Have I ruined my Sinopoly 100 AH batteries?

[SCClockDr]

An ATX power supply from a retired PC. Search youtube for an endless supply of videos on how to. There is a 3.3 volt rail with lots of amps.

 

[Maple Dave]

I'm just heading out to work now, I will look into that later. One of my sons is an IT at a private corp. working for a local college, he or his team repair computers, maybe he will have an old ATX power supply.
Is it a bad idea to connect 3 cells in series and first put 6V to them, then 8V, I could do that, or connect 2 in series and charge as 4V then step to 6V. By then the LiPo setting should work and I could charge all 16 in series with the BMS connected at up to 50A. The limitation of 5A is only in the PB setting.

 

[SCClockDr]

I'd suspect the 3.3 volt rail has at least 3 wires. Placing a diode in each would isolate the paralleled cells from each other. Yes you will drop a bit of voltage but your goal is to get above 2.4V for now. Then you can rearrange the setup.

 

[SolarRat]

Is it a bad idea to connect 3 cells in series and first put 6V to them, then 8V, I could do that, or connect 2 in series and charge as 4V then step to 6V. By then the LiPo setting should work and I could charge all 16 in series with the BMS connected at up to 50A. The limitation of 5A is only in the PB setting.

Normally I'd say no problem. But we are still not 100% sure if all these cells will take a charge, and if one doesn't the rest in series will get overcharged. But if doing it in small steps like you say, and you are careful and closely monitor each cell once in a while, go ahead.

@SCClockDr 's 3.3v ATX rail is a good idea for more amperage, and you could also use the 5v rail for two cells in series.

 

[SCClockDr]

Normally I'd say no problem. But we are still not 100% sure if all these cells will take a charge, and if one doesn't the rest in series will get overcharged. But if doing it in small steps like you say, and you are careful and closely monitor each cell once in a while, go ahead.

@SCClockDr 's 3.3v ATX rail is a good idea for more amperage, and you could also use the 5v rail for two cells in series.

Use the 12 volt rail to charge the 4 in series once you are assured you've got them back. Employ a boost buck CC CV DC>DC converter off the 12 volt rail to provide an adjustable charger for experimentation/recovery.

 

[electric]

I would assemble in 4 x 4S packs, then parallel all 4 packs at 4S and hit with 15A from 12V charger, constantly monitoring all 16 cells for voltage rise to see if they all come up at similar rates. But of course your #1 cell is now imbalanced from remaining 15, so that must be accounted for. Maybe 3 groups of 4S and one group of 3S on a different charger?
To be clear, I would only do this to get them quickly to at least 2.5V , but might as well go to 3.0V or even 3.3V, as long as you are closely monitoring each cell voltage to make sure none go drastically higher or stay too low.
If this stage goes well, then I would put all 16 in parallel and charge to 3.65V with whatever max current you can make at this voltage.
This is just my opinion because I am very comfortable with this process and don't like wasting too much time. Your comfort level should tell you how fast/slow you want to take this.

 

[Maple Dave]

My son has an ATX power supply, not sure, he needs to check on a resistor for the 5V post. I think I will try this method.

 

[electric]

My son has an ATX power supply, not sure, he needs to check on a resistor for the 5V post. I think I will try this method.

The main problem with using ATX type supply is that it's not capable of constant current limiting, so if the load is high enough the PSU will just shut down and be useless. So length/gauge/resistance of cables from PSU to cell terminals becomes a current limiting factor, so you have to pay attention to that and tweak it if necessary.
Chances are if you apply 3.3V supply to a <2.0V cell, PSU will just shut down to protect itself, unless you can drop 1.3V on your cables.

 

[Pierre]

When bad things go wrong, does it mean things are all right?
Sorry, just busting your chops, no offense.
Totally agree not to leave the charge unattended when suspecting a bad outcome.

Bad batteries normally smell off as well.

 

[John Frum]

Bad batteries normally smell off as well.

Can you further characterise "off"?
Do you mean burnt?

 

[Pierre]

These batteries contain a variety of solvents. Should your battery cell have a leak you will smell odors like
alcohol or nail polish. Others have smelt a sweet chemical odor.

 

[Maple Dave]

I've been charging at the 2V PB setting so far, but it is very slow. Seems hard to get the voltage over 1.8. Tomorrow I have time, I will try setting up the ATX power supply. I bought some variable resistors (2@100ohm variable) and 2@25 ohm) that I hope will drop the voltage enough to get the 5V post to work, if not I'll use the 3.3V and drop that voltage using the resistors to see if that works. If that fails I will try 2 cells in series on the 5V post, then experiment from there.
At this point I have 4 cells at 1.8V and they seem to hold there, the others are at the 1.6 or 1.7 from when I found the issue.

 

[electric]

Depends on your charge rate, but I'd say this is not a good sign. Usually a cell recovers to above 2.5V almost immediately, with very little charge applied to it. I would guess that a 100AH cell discharged to 1V should jump back to above 2.5V with 1A current applied for 10-20 minutes.
If you are not seeing fast rise above 2.5V, chances are your cells are toast. I hope not, but this has been my experience.

 

[SCClockDr]

I've been charging at the 2V PB setting so far, but it is very slow. Seems hard to get the voltage over 1.8. Tomorrow I have time, I will try setting up the ATX power supply. I bought some variable resistors (2@100ohm variable) and 2@25 ohm) that I hope will drop the voltage enough to get the 5V post to work, if not I'll use the 3.3V and drop that voltage using the resistors to see if that works. If that fails I will try 2 cells in series on the 5V post, then experiment from there.
At this point I have 4 cells at 1.8V and they seem to hold there, the others are at the 1.6 or 1.7 from when I found the issue.

I'd use an adjustable buck converter tied to the 5v rail. That allows you to set the voltage as you desire.

 

[Pierre]

In the old days we used to shock dead NiCad batteries (1.2v cell) with about 12 volts (limit current to about 10 amps).
I know the chemistries are totally different but seeing that it seems your cells are toast , maybe it will work.
Good luck.

 

[Pierre]

The quickest way would be to use a CV / CC bench power supply. This way you can see exactly at what point the
cell will start accepting charge current and at what voltage.

 

[electric]

In the old days we used to shock dead NiCad batteries (1.2v cell) with about 12 volts (limit current to about 10 amps).
I know the chemistries are totally different but seeing that it seems your cells are toast , maybe it will work.
Good luck.

Sadly this method doesn't work on Lithium cells. You can't shock plated metallic Lithium back into the free ions