Old AGM battery.

[potentillaCO32]

I have an unused AGM battery, 120ah i think, in the garage bought around 7 years ago. All boxed up and in the dry with only a gt6 and 2cv and dehumidifier to keep it company.

I need to replace one in the boat and I wondered whether this would still work, be safe, not explode, not die, not harm anyone etc.

Would being left there in it's box damage it?

Would it be safe to charge it and see? Be nice to use it rather than chuck it.

Thanks in advance for expert battery insights.

 

[wonkywinch]

Measure volts across it's terminals before you connect a charger. That will give you a big insight whether it's going to be any good.

 

[Chiara’s slave]

Most likely dead after that time. But you can’t be sure til you try it.

 

[lustyd]

I’d not charge it unattended the first go, and as above check voltage before you try and after it’s charged. Perhaps charge it away from anything valuable too, just in case.

They don’t just explode it’s a result of a failure or overcharging and they get warm first. If the charge goes well and it holds voltage then it’s probably fine.

 

[potentillaCO32]

I’d not charge it unattended the first go, and as above check voltage before you try and after it’s charged. Perhaps charge it away from anything valuable too, just in case.

They don’t just explode it’s a result of a failure or overcharging and they get warm first. If the charge goes well and it holds voltage then it’s probably fine.

I'll put it by the 2cv then when i charge it. That would survive most things.

 

[jamie N]

If you've a bench power supply, you might try that. As others have said, check the V's beforehand, then wire it up to the bench power supply. For a start off, I'd dial it in to charge at 12.8V and <0.5A. You're not going to 'surprise' anything, or cause harm either. Monitor it, but let it do its thing for (quite) awhile, then see how it's doing. If it holds a charge, great stuff, connect it to a regular charger. If it doesn't, put it on eBay dispose of it properly.

 

[lustyd]

I'll put it by the 2cv then when i charge it. That would survive most things.

They’re pretty valuable though these days

 

[pandos]

Up to a few years ago I was still using a 15 year old agm which spend several of it's earlier years sitting in boatyards.. (un cared for) .the difficulty I had was finding a "stupid" charger to get it going, as the modern clever chargers just say no if the bat is comply flat..I used an old caravan charger/ power supply..

 

[Refueler]

Up to a few years ago I was still using a 15 year old agm which spend several of it's earlier years sitting in boatyards.. (un cared for) .the difficulty I had was finding a "stupid" charger to get it going, as the modern clever chargers just say no if the bat is comply flat..I used an old caravan charger/ power supply..

The old dumb chargers are actually more use than many realise ...

As you found - the 'smart chargers' - most do not accept a deep discharged battery and default out ... also they do not like charge splitters with regulators such as KEMO etc.

 

[samfieldhouse]

I had the outboard on the back of my Mehari (2cv based) and the Waitrose delivery chap earnestly asked “what is that car, does it go in the water”

I’m debating what to do with my current AGM. It’s 6 years old and not holding quite as much power as it used to, plus I’d like a pair for a bit more winter umph.