My 2nd Ping Battery Goes Pop Because BMS LVC Failure

[el_walto]

I was about to sell off my 2009 15Ah 48V Ping V1 battery for cheap to a keener i met on the street, so I took it for a full test ride to make sure it still had an OK amount of capacity.

Tested each cell voltage after fully charge and it was in check.

After Draining 10Ah, a couple cell groups were a little out, but they all seemed a bit above cutoff.

I decided I'd ride it to cutoff to make sure things were working correctly for the newbie buyer. At 13Ah I was getting really suspicious thinking it should be cutting out by now, seemed to be such a low voltage. I decided to keep going until cutoff since i was selling this thing without a Cycle Analyst. Battery never cutoff. At 14.5Ah out of the 2009 battery, I decided to stop and have a look.

I opened the ammo box up to the stinky stench of electrolyte, the sides of the ammo can were bulging. 1 cell group at 0v, another cell group at 1.1volts etc. Some cell groups were fine.

No flames or smoke. Managed to pull battery out of ammo box, cut a bit of tape off and the battery pushed itself apart becoming double the size due to inflated cells. Inflated cells were hot. Not wanting an embarrassing fire in the front yard, I tossed the bad cells in large bucket full of water. Added some salt so they should completely discharge themselves to later be trashed.

This is the second ping battery I've had fail in a month because the LVC did not trip. V1 and V2 BMS. No i don't have a precharge resistor. Did this kill my LVC on my BMS?

I no longer trust these batteries at all, will not store any sort of lithium in my house. Quite possibly could of had flaming bike ammo box if i kept riding for another minute or two.

Will post pictures later today.

 

[dnmun]

did all of them swell up or just the ones that drained to 0V?

is this the old v1 ping pack with the 4Ah pouches or the old v1 with the 5Ah pouches with the narrow tabs?

did any of the cells survive after you soaked it in the water? i woulda bot them from you like i said.

i still need more pouches to repair these packs i have here now.

 

[el_walto]

 

[dnmun]

those are the really old 4Ah pouches.

looks like it is now a 12S instead. if you don't wanna sell the carcass i can send you a 12S BMS and sense wire cable. and i even have some 36V chargers.

what is the voltage on the other cells? did they all drop really low together or just the bottom cells that supply the BMS with the circuit current?

i have never had a signalab fail to cut off at the LVC. i thought this was kinda impossible.

 

[dogman dan]

That bites. I no longer trust a ping bms so much either. I got a suprise the other day when mine tripped on the 48v 15 ah v2 at about 10.5 ah. I knew it would be drained early, and I was taking a chance, but I just sort of expected it to go at about 12 ah. I just put a 5304 on the longtail, and knew running even a 20 amp controller with my ping was pushing things. It pulls 1200w for a long time now.

Fortunately my lvc still works. I wasn't watching the CA voltage close enough, since it did suprise me. I know at 48v under load it's coming. Wish Justin would put in a loud alarm in the CA you could set to a voltage of your choice. Tell you when to wake up and start paying attention.

If it was that easy to do, you could buy one at HK. Everything seems to come set to a certain voltage in the lvc alarms, and made for lico. I'd like adjustable so I could set it for lipo one day, pingbattery the next. Up to 100v of course.

I must also have a weak cell by now, but last time I rode to trip it was 14 ah. Time to finally wire my ping for cellog 8's. I'm planning to run the bike on 12s lipo now, or paralell 14s with the ping.

 

[dnmun]

i am using a used (either nick or chris) v1 signalab now to test this new battery i just built so i could compare it to the headway BMS for balancing and i discovered that it also has this problem with the opto isolators that manifests itself as a large voltage drop across the transistor that makes the connection for the circuit current to the gate on the charging mosfet.

this results in the voltage on the gate of the charging mosfet to drop down to 5V, way low for the mosfet, but enuff to work. lower voltage than this is where it doesn't fully turn on.

i think this why the charging mosfet gets so hot sometimes from running with a low gate voltage which puts the mosfet in the transistion region, and i think it is why ping changed the design of the HVC circuit in the v2.5 signalab.

this is not the first time i have noticed this problem either and someone else had an identical problem and replaced some of the optos so i will try that when my package of 817B optos arrives from hong kong.

this should not have been the same problem you have with the LVC line failing to cause the 14 pin comparator down at the bottom to cut off the gate voltage to the output mosfets. that is so solid usually since the voltage is supplied directly from Vcc and does not go through the optos.

now i am gonna watch it like a hawk. the gate voltage does climb though as the pack charges up from full discharge so it seems it would only be a problem initially when starting to recharge from fully a discharged state.

