Unfortunately 18 year old brain got my 50 yo broken body in over its head and everything is taking much longer on this little project.
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That's a pretty interesting building...  

Forklift battery seems to have recovered...

The SG is up to 1270 and it absorbs nicely at 15.4 vdc.

Pix how I divided it into 2 12 volt batteries and all the new controls soon...

I keep learning here

Love these $30 tanks from an auction...

That's the idea!

Last week went to the barn and measured the SG of the Fork Lift battery.

It's improved to ~1.275.

The 'scale' on top of the perforated insulators on top of the plates has loosened all up...

Today it absorbed 4.2kw and was only in 'absorb' mode for 20 minutes...

So it can take a lot more...

One of the L16's seems to have a bad cell, and now the cell next to it is weak.  Might be a leak in the plastic case... The other cell is normal as is the other L16 in series...

Got another forklift battery recently...

All the $$ and weeks of investment in the lab power supplies, knowledge, set-ups, cables, etc...

Were implemented on it in 30 minutes, and it's getting charged right now...

It's ~ 15 yrs old, guessing, have to call the mfg'r to determine.

Looks like it wasn't used much, poorly cared for and that 3 cells of the 12 may not respond, ---even if any of them do...

Plenty of pix taken...

Oh boy ---the story of the 'new' forklift battery...

Have a ton of pics to post, need to get them on Photobucket...


The 3 cells were indeed bad.

We spent Sunday afternoon to 11PM removing the two that are on the 'right' side of the battery...

And Monday and Tuesday removing the remaining 'bad' one on the left side


9 or 10 hours a day the past 2 days...

The first two we got out on Sunday by 11PM by using a Forstner bit and extensions and boring out the 1/4" Masonite slats the mfgr had cut and vertically 'shimmed' the empty space between the two cells and the steel housing.

The cells are about 27 inches tall and about 8" x 5" square.

We used a Lodestar electric hoist with a Dillon dynamometer [weighing scale] both from eBay about 15 years ago, to weight and remove the battery from the trailer onto a pallet jack and to pull the individual cells.

Battery weighs about 1500#

Each of the 12 cells weights about 120#  The very heavy battery "tray" weighs I'm guessing about 200#.

Here's a representative picture.

There's some differences, the cells are rectangular as already mentioned, and the steel case is larger, requiring Masonite 'filler' slats to fill the vacant spaces at each end...



Good spec resource...

Capacity, sizes, prices...

http://gbindustrialbattery.com/Forklift_Battery_Sizes_and_Specifications_Zone15.html

The vacant Masonite areas on each end of the battery are like a solid mass of compressed wood.

They've swelled and so have the batteries slightly or maybe not-  and were locked in place...

The 2 bad cells that were together were relatively easy to pull after spending about 6 hours drilling boring and cutting away the hardened Masonite.


The one bad cell on the left side was Hell to get out, without damaging the -hopefully good cell across from the mass of wood.

It took two days of drilling, sawing, picking, chiseling, etc.,  in a small cavity about the size of 2 playing cards -side by side.


The little area is about 28 inches deep and using the hoist and the weight of the battery, wouldn't slide out until all the Masonite was removed all the way down abt 28"


We made ~.03" or thicker, metal 'shims' from large floor scraper blades, metal yard stick, etc., to hammer down beside the two cells to protect them from the aggressive cutting.

Even with most of the Masonite removed with just a seeming inconsequential septum of the wood left a couple inches, the cell wouldn't budge.

My SO was impatient, often wanting to try pulling it again, sometimes we did to no avail.


I finally got everything out using an array of Forstner  and spade, bits, hole saws, homemade chisels, shop vac, extensions, and an array of tools [see picture]

I was planning to cut the thick steel case if necessary.

Or try to pull the guts from the cell 'jar' first if possible.

There were some nails at the 23" level that ruined a couple Forstner bits.  1 1/2" size... Switched to a hole saw at that level...

Battery cells are pulled lifting from the negative post -we pulled the positive and negative posts simultaneously using small chains, vice grips, attached to larger chains.

Then the ceiling hoist.

See pictures.

The day before we started pulling the cells, I charged the battery for about 20 hours.

The 2 Hewlett Packard supplies were individually connected to each 12 volt half of the battery. Charge current was set to 22 amps with the constant current function.

A towel covered the battery to capture most of the microscopic droplets released during aggressive bubbling.


After charging I ran the good 12 volt interconnected [fortunately] string of 6 cells to a 12 volt 10 amp car heater and a Xantrax inverter driving a 125 watt flood light for a total drain of 22 amps.

