and stopped immediately if the current being taken is above 20-30 amps. Smaller props will reduce the current to an acceptable level and your model will go faster and for longer. As a guide 14 volts at 70 amps will be using 980 watts so you will perhaps appreciate why cooling is necessary. Also at such high currents the wiring from battery to ESC then motor will need to be capable of carrying such high currents. As there are three wires to the motor and the power is pulsed at high frequency they are usually not as heavy as the battery to ESC. Your battery to ESC connectors also need to be capable of high current such as Deans, Euro or bullet type. Having looked on U-tube it does appear that others have had similar experiences with this ESC. The specs say it is capable of running at 14.4 volts so when you buy a replacement I would ask your local store to run your motor with the ESC and your battery to ensure it works OK. If they have a wattmeter ask them to test the open current then also buy the wattmeter and a smaller 3 blade prop of slightly less diameter than that of the motor without the water jacket. Do a final brief test at home holding the model and see briefly what the wattmeter reads, this will be near the max current draw. If it's too high you need a smaller prop. There are several Perkassa builds on the site and some use brushless with success. If you search you will find details of their power train which may help you choose the best set up. I do hope you will soon have your model speeding round your lake. Dave

Battery problems by RNinMunich Fleet Admiral!   Posted: 1 month ago
Hi Patto, forget the 'watt meter' and consequent P=IV -> I=p/V conversions! What you need to measure is the actual current drawn, especially the stall current, if you can manage that without getting any fingers chopped off 😡 On the lake anything can choke the prop so just testing 'free running' is not the whole answer. Sounds to me simply that your setup is drawing so much current that any battery or accu will go flat in a few minutes. Your example of a 5300mAH (i.e. 5.3AH) means that in perfect (!) condition, fully charged and almost zero internal resistance (int. cell resistance wastes power so buy the best quality you can possibly afford) it can theoretically supply 5.3 Amps for 1 hour. or 53 Amps for ~ 6 minutes (1/10 hour). and so no. LiPos with C values of 130 sound great BUT the discharge C value is related to the AH rating. So taking your example of 5300mAH = 5.3 Ah 130C = 130x5.3 = 689Amps! The Accu would supply that for ~ 27 seconds before departing to the great recycling centre in the sky! If you ever decide to try such an experiment PLEASE let me know in advance and I'll fly over the record the event for posterity 😉 Seriously though folks: I can't comment on the prop/motor setup, one of my weaknesses - I always check my stalled motor current draw with an ammeter before selecting the ESC - but as an electronics engineer I do have some idea about power supplies and circuit requirements etc. Can't imagine that your setup exceeded the 160A (short term remember!) rating of the ESC so that seems to be faulty, but you still need to find out what current your setup will draw under severe load i.e. stall. If just holding the boat cause blow ups then something else is fundamentally wrong 🤔 Bit long-winded perhaps, much of the above makes sense but not the whole story, time to cut to the chase I thought. MEASURE THE CURRENT! Good luck. Doug 😎 By the way the above comments about lead acid & hi current are OK. They are more useful for long term supply of low to medium currents. I still use them in some larger scale models (~ 1.5metre naval ships) as they provide useful ballast (i.e. payload) instead of JUST ballast! The 20HR of your lead acids refers to the Hourly charge Rate, i.e 1/20 of the capacity in AH, in your case 7/20 = 0.35A or 350mA.

Battery problems by Dave M Fleet Admiral!   Posted: 1 month ago
Hi Patto I agree with what has already been posted, but it would help if we knew the size and type of prop you are running with your brushless motor. Fast large racing props do not work well with brushless unless your battery can provide the very heavy sustained current required. As Haverlock suggests a Wattmeter will allow you to select the best prop for your set up. LiPo power will give you all the speed you need but at an initial high cost as they require special chargers and correct management. You could use NiMh batteries which are lighter than SLA and are more suited to high discharge currents. You can get these in 12v packs and 5000mAhr would be a good starting point. If your motor is cutting out it is more likely the ESC is the culprit due to too high current draw. Another possibility is that the propshaft is too tight, it should turn freely with no tight spots and have thrust washers at both ends. Dave

Li-Poly batteries by nasraf Commander   Posted: 1 month ago
pmdevlin Sorry to confuse and you are right in what you say. What I was trying to point out was the relationship between energy storage and power availability. A big battery will usually have a greater energy storage capacity and depending on its design a greater power output but this is not always the case. As I would imagine the construction and manufacture of LiPo's is a bit of a " Black Art " as was the manufacture of many lead acid batteries and the likes of Boeing and Samsung have found out at great cost to themselves, if anyone has done any controlled tests on batteries used by the likes of our members it would be useful.

