Dead Cells

[suntex]

My solar setup lasted less than 2 months, the other day everything shut down. Checked the 2 BMS'S and the cells read
3.2v, 3.2v, 2.6v, 2.8v, 2.6v, 3.2v, 3.2v, 3.2v so i assume the cells under 3v are dead ...
My only source to charge them is the solar panels which im gonna go ahead and find a 110v charger to have on hand...
Can anybody recommend a good charger with adjustable voltage thats cheap?

 

[Sojourner1]

Your cells should not be "dead" at 2.6-8v it's just that your pack isn't matched well at the low voltage end, not the end of the world.

Did these cells get properly top balanced?

 

[RCinFLA]

You went to fully discharged. One of the two 2.6v likely tripped the BMS 2.5v low cell shutdown and with no load current recovered a bit up to 2.6v.

Just need recharging. You are fine. The reset actvation of BMS may require all cells to rise above about 2.8v depending on your BMS setting. It will allow a recharging but perhaps only with a lower charge current. Depending on your charger / charge controller it might have a problem with this high resistance charging cycle. In worse case you may have to do some initial charging with a power supply until BMS resets.

You actually have reasonable balance at end of discharge, ranging from about a high of 13% state of charge for 3.2v to 1% state of charge for 2.6v. .

 

[suntex]

I did top balance them, this is my first experience with lithium batteries so Im still learning.
If all I need is to charge them back up then Ill have to find a charger to get them back up, Ill
see today if the solar will kick in since not working today but if not ill just have to wait.
Can anybody recommend a charger with adjustable voltage that is cheap?

 

[suntex]

Is there any where to get something like this local or making something like this,
Im guessing this could charge either one cell or whole pack...

Voltage Current Adjustable Lifepo4 Lipo Li-ion Battery Charger 3.65V 4.2V 2S 3S | eBay

The battery manufacturers are different. The instructions on the battery label shall prevail! Can also Baidu query! Output current: DC constant current is adjustable to 1-53A. Step 2: Adjust the current to a minimum.

www.ebay.com

 

[Sojourner1]

What do you mean by your solar setup lasted less than 2 months?

 

[suntex]

What do you mean by your solar setup lasted less than 2 months?

Live in an RV, Ive only been running lights and few other dc loads, so not to sure how it got depleted.
Have 1000 watts solar feeding 8- 270ah cells at 12v.

 

[Sojourner1]

I do the same as a fulltimer in an rv and mainly boondock, as of today 1,804 (boondocked) of the past 1,979 days and the times I was on hookups I turn off the charger and allow the 120v to pass through to run the ac loads and leave solar to run the 12v loads/ top the batteries off after a small dod during the night. See sig.
I don't turn my inverter off, it's been on since day one.

Again why is the solar not topping off the batteries or carrying loads during the day?

 

[2Big2B]

My solar setup lasted less than 2 months, the other day everything shut down. Checked the 2 BMS'S and the cells read
3.2v, 3.2v, 2.6v, 2.8v, 2.6v, 3.2v, 3.2v, 3.2v so i assume the cells under 3v are dead ...
My only source to charge them is the solar panels which im gonna go ahead and find a 110v charger to have on hand...
Can anybody recommend a good charger with adjustable voltage thats cheap?

Actually I have an idea for you.

I am using a 8s 29.2v 100ah DYI pack to run my power wheelchair. I use a 10A LiFePo 28.8V Battery Charger designed for it. If you found one of those cheap you could charge yours in series. I bought one used on ebay for $20.



OTH, you probably really should have a variable amp/voltage power supply to directly charge cells independently. You can usually find them new for less than $100 - typically with a variable voltage around 15v with maybe 30A output. That way you can troubleshoot and balance cells independently. That's how everyone seems to do that.

