What to do with used forklift type 8 volt battery banks?

softdown · September 2016

Each bank weighs 270 pounds. Composed of four 2 volt cells. Busbars/interconnects are the giant external forklift type. These batteries have been sitting for an undetermined period. May be over a year or two. They were scheduled for ~scrap value. Selling claiming that he could get .23 cents/lb. Perhaps after shipping direct?

bank #1...6.2 volts (current reading)
cell 1...1200....these are all specific gravity readings.
cell 2...1175
cell 3...water
cell 4...1125

bank #2...8.1 volts (current reading)
5...1175
6...1160
7...too low to check...later filled prior to voltage reading
8...1110

bank #3...5.9 volts
9.....water
10...1150
11...water
12...1185

bank #4...7.9 volts**************************
13...water
14...1200
15...water **************************I combined these two banks for this reading.
16...1150

bank #5...7.9 volts**************************
17...1140
18...1150
19...1200
20...too low to check...later filled prior to voltage reading

bank #6...6.7 volts
21...water
22...1050
23...1120
24...water

bank #7...7.9 volts
25...1140
26...1180
27...1050
28...1130

bank #8...6.2 volts
29...1030
30...water
31...1040
32...water

***These voltage readings are different than shortly after I hauled them over a washboard roads couple days ago...thus mixing the electrolytes....and apparently increasing the voltage readings of all battery banks.

softdown · September 2016

Pretty clear that many of the worst cells don't actually have water. Looks like I need a gauge that gives read outs in the lowest areas.

softdown · September 2016

Considering options:

1) Get forklift battery charger with week-end equalization setting. This would help de-sulfate these old batteries.

2) Get strong de-sulfator capable of 24 volts.

3) Salvage best four banks...yielding 32 volts. Use as 24 volt bank with 8 volt spare. The lazy approach.

4) Attempt to salvage best 18 cells...yielding 36 volts. Would require cutting every bus bar and re-soldering. Likely the best approach. Any solar controllers and inverters working at 36 volts?

Wish it was easy to make 12 volt batteries from. Then simply charge and de-sulfate each 12 volt battery. Then I would have a good idea where each cell stands.

westbranch · September 2016

I would also measure the voltage of each cell and add that to the above table then get a 6V / 12V charger and arrange the cells so you can charge them before desulphating or ?? When they are charged measure again and record all values... once you have cycled them a few times to ~ 60% SOC and back to full.... measure each time you cycle them, looking for cells that do not recover then try desulphating... this is an experiment! be rigorous...

Photowhit · September 2016

You're in a bit of a tricky situation, what do you have for charging? I personally would not want to fight most of the battles ahead. I would use the 3 batteries banks that are above 8 volts, top them off with distilled water, and use a 24 volt charger/solar array to bring them up to as high a charge as they would take then equalize... I might check the results carefully and choose to replace selective cells if I can't get the SG up to the 1270 range. Even at that range, you may have very minimal capacity. You can get a feel for this when you charge them, If they come up quick, they are likely to have diminished capacity. If they take a while, but do come up, you may have some worth while capacity. I'd figure the rest for scrap.

softdown · September 2016

Obtained some different voltage readings after using a better meter. This meter used to bounce until I bought a meter that is too sophisticated to use right out of the box. Now it works perfectly. Technology and me............

It would be so easy to make 24 volt banks if I was not working with 270 pound batteries. The plastic cases are in bad shape too. Snow melted then froze...thus bursting the seams.

I have solar 24 volt charging abilities. After letting the data sink in, it seems clear that I should use that to charge three 8 volt batteries at a time. This will give me a better idea about what I have to work with.

Worthwhile? Good question. I got about 2200 pounds of old forklift batteries for about $450 and a couple trips. The scrap value is about $370. Apparently the MSRP on this group is well over $10,000. These are expensive specialty batteries. Of course MSRP can be a marketing gimmick. Perhaps it included free shipping?

Photowit...the mfr. spec sheet on these batteries is 1.24-1.26. Perhaps they are made for longevity?

There are so many options. For example....I could use short 1/0 cables instead of trying to solder these giant bus bars back together. That would make them easier to work with. Perhaps I should disconnect them all and use the best 2 volt cells. That makes sense right now.

softdown · September 2016

Should I re-construct cut bus bars with 1/0? 2/0? 4/0? Flattened 1" copper bar?

I may be traveling where relatively few men have traveled before. Seeking out new life...boldly going where...

softdown · September 2016

There is a little risk with working with batteries in this condition. I did serial connections with battery banks 4 & 5. This should have yielded a voltage reading of ~15. It now reads above 10 while starting at 7.9. The batteries were at 7.1 and 8.1 prior to serial connection.

This is where it gets interesting. Went out in the field to check on things. Hear some "boiling" going on and note that two cells are warm to the touch. Started moving faster. Got my wrenches and infrared thermometer. The two cells that showed "water" were at 112 F and 117 F. Starting moving fast. Removed serial connection. Boiling stopped immediately of course. Noted that 117 F cell now showed 120 F. Made an executive decision to leave that area of the field.

Six of the eight cells are reading ~2 volts. The two cells with "water" as specific gravity read about 1/2 volt. Conclusion: the cells that read "water" are both unrecoverable and a safety hazard.

What to do with used forklift type 8 volt battery banks?

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