Battery problems by Haverlock Admiral   Posted: 1 month ago
A quick check on the specs of your motor /esc combo states its good up to 5s LiPo. So step 1 get a watt meter ( cheaper than burned out motors ) Step 2 check with your bank manager ( or wife) for available funds Step 3 buy the biggest 4s or 5s LiPo you can fit in the available space. you will also need a LiPo charger do not attempt to skimp on that step LiPo batteries need special handling and can be spectacular if you do it wrong. You have not mentioned the prop your using if you use the watt meter you can play around with different props so the current used by your setup heads towards the point you pick twixt performance / running time. If you do go LiPo you will also need a battery monitor part of the careful handing includes not discharging them below around 3.3 Volts per cell. 3s =3cells 4s=4cells etc. So if you go 4s then you should not discharge below 13.2V. http://www.rchelicopterfun.com/rc-lipo-batteries.html http://www.4-max.co.uk/pdf/prolong-life-lipo.pdf some text on the care and feeding of LiPo batteries. The reason for your problem is a simple case of battery chemistry a lead acid accumulator cannot deliver a high current for extended periods gasses on the plates prevent the electrolyte coming in contact so the battery loses power. After a while the gasses are re dissolved and the battery can then go on providing power. Nothing wrong with the battery its just a case of wrong tool for the job.

Li-Poly batteries by nasraf Commander   Posted: 1 month ago
I do not know much about the detail design of Li Po batteries but in the past have spent quite a lot of time and tax payers money looking at the performance of lead acid and nickle cad batteries when starting petrol engines over a large ambient temperature range and have the following observations, my interest in model boats is restricted to modest speed versions and I have enough trouble there with Li Po's. It is a pity that to impress those who have a limited knowledge that the capacity of these batteries is quoted in ma. hours rather than amp hours, I know it is easy to convert if you have a bit of a mathmatical background but not eveyone does. It took me many years before I understood the difference between energy and power and I think a lot of people still do. Basically the ma. hr. rating is the amount of "energy" that the battery can store but how much of it that you can get out is very much dependant on the rate of discharge ( i.e. the "c" value with its multiplier ) in general the higher the rate of discharge ( i.e. the "power" ) the less of it you can get out. In addition batteries have an internal resistance so the higher the " amperage " the lower the " voltage " applied to the motor terminals, so as "Watts" ( Power ) equals volts times amps the actual power available to drive the boat is reduced. Also the loss due to the battery internal resistance ends up as heat in the battery which does not improve its life. It must be almost impossible with the information available to be able to select the best battery available for the high rate discharge uses, I wonder if ayone has done any comparative tests?

Motor Mounts by Dave M Fleet Admiral!   Posted: 1 month ago
Hi Steve Yes I intended to use silicon to fix the motors on the Perkassa. Works well and acts as a damper to any noise. The battery really depends on your speed controller as that may have a max voltage of say 12v. It's not a big model so I suspect a 3 cell 11.1v at 2200/3000 mA would suffice and provide plenty of power for the two motors. If you have a 7.2 NiMh available I suggest you try that and see if its fast enough. A 7.4 LiPo will give more endurance and speed so a 2 cell may suffice. LiPos do need protecting from over discharge so make sure your ESC has such protection or buy an add on unit that warns you when the battery voltage is too low. The ESC version is better as it cuts or reduces the current before damage is done. The Amp/Hr rating gets dearer the higher you go, so its down to you as to what you buy. Higher ratings will give you more speed but also longer running times. Glad the coupling worked. Dave

Motor Mounts by Dave M Fleet Admiral!   Posted: 2 months ago
Hi Steve Yes that looks like it. You do need to fiddle around with the mounting to get a good smooth alignment. If you can align both couplings with a length of close fitting tubing or four strips of wood and two rubber bands this will give you a good starting point. I use a 1.5v battery to power the motor and adjust for best speed and lowest noise level. You can use an ammeter to monitor the current and adjust for the lowest level for best results. Dave

dicky motor by marlina2 Petty Officer   Posted: 2 months ago
It may be a transmitter/receiver problem or it may be in your drive setup that rears its ugly head once your on the water and your motor is under load. I had a similar problem with a twin motor setup which was fine out of the water but after 10 mins in the water I would lose drive to one or both props or one would slow down and just go round in circles (very embarrassing). I had no problem with radio setup so it had to be in the drive chain. I ended up changing both motors for ones with more armature poles, higher torque output and a different gear ratio. It also highlighted a problem with my first choice of battery which quite frankly were pants and used to produce similar symptoms as you describe. I now use Lipo power packs, they do have disadvantages but you can not knock the power to weight ratio. The main problem I was having appeared to be down to the 3 pole motors that were fine until they were under load, this caused the motors to overheat which in turn increases the current drain on the battery's, the net result is the motor starts to arch across the commutator and effectively becomes a dead short which in turn shuts down your ESC's or drains your battery's very quickly. As you probably know if this was to happen with Lipo's there would be no need for a smoke generator! Of course this only applies to brushed motors if you are using a brush-less motor then it will probably not help you.