Battery query for Chinese e-bike

[Mike Anderson]

Hello everyone. I will be most grateful for your advice.

I purchased a basic folding e-bike which has proved to be quite adequate for my needs. In fact I would be pleased to recommend the bike given it is obviously very basic and not for serious e-bikers. Photo attached.

The battery is 36v 7.5Ah. The bike was not used for about 3 months. The battery will now not charge. Having done some research I understand that when a lithium battery lies dormant for a long period it can deteriorate and it is not possible to resuscitate it? I put a multimeter on it and the voltage was down to 4.5. I read somewhere that you shouldn't let lithium batteries lose more than 70% of their charge if they are not in regular use or they will become nonchargeable.


I assume that the battery is now completely naffed, and I will have to buy a replacement. But where? The bike sellers do not sell batteries separately. The battery is housed inside the frame so the physical dimensions are crucial.

If I replace the battery with one of a higher voltage could this cause a problem with the motor/electrics?

Sorry if questions are simplistic.

 

[cyclebuddy]

The voltage does seem way too low to be recovered. Your e-bike appears to sell under several different brand names. I've seen a few youtube videos showing your bike with battery testing, removal, replacement (same capacity or larger)… even adding secondary batteries to increase range. Sources for new and replacement batteries or the option of re-celling are often discussed in the comments sections there.

 

[Mike Anderson]

The voltage does seem way too low to be recovered. Your e-bike appears to sell under several different brand names. I've seen a few youtube videos showing your bike with battery testing, removal, replacement (same capacity or larger)… even adding secondary batteries to increase range. Sources for new and replacement batteries or the option of re-celling are often discussed in the comments sections there.

Thank you, Cyclebuddy,

I will check out youtube

 

[Nealh]

You will have to stick with 36v as I doubt the controller or display will except 48v, at the very least the controller will go up in smoke. If the battery was at or above 28v then it might have been recoverable but 4.5v is dead.

 

[Mike Anderson]

Thanks nealh

That's what I figured