OK - so what am I doing wrong now?

Another weeks solid work on this bike and I'm still baffled

So, I've wired my 2 36v batteries up in serial and connected everything up to the controller -

I have a couple of obvious problems ...

Firstly the batteries - I've charged them both fully and one is giving out 40V, the other is giving out 22.8V, when I connect them in serial I get 57.6V through the new PING BMSes

The batteries have been sat in my garage for over a year now in a mixed state of charge/discharge - my newer battery didn't show as charging when I connected it to the charger (the LED stayed green) - my older battery (the one which is now giving out 22.8V) took charge overnight.

Secondly the Cycle Analyst - the first time I connected it showed "The cycle analyst version 2.0" on the display for less than a second then the screen went blank - the backlight remains on but that's all I have - if I turn it on now I just get the backlight

I've wired up the various components as follows :

3 speed switch (as supplied by Geoff57) : orange-orange, brown-brown, yellow-yellow
e-brake: not connected (open) as I presume the only way to know which is the right way to wire it is to try it! - I have got the reed switch mounted and operating, I've just not connected it.
speed sensor - not connected (open)
throttle plugs connected as designed by Geoff57

I wired phase and hall as per recommended settings for infineon-bafang (I've got a 5A fuse inline with the battery) and got nothing at all.
I then went through the whole spreadsheet of possible hall/phase settings and got nothing at all - I had my meter inline with the negative feed from the battery and got an unswerving 0.01A through all the testing positions.

So I'm stuck again! is my 57.6V tripping the LVC on the controller? If so how do I get my batteries back to fitness?
Is the lack of an e-brake connection stopping the controller from working?

oddjones said:

Another weeks solid work on this bike and I'm still baffled

So, I've wired my 2 36v batteries up in serial and connected everything up to the controller -

I have a couple of obvious problems ...

Firstly the batteries - I've charged them both fully and one is giving out 40V, the other is giving out 22.8V, when I connect them in serial I get 57.6V through the new PING BMSes
?

Click to expand...

do not proceed until your 2nd 36v pack measures at least 38 v. Not only is the voltage wrong, but in series it affects the available current and power.

Nothing is predictable when your available power is wrong; fix that pack, know exactly what is wrong with it, or convert it to a different voltage. this might cause other things to clear up, either by going away, or, by having fewer choices as to the cause.

d

I agree. The battery is problem 1. After that is sorted out, other things can be worked on. Chances are the 22v battery is toast, surely some cells are way below 2v in it. Using the bms leads, or the place where they go to as they enter the bms, check each one with a voltmeter, keeping one lead on the first wire, then moving the other lead of the voltmeter down the row. cell one will be the actual voltage, cell 2 will be the actual voltage after subtracting the voltage of cell one, and so on.

Unfortunately, I bet you have some dead cells in there. Sometimes one that is above 2v can be tickled back to life with a 3.5v charger like a phone charger.

Took the 'poorly" battery out of series after talking with Geoff57 - the bike works just fine as a 36V - going to have to have a think about this other battery though as would still like that extra speed.

Does anybody else have experience of LiFePO4 batteries "going off" after a significant period of dormancy? the batteries have been unused for over 18 months and uncharged in the meantime. One has never been used in anger (this one is fine) the one which had been charged and discharged a few times is now only reporting 22V.

Geoff seemed to think that the battery may well be junk - but if it's still giving out 22v then can it not still be used? Is there any way to recondition it? (It cost me a frightful amount of money to just throw away)

I was wondering whether there'd be any benefit in bypassing the LVC circuit in the BMS and just adding whatever the battery does have to give to the other one - surely 50 odd volts is better than 36?

Perhaps I'm showing naivety here - would this possibly damage my other, good battery?

(I have an infineon controller with an "Any Voltage" fix - the LVC shouldn't kick in on that until 29v or so)

- sorry, did start writing this post before your posts Dogman/deardancer - but thought it was still pertinent

What can happen is either the bms or tiny trickle short can discharge the battery to death without the bms being able to stop it. So 18 months without topping it off likely killed cells. The thing isn't going to charge right unless it's fixed or replaced, trying to use it wouldn't last long at all. Using it in the condition it's in will only make it worse. Unfortunately this problem is designed into the bms, but check the voltage on the individual cells , maybe you get lucky and they are all above 2v and can be brought up again with some carfull charging.

You need to check the battery at the parallel cell level. You can get to tabs to measure the individual voltages by disconnecting the BMS plug. You won't know much until you check each pack of cells.