I did a bad bad thing!

[russ_drinkwater]

Ok I did something stupid!
Recently went to my 2nd hand panel supplier to pick up another 80 panels (not all for me mind you!).
He still had the rolls batteries I have previously posted about.
I tested the cells and they all had just under 4 volts per pack.
Inside looked clean with no obvious deformation from sulfation.
To cut a long story short I took a gamble and bought 12 x 1350 amp hour 4 volt packs.
The retail on those here at the moment is just under $20,000 and I got the 12 for $2,000 cash in the hand and no comebacks or complaints!
I have managed to 8 out of 9 packs up and going so far.
There is one really suspect cell in one pack.
It does not gas like the rest and the specific gravity does not rise even after long charging sessions.
I now have one 24 volt bank hooked up to my second array and other mid nite 150 reg.
Just letting the reg do it's magic for a week or so with the desulfators and then I will start to apply load to the bank to slowly exercise
them and see what if any capacity them still have.
Specific gravity on all cells in the 24 volt pack all read 1285 SG and the pack voltage drops 3/10's of a volt overnight with no load.
Early days, but worst case is I will have bought 1 1/2 tonnes of scrap lead, lol.
If I only get one bank of batteries at 24 volts which are serviceable then they are still cheap.
I would imagine there is some rat chews marks on the bottoms of the plates from stratification as well.
I will keep you posted!

[tecnodave]

Russ,

Before giving up on them try my backwoods battery recovery technique.

If you know that you have only bad cell isolate that battery and connect a higher voltage panel to it. I use 6 Siemens SM-55 panels connected in series directly to the bad battery. This will apply approximately 130 volts at a max of 3 amps to the failed battery. The good cells will have a voltage of 2.5 volts of so , assuming s.o.c. 1265 or so, and the remaining voltage across the sulfated cell. When sufficient conduction occurs through the sulfate the voltage will drop little by little. The high voltage on the sulfated cell will burn off the sulfate. Any "soft" power source can be used but old panels are perfect for this as the voltage will drop rapidly when current breaks through the sulfate.

This works is based on old school battery shops use of "String Chargers" also known as " Tungar bulb Chargers". These units had a large vacuum tube diode that is much like a mercury vapor street light. Totally obsolete now but they were used in the 1930's-1950's battery shops. They applied a high voltage limited current power to the failed battery to accomplish this task. About 80 volts DC pulsing half wave at 8-10 amps or so. I used such apparatus at Alaska Husky Battery in Fairbanks, Alaska and have recovered many sulfated batteries via this technique.  The Rolls-Surette set I am using was purchased for $20.00 USD for the set of 4 L-16 S-530's on the way to the scrapyard. s.o.c. on all cells were below minimum reading and the set was at .05 volts........they are worth $70.00/ ea. here as core trade in due to tough environmental law here so I'm not going to lose. Slow charging for 30 days with the Siemens bank recovered all cells to balance and volts to 24.0 At that point I put a Beta Kid with 1 kW of panels on bank and slowly ramped up the current. Fully recovered and in use for the last year. They have a bit more capacity than my Interstate floor sweeper L-16's.

Sounds tedious but I spent a few minutes reading volts/amps and manually setting the charge rate several times a day. Not letting the controller control. Total manual mode as seen in picture below.
That is in bulk mode but I am equalizing for cell balance.....yes I keep a close eye on it at this stage as copious amounts of hydrogen gas is generated in this mode......Don't run your controllers this hard without continuous monitoring.

Lots of luck in your recovery

David

[russ_drinkwater]

I am not going to give up Dave. Will remove the top of the two cell pack so I can get the single cell that is faulty.
There does not appear to be any obvious deformation I can see.
The 24 volt pack I am now charging with the 150 has lost all the sulfation deposits (light grey powder on surface of internal structure) that were visible. I would imagine it will take some time for the process to work its way through the length, depth and width of all plates.
Electrolyte is now crystal clear and looks great.
All cells readily gas under charge bulk 18.5 plus amps.
Well down on the recommended 135 - 270 amps that is recommended!
If I get a chance tomorrow I will be connecting the three switch and applying load the the new bank and see what happens.
I will have to get another whiz bang as my plans for follow me have been changed with the additional batteries.
Will try the unregulated panel on the funky cell trick tomora as well. 
It only puts out 5 amps.

