ping battery cut off problem

[lifepo4ever]

hi again everybody,

so my question is what can happen to my battery (36v ping )or controller if i accidentally plug the blue wire to my controller ?
since 2 week now i have problem with battery cut off . even with the new bms ping send to me yesterday i have the same problem
my battery charger is working, i mesure it with a multimeter and i got 45.5 volts (but take fews hour to balance)

the problem is very weird because i can not ride my bike more then 10 minutes at full trottle and after the battery
cut at 36.6 volts i don't know if is my battery the problem or the controller (40 amp 72 volt)

maybe is a dead cell in the pack but how can check this? or maybe the controller ?

can someone can tell me how to do this thank you

i forgot to say i have this problem since i plug the wrong wire (blue)

[dogman]

A little more info would be helpfull. Which wire you put where, when? Colors may not be the same on all batteries, so identify which one by what it is supposed to do. Most pings have 3 wires, a usually red + wire that connects to both charger and controller, and two negative wires, one fat one to the controller and one skinny one to the charger. If you discharged through the negative charge wire, something cooked wouldn't suprise me.

Which battery is this, don't you have a big one and a small one? And I always need reminding what motor you are running too. If I have this straight, you switched the wires accidentally, and cooked a bms, but still have the problem with a new bms?

To test the cells individually, you start on one end of the bms plug, and work your way through the wires one by one, leaving one probe on the first wire. So reading ought to be something like 3.5, 7, 10.5 etc. doing the math will give you each cells individual voltage. A dead cell group could sure cause the problem you describe. If one cell group is only a 2 ah cell now, you would run the pack dead in 2 ah, regardless of the rest of the packs capacity.

[lifepo4ever]

ya i have the same problem with the new bms

my set up:

406 motor

40 amp analogic controller 36- 72 volt crystalyte

36 v 20 ah version 2.0

blue wire for charging

red positive wire

black discharge wire

[lifepo4ever]

my last ride was today and run my bike for 18 minute and consume 3.5 ah on my battery pack and then cut off and everytime i try to ride again at load (sit on the bike ) the motor cut but if i just lift the wheel it will spin with out problem

[dogman]

Wow. That sounds grim. Did the bike run with the negative wire connected? and how far did you ride? If that was done, you could have overdischarged the cells since the bms would be not going though protective circuits when discharging through the charge negative. Time to start checking cells. You can also have a problem if a bms wire got disconnected inside the pack so you will want to carefully peel some tape off the top of the pack, exposing a cardboard cover that can be removed, revealing the soldered connections. What a bummer man! Even when I ride my pack to cutoff, I still have close to 40v in there so it sounds like your pack is pretty unbalanced now. Dead cells are definitely a possibility.

[lifepo4ever]

yeah my last ride was with the new bms and the negative wire (black) the good one but still have the same problem

what happening 2 week ago i was riding my bike with the charging wire (negative blue ) for 10 minute

since that something happen

[lifepo4ever]

here is my reading from the multi meter from the tiny wire cable plug from the battery :

on cycle analyst is read 38.9 volts with the black and red

and with the blue (charging lead) and red i have 40.8 volts

if i disconnect the plug with the 12 wire i measured total 35.9 volts

3.4/6.8/10.2/13.7/16.2/19.6/22.6/25.8/29.2/32.6/35.9

i do some math and there one cell is at 2.5v and a other one at 3 v and the last one 3.2 v

so 2.5 volt is the dead cells?

all others cells are 3.4 and 3.5

[dogman]

If it's a v2 pack then you have 5 pouches paralell connected in each cell group, and 12 cell groups in a 36v pack. So it is possible that the weak ones have a dead pouch or several dead pouches in them. Untill you have the things unsoldered and seperated into individual pouches on the suspect cells, I don't know how to tell which ones are the bad ones. Don't despair though, if the individual pouches haven't fallen below 2 volts then they may be saveable. If you have a 3.5 or 4 volt power supply, you could try charging up the weak cell groups, If not, then just put it on the charger for a really long long time and see if any come up. But chances are, your pack is pretty useless till you get some new pouches from ping. What a bummer. There are some theads about broken pings that have how to replace cells info. I'm not sure if it is in the tech section yet, but I'd look there first, and then in threads that complain about a ping.

[lifepo4ever]

thank you dogman what i am doing right now is a full charge again to see what happen and once i finish to charge it i will post the result in this tread

[dnmun]

sounds like the controller was damaged if you have trouble after replacing the BMS.

when you discharged the pack through the charging FET, it may have allowed some current to get to the cells, but they would have been isolated by circuitry and the optoisolators so i can't see how that would have damaged the cells.

how did you charge it originally? through the black wire that normally goes to the controller?

i don't think your pack is bad, but i don't know how the controller coulda been damaged.

once you charge it up, and know for certain that all the cells are up to 3.7V, then try running without the BMS and see if you can go as far. it could be that the controller has a higher LVC now or maybe that was what ended up damaged when you ran the current backwards through the charging FET, but who knows?

[lifepo4ever]

so here my last charge of my 36 v 20 ah pack :

3.7/7.2/10.6/14.0/17.3/20.6/23.9/27.3/30.7/34.2/37.6 so as you can see i got 3.3 on some cell and 3.4

better but again if i go ride the bike it will cut after 10-15 minute at full trottle and before i was able to run 25mph on flat
and now i get 22-23 mph

i can try to run the pack without the bms but its sound risky

the battery consume 3-4 amp sometime 2 amp and cut after

[lifepo4ever]

i always charge with the negative blue wire and the positive

there a negative black for the discharge and the positive are both connected to the molded shunt to the controller

this shunt handle 45 amps and 100 peak but connected between the batery and the controller maybe if the resistor fail

it can be the problem because what i see on my CA i got peak of 54 amps and my controller is rated to 40 amps i don't

know why the thing i know he is analog and i can not program my CA so i can not i can not set the cut off

[Yesa-battery]

Possible the BMS can not hold the current,

your controller is 40A, if BMS cannot hold 40A constant current, it will cut off.

[dogman]

I don't think it's quite that simple, a 406 shouldn't be pulling 40 amps continuous regardless of the controller. With a 5303 that would make some sense. I think he needs to test the bike with a different battery, confirm that there is or isn't a controller problem. Then if the bike works, we can dig into what is going on with the battery. It could even be a defect in the new bms. I once spent $1000 trying to find a problem in a truck. It turned out to be one of the NEW sparkplugs. It can happen.

[GGoodrum]

Sounds to me like maybe some of the cells in the weak group might have disconnected somehow. That would not only mean that the capacity for that block has been reduced, it would also mean that the effective "C" rating for the whole pack is reduced as well. The would mean you are going to get a lot more voltage sag, under your 40-50A load, enough to trip the LVC function way too soon. This would also explain why that one block of cells is getting so out-of-balance with each cycle.

-- Gary