NiMH 4600mAh Sub C cells

[jerrysimon]

Been having a look round for a lighter setup using a Tongxin motor. My daily commute is only 10 miles return.

The new NiMh Sub C batteries go up to 4600mAh now. (edit just found some 5000mAh ones). Quite high discharge rates of 30amps as well.

What "actual" voltage is required to power a 36v or 24v hub ?

e.g would 4 series 9.6v packs i.e 38.4v be sufficient for a 36v motor. I guess its down to the controller more though ?

These would only wiegh about 2.2kg. You could probably fit them cylindrical water bottle type case as well

Regards

Jerry

 

[jerrysimon]

Hmmm

Endless-sphere.com • View topic - Overvolt Controller, bad for batteries,

Looks like you would need 4*12V packs as the voltage sags alot under heavy load.

Regards

Jerry

 

[flecc]

Cytronex use 36 volts nominal of NiMh cells which are probably sub C in their bottle battery with the Tongxin Nano motor and they don't have voltage sag problems. If the voltage does sag appreciably, the 30 amp rating is false.

The only thing to watch out for when using a lower voltage is the BMS low voltage cutout which normally occurs at around 31.5 to 32 volts on a 36 volt system, but good NiMh cells rarely suffer large drops, it's more a lithium problem.

When saying a 36 volt battery, I'm referring to the nominal voltage for NiMh of 1.2 volts per cell, i.e. 30 cells, not the actual voltage of that which is around 41 volts fully charged.
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[jerrysimon]

Thanks Flecc.

That thread was obviously referring to poor quality cells.

Something to think about I guess.

Regards

Jerry