cheap ~70 Volt Battery Solution

[darius]

Hey guys

I currently plan on buying a cheap used GoKart to convert it to electric.

The motor i want to use has ~10kW of mechanical power (dont know how efficient it is) and ~16kW (maybe more) of electrical power (@70V).
Do you think this is somehow suitable to be used in a GoKart?

If this is the case, what would be the cheapest battery solution capable of delivering enough current at 60-70 Volt and around 15 minutes of "normal" driving? (the lighter the better)

I think LiPo-batteries are lightweight and not too expensive.
But they are also too dangerous and difficult to manage/charge.

I hope someone can help.
Thanks in advance!

 

[itsid]

kurz: vergiss es!

longer:
RC motors like that are almost always rated in electctrical power.. and that's MAX power (short bursts of power .. not continous use)
means.. yes maybe 10-16kW but for ~10secs or it'll catch on fire /burn the internal wiring

and as always: the mechanical power at such max rating is always less than 50%!

And then.. with 10500 rpm you have to fit a decent gear ratio wich might be an issue in itself.

All the info on hobbyking are completely absurd!

it's said to run on 70V.. okay plausible...
it's said it has an internal resistance of 0.004 Ohm
sounds good at first...
But 70V/0.004 Ohm means it'll draw 17500 Amps!
seventeenthousandfivehundred fricking amps.... that is nowher near a realistic number!
70V times 17500 amps means it's powerdraw would be 1225000 Watts
more than a MILLION WATTS!!!!
*cough* *cough*

So, I assume it has 0.4 Ohms

means it'll draw 175 Amps (more likely)
70V * 175A are 12250 Watts (12kW)
that's electrical power.. MAX electrical power... efficiency below 50%!

say ~5kW mechanical power.. and for no more than maybe 20sec if you're really lucky...

okay let's just stick with 175Amps and 70V for your lipo packs...

that's five packs in series (14.8 V each 4S) and let's assume 4500mAh per pack

means 0.025h (~92seconds) per such five packs in parallel... until they're completely dry...

for a 30 min ride that's 19 such 20S packs in parallel
95 x 4S.4500mAh batterypacks in total each pack is ~25€
that's 2375 € for batteries...
for 15mins I would say you still need closer to 11 such 20S packs (1375€)
not too expensive you say?

okay, I wouldn't even try!

'sid

 

[darius]

ok, thanks

im not really surprised about the info on hobbyking not being accurate but they seem to be really wrong.
and you're right, all in all it would be nonsense to really use this motor.

But what kind of motor is really suitable?

I still want it to have high torque/power (at an affordable price).
i know that golfcart-motors or forklift-motors are pretty much perfect to use.
But there dont seem to be alot of them available (used) here in germany?!