Ressurecting/rejuvenating batteries

[SubnetMask]

I just acquired several UPS external expansion batteries that were BNIB, never been attached to a UPS, but have been sitting in box on a pallet for 'several years' - based on the manufacture date, I think somewhere around 2.5 years. So obviously, self-discharge is an issue. I was expecting them to be at like 11v per battery, which would likely be a tough recovery at best, but each pack worked out to 96-97v or so (each pack is 8s), and every battery I individually checked was 12.1-12.2v, which based on some charts I've seen, correlates to 75-80% DoD.

That being said, I'd like to try and resurrect these batteries - I can't use the packs as designed, but if they can be resurrected to full or near full capacity, I CAN use the batteries inside for my active UPS's as they're the exact same batteries, just a different configuration (16s2p for 192v on these vs 10s for my UPS's). If they can be resurrected and (those that I don't immediately use) can be kept optimal for years, the batteries involved could keep my main UPS's going for quite some time.

What's the best way to try and rejuvinate these batteries (charger, settings, etc)? I have a few NoCo Genius chargers - would these work? If so, what's the proper setting (there are several - standard, AGM, etc), or is there a better option, and if there is, what is that better option for this use case?

 

[sunshine_eggo]

Assuming AGM.

AGM need to be recharged every 3-6 months, but they will likely have some usable life given the 12.1-12.2V measurements. I wouldn't expect anything above 80% health and would expect less.

Immediately charge to full using suitable 12V chargers preferably at 0.1C or 10% of rated capacity (10A for 100Ah battery). This is to immediately halt the damage process.

The problem with chargers as recovery tools is they expect to work with reasonably healthy batteries and most that have some function to recover batteries is only appropriate for flooded.

You should gather any available battery data.

The typical 30V/10A power supply common for top balancing cells has a lot of utility.

A digital battery tester that can measure IR is a very useful tool. IR has a direct correlation to health. I'm a big fan of the ANCEL BST200. It's IR values correlate extremely well with an IR tester I have used commercially for years.

Holding each battery at its peak absorption voltage for several hours is not an uncommon practice for "recovering" AGM. Additionally, an extended float at 13.8V on the order of 7 days is also beneficial.

Assuming they are AGM with a 14.4-14.8V absorption voltage and a 13.8V float voltage, here's what I would do:

After fully charging above, use the Ancel tester and record the mR (mΩ) value.
Use 30V/10A supply to hold at 14.8V for 8 hours.
Reduce voltage and hold at 13.8V for 7 days.
Use the Ancel tester and compare the mR value.

If the PSU can support multiple batteries in parallel at the referenced voltages, you can apply the process to multiple batteries in parallel.

 

[SubnetMask]

Thanks for the info - for more detail, the batteries inside are 'Vision CP 1250HC' 12v 5AH Valve Regulated batteries, and the info on the side states '14.5-14.9v Cycle use' and '13.6-13.8v Standby use'. Edit: I found this datasheet on them: https://www.vision-batt.eu/sites/default/files/public/docs/products/manuals/CP1250.pdf

I've ordered a battery tester, and when you say, '30V/10A supply', I assume you mean something like this: https://www.amazon.com/Adjustable-Switching-Regulated-Adjustments-Jesverty/dp/B09YSJQWRG

When you say 'Immediately charge to full using suitable 12V chargers', I assume you mean use one of my existing NoCo chargers to start charging them, and then switch over to the other supply? If I were to charge eight at a time, as they are 5AH batteries, I'd need 4A to get 10% of their rated capacity - is slower ok? The two NoCo chargers I have are a 10A and a 2A.

After I determine just how 'ok' these batteries are, if they're still decent, I plan on re-wiring the modules from series to parallel to allow me to easily keep the ones not being used charged up - just plug in the main connector and let it go. I have a total of 12 modules/96 batteries, and if they end up recovering to a decent degree, I'll use 30 of the batteries right out of the gate, with eight modules 'just sitting'.

 

[sunshine_eggo]

Thanks for the info - for more detail, the batteries inside are 'Vision CP 1250HC' 12v 5AH Valve Regulated batteries, and the info on the side states '14.5-14.9v Cycle use' and '13.6-13.8v Standby use'.

