Lifepo4 dead HELP

[D71]

Im charging it up now to try something so once the charger shuts off ill check the pin.

Im charging it up now to try something so once the charger shuts off ill check the pins

??? The cell - pin with suspected problem might be the one with red positive lead. Each step over from common negative is additional cell voltages. Next step is look at pcb for something missing as in blown off - compare to Will’s screen shot of the board and components. Sometimes something missing is not obvious.… except 2 solder ends nothing between them again compare to screen shot picture of Will’s

backside of bms board might show something too

 

[Texas-Mark]

I think you damaged this when you were incorrectly checking total cell voltage and only going across 3 cells for reported ~10. Volts
vs going across all 4 cells

He said all of the problems started after making some setting changes and before ever removing the sense cable. Since the BMS is still reading all four cell individual voltages, that is an indicator there is nothing wrong with the harness. Seems like something in the firmware got messed up.

When you posted your picture you were measuring the battery voltage across 3 cells with the meter…. that would be 10 volts.
when you read the plug it reported correct voltage. If it is not the plug female pin spread then bms - software.

But it is the BMS that says it is only around 10 volts because it thinks it is a 3 cell battery, not 4 cell.

 

[D71]

He said all of the problems started after making some setting changes and before ever removing the sense cable. since the BMS is still reading all four cell individual voltages, that is an indicator there is nothing wrong with the harness. Something in the firmware got messed up.


But it is the BMS that says it is only around 10 volts because it thinks it is a 3 cell battery, not 4 cell.

I am only asking him to look at the connector end of the female pins now. Does it hurt? Do you understand why?. If that is not it then as stated “happened after his software adjustments and charging” . he admits “probably caused it“ which is honest. I already think he popped the bms…. But better to complete visuals…. Before spend money.


Again
looking just takes but a second or 2. The old school of hard knocks sucks. ??? i’ve already guessed bms is damaged or software… it would suck to find it was a pin wallowed out….. the wiring will in fact read good but the spring tension inside female pin will not mate to the bms male pin. Hotdog down the hallway. The big tip of meter lead is much bigger then the female pin.…. Da ho gets stretched never connects with another male unless big ol tippy. He obvious did not remove sealant to check from back side plug…. Neither would I. Look at picture. See size of those holes. Very important with happy or unhappy relationship. ?

 

[Texas-Mark]

I am only asking him to look at the connector end of the female pins now. Does it hurt? Do you understand why?.

Yes I understand, but he already had that connector off a few times to check the harness and to try and restart the BMS. If there was a problem with that connector, the BMS would not be reporting the correct voltages for all 4 individual cells. And since the issue started before even touching it, doubtful it just magically went bad.
Point being, pretty much every test has already been done over the last 6 pages of this thread.

 

[Mickie]

Currently charging. I think there is a way to make it work @Texas-Mark said with some adjustments to the low voltage and high voltage and pack voltage. I think the main issue would be pack voltage id need to set that very low but it seems the bms is still doing its job based off the cell voltages. So maybe i can keep using it until i can get a bms to replace it. I would set the over voltage lower than my other 3 batteries and the low voltage cut off higher than the other 3 battries and then there is still the charge controller and the inverter as redundancy so as to not cause this battery to over charge. What do u guys think?

 

[D71]

Currently charging. I think there is a way to make it work @Texas-Mark said with some adjustments to the low voltage and high voltage and pack voltage. I think the main issue would be pack voltage id need to set that very low but it seems the bms is still doing its job based off the cell voltages. So maybe i can keep using it until i can get a bms to replace it. I would set the over voltage lower than my other 3 batteries and the low voltage cut off higher than the other 3 battries and then there is still the charge controller and the inverter as redundancy so as to not cause this battery to over charge. What do u guys think?

Good luck

 

[D71]

Yes I understand, but he already had that connector off a few times to check the harness and to try and restart the BMS. If there was a problem with that connector, the BMS would not be reporting the correct voltages for all 4 individual cells. And since the issue started before even touching it, doubtful it just magically went bad.
Point being, pretty much every test has already been done over the last 6 pages of this thread.

If he got for say, the software to work now and destroyed the pin in the process of previous troubleshooting - it will never read the cell voltage again through the bms. The stretched female pin will create an open In the circuit…. at the plug. If that is the case He has compounded the problem by the look of the picture - by cramming the meter lead into the female pin of the plug To read the cell voltages…. That he posted about earlier. That is all am saying I have obviously failed to communicate. I have unfollowed this post Good luck.