 

[dnmun]

so now i go look at the optos.

this may be your problem too, now that i see how it coulda failed.

i went and measured the voltage drop across all the optos after the battery got some charge back. turns out is only #16 that is over range.

so i examined closer, WTF, all the optos look like a truck ran over it, or maybe somebody left it in their tool box when the they went off road!! chris, does that ring a bell?

anyway, 3 or four of the outer row are pushed over and almost touched the other row, so i was pulling them up straight and i realized the the #16 was crushed from on top and is torqued and the lid is slanted, not level so i wonder if the led inside is affected or the transistor was damaged. so glad i got new ones coming.

if you have another 16S ping BMS sense wire harness on a battery that is providing current to their BMS, you could unplug that BMS and plug your bad BMS into that harness, tie the grounds together, and then test each of the opto isolators to see if they all work, and if the dead ones are on the channel that died. this could be a solution for the overheating charging fets too.

"NEW OPTOS" ,,,,in and out service, $19.99, tuesdays only.

 

[neptronix]

That's the problem with a BMS that drains power from a few cells.
It will eventually, over the long run, wear out that group of cells far faster.

Most pre-made packs are designed to do this.
And due to that, they last maybe half as long as they should.

Hence the nickname.. 'battery murdering system'

 

[dnmun]

ok now that the pack has charged up the voltage drops on each one are essentially all about .13V and i looked at #16 which would cycle between .13V and about .41V. as though the transistor or diode were trying to turn on and and stayed on holding it at .13V and then it just died, dropped to .41V as though the diode could not make the juice any more, and something happened to allow the transistor to turn on again and drive it back down to .13 before failing, over and over, the battery was on the charger and 'idling' at the balancing voltage of 58.4V and the cell was at 3.65 so no HVC signal should be generated, so this cycling of the transistor was not determined by the voltage of the cell. i wonder if the failure could be in the comparator and the driver inside the comparator is the bug. not enuff kick to turn on diode itself. if this continues after i swap out the opto, i may change the resistor on that comparator output to see if holding back on the current allows it stay on. does that makes sense electronic circuit wise?

now to figure how this coulda been related to walt.

 

[Jason27]

I just think it's ironic how some people on this forum speak so highly of ping, yet if you. search the threads on this forum you'll read about lots of people with problems with their ping batteries. I guess you get what you pay for.

I got burned by a supplier in China once before.. never again.

 

[dnmun]

i actually do follow all the posts on here about the ping BMSs and also about the batteries themselves. in almost every instance where someone has made a wild thread title, there was never any substantial evidence of failure. i find that people are overwhelmed with the seeming complicated nature of the BMS so when they have problems then the BMS gets blamed.

there was even a guy who got a ping battery last year whose pack worked ok initially by his own evidence, and then posted up a nasty review about the ping saying it was built with second hand parts and did not work from the start. but in fact i felt he had broken it after he got it when he cut it open "to fix it" and tore the sense wire off the tab, then accused ping of sending him faulty product.

there are a number of claims of defective BMS because the led stayed lit all the way down to nothing, but the lowest voltage reported by them was only 3.61V and the leds stay lit until 3.6V.

in short, i feel most of the claims made against ping were due to newbie mistakes and lack of understanding.

but when ping agrees to replace the part without question, it just reinforces their view that they were right to begin with.

that is currently the idea about cargo tom's chargers. that ping was responsible for the defective charger that was manufactured by kingpan. it is now clear that the new design of the universal input charger is vulnerable to a failure to use a grounded 3 prong plug and these chargers have been failing regularly but ping did not know why. he was genuinely glad i had helped find the cause of these failures, made me feel like i had helped.

after i discussed this with him, he immediately has taken action to prevent this from being a problem for others too and he is gonna make kingpan respond to the failure of these new type chargers so it is this proactive interest in his clients that made him the name every other copycat uses to sell their batteries.

 

[neptronix]

I just think it's ironic how some people on this forum speak so highly of ping, yet if you. search the threads on this forum you'll read about lots of people with problems with their ping batteries. I guess you get what you pay for.

Have you seen one where ping has left the buyer out in the cold with no solution to a problem?
GJ making it sound like another piece of China trash though, may get a raise from the company that hired you to astroturf this forum :lol:

 

[dogman dan]

In this case, v1 packs. That makes them packs that lasted a lot more than one year. One year of good use from a ping, and it's all free after that, soooo.

I left my v1 ping plugged into the controller, with the controller on, when I arrived home with west nile virus. Two weeks later, I notice that the pack is all puffed to hell. Seems like the bms should have tripped, but I didn't go and blame ping because I killed my 3.5year old pack. Looking at the bms, it did have a fried looking fet, but I think that one is the charging fet. In the pic posted above, the one not in a row with the others. It got hot enough to seperate from the board at the back.