Daly BMS let cell voltage drop to 1.5 Volts, are the cells now toast?

[Checkthisout]

So ongoing issues with this bms. The generator at the sight has failed and its winter so not enough charging.

Unfortunately I cannot make it out there until Friday night.

So as you can see, Discharge Mos is off but the bms shows a 70 amp charge even though no though no charging source is being supplied to the battery. The voltage readings are accurate.

 

[sunshine_eggo]

A gentle charge (.01C) until cells will hold 2.8V resting should recover them.

I would expect a near full recovery.

 

[Checkthisout]

A gentle charge (.01C) until cells will hold 2.8V resting should recover them.

I would expect a near full recovery.

Thank you!

 

[MisterSandals]

So ongoing issues with this bms.

Can you post a pic of the BMS parameter settings?

Does all the charge and discharge current go thru the BMS, including the generator start?
Happen to have a pic of the battery wiring?

 

[sunshine_eggo]

Thank you!

Meant to indicate that once they will hold 2.8V, you can charge normally.

I have 70-ish 40Ah CALB cells that were taken out of an aftermarket 10kWh plug-in-hybrid kit for the 04-09 Prius. The owner removed it from the car when sold and set it aside. Unfortunately, the balance boards on each cell drew them all down to 0.6V. A handful were loose and held > 3.2V.

Most of them recovered to ~60% SoH and were completely consistent with the loose cells (60% SoH). Many had notably reduced capacity and very high resistance. I would conclude this had more to do with abuse in the car than the discharge to 0.6V, OR both.

 

[Tomthumb62]

Unfortunately, the balance boards on each cell drew them all down to 0.6V.

You would think that a major car mfr would have designed balance boards that were designed to STOP balancing under say a certain voltage, say 2.0V, to avoid such a situation. But I know next to nothing about EV's, so perhaps overall designs are better across the board of different EV mfr's.

 

[HighDesertOffgrid]

Meant to indicate that once they will hold 2.8V, you can charge normally.

Just curious, did you charge to 2.8v with 2.8v cv and check them, or monitor a standard charger and stop, check, wait, check.

 

[Checkthisout]

Can you post a pic of the BMS parameter settings?

Yes.

Does all the charge and discharge current go thru the BMS.

Yes.

including the generator start?

No. Generator has its own isolated battery.

So 2 cables run from the battery to the multiplus and 2 other cables run from the battery to a couple of junction blocks. There is a 24-12 reducer here that floats a 12V batter and powers up my DC side stuff.

Happen to have a pic of the battery wiring?

Continuing from above, there is nothing bypassing the BMS.

In my limited experience with milivolt shunts, I would say the daly induces noise on its shunt when it shuts off the Charge or Discharge Mos and I can see that the discharge MOS is damaged or not manufactured properly.

Fresh screenshot, the MPPT is up and gassing up the battery. Rainy and cloudy so not much (that shunt reading is not correct) but that's a good thing if a low C rate is needed.

Going to go ahead and make the trip this afternoon to grab my faulty gen and charge up the battery with a suitcase gen.

 

[sunshine_eggo]

You would think that a major car mfr would have designed balance boards that were designed to STOP balancing under say a certain voltage, say 2.0V, to avoid such a situation. But I know next to nothing about EV's, so perhaps overall designs are better across the board of different EV mfr's.

Not a major car mfr...

aftermarket 10kWh plug-in-hybrid kit for the 04-09 Prius.

The 04-09 prius is a pure gas-electric hybrid. This was a "bolt-on"

Worth noting that ALL companies that offered these products are out of business now.

Just curious, did you charge to 2.8v with 2.8v cv and check them, or monitor a standard charger and stop, check, wait, check.

They were in series in 19S modules. I actually bolted the entire pack 4S(19S) together and used a high voltage LED driver @ 0.35A to charge the entire pack at once. I monitored full pack voltage periodically checking all 76 cells. Once I saw 230V, I disconnected the PSU and let them sit overnight. They all held right around 3.0V.

At that point I whipped out a 6A 300V supply and continued charging in series periodically checking voltages. Discovered that the balance boards illuminate a red LED at 3.50V and begins to burn 0.27A off the cell.

Dialed power supply back to 268V and 0.27A and let it run until all the LED were red and all cells were sitting around 3.5XV.

 

[Checkthisout]

Alright. So the Epever got the voltage up to 3 or so.

Just got here and unplugged the Yamaha and hooked up the Honda.

Slowly bringing it up.....





