Battery issue

[Moparopkop]

Hi everyone....got my first conversion kit last week.a bafang 750w and 48v battery...im over the moon with it....the freedom it gives me is brilliant....time away from the house and peace and quiet away from the kids for a few hours is priceless....

Having a problem with the battery...when I built the kit up the battery was showing 86% on 500c display....I rode away on it and put it on to charge when it showed around 64%....the charge only took 4.5 hours....when I checked the display it was 53.6v and 100% after the first charge....that was all good was using the bike as normal for about 30 miles getting used to everything....2nd charge I done yesterday and it took about the same time 4.5 hours to charge....so turned the display on it was reading 53.6 again....happy days I said all charged for work the next day....then the voltage started to drop to 53.5 then got lower as I stood there....53.4 53.3 down to 53.1 in the space of 10 mins.then I turned everything off....gave it ten minutes or so and tried it again....got 53.6 initially then started to drop again as before....
Next step i check the battery with multimeter and got a reading of 00.0...strange I thought.....put battery back on bike and run the motor and it ran ok with rear wheel lifted....woke this morning turned it on and the same 53.6 on start up then dropping slowly....

One thing to add is i was tidying the cables up and the red and black wires did touch... battery voltage was normal after that no dropping....just after the second charge it this has started.....hopefully I've explained this right...

Any help or feedback much appreciated
Thanks for looking....

 

[Nealh]

Even at 53.6% I wouldn't have been happy as it is 1v less then it should read when fully charged. Momentary shorting shouldn't cause to much issue but tbh from the first instance of the lower voltage reading I would have gone back to the seller.

You don't say which cells are used, battery capacity or the battery continuous discharge rating.
Often a lower voltage is due to unbalanced cell groups, a poor cell group or even the charger.
Have you checked the charger output with your meter, it should read 54.6v.

 

[Moparopkop]

I'm not sure what cells they are...its a 48v 20a hailong battery....how do I check the battery continuous discharge rating.i haven't checked the charger output either....

 

[Nealh]

Continuous discharge rating is in with the battery specs on the sellers listing or at least should be, post a link to the product page you bought from.
As it is quite new one needs tt contact the seller as it is guaranteed for 12 months, but first make sure the charger output says 54.6v.

 

[Moparopkop]

 

[Nealh]

One hasn't come back yet with a charger output voltage.
The 50E is a good cell so one likely if only seeing 53.6v needs to speak to the vendor, as it is 1v short. To most 1v might not appear to be an issue, it does mean that somehwere something is not right which one shouldn't be pleased with.

 

[Moparopkop]

One hasn't come back yet with a charger output voltage.
The 50E is a good cell so one likely if only seeing 53.6v needs to speak to the vendor, as it is 1v short. To most 1v might not appear to be an issue, it does mean that somehwere something is not right which one shouldn't be pleased with.

Just tested there and it went to 13 then just flickering around randomly at low numbers.. have a video but its saying to large to send....

 

[Moparopkop]

Just tested there and it went to 13 then just flickering around randomly at low numbers.. have a video but its saying to large to send....