So I F**d up! I did some work on the boat where i keep 3 x 12v 100ah amp batteries connected in parallel so i get 300ah.
When reconnecting everything, I reversed the connection on 1 of the batteries. All 3 batteries went completely flat dead.
I'm recharging them now. they seem to gain charge.

I'm just wondering how much I could have damaged them. Im concerned the ah of each batteries would be diminished or worse?
Anyone here understands what happened and it means?

Thanks

 

Welcome to AAC

It means that you are lucky they did not blow.
What happened here was you got careless around high capacity batteries.
If the batteries are completely flat as in below 10V, they won't last long

 

Welcome to AAC

It means that you are lucky they did not blow.
If the batteries are completely flat as in below 10V, they won't last long

Damn, That's what I thought. Do you think there is any danger in charging and use them again until they really die?

 

If your connections are correct there is no danger.

Thinking about you survived a dead short on 24V 100AH battery ( 2 X 12V = 24V ) and all it did was flatten them without fire or explosion, don't you think the batteries are worn out to begin with. Cause a fresh one will definitely cause a fire

 

If your connections are correct there is no danger.

Thinking about you survived a dead short on 24V 100AH battery ( 2 X 12V = 24V ) and all it did was flatten them without fire or explosion, don't you think the batteries are worn out to begin with. Cause a fresh one will definitely cause a fire

they're actually 3 x 12v in parallel, so still 12v. but yeah. sure will check the connection properly next time. I'm just shopping around for fresh batteries. couple hundred dollars down the drain. got to pay to be stupid.

 

I said 2 X 12V = 24V because you said you revered one battery.
Meaning 2 are in parallel giving 12V and the other one is revered causing 24V short circuit.
I believe the reversed one will suffer most as you are shorting a 12V 200AH battery in series with a 12V 100AH battery.

You can check for battery capacity with a tester but you are better off buying new ones in the long run

It's a simple mistake that you need to learn from. A couple of hundred $$$ bucks is nothing compared to your life.

 

I said 2 X 12V = 24V because you said you revered one battery.
Meaning 2 are in parallel giving 12V and the other one is revered causing 24V short circuit.
I believe the reversed one will suffer most as you are shorting a 12V 200AH battery in series with a 12V 100AH battery.

You can check for battery capacity with a tester but you are better of buying new ones in the long run

Got it! I think I'll bring all 3 to the shop so they can test it and will replace if need be. but yeah, Thinking I left them overnight in my boat, lucky I didn't find it at the bottom of the bay.

 

You left the batteries connected all night long ?
Boy ! you are lucky.

Advice....Buy new batteries and always double check before connecting batteries.

 

When you connected the battery in reverse you should have seen a huge spark and your connecting cables would have burnt up.
Maybe the batteries were dead initially. Marine batteries are designed to tolerate deep discharge, unlike automotive batteries.
Recharge the batteries one at a time and do a load-discharge test.

 

When you connected the battery in reverse you should have seen a huge spark and your connecting cables would have burnt up.
Maybe the batteries were dead initially. Marine batteries are designed to tolerate deep discharge, unlike automotive batteries.
Recharge the batteries one at a time and do a load-discharge test.

No spark, no hot wire. the first battery is charging now, so I'm just kind of praying for it.