Battery Charger.

[LDVV]

I bought this battery charger, and the manual is a bit lacking.

By the look of it, it's a generic design, that has been relabelled to suit the local retailer here.

If any of you have, or have had, a similar one, what would qualify a battery for the "Repair" cycle?

...and I always charge at either 5A, or 10A, setting. I'm guessing the higher current would charge batteries a lot faster, but I don't know, in what instances, when I can use 20A or 30A.

 

[LDVV]

Also, I plan to use four of these batteries to create a 24v 240Ah system, in my Garage.

Having read so much recently, I've lost track... However, it was apparently a good idea to charge two batteries at once, to attain a good level of balance.

If there's any truth to this, would I do this in Parallel?

Or does this practice of "balancing" only create a negligibly positive result?

 

[joanna_lannie]

If you choose to assemble a 24V battery pack, then a dedicated 24V charger would be fine, which doesn't require you to charge the batteries individually, and the question about battery balancing you mentioned is no longer an issue.

 

[Rednecktek]

If any of you have, or have had, a similar one, what would qualify a battery for the "Repair" cycle?

For me when I use the Repair function on mine it's always FLA or AGM, NEVER LFP!

I do it when I have a battery that was:

Deep discharged for long periods of time
Unattended sitting idle for long periods of time
Not holding a charge worth a damn
Had to add a LOT of water

As to the high amperage, my 4x 12v bank at the camp doesn't get charged at all while I'm gone, so when I first get there and fire up the generator I'll kick the battery charger up to it's 25a max and top off the whole bank. Probably not healthy but I'm still learning here.

 

[Browneye]

I bought this battery charger, and the manual is a bit lacking.

By the look of it, it's a generic design, that has been relabelled to suit the local retailer here.

If any of you have, or have had, a similar one, what would qualify a battery for the "Repair" cycle?

...and I always charge at either 5A, or 10A, setting. I'm guessing the higher current would charge batteries a lot faster, but I don't know, in what instances, when I can use 20A or 30A.

'Repair' is a trickle charge at high voltage for flooded lead acid batteries. Don't use this on a lifepo4 battery.
If you're going to series and parallel four batteries together make sure the manufacturer recommends such - in many cases the built in bms for these types will not support this type of arrangement.

But assuming they can, then before you connect them in parallel you want to charge them to the same state of charge. Otherwise you'll have a giant current flow from one to the other if they are severely mis-matched. Users have reported up to 500A in these situations. We don't want your burning your place down.

Depending on the BMS, most lifepo can be charged at 1C - or 120A in this case, but again, you'll want to check your specs. .5C is more common, or less, but 30A is fine for charging one or two in parallel.

The GEL setting on the charger would likely work, they tend to have compatible charge voltage parameters. Again, I would be nice to see what those values are. Generally a 'smart charger' will have three-stage charging - boost in CC to a set voltage level, then absorption at CV for a duration or tail-current, then float at a CV maintenance level.

What are you planning to do for charge maintenance for the built pack at 24V?

 

[HRTKD]

@LDVV, before putting those batteries in series, they should be charged to the same state of charge. Let's say one battery is at a lower state of charge (battery A) than the other (battery B). When you put the two batteries in series and connect them to a 24 volt charger, the BMS on battery B will stop charging when it hits the over voltage threshold (either on the battery as a whole or on an individual cell). When that happens, battery A is no longer charger. This will start an unfortunate cycle where the two batteries may never get in sync.

If you haven't already purchased the batteries, consider buying 24 volt batteries instead of putting two 12 volt batteries in series.

 

[rmaddy]

When you put the two batteries in series and connect them to a 24 volt charger, the BMS on battery B will stop charging

in many cases the built in bms for these types will not support this type of arrangement.

The OP has LA batteries, not LiFePO₄. No BMS.

 

[Browneye]

The OP has LA batteries, not LiFePO₄. No BMS.

Ah, I missed that. I looked at the pic and thought I saw a OFS lifepo pack.

In any case, 'repair' is not used on a sealed lead acid battery. And equalize is questionable, some chargers only do this for a few minutes.

What else did we miss?
What is OP using for the 24V pack for charging? Same charger?

 

[HRTKD]

The OP has LA batteries, not LiFePO₄. No BMS.

Well crap. You're right. It's a VRLA AGM battery.

https://www.fiamm.com/fileadmin/user_upload/SP_FOLDER_FAP_ENG.pdf

With that in mind...