 

[Texas-Mark]

If he got for say, the software to work now and destroyed the pin in the process of previous troubleshooting - it will never read the cell voltage again through the bms

But it is reading all 4 cells individually properly. The issue is the BMS thinks it's only a 3 cell battery and thus only adding up 3 cells for the total pack voltage. These two BMS readings contradict each other and that is why it seems most likely the BMS firmware is borked.

 

[Texas-Mark]

So maybe i can keep using it until i can get a bms to replace it. I would set the over voltage lower than my other 3 batteries and the low voltage cut off higher than the other 3 battries and then there is still the charge controller and the inverter as redundancy so as to not cause this battery to over charge. What do u guys think?

That will work as a temp band-aid as the cells will still be protected. But yes, a new BMS is probably the only real fix at this point.

Note: you would need to set the low voltage cutoff lower, not higher. Not sure how low you can set it, but for 3 cells it would be like around 7.5V

 

[Mickie]

That will work as a temp band-aid as the cells will still be protected. But yes, a new BMS is probably the only real fix at this point.

Note: you would need to set the low voltage cutoff lower, not higher. Not sure how low you can set it, but for 3 cells it would be like around 7.5V

Im gonna charge them up over the next few days and reconnet them in parallel to get them balanced and them ill hook them back up in 2s2p. I also have a powmr battery balancer so that will help keep the voltages close. Within 20mv of each other.

 

[Pim57]

Currently charging. I think there is a way to make it work @Texas-Mark said with some adjustments to the low voltage and high voltage and pack voltage. I think the main issue would be pack voltage id need to set that very low but it seems the bms is still doing its job based off the cell voltages. So maybe i can keep using it until i can get a bms to replace it. I would set the over voltage lower than my other 3 batteries and the low voltage cut off higher than the other 3 battries and then there is still the charge controller and the inverter as redundancy so as to not cause this battery to over charge. What do u guys think?

That would be a good thing to do. Just configure the bms settings to a 3 string.
That way you can keep the bms as it will still protect you from over- and undercharging, cell under- overvoltage, temperature.

The only thing I can think off, is that even though the bms can measure cell #4 will it protect cell #4?

 

[Mickie]

I reconnected the battries today back into 2s2p and did some amount of discharge and charged and the charging stopped and i also tried charging the damaged battery by itself yesterday and it charged and stopped when it was supposed to so it seems its ok so far. It seems to be reading all 4 cells on a cell level its just not seeing 1 of the cells as a part of the pack. So i set the pack low voltage to 9v and left the rest.

 

[Mickie]

I reconnected the battries today back into 2s2p and did some amount of discharge and charged and the charging stopped and i also tried charging the damaged battery by itself yesterday and it charged and stopped when it was supposed to so it seems its ok so far. It seems to be reading all 4 cells on a cell level its just not seeing 1 of the cells as a part of the pack. So i set the pack low voltage to 9v and left the rest.

I also ordered an active balancer to balance the cells its not just thebad battery that needs balancing all 4 batteries do. So ill use that to balance them alto it seems that its gonna take a very long time to balance all of them but i can still use grid power while i balance them.

 

[Texas-Mark]

I would still put a new BMS on the shopping list at some point .

 

[Mickie]

I would still put a new BMS on the shopping list at some point .

I plan on buying another himassi battery and eventually getting a bms and use this one for a different setup. As i dont want to have mismatched bms in 1 battery bank.

 

[Texas-Mark]

As i dont want to have mismatched bms in 1 battery bank.

I get that. I have one different battery in my bank that uses a different app. Sort of a pain.

 

[Mickie]

I get that. I have one different battery in my bank that uses a different app. Sort of a pain.

Do they work well together tho? In terms of charging and cut off and being in sync?

 

[cs1234]

I plan on buying another himassi battery and eventually getting a bms and use this one for a different setup. As i dont want to have mismatched bms in 1 battery bank.

I have a bank of mismatched 12v lifepo4s, same amp hour amount, but different brands with different BMS's. They don't care or work any worse than the all the same brand banks I have going. Just make sure you keep them balanced if in series with a balancer, that's what has made mine work a bit more consistently with less issues.

 

[cs1234]

Do they work well together tho? In terms of charging and cut off and being in sync?

They wouldn't be synced up even if they were the same brand and bms. Each one is it's own unique snowflake with cells at different states of charge. They aren't talking to each other or helping each other out in any way.

They are like Surly.

 

[Mickie]

This is the bad battery in the pack it looks so weird in there, really frusting me but its actually at the same voltage as the rest of the batteries and currently all 4 are dischargingbat basically the same amps. Its just uncomfortable to look at tho.