I was amazed when the load was still running 14 hours later and then the inverter tripped out at about 10.5 volts but the heater continued to run even after the SG of the battery got down to about 1.110


Oh, the first charge got the batteries to about a SG of 1.200


Looking at notes here about the first forklift results, it went flat with a load of just 300 watts in 15 or 30 minutes.  It's now in the mountains on the solar system with excellent capacity and a charged SG of 1.270 as of a few days ago.

After the first ~20 hr charge, the next day when I came to measure the cells, the battery was close to being hot!

It turned out the 3 bad cells were heating up the whole bunch, by some sort of reaction.

After I disconnected the battery from the loads and used the pallet jack to move it under the lift to remove the bad cells...

For aesthetic reasons ---


I heard the 3 cells fizzing inside...

Fearing an explosion -I got my SO to mix a concentrated solution of baking soda and pour some in each of the 3 cells.

After the liquid foamed and overflowed the cells, we poured more in...



The cells quit fizzing...  I suspect there was an air lead salt reaction going on but the cell was pretty much properly filled when I started the charge...

We cut the interconnecting straps of the 3 bad cells with a sawzall, and isolated them.

LUCKLY the remaining possibly good cells connected in a group of 6 [12vdc, 'front side'] and a group of 3 [6 vdc, 'rear' side]


Just looked at an IP cam pointed at the battery and floodlight and the inverter is tripped, after about 15 hours, and I'm not sure the battery was charged as much as it could hold even in its deteriorated state.

I'll start charging it as soon as I get there for about 24 hours...

The heater is no doubt running still drawing about 10 amps...

Once I get it charging again, we're going to remove the lead core of a cell from a jar and evaluate the sediment on the bottom and the remaining positive plate thickness...

We determined the age of the battery because one of the cells we pulled was marked with a date of 1994...




There was no scale on the top internal horizontal perforated insulators -unlike the scale I mentioned on the first forklift battery. Suggesting this battery was not used much and was left unattended to sit for a long time...

The second charge before we took out the bad cells got to a SG of ~1.215


Yep-  we'll see how this goes...

The 1994 Trojan forklift battery was connected to the system in the mountains a few weeks ago.

Lot of pics to show how we transported it, lifted it, etc. It weighs with all cells about 1500 pounds.


It's definitely weaker -at present-  than the forklift battery we installed last year, that one seems to be working pretty good and got us through the winter in combination with the aging and failing L16 batteries.

We had to replace two of those in the past month or so, and I expect more will be failing sooner rather than later. They failed during the winter and I didn't realize it to about 6 weeks ago.



The 'new' Trojan battery uses cells specified as 125-13. This means each of the positive plates is rated for 125 amps at a 6 hour rate.

There are 13 plates, 7 negative and 6 positive, and so 6 times 125 amps yields a cell with a rating of 750 amps.


One thing to note is the cell plates are much thicker, in the Trojan battery, from doing an 'autopsy' on a bad cell, the negative plates are almost 1/4 inch thick.

This is several times thicker than the L16's


So, the forklift battery may be heavier, but this doesn't translate linearly to 'capacity'.  The forklift battery will last many years longer.


Individual cells can be purchased as a DIY replacement to repair forklift batteries.

I've found that the positive plates are the real failure point in a wet cell battery.

More info on the 25 year old Trojan forklift battery.

Until about a month or a little longer it was connected to the barn solar battery buss through a Schottky high current isolation diode rated at about 100 amps.

The reason was to limit the charge voltage to less than the -around 15.2 max charge voltage, or so, depending on battery temperature- by about a difference of 0.3 volts less.

I installed a contactor, -remotely controlled by a DAQ device connected to our network that is linked to various locations- to control the contactor.


So recently I've been leaving the energizer activated, connecting the battery buss directly to the 1200 pound Trojan battery.

[Incidentally, I think Trojan got out of the forklift business years ago]


The specific gravity of the Trojan hasn't come up much more than 1.250 after months of charging.

The 15 year old DEKA forklift battery on the other hand, has come up to close to new specs and is working great. It saved my bacon when we had some extended cloudy days or snow on the panels this past winter went it would have been difficult to get to the barn and while at the same time the 7 year old L16 batteries were beginning to fail.

At this time only 4 of the 8 L16's are still in service and they are likely to fail at any time.


The Trojan forklift battery has an internal high impedance, as would be expected since the SG hasn't moved much past 1.250.  It will provide 50 amps for a few hours but if I try to start -say a drill press, the voltage drops and the Xantrex inverter trips out.

The DEKA battery will start a big DeWalt chop saw with no issues.

The thinner plate -and more plates- L16's are good at providing high currents briefly, even in their aged state.


We disassembled a couple of the Trojan battery 2 volt cells and the positive plates were in sad shape, the negative plates almost like new after 25 years.

Unloading Trojan forklift battery at the barn...