can someone please explain lipo batteries to me...

[hedgefinder]

can anyone please explain lipo batteries to me... C rating etc...
I have an rc race boat with 125amp esc which the manufacturer recommends a single 4000mah 25C lipo battery.
nw as far as I am awae you need batteries with a high enough rating for the maxiumum draw from the ESC?
now I was going to buy 2 x turnigy nanno 5000mah 2S 35~70C Lipo packs... which are larger than the manufacturers specs, but everyone seems to recommend higher C the better...?

[Magic919]

I wouldn't get too carried away. The recommended battery could, in theory, deliver about 100 amps. The ESC can cope and it largely depends on the current demand from the motors.

Have excess C rating won't hurt, but whether it'll benefit is another matter.

[hedgefinder]

so a pair of 4000mah 2S 45~90C might be a better choice?

[hedgefinder]

just to get this straight in my head...
I can go as high as i want on mAh and C rating and it will not have any adverse effect on the ESC just increased power delivery and discharge rates....as long as I stick with 2s at 14.8v max..

[tubbinthug]

2s is only 7.4v, unless you run the 2 packs in series. A higher mAh or c rating will not blow the speedo, but 4s instead of 2 probably will, as a higher voltage for the same resistance will also increase the current. mAh is the capacity, how much current can be supplied for 1 hour. C is the maximum discharge rate in multiples of capacity. So a 20c 4000 pack can be discharged at 20 x 4000 mA = 80 amps without damaging the pack. In truth, discharging at 10 c continuous will only give 6 minutes of use before the pack is flat. However c ratings are often inflated. I would always run at least double the c rating required, as they are usually inflated by the seller

[hedgefinder]

2x 7.4 run is series gives me the 14.8 recommended in the manual and allows the weight to be equally distrubited in the sponsons either side..



oddly spoke to hobby king who said that the boat should run
1x 4000mAh 3s....
contrary to the instructions and battery tray layout in the hull..

[Magic919]

Greater mAh will improve run time. Higher C batteries may or may not make the motor more punchy. The motor will only pull so much current, so that's the limiting factor if the ESC is correctly sized.