Help! E-Plus Mantra Electrical Issue - Help Please !

[Nealh]

e bike battery cells are rendered useless once they fall below 80% of the max charge rate, once this occurs the voltage just simply collapses.
The indications of cell ageing are the loss of ability to hold a decent charge of 4.15 - 4.2v, the causes of cell ageing are over discharge or over charging by to much current, high internal resistance or simply past their life cycle.

Take my wireless bike computer it stopped working the other day although the computer head still turned on no speed registered, I changed both of the 3v cr2032 batteries.
Brand new they hold 3.15v spent they are at 2.85v and only fit for recycling.

 

[chris301up]

It's simple maths, 36v has more voltage then 24v but the maths are exactly the same, one divides the voltage by the cell group numbers.

24v is 7 cell groups in series aka as 7s/24v, each cell group has max voltage of 4.2v. A max charge is 29.4v so a max charge of 27.2v divided by 7 = 3.88v = a defective or knackered battery.
I would be concerned if a 24v battery didn't charge to 28.7v let alone a poorly 27.2v.

36v is 10 cell groups in series so 10s, again each cell group is 4.2v max.
44v is 12 cell groups, 48v is 13 cell groups etc,etc.

I think I've got the gist of it. Not so simple for me I'm afraid.

Just an update. I haven't had a lot of spare time but I've just recharged the battery and it now reads a steady 28.8 volts. I'm thinking of discharging the battery completely, doing another recharge and go from there. Not sure how I am going to discharge the battery though, unless I prop the bike up somehow and keep turning the pedals.

Is there anywhere I could send the battery to for inspection and testing?

 

[chris301up]

Just an update guys. Had a bit of spare time today and popped the bike in the kitchen for a few hours in an attempt to remove any residual damp. Following a full recharge the battery holds a steady charge of 28.8 volts now. I have noticed however that once I insert the battery and switch on, the displayer, after a few seconds, dims and repeats this process a couple of times, then comes back on fully. This 'cycle' continues to repeat this. The battery continues to show a full charge. Rather than damp, does anyone perhaps suspect the controller may be faulty?

 

[Nealh]

The dimming I think is still down to damp affecting the pcb, electronics just don't like moisture on the circuit board. Unless a wire comes a drift (not unknown) or it gets smashed/damaged they rarely go wrong apart from damp.

 

[Nealh]

28.8v isn't too shabby but still a wee low , if you can get 29.05v then that would be better.

 

[chris301up]

The dimming I think is still down to damp affecting the pcb, electronics just don't like moisture on the circuit board. Unless a wire comes a drift (not unknown) or it gets smashed/damaged they rarely go wrong apart from damp.

Ok. I understand what you're saying. I was hoping not to have to strip everything down but it looks like I'll have no choice but to go through all ancillary components individually, dry them out, and go from there. I'm not convinced the battery is at fault so will leave that until the last item. Thanks

 

[Nealh]

The led is I believe where the issue stems from.

 

[chris301up]

28.8v isn't too shabby but still a wee low , if you can get 29.05v then that would be better.

Hi. I'm going to try to completely discharge it and the recharge and see if that improves the situation?

 

[chris301up]

The led is I believe where the issue stems from.

Yes. That is what I'm thinking. I'll take a look at that first and go from there

 

[Nealh]

The battery may well likely balance out a bit with a few charge/discharges, the inactivity from use and the cold it will have likely self discharged a little (one cell group has done so often the first or last one). Used often and they tend to remain balanced, if the battery is kept out side it might be better indoors.

 

[Guilherme.ghbds]

Hello, my ebike use same system than yours and now I'm with same problem, how do you fix it ?

 

[Guilherme.ghbds]

Yes. That is what I'm thinking. I'll take a look at that first and go from there

I Really would like to know if u sover that problem

 

[cyclebuddy]

I Really would like to know if u sover that problem

If you search for and follow the OP's subsequent threads, you'll read that (although he did re-cell his battery) he dried his bike out and that seems to have corrected the problem(s) he was having with the display.