Is my battery shot?

[VMS]

Pulled the cranking battery out to give it a charge last night, and gave it about 3 hours or so of charging. Went down to check and noticed that the auto shut off light kept going on and off, and the charger would kick in about every 30 seconds, then go off again. The charger is new and worked on my deep cycles earlier this week.

Yes..the settings were correct on the charger (15 amp 12 volt regular battery...not deep cycle)

Thanks much..

Steve

[Shellback]

To answer your question, yes, it probably is, not good to let them go stone dead. On occasion I have put a good battery in a parallel circuit with the bad battery, charging both at the same time. Sometimes that seemed to allow the bad one to start taking a charge. Personally, if it did take a charge I'd use it in a lawn tractor or other piece of equipment that ain't gonna leave ya stuck somewhere. Get yourself a new one for the boat.

[VMS]

that's kind of what I figured. The battery is 4 years old, and has had a bunch of use. Plan is to move one of my stowaways back there, move the 2 bank charger and make a parallel circuit so I have more time up front between charges and a little charging on the go...

Steve

[fishin4fun]

Four years on a wet lead acid battery is not too bad. Letting them set while dead is really hard on them. Even a day or two will let them sulfate and degrade their capacity. Time for a new one!:-)

[REW]

Steve,
Before you give up - take the battery to a battry service center - which sells and checks batteries.

It is possible that you simply have let the battery get too low and is not accepting a charge with your charger.

Have them give the battery a boost charge, and then give the battery a good test. They will tell you within a few minutes if there is any hope for the battery.

My guess is that you have one of the 6 cells shorted out.
This is a very common mode of battery failure. i.e. after a few years of use, etc. pieces of material build up on the bottom of the cell, and short out the plates of one of the 6 cells.

If this happens, the battery is toast, and replacement will be required. No sense in keeping the battery for any use - if this is the case. Just lugging around an anchor.

Take care
REW

[fishhunter]

Have you checked how many volts the battery shows. Is it fully charged? On my charger that is exactly what it does when its charged, the auto feature is turning the charger on and off.

[Zip649]

It sounds full.
Do a load test if not sure.

[JCarp]

Let the battery sit on the autocharger for a day. From what you describe, everything was working as it should. The autochargers I use start out on full time, then cycle on and off until the battery is charged. The on/off cycles are a little different when set for starting batteries vs deep cycles. Your instructions should explain it in more detail.

Did you leave anything connected to it? - if so, don't unless attached to autocharger.

If it keeps cycling on and off after a day or two, it is not taking a full charge. If it doesn't take a full charge with the correct water level, it's days are numbered if not over.

You can buy a tester to check specific gravity on wet cells. Load test at parts store can test sealed ones and wet cells.

Hope this helps,
jc

http://www.uuhome.de/william.darden/carfaq.htm