[russ_drinkwater]

Ran the house over night on the 24 volt surrette pack. Surface charge dropped off rather quickly and I was a bit concerned around 9pm.
The voltage was sitting on 24.9 when I went to bed at 10pm and dropped to 24.6 when I checked it at 6am. So roughly sitting at 65% capacity just before sunup.
I admit it is not fantastic, but I will continue to work them to see if their holding ability increases.
3 of the remaining battery packs are resisting charge and I continue to poke and prod them with various dc supplies.
Worst case is I will end up with 24 volt pack and a 12 volt pack for my sons workshop.

[russ_drinkwater]

Well things progressed well with the surrettes. Out of  24 cells I managed to get 21 going again really well. The other 3 are as previously described as "funky". The lowest voltage in the 3 tight cells is 2.12 volts. I will keep working working them. The pack will run the house overnight.  The 21 "good" cells gas well when equalized while the heavier sulphated 3 are a lot slower to gas and have a lower response to the charge.
I wish I had a means of doing a digital test of the internal resistance of all the cells as this would give me a better idea of what is happening!
Worst case is I will go through and test the packs and select the best 6 for a bank and use the best 3 remaining one for a 12 volt bank to use elsewhere!

[Vic]

Hi Russ,

Sounds like you are making good progress.

What are the SGs on the three lagging cells?  Are two of the lagging cells in a single battery?

Assume that these Surrettes are the 4KS25s (?).

Thanks for any info,   Vic

[tecnodave]

Russ-drinkwater,

I use an iCharger i208b Synchronous balance charger/discharger which does test battery internal impedance.      (www.jun-si.com)
This is a model airplane LiLo LiPo charger that also has built in profiles for Pb, NiCad, NiMh, LiLo,LiPo,LiFePo4 and does charge / discharge programmable in .1 amp steps to 20 amps......you don't set the voltage on this one , set the number of cells in the pack.

Really meant for high performance model airplanes using lithium batteries.....but seriously a really good charger......can be programmed to any custom profile you want or some new battery just invented.....USB port for downloaded firmware available from manufacturer

Logging software available.....standard logview software has the iCharger line programmed in
www.logview.com
www.jun-si.com

I have LiLo model airplane packs in my Panasonic portable tools which had NiCad packs no longer available, these power tools were available for a short window but disappeared from US markets quickly...don't know why, they are much better than DeWalt......I hacked a model airplane cell balance port into the battery housing....use iCharger on all my power tools

Input 12-32 volts DC

When I need to boost one cell when doing a difficult battery recovery I use the Classic 150 or other multistage charger as the main charger for the whole string and then connect the iCharger to the reluctant cell to boost current/voltage on that cell.........but because the iCharger is a buck/boost converter it's source of power cannot be the battery that is being boosted......it must be totally isolated.....I sometimes use a jun-si P-350 power supply which is AC in and 15.5 volt DC out to run the iCharger.......other times a totally isolated 24 volt bank......anyway I think you get the idea of what I'm doing there

I also use the iCharger in logging mode with the balance port connected to each cell and logging in logview, charging done by other device

Nickel-Chromate wire probes inserted through special battery caps to connect internally to batteries that are internally connected......6 volt L-16 and such....I much prefer 2 volt cells...now you have total balancer technology available.

Check it out, it's a neat tool.

David

[russ_drinkwater]

Hi,
Yes the batteries are 4 ks 25p 's.
One pack with the doggy cell reads 1200 sg (just the one cell other is 1275)
The really toast one is unable to register with a hydrometer on either cell in the pack!
I suspect that particular battery has been tipped over and lost fluid as both cells were extremely low when I got them.
Have been toying with the idea of emptying both the cells out and replacing the electrolyte?
If the acid percentage is not right then it can not be expected the the 2 cells will ever be able to be charged correctly!
I really not sure what to do with those last 2 packs as the rest came up so well!

[Vic]

Hi Russ,

Thanks for the info.  Still seems like you got a very good deal on those batteries.

Wonder if the lowest batteries have the same or very similar date codes.

On the very low battery,  you may well be correct about the battery being knocked over,  and drained for some period of time,  and refilled even before you got them.