14.9 and 13.8 are the desired numbers.

I had no idea these were so small.

Note that batteries should not be dealt with in series. Batteries should be either individual or in parallel for charging.

I've ordered a battery tester, and when you say, '30V/10A supply', I assume you mean something like this: https://www.amazon.com/Adjustable-Switching-Regulated-Adjustments-Jesverty/dp/B09YSJQWRG

Yes.

When you say 'Immediately charge to full using suitable 12V chargers', I assume you mean use one of my existing NoCo chargers to start charging them, and then switch over to the other supply? If I were to charge eight at a time, as they are 5AH batteries, I'd need 4A to get 10% of their rated capacity - is slower ok? The two NoCo chargers I have are a 10A and a 2A.

0.1C or 10% of 5Ah means 0.5A charging, so you should parallel charge 15-20 on the 10A NOCO and 4 in parallel on the 2A NOCO.

However, according to this:

Vision CP1250-F1 Battery 12v 5Ah VRLA

This Vision CP1250 battery has F1 .187" width terminals. Vision CP1250-F1 valve regulated lead acid batteries are designed for use in a variety of applications including alarm systems, emergency lighting systems, uninterruptible power supplies, medical equipment and much more. OSI Batteries is...

www.osibatteries.com

The battery appears to say 1.XA. If yours has that marked as well, respect that limit. If the value is 1.0A, then you would charge 10 in parallel on the NOCO 10A and 2 in parallel on the 2A. You can put more on if you want to charge each at 0.5A.

After I determine just how 'ok' these batteries are, if they're still decent, I plan on re-wiring the modules from series to parallel to allow me to easily keep the ones not being used charged up - just plug in the main connector and let it go. I have a total of 12 modules/96 batteries, and if they end up recovering to a decent degree, I'll use 30 of the batteries right out of the gate, with eight modules 'just sitting'.

Given the quantities, then parallel charging to full on the NOCOs should make quick work of them.

 

[SubnetMask]

Thanks again for the info - yes, for charging, parallel for sure. The UPS is designed for using them in series - my UPS has 10 in series in the pack, the UPS these came from have two 8s packs in series.

The only amperage marking on the batteries is 'Initial Current: Less than 2.0A', and the PDF shows a max charge rate of 2.0A.



I think the most efficient method would be to re-wire up the packs for this initial charging, and then parallel two paralleled packs to charge with the 10A NoCo, which with 16 batteries, would be .625A per battery. I've also ordered a power supply (been thinking about getting one for a while, so this was a good excuse to order one), and once charging with that, it looks like I could specify the charging current, up to its 10A limit.

 

[sunshine_eggo]

Thanks again for the info - yes, for charging, parallel for sure. The UPS is designed for using them in series - my UPS has 10 in series in the pack, the UPS these came from have two 8s packs in series.

The only amperage marking on the batteries is 'Initial Current: Less than 2.0A', and the PDF shows a max charge rate of 2.0A.

I would be hesitant to push these batteries to 2.0A in their state. 0.1C is preferred for all lead acid, but AGM can often handle more. I would still shoot for 0.5-1.0A.

I think the most efficient method would be to re-wire up the packs for this initial charging, and then parallel two paralleled packs to charge with the 10A NoCo, which with 16 batteries, would be .625A per battery.

Perfect.

I've also ordered a power supply (been thinking about getting one for a while, so this was a good excuse to order one), and once charging with that, it looks like I could specify the charging current, up to its 10A limit.

They're a great little tool for a lot of things. Off-the-shelf chargers are generally just "okay" for charging 12V. It's really nice to be able to control your voltage and current. Ours even saved Christmas...

DIY Solar Forum Saves Christmas!

