Repairing Ping 60V BMS

[Speedfreke]

I have 3- 60V and 1- 72VPing BMS' all not-working properly. I think the 60V's - one light stays on all the time and the 72V may be the mosfet. I would like to have 1 60V repaired if there is somebody out there interested in exchange for the other BMS' and/or cash. I live in the Toronto area.

 

[heathyoung]

If the light stays on all the time, it means that the discharge transistor is stuck - or its driving TL431 is shorted. Easy to check.

I would fix for you but too far away on the other side of the world. Mind you postage is pretty cheap if slow is OK.

 

[Speedfreke]

I will consider your offer but I'd prefer to stay within N. America

 

[dnmun]

if you have the battery built already for the 20S BMS then you should put the BMS on the battery, start charging and then post up the voltages of each cell. you can check the voltages across the shunt resistors when the shunt transistor turns on to check their performance. have you ever done capacity test on the battery?

 

[Speedfreke]

The battery is working fine with a new bms. According to Ping a capacitor is the problem with the 60V bms'. Fixing these bms' is beyond my capabilities. I just want one of the 60V bms'fixed to keep as a spare. Since there are 3- 60V bms' some capable individual can repair 2 of them with parts from the third one and maybe even ffix the 72V one as well and keep them. I will pay for shipping both ways

 

[dnmun]

i did not ask if the battery was working. i asked if you could put the bad BMS on the battery in order to try to diagnose what is wrong. in case you have not noticed, if you cannot fix it, it is not gonna get fixed. if you cannot measure or test it yourself, why bother asking others?

 

[Speedfreke]

No, I can't mount them on the battery without a lot of trouble. If one of cells stays lit all the time it must be something wrong with the tiny gizmos on that corresponding cell and replacing that gizmo with a good one from the extra bms' should correct the problem. Ping said to use a meter to check which gizmo is giving an off-reading and replace it. Sorry, this was many months ago and I don't have the correspondance to give you more precise info.

 

[dnmun]

no, if one stays lit it does not mean there is anything wrong. it means the cell voltage has not dropped after charging. the led remains on down to 3.6V. from what you have said there doesn't appear to be anything wrong with it.

 

[Speedfreke]

It's the light corresponding to the last cell where the lead connects to the other half of the battery. I think that a poor anderson connection (which joins the 2 battery halves) has damaged that component on the bms. If I remember correctly the corresponding cell charged up properly but didn't discharge properly. Anyway, I replaced the bms and fixed the anderson and all works well.

 

[heathyoung]

That would make sense, it probably copped half the pack voltage across it. You could do as you said, turn two bad into one good. I'd be soldering that connector though (the anderson) or using something better.

 

[Speedfreke]

The pack originally came with humungous andersons joining the 2 halves. I think Ping does that so riders can separate the halves and mount them on both sides of a rear rack . That's why the thin wires joining the battery and bms are soooo long and inconvenient for someone who keeps the 2 halves together as one unit. But I don't think soldering the 2 thick wires together is an option as instructions say to separate the 2 when working on battery or bms.

 

[dnmun]

ok, i'll try. i was looking at the part that heath calls the 431 which is a voltage reference. but this one has 2R22 printed on it. so the shunt transistor is turned on by that device to make it work.

i can build a 20S battery from parts here to test it too, and i can hack my charger to the right voltage. it is set up for 22S pack now so i can use that.

do you have the 20S sense wire cables too? i have a few v1 and v2.5 BMSs here for parts too. what was wrong with the others? more mosfets shorted?

 

[Speedfreke]

The 3- 60V bms' have the 'light-on' problem in the same location on the board (approx. in middle) although one of those has a couple of condensors (or capacitors?) missing as a friend tried unsuccessfully to repair one. The 72V board has 1 or 2 burned out mosfets I don't remember, it's been a couple years. And yes I have several 20s wire units I will ship with the boards as well as well as for the 72V board. I need one 60V bms shipped back as a spare so there's no rush for it. I hope you can use the others. Ping said that checking the ohms? between the capacitors will reveal the faulty capacitor.? You can PM me as regard to your address and other particulars.

 

[dnmun]

i have all those parts on these other dead ones i have. biggest problem is making a test setup to figure out what is wrong.

 

[Speedfreke]

OK will ship tomorrow, good luck!

 

[dnmun]

fixed. the shunt transistor was turned on slightly. it was stuck at -1.38V between the base and emitter. normally when the shunt transistor turns on the base is driven all the way to about -3.8 or so because it is the full cell voltage that is pulling the base down through the comparator on the underside of the pcb.

speedfreke sent me two 20S v2.5 signalbs that had the led on constantly. both had the led lit on channel #11. after i built up a 20S pack from scraps, i measured all the base voltages and found out how it worked, and when the cell drops below the 3.60V level then the base is off and the voltage drop from the emitter is only about 10mV or less.

so i worked on the BMS that was dead first to expirement. i replaced the 5 pin comparator on the underside by desoldering the old one with solder wick and replacing it with one i swapped out of one of my parts BMSs. it worked right away. the led was off and the base was only about 10mV off the emitter.

so i worked on his good one next, figured i had it down pat since the first one had worked first time.

i replaced the comparator on the underside as i had with the first one, then plugged in the sense wires and it still had the same problem of the led being on all the time, and the base was stuck at -1.38 as before. so then i swapped out the shunt transistor, and it still did not fix it, the led was still lit and the base was at -1.38V.

so i decided to replace the comparator on the bottom again!!!! with another one from my parts BMS, and this time it worked!!! i am charging that cell up now since it had drained down with the led partially on. but i am fairly certain that was the problem so you will get your BMS back as soon as i can ship it.