1s lipo

Novak Booster on 1/F.
Another option is to use receiver pack.

a receiver pack is a separate battery pack to power the reciever and servo. So the main battery (1s lipo) will only power the motor via the esc.

a receiver pack can be:
a) 4 cell NIMH (4.Bv)
b) 2s lipo (7.4v)   may need external bec to down to 6v
c) 2s a123 (6.6v).  this is the best because its small and light.

1S lipo on 1/12 seems to be the future legal racing spec.
but i agree, 2S is more simple than 1S

yes, some 2s-lipo will fit the r5.  my friend used 7.4v 1800mah GE brand.  you can buy it at KWS. i think it costs about $120 each.  Just pair it with 3000kv to 4000kv motor.  the speed should be pretty fast.

回復 19# 湯瑪仕

Can you set the voltage cutoff to a lower voltage? (or disable cutoff)

但係無著電變就無節電功能, 舊電會否因過放導致死電呢?
湯瑪仕 發表於 2010-3-16 08:04

                               
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會  

When the car is slowing down, stop playing.  
or
after 7-8 minutes, stop playing.

using 1S + receiver pack is better

1.須要開電變開關嗎？
--> esc can be 'off' (but not 100% sure)
2.A123 充滿電會超過6.6V ,對接收會有影響嗎？
--> When fully charge, 2SA123 is about 7.4v so it is slightly over voltage.  It should be 90% safe to servo & receiver.  but you may add a voltage regulator to drop it to 6.0v to be on the safe side.

200mAh about 2-3 packs.

I think 2S123 @ 6.6v (or 7.4v charged) can plug directly into the receiver without problem.  Some people even plug in 2S lipo directly.   Also 5cell NiMh full charged will be around 7.2v and people has been using 5cell NiMh as Rx battery for a long time without problem.  

Of course with a 6V regulator is the best, just a little bit bigger/heavier.

Not 100% sure, but I think you can connect in 2 ways:

1) ESC Off, RxBattery plugs into Rx.
2) ESC On with red data cable taken out (this will disable the internal BEC), RxBattery plugs into Rx.