Actually this might work for you: 30v / 5A. Slow but do-able for less than $50.

https://www.amazon.com/Variable-4Digital-Adjustable-Regulated-Switching/dp/B08FT2YH2B/ref=asc_df_B08FT2YH2B/?tag=hyprod-20&linkCode=df0&hvadid

 

[suntex]

I do the same as a fulltimer in an rv and mainly boondock, as of today 1,804 (boondocked) of the past 1,979 days and the times I was on hookups I turn off the charger and allow the 120v to pass through to run the ac loads and leave solar to run the 12v loads/ top the batteries off after a small dod during the night. See sig.
I don't turn my inverter off, it's been on since day one.

Again why is the solar not topping off the batteries or carrying loads during the day?

Not sure....I know about a week ago I was working in the bay where the batteries are, accidentally hit breakers shutting controller down...should have checked if it booted back up when turning back on...

 

[Sojourner1]

Is it working now? If not tell us what you have and maybe we can get it figured out.

 

[suntex]

Is it working now? If not tell us what you have and maybe we can get it figured out.

I jump stated it with a power supply......gonna watch it for a few days to see if it gets charged back up

 

[suntex]

Actually I have an idea for you.

I am using a 8s 29.2v 100ah DYI pack to run my power wheelchair. I use a 10A LiFePo 28.8V Battery Charger designed for it. If you found one of those cheap you could charge yours in series. I bought one used on ebay for $20.

View attachment 65337

OTH, you probably really should have a variable amp/voltage power supply to directly charge cells independently. You can usually find them new for less than $100 - typically with a variable voltage around 15v with maybe 30A output. That way you can troubleshoot and balance cells independently. That's how everyone seems to do that.

Actually this might work for you: 30v / 5A. Slow but do-able for less than $50.

https://www.amazon.com/Variable-4Digital-Adjustable-Regulated-Switching/dp/B08FT2YH2B/ref=asc_df_B08FT2YH2B/?tag=hyprod-20&linkCode=df0&hvadid

5amps is to little, my setup is 12 volts, would like a charger around 20 or 30 amps...but thanks for input

 

[Tecnodave]

I have been using Meanwell CC/CV adjustable power supplies for charging lithium batteries, they are reliable and settable to the voltage but they are very plain and simple, you will need an external voltmeter to set them up to the voltage.....these are not battery chargers, they are not appropriate for lead acid, but perfectly suited for lithium, I buy mine on Amazon.

for cell balancing I use the Meanwell MS-150B , a 3.3 volt 120 watt supply which is adjustable 2.6 volts to 4.0 volts
I have set it to 3.65 volts for LFP ( this one I had to dig deep for did not find on amazon but i forgot where i found them)

meanwell.com

 

[time2roll]

Does the chassis alternator charge the batteries? I would think this is enough to jump start them and get the solar started.

Did you remove the converter? With generator or utility power the converter should charge the battery just fine.

In the future... watch your battery voltage closer to avoid going to low voltage disconnect. Solar will continue to drop in power as the sun gets low for winter. You may need more panels.

 

[suntex]

Does the chassis alternator charge the batteries? I would think this is enough to jump start them and get the solar started.

Did you remove the converter? With generator or utility power the converter should charge the battery just fine.

In the future... watch your battery voltage closer to avoid going to low voltage disconnect. Solar will continue to drop in power as the sun gets low for winter. You may need more panels.

No....only have solar setup to charge the batteries. Ive got almost 30yrs experience with solar but lithium batteries are new to me, ive been
pretty busy lately between work and other things, Seemed to be working fine up till when I hit the breakers. Soon has i get them charged back up
Ill check everything out.

 

[suntex]

Ok I'm lost...works great for about 2 weeks then seems like batteries just start discharging, not taking charge from solar??? What could be the problem

 

[Texas-Mark]

Is your charge controller set up properly for Lifepo4? 13.2V seems low.

 

[suntex]

Is your charge controller set up properly for Lifepo4? 13.2V seems low.

yes....I set it up for LifePo4 batteries, works fine for about 2 weeks then batteries like quit taking charge from solar,,,,
and yes batteries are depleted again

 

[suntex]

Correction for some reason 1 bms is at 98% and other one is reading 70%