Bought a used forklift battery. What did I get?

softdown

Some of you know that I have been looking for a used, but usable, forklift battery for some time. Found one that looked like a decent prospect and drove to Sheridan, Wyoming....a very long trip. The story is that the owners thought this battery had died so they replaced it. Turned out to be the forklift computer. So this battery sat for a year before they traded it to an engine mechanic.

The new owners measured "48.1" volts and decided to sell it after a month. The electrolyte level was a bit low....took two gallons of distilled water. Measured 22.2 volts...basically dead for a 48 volt battery. But its a forklift battery. So I paid ~ scrap value...$375 for a 1652 lb battery. The case may be ~ 100 pounds...or so.

Would try charging it but this may be a 24 volt battery. There appear to be 12 cells.

Dimensions:
Width: 35"
Height: 29"
Depth: 13"

Just got back from a very long drive including Mt Rushmore. All of the presidents were in tears but thats another story. Can't call the manufacturer until tomorrow.

Most important thing right now is to determine if this battery is 48 volts (as advertised) or 24 volts (as it may appear).

EDIT: I believe this is a 24 volt battery. So it is probably still good with 22 volts. What a journey...
Attachment not found.

BB.

Looks like 12 cells--So 24 volt maximum (assuming all cells are in series). Checking the Specific Gravity of each cell will give you some idea of the overall health too.

-Bill

softdown

Agreed...think I can charge it with a 12 volt charger after finding the proper points.

The water level was too low to check SG at the time of purchase. But believing the battery was dead saved me a little. How in the world did mechanics and such think this is a 48 volt battery?

BB. wrote: »

Looks like 12 cells--So 24 volt maximum (assuming all cells are in series). Checking the Specific Gravity of each cell will give you some idea of the overall health too.

-Bill

softdown

Problem with S.G. check is there is ~1" of distilled water sitting on the top. So the readings are extraordinarily low....as can be expected.

Have two 8 amp chargers/de-sulfators going and started reading 23 volts almost instantly. Looking good...

I can store the battery after getting it to ~25 volts....with luck. This will take...awhile. 1-2 weeks is my guess....with 16 amps of charging power.

Then I'll buy some old solar cells and simply have another bank for a couple big loads.

EDIT: Almost up to 24 volts with two car battery chargers going full blast. Took less than an hour.

Dave Angelini

Taking less than an hour is not a good sign and actually indicates that the battery has lost most of its capacity.

softdown

While actively charging the batteries, one is, to an extent, reading the battery charger. I have a couple 8Ds that I probably killed last spring. They read 13.8...while charging.

The voltage quit climbing at 23.5 volts....this battery bank is hardly getting tickled by 16 amps.

Generally speaking....I'll agree with what you said.

Thinking about firing up the diesel genset and charging at 40 amps for awhile. That might get the fluids moving a little.

Dave Angelini wrote: »

Taking less than an hour is not a good sign and actually indicates that the battery has lost most of its capacity.

softdown

Charged them until my inverter shut down building power....presumably due to low voltage. The forklift battery bank now sits at 23.2 volts while starting at 22.2 volts. Took a lot of power to get from 22.2 volts to 23.2 volts. Which, as Dave Angelini indicated, is a good thing.

Wondering about using a 5500 watt genset to charge battery at 65 amps. I've heard this may harm the genset...

inetdog

softdown wrote: »

Wondering about using a 5500 watt genset to charge battery at 65 amps. I've heard this may harm the genset...

Running a diesel genset at less than half power for an extended period (as needed to charge the battery) can harm the diesel. Other than that, running a battery charger at ~1800W should not harm a generator at all.
However, note that the rectifier in the battery charger will essentially be pulling power only during the peaks of each voltage cycle, and this "non-linear" load can be harder on a genset than a resistive load.
As long as you stay below 50-% of the generator capacity, you will probably be OK.

PS: Any parts of the plates that were sticking out above the electrolyte level will be permanently damaged, and the rest of the plates may be badly sulfated from sitting for a long time at less than full charge.

softdown

11 out of 12 of the cells were ~ 1/8"-1/4" above the electrolyte level. Which one might expect of a battery that sat for ~ 1 year.

Opinions seem to vary on how many watts are required of a genset to produce, say, 40 amps of 12 volt power. At first glance, one would think that only 4 amps/480 watts are required. I know a master electrician who says a genset should be rated for 40 amps to run a battery charger at 40 amps. This seems counter-intuitive to me.

Yes...I am sure this battery is suffering from heavy sulfation. Being a forklift battery, I think it can be rescued...to a degree.

Thinking my best strategy may be to charge it at 65 amps until it is "fully charged". Then run 8 amp de-sulfators on "both sides" for a couple months.

It will likely be a couple months before I can acquire the panels and electronics to fully employ this forklift battery.

inetdog wrote: »

Running a diesel genset at less than half power for an extended period (as needed to charge the battery) can harm the diesel. Other than that, running a battery charger at ~1800W should not harm a generator at all.
However, note that the rectifier in the battery charger will essentially be pulling power only during the peaks of each voltage cycle, and this "non-linear" load can be harder on a genset than a resistive load.
As long as you stay below 50-% of the generator capacity, you will probably be OK.

PS: Any parts of the plates that were sticking out above the electrolyte level will be permanently damaged, and the rest of the plates may be badly sulfated from sitting for a long time at less than full charge.

softdown

Changed my strategy upon consideration of inetdog stating that gensets are less than ideal for making power for a typical battery charger.

Now running the genset into my inverter so I am now charging the main 48 volt battery bank which fell to ~64% charge from yesterdays forklift battery charging exercise.

Using household power for the battery charger which shows it is giving 60 amps to the forklift battery.

softdown

Blah...65 amp battery charger died. Can't go a day without something dying it seems. Back to two 8 amp chargers and waiting a couple weeks. Oh well.

inetdog

softdown wrote: »

Blah...65 amp battery charger died. Can't go a day without something dying it seems. Back to two 8 amp chargers and waiting a couple weeks. Oh well.

Was you main inverter by any chance a Modified Square Wave (MSW) output type? If so, the steep voltage edges can cause excess current in the diodes of a simple battery charger and burn them out eventually.
Even some PSW output inverters can be bad for battery chargers.

softdown

Good theory but it is an Outback 3648. Apparently the charger got hot enough to shut itself down. It is working again.

But I'll stick with the two 8 amp chargers....working 24/7. If my main battery bank can handle that.

inetdog wrote: »

Was you main inverter by any chance a Modified Square Wave (MSW) output type? If so, the steep voltage edges can cause excess current in the diodes of a simple battery charger and burn them out eventually.
Even some PSW output inverters can be bad for battery chargers.