Big Ole batteries

I have some large batteries. They weigh 350lbs a piece they are 2v calcium plate batteries. 2515amphr.
Any thoughts on a charger that would work with them?

You're going to love it here, MaintenanceMan2!

Holy cow, those are large batteries!

Yes they are. Lol
I’m just a consumer can you imagine me unloading 6 of these from the back of my truck with a tractor bucket and some ratchet straps? Lol

I saw your Thread on DIY Solar

I figured. Lol
I used the same name just for that reason.
I can’t find an effective way to charge these batteries.
I am joining all the forums. Lol

Do they not take a charge when connected, e.g. connect all 6 in series then use a 12V charger such as car battery charger, the higher the amperage the quicker the charge. It may take a while unless you can find a high current charger, 75 - 100 Amp, even then long time.

What (flashlight?) are you gonna use them?

Lol. They won’t be used for a flash light that’s for sure!
In order to charge them properly I need 250amp hrs worth of charger.
That’s 10% of the capacity.
Or so I have been told.

Most of the time you Paralel charge batteries before connecting them in series

Once they are hooked up in series how do I keep them charged?

A Big A—S charger or multiple chargers in parallel — the problem you are going to have is — used batteries — no telling how much each one can actually hold — therefore when you series charge them — some might get overcharged

How can I overcome these issues.
I hate to just scrap them.

You would just have to add distilled water to any cells that reached the upper end, which isn’t likely to happen anytime soon. but a 12V charger is easier to come by than a bigassed 2V power supply for parallel charging. Ignore the 10% rule of thumb for now.

The 6 series 12V string would let you know whether it could accept charge and would be worth buying an expensive power supply or even pursuing. Charge it for 24 hours then check if the OCV has risen or not; if not then they are scrap for recycling. If they do come up then it might be worth investigation of higher current power supplies/chargers, make or buy, etc.

We had a bank of cells like that for our lab, the charger was the size of a phone booth or Tardis.

There may be some used 6v or 12v golf cart battery chargers out there for low cost, high current, etc.

If you can, label them all and measure/record the at-rest open circuit voltage first; then connect in series and charge with the biggest 12V car charger you got for 24 hours; then disconnect everything and remeasure/record to compare.

That capacity is surprising at that weight. Aren’t those essentially lead-acid deep cycle cells? When I was in that world 2 amp-hours per pound was doing pretty good.
Edit: silly me, forgot that’s for 6 cells. Sounds like a typical solar battery. If you can get a single-cell lead-acid charger you should be fine. I’d want to balance-charge them.
Also, note that the 20hr rate is likely 1700Ah capacity, and 2500 is probably the 100hr rate.

Well I didn’t test every one but the ones I did test were at 2.2 and 2.3 volts…I pretty sure they are charged already!
I tested them with a chep DMM.
I need to get a Fluke.

Are you talking about discharge capacity?
The tag on the battery says 2515 over 8 hrs

Welder

The charger was interesting 415v 3phase delta incoming a transformer with 120v star delta secondary into a 12 pulse bridge rectifier. The inductor was 300mm wide copper sheet and weighed 100kg

Best brain can come up with is a forklift charger. Lol

solar panels?

look up the chemistry

are they lead acid?

what does calcium plates mean?

Calcium is the additive used in the lead plates. Yes lead acid.
I don’t have any panels.

a car battery charger would work - if there are 6 in series, and you have 200 hours

it doesn;t make sense to charge them unless you can use them though

if they have been discharged below 1v per cell for over a month, they may not be recoverable

also check electrolyte levels

you need a 250A charger, which would need 240VAC input, and would be $$$, to do it in 10 hours

wle