This may not apply to your situation,  but am sure that you know that if you pop off the top cover of these batteries,  you will be able to get to the two bolts that bolt the cells together.   Obviously,  when unbolted individual cells can be removed,  and perhaps swapped around ...  you may not have enough bad cells to have this make any difference (a good thing!).

Good Luck,    Vic

[russ_drinkwater]

Vic,
I am happy with the buy after being very nervous for the first 2 days after getting them home and seeing them fail to take charge!
It was omg, was I really crazy enough to do that?
But the first bubbles in the bank of 3 packs (12 volts) lowered my pulse rate about 60 bpm and quelled the nausea!
The plan is to use the 6 best packs for myself. And worst case is a 12 volt pack for my sons workshop as he has a 12 volt latronics inverter as well. I have another 150 classic reg coming so I can charge my trojans independently and have 2 x 150's and 4400 watts from all my good panels going into the rolls bank. I have some sharp 30.2 volt panels I picked up for $50 each and I will use them on the trojan bank.
What do you think about draining and refreshing the acid in the dodgy 3 cells?
I would need to find out from rolls what acid strength is the recommended replacement.
Are the date codes stamped on the terminals?
Out of 24 x 2 volt cells I have ended up with 3 dodgy cells and I am not sure what the hell I can do in regard to getting another 3 cells or
just cut my losses and go 12 volt on one pack. The buzz bars inside and all still look great and I feel it will be either very low acid strength or heavy sulfation causes the issues. What should the voltages on a 4 volt pack be after surface charge has dissipated be?

[Vic]

Hi Russ,

All of the Surrette Solar batteries that I have seen want 1.265 SG electrolyte.  They spec Capacity as if the electrolyte is 1.280,  but  everything we have seen in the USA,  is 1.265 SG.

A Rested Surrette cell should have a terminal voltage of about 2.11 V,  at 25 degrees C.   Some might say that it is about 2.13 Vpc,  but right in that range,  IMO.

Yes the Date Codes are on one flag terminal,  and possibly also on the large label on the side of the battery.  The other terminal usually has the plate type  --  KS in your case.  Have not seen recent vintage 4KS25s,  so some of this may have changed,  as both of the banks with this battery model are 11 years old.

Good Luck with the recovery process!   Hope that you enjoy these batteries,  have been very happy with the ones here.    Vic

[russ_drinkwater]

Good news Vic!
I split the bank in two and only have the 1340 amp bank with the dodgy cells running off the controller.
Usually I let the reg do the work with bulk charge etc.
But I have been doing a manual equalize every day to try stir up the electrolyte in the remaining stubborn 3 cells.
So I came home for lunch and TADA the cells in the last battery are starting to gas at last!
That leaves just the one cell to get going.
I will try to some electrolyte from a battery shop, but as I have stated before they do not want to sell it in 5 liter bottles anymore because
all people who have acid in bottles are of course bomb makers in this country
Any suggestions where else I may look as a source of H2SO4?

[Vic]

Hi Russ,

Great news on those batteries starting to come to life.

Perhaps you will not need to add electrolyte to that one remaining lagging cell.  Perhaps it will also come alive.

We are still able to buy electrolyte in 5 gallon containers,  for a relatively low price.

If you measure the voltage of each battery,  you should be able to watch the voltage on the lagging batteries increase,  as their SGs rise.  This should give a good approximate indication of how the SG is increasing,  when the charger is in a voltage regulating stage,  (Absorb and EQ).

Good Luck!   Vic

[russ_drinkwater]

Thanks Vic.
The reason I am so fixated on that one pack with the low electrolyte levels is that both cells were so low!
None of the other packs were anything like it.
I do have some settled out electrolyte stored and I may take a sg sample to see how conc it is.
Will see what happens today after a few hours of sun and what those 2 partially activated cells are doing.
I did note that their sg had risen to a measure-able level before sundown!
Have also got 3 x desulfators attached to them as well.
The sg in all other cells has come up over 1265, so I am happy with that. Will have to see how the batteries progress as far as life goes.
But they are good enough right now to save me a further 10 kws a day in grid-tie power!
Sounds a bit pathetic, but at x-mas when the power companies cough up my bonus grid-tie cheque I will be interested to see how much
extra we have saved. The usual amount will pay the $2,000 for the rolls and still have change.
Is it evil to gain pleasure from having power companies pay you money for extra solar gear??