21700 5000 mah run time in ebike

[raggie33]

it uses 250 watts

 

[TILL-22]

About 4,5 minutes if you use only 1 battery. It won't be able to provide that much power though.

If you elaborate your question we'll be able to give a better answer.

 

[raggie33]

just thinking of a way to get a extra battery for the ebike im looking at

 

[snakebite]

many ebike packs are 36v.
so 10s li-ion.
the answer is forget it and buy a bike with the range you need plus some reserve.
your sub pack needs a bms and charger too.
if you know what you are doing you can build your own custom pack.