CHARGING A SINGLE CELL OF A FORKLIFT BATTERY

Ralo

Solar Enthusiast
Joined
Jan 12, 2020
Messages
203
I have a weak cell in one of the lead acid forklift batteries on one of my DC Solar trailers. One of the members here has used and recommended this HindlePower Single Cell Charger to individually charge the weak cell in hopes of bringing it inline with the other cells. He has reported good results, so I went looking for one. I found one on eBay for $200 and I thought I had gotten lucky (since a new one is over $500), but it was dead on arrival. I was also surprised that it was rather small and lightweight. And it is limited to 2.6v @10amp (when it works).

Not much to it that I could tell, so I got to wondering why wouldn't one of these cheap lab power supplies not do the same thing? The voltage can be set to 2.6v @ 10amps just like the expensive single cell charger. Voltage is voltage, right? Amps are amps? So will it perform the same task?
 

RCinFLA

Photon Sorcerer
Joined
Jun 21, 2020
Messages
1,779
Looking the picture, the battery cables are a joke. Looks like #14 gauge wire.

To do any real equalization on a forklift battery you need some serious amperage, like over hundred amps.

Don't waste your money. If you want to play, get a couple of these. They are cheap.

 

time2roll

Photon Sorcerer
Joined
Mar 20, 2021
Messages
3,887
I thought equalization should be done after a full charge and at fairly low amps around 2% to 4% of capacity to let the voltage drift up for a couple hours.
 

RCinFLA

Photon Sorcerer
Joined
Jun 21, 2020
Messages
1,779
When there is hard sulfation that will not recharge, the best that can be done is to hit it initially, while still low in charge, with high current density to knock off the hard sulfated crystals, exposing fresh lead plate surface. Slow recharge rate on a sulfated battery can actually re-grow lead around crystals encapsulating them so they will not drop off.

High recharge current and vigorous bubbling will help dislodge the crystals. At the top end equalization, the vigorous bubbling is providing the mechanical force to knock off the sulfation.

What is knocked off will make its way to bottom of cell. Forklift batteries have very thick plates and a lot of room at bottom of battery casing for sludge collection. Sulfur chemically bonded with lead in crystals that drop to bottom ties up sulfur that will no longer be available to recharging back to electrolyte sulfuric acid so specific gravity of electrolyte will not come up fully.

A common problem with lead acid batteries that have been sitting around is stratification of electrolyte which causes lower half of plates to be exposed to higher acid concentration causing more sulfation damage on bottom half and little damage on upper half of plates.

The vigorous bubbling is water electrolysis with oxygen from positive plates and hydrogen from negative plates so be in a well-ventilated area. The equalization process will consume a lot of water. Keep replenishing electrolyte level so it stays above top of plates by adding distilled water.
 
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Ralo

Solar Enthusiast
Joined
Jan 12, 2020
Messages
203
Well, I already own one of the cheap lab power supplies, so I used it. It raised the voltage of one weak cell and exposed another. So now I’m boosting the new weakest cell but I will soon be connecting much more solar so I should be able to fully charge the batteries almost everyday, and equalize the pack on a regular basis. Hopefully with the additional solar I can keep the pack above 50% SOC.
 
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