Oh and ha ha. Look at the amperage reading with a 2 amp discharge on the system.

331 amps going in. Thanks Daly.

 

[Checkthisout]

So charged battery with Honda gen overnight. Was pulling 1800 watts for at least 4 hours. Woke up to gen idling and Multiplus in float.

Went to leave and Multiplus cut out. Checked Voltage, 22 Voltage at 22 volts and jumping around.

Can no longer log into BMS. I assume it's totally fried now. Grabbed battery, bad gen and honda gen and heading home.

Had to go to work. No time to dig in yet. Will report back later.

Very frustrated. The Multiplus also rejected the Honda generator this morning. I assume this was due to the low battery. Didn't have time to pull the Multiplus so I hope it's ok.

 

[HighDesertOffgrid]

So charged battery with Honda gen overnight. Was pulling 1800 watts for at least 4 hours. Woke up to gen idling and Multiplus in float.

Went to leave and Multiplus cut out. Checked Voltage, 22 Voltage at 22 volts and jumping around.

Can no longer log into BMS. I assume it's totally fried now. Grabbed battery, bad gen and honda gen and heading home.

Had to go to work. No time to dig in yet. Will report back later.

Very frustrated. The Multiplus also rejected the Honda generator this morning. I assume this was due to the low battery. Didn't have time to pull the Multiplus so I hope it's ok.

Time to can that bms. Did you verify voltages with meter?

 

[sunshine_eggo]

Had to go to work. No time to dig in yet. Will report back later.

Looking forward to hearing the results. Good luck! Hope it's just the BMS. I've personally written off DALY simply based on the numerous failures documented on this site... definitely the lion's share.

Very frustrated. The Multiplus also rejected the Honda generator this morning. I assume this was due to the low battery. Didn't have time to pull the Multiplus so I hope it's ok.

Yes. If battery is below cut off, the charger is inactive, and it won't charge. Best option is to switch to charger only mode and hope the cells will drift upwards above cut-off.

 

[Checkthisout]

Time to can that bms. Did you verify voltages with meter?

No, work week so had to grab and go. I have a 5 day stay planned in a little less than two weeks..was gonna refine my install (had recently swapped from lead acid and aims inverter to lithium and Multiplus) but now it looks like I'll be doing repairs.

Will get it on bench at home this weekend.

 

[Checkthisout]

Looking forward to hearing the results. Good luck! Hope it's just the BMS. I've personally written off DALY simply based on the numerous failures documented on this site... definitely the lion's share.

Thanks. I got a good deal on the MP $400.00 but it was 24 volt so I needed (or thought I needed) a very high amp BMS. Only Daly had that.

Yes. If battery is below cut off, the charger is inactive, and it won't charge. Best option is to switch to charger only mode and hope the cells will drift upwards above cut-off.

Yeah I dunno. I would have thought it would reject charging but allow pass-through.

Just didn't have time to tinker to see what was up.

Thank you.

 

[sunshine_eggo]

Thanks. I got a good deal on the MP $400.00 but it was 24 volt so I needed (or thought I needed) a very high amp BMS. Only Daly had that.



Yeah I dunno. I would have thought it would reject charging but allow pass-through.

Nope. It has to energize the passthrough relays, and it won't do that if voltage is below cut-off.

 

[Checkthisout]

Nope. It has to energize the passthrough relays, and it won't do that if voltage is below cut-off.

Well there it is.

 

[Checkthisout]

K, well, pull off BMS.


Take covers off. Nothing to see. The thing is so heavily potted yet still somehow still not sealed very well as the covers just come right off.


So my generator, I was observing on video. It had stopped producing power shortly after startup. I could hear it bouncing off the rev limiter. So i shut it down. It wouldn't restart. Also, while it was redlining, it showing 25 volts on the engine start battery. I went and picked it up and finally got it on the bench today. The failure is obvious. My starter stuck and became a generator. The engine speed control uses 12 volts which explains the going to recline but at the same time it doesn't because the starter relay would have disengaged not allowing voltage to make it back from the starter? I'll have to check my schematic for my homebrew autostart to see if voltage could have made it back into the system.

I actually ordered a champion inverter gen as a backup but I'm not sure I'll trust it better than this yamaha. The thing has been fantastic.

 

[MisterSandals]

K, well, pull off BMS.

What are the wires going to every cell negative?

 

[Lt.Dan]

What are the wires going to every cell negative?

Could be an external balancer that is just using the other post as to not double up on the Balance leads?

Interested to hear what it is too.