Have I killed my lifepo4 batteries

[bds70]

I had an internal Victron mppt fire last week. Supplier gave me a new one. Didn't tell me it was a 12/24v charger and default setting was 24v.

I failed to check that setting and connected my 2 X 340ah batteries. A day later the 12v appliances starting acting weird, and I immediately went to the solar box, checking the battery charge. Blow me down it was 27v.

I 8mmediately switched off the PV input and put all my 240v appliances on full to draw the voltage down as quickly as I could.

Having set the MPPT correctly the batteries seem to be okay. But once of them has a clear small bulge on top.

Should I discard that battery for safety or will it be ok to continue to use it?

 

[AntronX]

Pics? Did you use BMS? 12V system?

 

[400bird]

I had an internal Victron mppt fire last week.

? That's bad!

Supplier gave me a new one.

That's good! ?

Didn't tell me it was a 12/24v charger and default setting was 24v.

I failed to check that setting and connected my 2 X 340ah batteries. A day later the 12v appliances starting acting weird, and I immediately went to the solar box, checking the battery charge. Blow me down it was 27v.

I 8mmediately switched off the PV input and put all my 240v appliances on full to draw the voltage down as quickly as I could.

Having set the MPPT correctly the batteries seem to be okay. But once of them has a clear small bulge on top.

Should I discard that battery for safety or will it be ok to continue to use it?

The real question is did the BMS in your batteries disconnect to protect themselves? If so, the batteries are probably fine. If not, yes those BMSs are trash. If you don't have a BMS...

 

[bds70]

? That's bad!

That's good! ?

The real question is did the BMS in your batteries disconnect to protect themselves? If so, the batteries are probably fine. If not, yes those BMSs are trash. If you don't have a BMS...

That's what's confusing me. My impression was that the Daly BMS should have prevented the overcharge yet didn't. Was that because it was incoming at 24v so the BMS decided to charge to where a normal 24v battery would? Don't know if that makes sense.

 

[400bird]

If the BMSs did disconnect, the charge controller can continue to output and continue to increase voltage. Do your BMSs have Bluetooth or some other way to communicate with them and check fault logs?

Did you measure battery voltage after disconnecting the MPPT/solar?

 

[WindWizard]

If the BMSs did disconnect, the charge controller can continue to output and continue to increase voltage

I am not sure what you mean by this. On my system if the BMS has a Cell overvoltage then it disconnects the connection from the shunt to the batteries. The Charge Controllers are connected to the shunt, so there will not be any further charge going into the Cells.

 

[400bird]

I am not sure what you mean by this. On my system if the BMS has a Cell overvoltage then it disconnects the connection from the shunt to the batteries. The Charge Controllers are connected to the shunt, so there will not be any further charge going into the Cells.

Output to the loads, not charging the battery. I can clarify more if that doesn't explain what I meant.

 

[WindWizard]

Output to the loads, not charging the battery. I can clarify more if that doesn't explain what I meant.

Okay that makes more sense. The Charge Controllers still supply power to the loads. Got it.

 

[400bird]

I definitely left that part out in my initial post, thanks for calling it out.

 

[WindWizard]

That's what's confusing me. My impression was that the Daly BMS should have prevented the overcharge yet didn't. Was that because it was incoming at 24v so the BMS decided to charge to where a normal 24v battery would? Don't know if that makes sense.

The BMS should have prevented your Cells from charging up to 24 volts. Without any data it is hard to speculate exactly what the damage was. I think that it would help to have a clearer understanding on exactly what your system entails. We can assume it is a 12-volt system. Also assume that you have some DIY Cells and a Daly BMS. Maybe you have an Inverter. The Inverter was probably not happy running at 24 volts if it is a 12 volt Inverter.

There is a lot of guess work that I am making so it would be helpful to have you describe your system and a few pictures.

 

[sunshine_eggo]

The only thing I'm worried about is 12V devices that might be destroyed by 27V.

Supplier gave you a used or at least one that had been run on a test bench and did not properly set to factory defaults.

That said, it's kinda nuts to put a charger on a system and not confirm it's set properly.

 

[bds70]

Pics? Did you use BMS? 12V system?

Daly BMS built in. Not sure what U mean by 12v system, but yes it's a 12v. RV system been running for 7 yrs until the bloody fire.

Pics show the bulge. Current voltage is 13.58 which is normal for this time of day.

 

[cs1234]

Those bulging battery cases are scary.

 

[AntronX]

Pics show the bulge.

That sealed plastic battery case looks pressurized with gas. Battery cells vented gas inside the case. Probably no longer safe to use, there could be a risk of fire.

 

[WindWizard]

Those bulging battery cases are scary.

Yes they look very bad. I would certainly investigate and find out what is causing the bulge. I would be afraid of a potential fire hazard.

 

[WindWizard]

Victron Charge Controllers are very easy to set up and use. Just download the Victron App on your phone and then verify the settings that you want to use including the Battery Voltage. That is the first thing that you should do with it. I would never rely on the Supplier to setup anything on my system. Solar is one of those things where you need to have everything setup correctly. There is too much potential for mishap.

 

[sunshine_eggo]

If that swelling followed the charging and wasn't a result of the fire, it's almost certain the BMS failed.

 

[bds70]

The BMS should have prevented your Cells from charging up to 24 volts. Without any data it is hard to speculate exactly what the damage was. I think that it would help to have a clearer understanding on exactly what your system entails. We can assume it is a 12-volt system. Also assume that you have some DIY Cells and a Daly BMS. Maybe you have an Inverter. The Inverter was probably not happy running at 24 volts if it is a 12 volt Inverter.

There is a lot of guess work that I am making so it would be helpful to have you describe your system and a few pictures.

These are manufactured 340ah Giant 12v batteries with Daly smart BMS.

The MPPT charge controller (not inverters) is a Victron smart solar 150-85 brand new. Incorrectly set to battery type 24v

If the BMSs did disconnect, the charge controller can continue to output and continue to increase voltage. Do your BMSs have Bluetooth or some other way to communicate with them and check fault logs?

Did you measure battery voltage after disconnecting the MPPT/solar?

I do have the Smart BMS App on my phone but it doesn't really show much.

Measured before disconnecting. I think I did it again after disconnecting, but can't swear to it.

 

[bds70]

Victron Charge Controllers are very easy to set up and use. Just download the Victron App on your phone and then verify the settings that you want to use including the Battery Voltage. That is the first thing that you should do with it. I would never rely on the Supplier to setup anything on my system. Solar is one of those things where you need to have everything setup correctly. There is too much potential for mishap.

The only thing I'm worried about is 12V devices that might be destroyed by 27V.

Supplier gave you a used or at least one that had been run on a test bench and did not properly set to factory defaults.

That said, it's kinda nuts to put a charger on a system and not confirm it's set properly.

Completely agree with you. It was my bad, not the suppliers. A lesson learnt.

 

[Checkthisout]

Well, what are the current overvolt cell settings on the Daly?

I would guess they are at 4.2 volts and the BMS didn't trip until then.