I messed up big time with my batteries

[25074]

We went on a trip and my bus was parked and I never plugged my battery charger in when I got home.

Something was left on (I think a light) and it completely drained my 2 deep cycle batteries.

I’ve had them plugged in separately on a 4 amp charger and it’s taking FOREVER to charge them.

I know, I know, that completely discharging the batteries is bad.

They are only like 2 months old and used very little.

Do you think I’m ok?

They’ve been plugged in for like 3 days straight and the charger isn’t showing green yet.

Any ideas?

[magnakansas]

some chargers have a kind of self checking mode.... If the charger does not think it is hooked up to workable battery, it will not turn on to charge.

here is what I do.

hook the charger up, find another 12 volt battery.... like umm the one in your car/truck. connect with battery cables.

you should see the charger start doing its thing. after a while you can disconnect the jumper cables. and the charger will still keep charging.

SAFETYNOTE It is common to make sparks when attaching, unattaching the jumper cables. charging batteries can give off explosive gases. Use eye protection, turn your face away from the battery. Batteries on occasion do blow up.

I am 50, working on cars for 30, seen batteries blow up three times now. No one hurt in all three cases.

william

[family wagon]

A deep discharge definitely makes its mark on batteries. Their capacity will be reduced, but you'll have to recharge them to find out whether you can tell the difference. At this point what's done is done, so you might as well recharge them and use them like normal to find out whether (how much) they're still good.

What size batteries are we talking about here? If they're, say, 200 AH then a 4 amp charger should take many days to get the job done (like all week, perhaps). You should really think about getting a bigger charger.

The first 70% or so of charging is called "bulk" and can go fast (if the charger is capable). In the remainder of the charge cycle the current tapers down, so the final part just takes a long time no matter what. At this point the bulk is probably mostly done, so a bigger charger might not do much for you now.

[25074]

I checked my batteries and they are reading 13.85 v. They are in parallel.

From the battery label

31 DC - Duracell
MCA -810
CCA - 650
Min at 23 amps - 225

The charger says it’s almost full but it’s been like 4 days now. But they were DEAD.

I really only use it for my CPAP machine (hooked to a 3000w inverter) and I have them tied into the overhead cabin lights and that’s only really when getting ready for bed.

I have an on demand water pump for the kitchen sink that I seldom use.

And USB plugs for devices.

Thoughts?

[family wagon]

Sounds like it's plenty of battery for the intended use, and it's getting pretty close to being fully charged.

An automatic low battery cut-off might be something to consider to prevent future deep discharges.

[25074]

I’ve installed a master switch that will turn everything off when I park it after the trip. Problem was that something was left on for like 2 weeks. But a low battery cut off would work as well.