Did I kill my batteries?

[Brian D]

I have two group 24 batteries as starter batteries for my outboard (overkill, I know). Anyway, it seems the last time I was on the boat I may have turned off the battery charger by mistake. I would say that may have been a few weeks ago (or more).

Today I was at the boat and went to lower the motor (electric). No go. I checked around and saw the battery charger wasn't on. Turned it on and lowered the motor. Wouldn't start. Of course not. After about 15 minutes of waiting, the motor started right up.

The charger is on now and the batteries are charging. But how will I know if they are dead. Should I disconnect the charger again and wait say 24 hours then try and start? Or should I just say, OK, new batteries and leave it at that? The batteries are about 4 years old but have worked great to date.

Thoughts?

 

[Stu Jackson]

What's the water levels in the batteries? What's the SG of the cells?

 

[Benny17441]

Brian I suspect the batteries may have already been weak from age and wear and this loss of capacity to hold charge was just exposed by the turning off of the battery charger. Irrespective whether my suspicions are well founded or not I suggest you have the batteries bench tested. Rather than spending time and effort in conducting your own tests I would suggest you haul them to your friendly auto parts store where they will test them for free.

 

[Brian D]

Stu, when last I checked (several months ago) water level was good. Didn't need to add any. But I did not check the SG.

Benny, you make a good point and given the age it just might be time to retire them anyway.

 

[Ken Cross]

I would ask myself why they went dead so quickly. Is there a load on them? If there is no load they should stay for a long time. In my case I found with all my circuit breakers off the refrigerator was still wired directly to the house bank.

I agree, having them bench tested is a good idea. I one time replaced some then found out later that the batteries weren't the problem $$$
Ken

 

[Maine Sail]

I have two group 24 batteries as starter batteries for my outboard (overkill, I know). Anyway, it seems the last time I was on the boat I may have turned off the battery charger by mistake. I would say that may have been a few weeks ago (or more).

Your batteries should not be going that dead in a few weeks unless;

A) They are extremely unhealthy/aged
B) There is a small internal short/bad cell
C) You have a bad parasitic load..

 

[eaststorm]

Depending on the age of the wet cell/flooded batteries ( and specifically the condition of the plates), you may be able to breathe new life into those batteries. Get your hands on a smart high output battery charger with EQUALIZATION capabilities. If the plates are sulfated, they will not hold a charge very well. During equalization, you may be able to get the sulfates back into solution and get those batteries back in shape.

 

[Gunni]

Isn't the real concern your ability to kill all your batteries at once? Stuff happens, but you need a plan B.

 

[Maine Sail]

Isn't the real concern your ability to kill all your batteries at once? Stuff happens, but you need a plan B.

If I recall, Brian's plan B is the pull cord on the outboard...

 

[Brian D]

Isn't the real concern your ability to kill all your batteries at once? Stuff happens, but you need a plan B.

That is what I am trying to figure out. But, yes, I actually have two plan Bs. First is as Maine mentioned, the pull cord. Second, is my house bank which is on solar and big enough to start the engine. I was just trying to figure out if my starter batteries are toast.

There were many good suggestions and I will pursue them when I am feeling better.

Someone asked if there was a load on the batteries. The only load that I know of is the motor and the charger. So it is possible that when the charger is not on, there could be a reverse current flowing. I will have to check on that. It is a Guest charger. That shouldn't happen, but I will check.