Ohms law is your friend

[OzSolar]

2v cell from a 23 yr old 48v FLA battery still alive in the wild. Doing well actually.

Last May (~8 months ago) I found this cell way under spec compared to his 23 counterparts. Pulled it, then wired around it, reprogrammed my inverter. Left alone until a few weeks ago. SG read was just over 1 and Voc was around 1.5. Mucho bad, right? Fool's errand to follow but as the king of fools why not??

So I started with dumping out the acid, rinsing it out with my well water ~6 times. I'd jiggle it around assuming I was knocking the bad stuff loose.

Then I added 40 grams of EDTA for ~24hrs. During that time I would try to shake it a little bit by rocking it back and forth. Dumped that out, rinsed a few more times, then put fresh battery acid back in, 1.5 gallons is what it this cell needs. Yeah it’s a beast, have to use a forklift to move it around.

Charged it back up and to my complete disbelief the SG has returned to 1290. Now I’ve dead shorted the battery with a random roll of #8 wire I had laying around, somewhere between 50' and 100' (Refer to the title of this post). It’s holding a 35 amp load @2.1 volts. Guess I’ll put back into service and waste a lot more time getting the others rebuilt.

 

[OzSolar]

Don't try this at home! I'm really on a fools errand here but I've always wanted to try. I'm going to try to pull several hundred amp hours out of it and charge it back up several times. Turns out my IOTA 12v 55 Amp charger will deliver ~70 amps @ 2.5 volts when I hook it up this cells.

If it survives I'll put it back in service. I've got at least one more cell that's trying to fall on it's face and I'm sure plenty more behind.

It took several attempts to figure out how in the heck I was going to safely pour the acid out of this cell. The front loader and the NRS strap came to the rescue.

Even though the old acid has a SG of not much over 1 it's still pretty dangerous. When I put even a tiny amount (1/4 cup) of baking soda in the bucket it boils quite violently. I had a full face shield on and all the other requisite PPE on the entire time.

 

[Bluedog225]

Wow. Well done.

 

[Mattb4]

... Dumped that out, rinsed a few more times, then put fresh battery acid back in, 1.5 gallons is what it this cell needs. Yeah it’s a beast, have to use a forklift to move it around.

Charged it back up and to my complete disbelief the SG has returned to 1290. Now I’ve dead shorted the battery with a random roll of #8 wire I had laying around, some where between 50' and 100' (Refer to the title of this post). It’s holding a 35 amp load @2.1 volts. Guess I’ll put back into service and waste a lot more time getting the others rebuilt.

Good news you are getting some more life from the cell. Just wanted to comment about SG readings. Adding fresh acid is going to give you a SG reading that would not mean the battery was any good. https://www.engineersedge.com/battery/specific_gravity_battery.htm

The cells capacity will have a lot to do with how the lead plates can interact with your fresh acid. Over time there is deterioration of the lead besides the plating effect of sulfur.

You likely know all of this but I thought it might help those that might be curious about it.

 

[Bluedog225]

Curious what you do with the waste water? Is there a way to remediate the lead before disposal? Does TSP bind with lead? Something to make it less bioavailable.

 

[OzSolar]

Good news you are getting some more life from the cell. Just wanted to comment about SG readings. Adding fresh acid is going to give you a SG reading that would not mean the battery was any good. https://www.engineersedge.com/battery/specific_gravity_battery.htm

The cells capacity will have a lot to do with how the lead plates can interact with your fresh acid. Over time there is deterioration of the lead besides the plating effect of sulfur.

You likely know all of this but I thought it might help those that might be curious about it.

Thank Matt! I will study this in detail. There's plenty I don't know and honestly I'm not being very scientific about it. Just playing around, albeit safely..

FWIW: I measured the SG of the battery right after I put the fresh acid in and found it to be ~1100 and the Voc was 1.8. It took many hours of charging @ 80 amps to get it up to 1290. I'll try to take very detail notes next time. Dealing some random Covid brain fog at the moment. I have good days and not so good days. Mostly good days though.

Curious what you do with the waste water? Is there a way to remediate the lead before disposal? Does TSP bind with lead? Something to make it less bioavailable.

