I see previously expensive E-Bikes sold for pennies on the dollar with missing or dead batteries.
Perhaps check:
Battery type:
- Lead Acid
- NiCad
- NiMH
- Lithium
- Etc.
Charger and type?
Interface?
Can you purchase replacement batteries and components?
Do you wish to hack something together on your own?
Hardware tool batteries?
I just purchased a little electric chainsaw & lawnmower. 40V, 4 AH modular battery packs. It looks like some E-Bike Batteries have similar voltages, but higher AH rating. Nonetheless, a lot will depend on your actual needs.
Keep in mind.
Serial connections ==> More volts
Parallel connections ==> More Amps or AH.