Charger for ping battery and BMS replacement

[bikezen]

Hi all,

I've just finished replacing my BMS card on my 36V 20AH Ping battery. Ping was pretty darned helpful through the whole process given we were emailing across half the planet and two languages.

I had taken my battery out of the case and when putting it back gotten a small spark when I was plugging things together. After that it wouldn't charge.

Through countless emails, Ping guided me to test the battery until we had determined the BMS was bad. Probably fried a chip on it. He sent me another and I soldered one cable into place.

All went pretty well, except for that one detail. Ping also sent me a charger replacement. The new one looked it was not as robust as the old one but Ping wanted the old one back along with the fried BMS so I sent it off.

The new charger worked for a few rides. Now it just sits there with a green LED and doesn't start charging. I've notified Ping but am thinking perhaps I should get a more robust charger. Does anyone have any suggestions as to a good model?

 

[dogman dan]

Check your connectors, the green light will stay green if there is a break in the connection anywhere. So that could be on the bms, the plugs, or the wire where it solders to the charger board. I bet that is your problem. I like my soneil, it has the pot inside to tweak it to the voltage of lifepo4. If you have an sla charger of the same nominal voltage you can use it for awhile.

 

[bikezen]

I've removed the battery so there's no connectors except one Anderson powerpole on the negative charging wire.

I get 45V from the charger when there's no battery on it. The battery reads 39V. I've got the charger going direct to the battery with no connectors intervening. Still no change.

Perhaps I should get a Soneil just to try it out and see if it works.

Todd

 

[dogman dan]

Well if the charger is putting out volts, it's not so likely to be that. Got any sla's around you could try the charger on to see if it still acts the same? Maybe it's a bms problem if the charger works. You could try bypassing the bms to see if it charges then. The bms won't be needed till the end of the charge so it won't hurt the battery.

 

[dnmun]

it is possible the battery is so discharged that it has not pushed the cell voltage up over the (39/12)V point yet. keep charging and measure the voltage across each cell during the charge, but don't leave it unattended, since the cells could suddenly climb to 3.9-4V which you don't wanna go beyond. mr ping makes good BMS's too, so don't assume it is bad yet if your pack will still take a charge. can you run the charger through a wattsup meter or do you have an ammeter scale on a voltmeter so you can keep track of the current?

 

[dogman dan]

I think what he is saying is the battery won't start charging, as in the charger says it is charged, when he knows it is not fully charged. That is why I suspect a break in the circuit somewhere, in the charger, in a plug, or in a connection in the bms. The green light will be on just the same with the battery disconnected.

 

[grimbasement]

I'm going to piggy back a question onto this topic. It applies because I have the same issue with my charger as well... always green. I'm going to send Ping an email too but what were some of the things you had to do to test your BMS?

I have only used the battery minimally so the initial charge is still there


Here's the quote from my other thread.

Status update. I ordered a new hub motor and one of the BMC "upgraded" controllers and was really excited about getting the bike put back together. But it is still very dead. I'm wondering if I blew my BCS on my Ping pack. I tested the battery with a multimeter and it read normal voltage but when I hook up the battery to either the controller or the CA I get nothing, no spark, no LEDs on the throttle, tried bypassing the CA... nothing.

 

[dnmun]

no reason not to piggy back, in fact maybe it would be good if there was a utube little lecture on the BMS and pack. it helps to just see the stuff and have people kinda just go through the normal procedure.

anyway, just was reading what bikezen said at the start about soldering one wire. seems like you should have to solder at least 2 wires, maybe 3 to the new BMS.

1. charger input
2. battery pack negative
3. negative wire from controller
can you show us in a picture where you soldered and where the wires run?

grim may not have discharged the pack enuff for it to allow charge current in through the charger FET on the BMS. the BMS logic turns off the current path for charging when the pack reaches total charge, to protect it from overcharging. that is the little charging FET over on the side next to the charger - through hole on the pcb. you can even follow the logic trace that drives the gate over to the 16 pin package where the comparators live.