What's wrong with this battery?

[Yakbird]

Hi, one of my leisure batteries got drained recently (due to the inverter being left on while the boat was unattended). There was only one leisure battery installed at the time, along with a starter battery. I've since had the engine running for quite a few hours over several days, and have even charged the battery with an AC charger, but it still won't power anything, despite the charger (and voltmeter) saying it's fully charged. My other leisure battery powers everything that's currently connected (lights and an inverter mainly), so there's nothing wrong with the wiring. I'm still learning about boat electrics etc, and still pretty ignorant, but I can't fathom why the charger can tell me the battery is fully charged but it won't act like it. Anyone got any ideas?

 

Cheers,

 

Steve.

[mayalld]

Hi, one of my leisure batteries got drained recently (due to the inverter being left on while the boat was unattended). There was only one leisure battery installed at the time, along with a starter battery. I've since had the engine running for quite a few hours over several days, and have even charged the battery with an AC charger, but it still won't power anything, despite the charger (and voltmeter) saying it's fully charged. My other leisure battery powers everything that's currently connected (lights and an inverter mainly), so there's nothing wrong with the wiring. I'm still learning about boat electrics etc, and still pretty ignorant, but I can't fathom why the charger can tell me the battery is fully charged but it won't act like it. Anyone got any ideas?

 

Cheers,

 

Steve.

 

Yup, it's knackered.

 

Fully discharging a battery and leaving it discharged will kill it in no time at all.

[Gibbo]

Yup, it's knackered.

 

Fully discharging a battery and leaving it discharged will kill it in no time at all.

 

Agreed.

 

A charger will almost always identify a knackered battery as fully charged. To many chargers they look like exactly the same thing.

 

It's possible that a good 4 or 5 days on charge at a higher than normal voltage might get it back to at least useable. But it's not certain.

 

Gibbo

[chris w]

If it was discharged and left discharged for a couple of weeks, it may never recover. The plates inside will have been coated with lead sulphate in the discharge process and this will now have hardened ("sulphated up" in the parlance) and will be cream-crackered without specialist equipment.

 

Although ithe charger might say "Full", that actually means "Full to the battery's present capacity" which is probably, near-as-damn-it zero.

 

What kind of charger are you using? A car-type Halfords thingy or a proper multistage boat battery charger costing many times more than the car type?

 

Chris

PS: post crossed with other posters

Edited April 27, 2009 by chris w

[Yakbird]

Ah, that sounds like that then. It's only a car battery charger I've been using, so that's probably not too great. But yes it was left discharged for something like six weeks realistically.

 

Thanks, folks. I won't be doing that again then.

 

 

Steve.

[bottle]

 

Monty Python dead parrot sketch.

 

 

Want to buy a new battery. know what I mean.

[Yakbird]

Yeah, this battery is currently eating sh*t on the floor of its cage.