Wife's enthusiasm for X-mas decorations is waning with age. She is within sight of my X-mas apathy... Her enthusiasm was somewhat renewed by the idea of a "popup" X-mas tree... Oh the glory... open the box, tree complete and decorated in 8 minutes! DISASSAPOINTMENT...

diysolarforum.com

 

[SubnetMask]

So I've started getting the batteries charged - Making the harnesses to convert the packs from series to parallel is kind of tedious lol. I've gotten 16 charged with the NoCo so far and another 16 are in process... According to tester, the batteries, at least the ones that I've charged with the NoCo and tested, 'appear' to be in surprisingly near perfect health based on the IR reading... According to the tester, the first batteries that I charged and have tested (I've only tested a few so far), tested in the ~34mOhm range, which according to the PDF, is exactly where they're supposed to be when fully charged. While the tester that I ordered (I ordered a BA301 as it had a few more features over the BA200) is great for testing car batteries (although I have NO idea how this little handheld tool can actually calculate the CCA capacity of a battery), any thoughts on a tester that JUST tests IR? I set it to 100CCA and have it test the batteries at that setting so I can get the IR. I have one that I bought for Lithium batteries, but apparently, it's not capable of testing lead acid batteries - it doesn't give me any valid readings. Apparently the ~34mOhms isn't within its ranges.

I'm 'cautiously optimistic' that these might actually end up being better than expected.... but if that doesn't pan out and they end up having really poor capacity due to their time sitting, well, the price was right (free) and it was worth a shot.

 

[sunshine_eggo]

Sounding really good.

 

[SubnetMask]

So I got all 12 packs charged up with the noco to halt any further degradation, and I got the 'harnesses' build to convert the packs from series to parallel, put them all back together in their new configuration, paralleled them all together and connected the noco again to top them all off together. Timing being what it is, I won't be able to do the next step with the power supply for a few weeks - any reason I shouldn't leave them on the noco until I can get to that step? Once I can run that portion, any reason I shouldn't do all 12 packs at once? I don't think we're looking for high current with the '14.8V for 8 hours' and '13.8V for 7 days' steps, so it seems that doing them all together shouldn't be an issue. Since they all have the same build timeframe and were stored together in the same conditions for the same amount of time, in theory, all batteries should be in pretty much the same condition.

In this configuration, (96 12v 5Ah batteries in parallel), I should have around 480Ah/5760Wh. What's the best way to test them? I know I can go through and use the tester on each battery, but for doing capacity tests, what's recommended? Things like this look promising, but is there a better option?

Here's what I have set up now:

 

[sunshine_eggo]

No harm in parallel. Voltage matters, not current.

 

[ericfx1984]

I have a nice AGM or at least it was nice... But I left something plugged into it and it got drained down pretty low

For the life of me I can't get it to come back above 11.3 volts

 

[mikeinnyc]

I did this same thing and was successful in reviving totally dead dried-out gel batteries fully charged from several APC units however don't forget we can't totally fix resistance ohms if the plates have bad sulfation buildup. I wouldn't be overcharging these either as adverse side effects are death and coffee cake face.

PbO2+2H2SO4+Pb → 2PbSO4+2H2O The electrodes are coated with a paste of lead(II) oxide (PbO) and finely divided lead; after insertion into the electrolyte, a ‘forming’ current is passed through the cell to convert the PbO on the negative plate into a sponge of finely divided lead. On the positive plate, the PbO is converted to lead(IV) oxide (PbO2).

You will need sulfuric acid and a syringe if they are totally dried out or won't hold a charge. I wouldn't do this again for safety reasons but then again I eat crayons.

Remember pour the "acid into the distilled water bottle and gently stir in the acid, and not the other way around." Pour acid into water or die
2/3 part distilled water first, 1/3 sulfuric acid stirred in slowly into the water. Start with a very small amount before you get brave. Also, have baking soda around to neutralize any spills. Neutralize Battery Acid

You will need protective breathing equipment, a rubber jacket, eye protection, and some brain cells not to do this at all.

Syringe up the solution and pour it into cell holes and pray. Make sure you put out all cigars while you are doing this insanity and have your friends film this from far away. Makes great views also, this is not advice, and don't do this at all. When done place these outside away from animals and not in an air-tight environment. Don't use these batteries for 2 weeks and leave the rubber tops off for a few hours. Test the batteries' resistance and if good make sure you babysit them the first few charge-ups. I saved thousands but your mileage may vary and your skin completion also.

 

[sunshine_eggo]

@mikeinnyc

What was their rated capacity?

