24V Giant Forklift Battery - Lead Acid Care

[Braddudya]

My company just took delivery on a heavily used crown walkie stacker forklift. It has a ridiculously huge 24V lead acid battery. It arrived fairly dead but I have charged it up to fill and it seems to work great and have plenty of capacity for our limited needs.

I want this to last AS LONG AS POSSIBLE!

What is the best way to care for this battery? If it was a lithium I would just charge it to 75% and try to keep it around there.

From my reading on these batteries it is suggested:
- don't over discharge
- when you do charge charge completely
- don't leave it at a partial charge state for extended periods
- try to minimize the number of charge cycles

This is a crap list of recommendations for us haha. We will use this machine for maybe 2-4 hours a month! So should we just charge it after every use and keep it at 100%? Should we charge it to full everytime it reaches a certain percentage? I am just struggling with determining what's worse extra short charge cycles or leaving it at a partial state of charge.

Thanks

 

[john61ct]

Yes, keep it well topped up, lead wants to sit at FULL 100% as defined by the mfg spec sheet, including a long Absorb (CV setpoint) stage, termination point based on trailing amps, before dropping to Float V.

Every 1-2 weeks if not cycled, maintain Float voltage overnight.

Of course it may be past EoL, only a CC cap test will tell SoH with accuracy, a coulomb-counting wattmeter for rough.

Obviously a huge unit needs a high amp charger, say up to 0.1C, not cheap. Ideally adjustable voltage setpoints.


When discharged, ideally stop at 50% SoC, the wattmeter will help once you establish capacity at the normal discharge rate (ballpark) will be a lot less than at 0.05C 20-hour rate.

Only pulling 30-40% might double remaining lifespan.

 

[Braddudya]

Yes, keep it well topped up, lead wants to sit at FULL 100% as defined by the mfg spec sheet, including a long Absorb (CV setpoint) stage, termination point based on trailing amps, before dropping to Float V.

Every 1-2 weeks if not cycled, maintain Float voltage overnight.

Of course it may be past EoL, only a CC cap test will tell SoH with accuracy, a coulomb-counting wattmeter for rough.

Obviously a huge unit needs a high amp charger, say up to 0.1C, not cheap. Ideally adjustable voltage setpoints.


When discharged, ideally stop at 50% SoC, the wattmeter will help once you establish capacity at the normal discharge rate (ballpark) will be a lot less than at 0.05C 20-hour rate.

Only pulling 30-40% might double remaining lifespan.

If this is all true I can probably maintain never pulling more than 10%!

We have a very small pallet racking area in our warehouse that we really use for long term storage more than day to day transfers. So most days the machine won't even run, other days it will only run for maybe a half hour.

For charging we are just using an old school metal box charger that has a 24V 30A setting. It took forever to charge from the low state but for our use it should keep up just fine.

Should I be looking at a 24V "maintainer" to leave it on when it is not in use?

Thanks again

 

[john61ct]

There are three parts to the charging spec for a given lead acid battery, not to be exceeded. (examples only)

CV setpoint, the max voltage transition point from CC / Bulk stage to Absorption. (29.2V)

The termination point, definition of 100% Full. Ideally EndAmps, based on trailing amps as a C-rate, (0.005 or 1/2 an amp per 100Ah capacity).

Often an approximated Absorb Hold Time AHT will serve as a proxy.

Float setpoint for after 100% Full is reached, can leave indefinitely. (27.2V)

Ideally these aspects of the charge profile can be adjusted on the charger.

The actual numbers should be found from the maker documentation or calling their tech support.

It is not necessary to keep connected at Float when not being cycled, but then the bank should be topped up at least every couple weeks or weekly better.