No power to ebike after replacement of dead batteries.

[mermaidnwuk]

Hello,

I was gifted an ebike a few years ago and everything was going fine until the batteries needed replacing.

Exactly the same batteries were purchased, were tested on arrival for power, were wired into holder the same as the old ones then battery holder mounted onto the bike. Switched on - NOTHING. Not even the power indicator, horn nor headlight could find any power. Dead as a DODO. What can be wrong, please?

 

[sjpt]

Please tell us what the bike is, and photos of the battery.

Did you replace all the cells and keep the old battery holder? I think that's what you are saying, but just making sure.

 

[mermaidnwuk]

The bike has been re-sprayed but I believe it originally started life as a Cheetah. Yes, I got new batteries and fitted them into the existing holder.

 

[vfr400]

The same as always, you can't do anything without a meter. First, you need to measure the voltage on the battery terminals.

 

[mermaidnwuk]

I measured the voltage, on both batteries, on receipt, Friday, 7 August, and before fitting today. Reading on each was 12v+

 

[vfr400]

I measured the voltage, on both batteries, on receipt, Friday, 7 August, and before fitting today. Reading on each was 12v+

You need to measure the voltage on the terminals on the case, where they connect to the bike.

 

[mermaidnwuk]

You need to measure the voltage on the terminals on the case, where they connect to the bike.

Thank you, will try that. Just need to put it all back together after re-checking batteries, connectors and fuse.

 

[vfr400]

Thank you, will try that. Just need to put it all back together after re-checking batteries, connectors and fuse.

!t would be better to check it before putting it back together in case you need to trace a fault.

 

[mermaidnwuk]

Wired the battery back into the holder and then did the following:

Turned on the key and connected multimeter to terminals on reach of key switch - no reading.
Put multimeter probes on terminals neutral on Battery One and positive on Battery Two - no reading.
Put multimeter probes on neutral on Battery Two and positive on Battery One - reading of 25v+
Put multimeter probes on neutral and positive on case terminals (where it slots onto bike terminals) - no reading.

So, I am thinking something wrong at the key on/off switch. Would I be right in thinking this? Not sure how to fix/replace key switch, to be honest.

 

[vfr400]

Resolder the joints on the key switch, otherwise bridge them as a temporary measure that will allow you to test or use the bike,