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>> Home > Tags > battery voltage

battery voltage
voltage
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LiPo batteries by MouldBuilder Lieutenant   Posted: 14 days ago
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.😊

Aerokits Patrol Torpedo Boat by RNinMunich Fleet Admiral!   Posted: 29 days ago
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 😎

Aerokits Patrol Torpedo Boat by RNinMunich Fleet Admiral!   Posted: 30 days ago
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!

Aerokits Patrol Torpedo Boat by MouldBuilder Lieutenant   Posted: 1 month ago
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.😊

Aerokits Patrol Torpedo Boat by canabus Fleet Admiral!   Posted: 1 month ago
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 battery voltage at the transmitter. Check out you tube about the radio. Canabus

Dumas 1203 Coast Guard Lifeboat (RNLI Waveney conversion) by Dave M Fleet Admiral!   Posted: 2 months ago
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.

Too Powerful Brushless ? by Dave M Fleet Admiral!   Posted: 2 months ago
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 battery voltage.

Too Powerful Brushless ? by RNinMunich Fleet Admiral!   Posted: 2 months ago
"The max current is the Max Watts divided by the Battery Voltage." 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

Too Powerful Brushless ? by Dave M Fleet Admiral!   Posted: 2 months ago
Hi Graham and Haig The max current is the Max Watts divided by the Battery Voltage. 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-an... Reducing the prop size will reduce the load.

LiPo Battery Monitor by Dave M Fleet Admiral!   Posted: 3 months ago
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... 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

LiPo Battery Monitor by Dave M Fleet Admiral!   Posted: 3 months ago
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

46" Firefloat What Motor/Battery by pmdevlin Fleet Admiral!   Posted: 3 months ago
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👍

MV TEAKWOOD by RHBaker Fleet Admiral!   Posted: 3 months ago
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.

NimH advice by Dave M Fleet Admiral!   Posted: 5 months ago
Hi Alex They will be connected in series with the positive connected to the negative. I suggest you carefully cut off the heat shrink covering, taking care not to cut into the cells. You can then check each cells voltage. The nominal is 1.2v rising to 1.4v when charged. Any around 1v or less will never hold a charge so mark them with a marker pen. Hopefully it will be one of the end cells that has failed. On your type of pack the bottom of the battery (negative) will be in a metal case attached to the top (positive) of the next cell. I use a flat blade screwdriver to separate the cells (they are spot welded) and sometimes you can get the case off the bottom of the dud cell, leaving it attached to the positive of the next cell. I suggest you then charge the remaining good cells to see if they all take a full charge. If they are OK you can get a new cell or just make a lower voltage pack. I use a piece of stranded wire to repair the joint. You will need a 40+watt iron and some solder paste, and may need to scratch the battery case and pin for the solder to take. If you were careful with removing the heat shrink you can use it to cover the pack with a bit of electrical tape to make good. Please ask if you need any guidance with the process. I have been doing this for many years and may not have explained in enough detail if it's new to you. Do remember if the battery is charged it can short in its unwrapped state so do make sure you bench is uncluttered and kept clear of any metal objects. Good luck

46" Firefloat What Motor/Battery by canabus Fleet Admiral!   Posted: 5 months ago
Hi What type of props are you using(size and number of blades). I see your basic problem is under powered motors and a very heavy battery. I made the big switch over three years ago from brush to brushless motors and to Lipo batteries. With the help on the forum and club members it was a learning curve, but, I would not go back. A 5800mah Lipo battery is in the weight of 450 to 570 grams and would give you a good 1/2 hour run time. A good balance charger and safety bag are the main requirements, also maximum charging for the 5800mah battery is 5.8 Amps(same as the old Nicads). Also a low voltage battery alarm. Your 600 motors can draw up to12Amps !!! Replacement same size motors for your mounts would be 35mm brushless motors, but, you will require two ESCs with a Y connector to run on the same throttle channel. Replacement brushless motors are far more powerful e.g. a Hobbyking 3639-1100kv with a 60Amp ESC on a 4S 5800mah Lipo Battery is 800watts and with two in your boat is 1600 watts!!! Your old motor would in the 100 watt each mark !! I have the same size crash tender, but, with a single brushless motor. I have all the order numbers for the motors etc. and a setup the ESCs if your require. Canabus