Good LEAD

[chloejay]

Hi,

What 12v supply would people recommend for 2 x 7.4v, 4000 - 5000mah

20c, racing an 1/8th electric buggie for a day?

Hurry up summer!

cheers James

[mark christopher]

Originally Posted by chloejay

Hi,

What 12v supply would people recommend for 2 x 7.4v, 4000 - 5000mah

20c, racing an 1/8th electric buggie for a day?

Hurry up summer!

cheers James

what charger and what amps are you pulling?, id say a mains psu powered by a gennerator

[Marvin]

Being 20C packs I'd guess at 1C most anyway, so 14.8V at 5A. 16.8x5=84W, then /0.75 (75% Charger efficiency) = 112W. So, at 12V, you'd need a supply capable of at least 9.5A continuous OUTPUT. That'd be a very big leisure battery or a pretty decent generator then.

[BRS]

This is something I've been pondering, how are you powering your charger at outdoor races Marv?
Would a decent leisure 12v last the day if you had one 5S pack to charge say 5 heats possibly 7min running in each then a 15/20min final (If you can run that long)

[Marvin]

I've coped all this season doing one charge all day (so has been on a normal car battery). I used a 5500mAh 5S pack - went out in heats with 1 minute to go, and came in when I'd finished (1 or 2 'cool down' laps). Then I'd charge at 3C at lunch, and easily be ready for finals.

Alternatively, have two batteries!

[gnr racer]

Marvin, do you caharge at 3c (when your lipo is capable of a 5c charge) because its kinder to the lipo's life?

[Marvin]

No, it's because I don't have a charger capable of 577.5W (5.5Ax21Vx5C) and 27.5A charge rates...

It is kinder to the LiPo though - I'd only charge at the higher rates when at a race day - when necessary, I wouldn't charge at that rate at home - there's no point unless you're running late.