Looking for what the lipo equivalent of 7xGP 3300 Nimh cells is?

[martin collins 1]

I bought an aircraft at the weekend that has not flown in a while, it uses 4 speed 400 motors and has the esc tucked away within the wing. It has written in the battery hatch GP 3300 X7 what would be the voltage of an equivalent lipo pack? It is years since i used those type of cells and i cant remember what the voltage is on them! Thanks for a point in the right direction..........M

Edited June 30, 2021 by martin collins 1

[Denis Watkins]

It's the volts Martin, 7 nimhs are 7 x 1.2 volts = 8.4 volts

A fully charged lipo cell is 4.2volts

So you need a brushed speed controller and 2 cell lipo, at 8.4 volts and 3000 mah range lipos are very popular

Edited June 30, 2021 by Denis Watkins

[martin collins 1]

Thanks for the quick answer, the controller is in it but unviewable as it`s built into the wing, would 8.4 volts power 4x speed 400`s enough to fly a plane?

[Simon Chaddock]

martin

The question really is how well did it fly on 8.4 V 3000mAh NiMh?

A 3000 mAh 2s LiPo will be about 40% lighter than the same capacity NiMh so it should fly somewhat better although you will have nothing to compare it too. Note the position of the lighter battery may need adjusting to maintain the plane's correct balance point.

The really big change would come from changing those heavy speed 400s for suitable brushless motors but that would require 4 new controllers as well so it is quite a significant task. However both the performance and duration would be greatly improved.

[Gary Manuel]

What Simon says plus ... another alternative would be to get a higher capacity LiPo weighing the same as the original 7 x NiMhs, perhaps a 2s 4000 - 4500mAh. This would give longer flight times and not require the battery to be repositioned.