The old battery acid is in a sealed bucket. I think my local battery place will take it. I've got some mixed messages from them about just taking old acid. If not, my plan is too add baking soda to it. One lbs. per gallon according to Google. FWIW: the first few rinse waters still reacted to baking soda and the limestone rocks in my driveway. Serious business.

I hadn't though about the lead in the old battery acid. Interesting story that I found was that EDTA was originally invented for the treatment of lead poisoning for workers in WW2. Here's one mention of Chelation therapy.

 

[HRTKD]

Turns out my IOTA 12v 55 Amp charger will deliver ~70 amps @ 2.5 volts when I hook it up this cells.

How did you get the converter to go down to 2.5 volts?

 

[OzSolar]

How did you get the converter to go down to 2.5 volts?

I didn't do anything special. I just wired it up to the cell and plugged it in. I tried several other 12v chargers and they didn't like being treated that way.

 

[HRTKD]

I didn't do anything special. I just wired it up to the cell and plugged it in. I tried several other 12v chargers and they didn't like being treated that way.

I don't get it. That converter should put out 13.4 volts. I would like to know how that magic works. Seriously, that's interesting.

DLS 55A Converter and Charger - 55 Amp AC\DC Power Converter and Battery Charger for DC load operation and 12V battery charging

The DLS 55A Power Converter/Battery Charger from IOTA converts nominal 108-132 AC voltage to 13.4 DC voltage for both DC load operation and 12V battery charging. As a power supply , the unit's

www.iotaengineering.com

 

[Hedges]

CV/CC

Wouldn't do that to Lithium, but for lead-acid the voltage won't run. One ought to shut off when it reaches a target voltage, though.

A linear supply would burn excess power. Maybe a switcher is better behaved.
I've killed a battery charger trying to bring up a 12V battery that was down to 6V. Should have connected a series light bulb.

 

[OzSolar]

I don't get it. That converter should put out 13.4 volts. I would like to know how that magic works. Seriously, that's interesting.

DLS 55A Converter and Charger - 55 Amp AC\DC Power Converter and Battery Charger for DC load operation and 12V battery charging

The DLS 55A Power Converter/Battery Charger from IOTA converts nominal 108-132 AC voltage to 13.4 DC voltage for both DC load operation and 12V battery charging. As a power supply , the unit's

www.iotaengineering.com

I honestly don't have a clue but I'm sure Hedge's is spot on though. This is a massive cell, 1104 AH and ~150 lbs so my theory was is that it didn't really care what I threw at it. I never did get it past 2.55. 2.65 is what Surrette recommends for equalization. The SG does indicate it is full at 1290.

FWIW: I tried both of the below chargers plus a low cost older Northern Tool 12v 1000w inverter/charger. Both chargers tried for seconds before they shut down and the inverter gave a "L in" error which I took to mean low input voltage.

 

[Hedges]

70A into 1100 Ah, only 0.064C charge rate

About half of what it would prefer?

 

[OzSolar]

70A into 1100 Ah, only 0.064C charge rate

About half of what it would prefer?

Right!?!?! I was really worried I'd never get it charged but I did. See this thread. I'm working on more detailed post at the moment so stay tuned. It's been a pretty fun exercise. Hmnn... I wonder why I don't get invited to a lot of parties.

 

[OzSolar]

Here's a hint.

 

[Hedges]

It's been a pretty fun exercise. Hmnn... I wonder why I don't get invited to a lot of parties.

Because we're geeks and nerds? How about them Kardashians? Olympian Bruce Jenner, or whatever "her" name is?
Now back to the important stuff, involving electron shells and quantum tunneling ...

Testing Magnetic-Hydraulic circuit breakers

I've built myself a circuit breaker tester. I assembled three transformers into a 3-phase wye auto-transformer, and by means of a breaker and cord/plug it can be repurposed into a current multiplier. A breaker connects X1 to H2 and H3, providing 4.7x current boost on X2 paralleled with X3...

diysolarforum.com

 

[JoeHam]

“Ohm's Law is a formula used to calculate the relationship between voltage, current and resistance in an electrical circuit.”

It’s not just a good idea….……….

It’s the law ?.