What capacity did the process yield?

 

[mikeinnyc]

@mikeinnyc

What was their rated capacity?

What capacity did the process yield?

Apc batteries The total rated capacity was 5.1Ah @ 192VDC = 1,000 est watts/hr
P = 192V * 5.1A = 979.2W This means that, theoretically, the battery should be able to deliver a current of 5.1 amperes for one hour at a voltage of 192 volts before it is fully discharged. Alternatively, it could deliver a current of 1 ampere for 5.1 hours, or 0.5 amperes for 10.2 hours, etc., until it is fully discharged. However, that's not realistic because of lead acid properties. Maybe 50% of that is because you will destroy lead acid life.
As you guys already know the depth of discharge (DoD) chosen affects the lifespan of the battery. In general, the deeper you discharge a lead-acid battery, the fewer cycles it will last. Using 50% DoD generally offers a good balance between getting reasonable capacity from the battery and preserving its life.

Now if you get these batteries free or dirt cheap "FOR SOLAR," then DON'T go ahead and do this however they probably won't last too long. I use this in my data servers exclusively and not for solar. I only need them to work once every 6 months. You could like I said use them to 50% and you're good.

The more cycles for solar the less valuable they become. I tested the ohms resistance for each battery before and after to see if within specs while the others were too high... garbage. You can tell because they won't hold a tiny load and the voltage drop falls apart easily.

For some perspective, a brand new gel lead acid battery tested to 10% load run time was 6 min 42 seconds vs 6min 03 seconds for reconditioning.
My capacity will always be different than the next. The actual performance can vary depending on factors like the load, the temperature, the battery's age, and other conditions.

It is also important to note that most lead-acid batteries should not be regularly discharged below 50% of their rated capacity to prolong their lifespan. Hence, the effective usable capacity might be lower than the rated capacity.

It's a worthwhile experiment if you have the time. Some of the batteries will be fubar no matter what you do. I've seen guys crank up the juice full blast using welders on youtube. NOT NORMAL No thanks.

Some final pointers:

• The process would generally involve carefully emptying the old electrolyte from the battery, refilling it with the new sulfuric acid solution, and then going through a series of NORMAL charge and discharge cycles to try to remove the sulfate deposits.
• Even if done correctly, this may not work, or it may not restore the battery to its original capacity. Also, if the battery was very old or heavily sulfated, this process may not be effective.
• Working with sulfuric acid and batteries can be dangerous. Sulfuric acid is corrosive and can cause severe burns. It can also generate hydrogen gas which is explosive. Hydrogen Therefore, always wear appropriate personal protective equipment (like gloves and eye protection) and work in a well-ventilated area.

Like I said you could do this for 50% of the rated capacity with lead acid but why?

This is not advice and you do so at your own risk.
I feel like I shouldn't even talk about this.

 

[sunshine_eggo]

Rather than a poorly delivered battery sermon with multiple errors, maybe just answer the questions?

5.1Ah - got it.

And your process yielded?

I feel like I shouldn't even talk about this.

I wish you'd realized that two posts ago.

 

[OzSolar]

I wish you'd realized that two posts ago.

Savage!

 

[sunshine_eggo]

Savage!

I have a problem with people doing things wrong, not realizing it and then telling everybody how great being wrong is.

 

[OzSolar]

I have a problem with people doing things wrong, not realizing it and then telling everybody how great being wrong is.

I hear ya. When I fiddle with old batteries it's 2v and a lot of AH (1104). EG: Something that if comes back to life is useful.

 

[sunshine_eggo]

I hear ya. When I fiddle with old batteries it's 2v and a lot of AH (1104). EG: Something that if comes back to life is useful.

View attachment 153600

I've never had the pleasure of a 2V cell. I've spent lots of quality time with Trojan T-1275 and Rolls S-605 as well as various "deep cycle" marine/RV type 12V.

 

[OzSolar]

I've never had the pleasure of a 2V cell. I've spent lots of quality time with Trojan T-1275 and Rolls S-605 as well as various "deep cycle" marine/RV type 12V.

It's almost the only type I've known. Lot's of HUP's, Exides, etc. Don't judge, I never take after pics.