Battery Care - a very quick question

[Steve_Jones]

Sorry, I know this has been on here before (many times I guess) but I'm helping out a neighbour with her batteries and I can't find the info I need.

I've charged 3 seperate batteries (wet lead-acid, non-sealed) with a proper 3 stage charger over the course of the last week. after being off the charger for an hour or two I have checked with a digital multimeter and they all read 11.95v. I think this proves they are dead (they were left onboard in a low-charged state for a few months). Can anyone just confirm this before I break the bad news?

Thanks.

 

[satsuma]

I would put them on load fırst and see how they react! If they flatten and dıe ın seconds, then yes, they are dead! But they may have just lost some of theır holdıng capacıty!
I had a sımılar battery myself once, flattened out to what I thought was dead. Recharged ıt at a garage but would rarely get to 12v, and certaınly never stayed there. It remaıned ın thıs state for over two years untıl I sold her on! Stıll goıng strong as far as I know (3 years)

 

[HBraf]

How many amps did you apply and is there enough water on the non-sealed batteries.
Just putting a multimeter on the batteries doen't tell you anything about the batteries state.
You need to put a load on it and see if it holds it.

http://www.batterystuff.com/tutorial_battery.html

 

[Steve_Jones]

Thanks guys, I'll take your advice and test further. I'll check the water level.

 

[PeterGibbs]

Sorry, I know this has been on here before (many times I guess) but I'm helping out a neighbour with her batteries and I can't find the info I need.

I've charged 3 seperate batteries (wet lead-acid, non-sealed) with a proper 3 stage charger over the course of the last week. after being off the charger for an hour or two I have checked with a digital multimeter and they all read 11.95v. I think this proves they are dead (they were left onboard in a low-charged state for a few months). Can anyone just confirm this before I break the bad news?

Thanks.

Before ditching the (service) batteries give them not just some float charge but 14.6 V (no more) to load them for a couple of hours. Then let them settle a short while and see if the voltage drops again, as before. Assuming it holds you can then load them with a frig or some heavier appliance - you need a few amps for perhaps an hour. What's the voltage when the load is removed? Back below 12? Then it's bad news.

But before you rip them out, you say you read the same V on all 3 - likely they are linked so isolate them and check if one (possibly the starter battery) is still ok.

If they're 6 years old or more (service batteries) you're into extra time anyway. Say goodbye nicely....

PWG

PWG

 

[VicS]

Charging with a charger which will "recondition" a deeply discharged battery that does not respond to other chargers may be worth a try.

I suggested , just suggested not recommended, the Ring Smartcharger range to someone on here a while back.
He bought one and it did the trick!

So I bought one too!

The (newer ) Smartcharger+ range I believe came out tops in a recent magazine survey.

 

[Colvic Watson]

Charging with a charger which will "recondition" a deeply discharged battery that does not respond to other chargers may be worth a try.

I suggested , just suggested not recommended, the Ring Smartcharger range to someone on here a while back.
He bought one and it did the trick!

So I bought one too!

The (newer ) Smartcharger+ range I believe came out tops in a recent magazine survey.

They are superb chargers, and because they are designed primarily for the automotive trade they are about 25% of the cost of a marine charger.

 

[Barry Jones]

It sounds that way, but you might be able to revive them - follow the other recommendations, you've nothing to lose.

 

[yacht surveyor]

Take them to a car workshop or a marine engineer such as the boys at Bray (if your boat is at the location in your profile).

They can put them on a battery tester and see if they are OK or dead. The better testers don't need the battery fully charged.

 

[Pye_End]

Sorry, I know this has been on here before (many times I guess) but I'm helping out a neighbour with her batteries and I can't find the info I need.

I've charged 3 seperate batteries (wet lead-acid, non-sealed) with a proper 3 stage charger over the course of the last week. after being off the charger for an hour or two I have checked with a digital multimeter and they all read 11.95v. I think this proves they are dead (they were left onboard in a low-charged state for a few months). Can anyone just confirm this before I break the bad news?

Thanks.

Presumably nothing was connected to the batteries after you charged them? Best way to be completely sure is to take them back to bare posts, so there is no interaction with each other (otherwise could just be one dead one), or something else draining them.

Once they are charged worth testing the cells with a hydrometer.

 

[Rigger Mortice]

If thay are all reading 11.95 volt then, on the face of it, they are passed it.
However, if the reading is always 11.95, I would be inclined to check the meter. Whilst possible, it's most unlikely that you will get exactly the same reading from 3 different batteries.
Try checking it on your car battery.

 

[pappaecho]

I assume that the three batteries were not connected in parallel when you charged them with the charger? I am very suspicious than each battery is 11.95 volts. That suggests to me that you have a duff one which is carrying down the other two.

Each battery should be isolated and charged independently, and stood for 24 hours before testing with a meter, and better a dummy load.

 

[Stu Jackson]

Steve, before you break any bad news, open the danged battery tops and see if there' any water in them.

www.amplepower.com, downlad the Primer from the tech docs tab.

 

[Cappen Boidseye]

Just bought a Ring 16 amp smartcharger, excellent charger.
Experience has shown me never to try charging multiple batteries connected in parralel. I had a battery in the house from an old landrover, I connected an older intelligent trickle charger to it to top it up and left it for a few days secure in the knowledge that the trickle charger would not overcharge, just do the maintenance thing. However,after a few days supposedly just being maintained, I checked the battery, which was very hot, almost too hot to touch. My theory is that the battery never got up to the target voltage so the charger just kept feeding it watts.
If you have one rogue battery in a collection, all connected in parallel, it could hold the voltage low so even an intelligent all singing and all dancing charger would keep going, baking the rest.
Of course my theory could be complete garbage, but it seems logical to me. Also the Ring Smartcharger does tell you not to charge multiple batteries.