Fabricating a battery

[halfmedley]

I'd like to fabricate my own battery and I'm aware that a few of you have already done this. Are there any dangers associated?

Presumably any battery that I make has to match the manufacturer's specification (ie 36V, 10AH) to get the motor to function? In other words, would a lightweight get-me-home battery (eg 6V, 12AH) provide insufficient power?

And finally, the battery connection on my Mistral is a triangular flat three-pin type (more commonly seen on electric kettles) how might this be wired to the cells? The charger uses the same connection to recharge the battery too.

 

[Jeremy]

The battery voltage needs to match the original, as if it's lower then it may well trigger the controller low voltage cut off and if it's higher it may damage components in the controller.

You don't need to match the Ah capacity, but you do need to ensure that the battery can source enough current safely. Normally ebikes need around 10 to 30 amps maximum, with few needing more than about 20 amps.

A 6V battery wouldn't work for a couple of reasons. Firstly, the controller might well cut off so you'd get no power at all. Secondly, if the controller actually worked then the power output from just 6V would be very low, as motor speed is directly proportional to voltage. If the bike does 15mph on 36V, then it would do 2.5mph on 6V.

Jeremy