Battery not holding charge

trobinson017

Petty Officer 2nd Class
Joined
Sep 12, 2004
Messages
183
I've had battery issues in the past and understand that most starting problems are due to bad/corroded cables from battery all the way to the starter. I've checked all that. Here's my issue:

3 weeks ago boat was starting just fine. Even after sitting idle 2 weeks it would start up. I had the lower unit serviced last week wherein the mechanic removed it, took it with him, serviced and came back and replaced it. During that time the motor was raised up at about 45 degrees. It sat like that for about 10 days until the LU was reinstalled, which at that time a big t-storm was about to hit so we didn't start it up. This was 2 days ago (Monday). Yesterday I found the battery was dead. I put the charger on it at 15 amps and it took all of that to fully charge it. Normally if it has any charge it will start at 15 then quickly drop to the proper amperage to fully charge the battery. As soon as it was done I tried to start the motor but it was weak. I put my starter charger on it (50 amps) which usually does the trick but it was still weak. I then put the regular charger back on and started it at 15 amps. It quickly dropped itself to 5amps and continued charging from there.

Today I went out and put the charger on without attempting a start. I put it on 15 amps and it continued from there to charge, it did not drop down to a lower amperage. When it was done, I tried to start, very weak, no start. Put the charger back on at 15 amps, it dropped to 5 but then quickly rose back up to 15 to continue charging. Oh, and I have removed all cables and steel-wooled every connection point between battery and starter. I even used a Dremel sanding bit on the big cable terminal ends.

This battery is only about 1.5 yrs old and it was working fine before the LU work. Why would it be in this condition now just by sitting for 2.5 weeks? The regular charger has a "Battery Recondition" button on it that's supposed to undo sulfidisation (correct term??) but I dont' know if that's worth trying.

Any ideas on what happened? I can buy a new battery, no problem. But I'd really like to understand why it won't work now.

TIA!
 

trobinson017

Petty Officer 2nd Class
Joined
Sep 12, 2004
Messages
183
Re: Battery not holding charge

A couple relevant things to add: the mechanic left the battery switch in the ON postion when he took the LU. Also, my bilge pump was set to auto and with the rains we had over those 2 weeks it was running quite a bit I'm sure. The water gets in from the anchor hatch at the bow that has a large hole for the anchor chain, as well as from around a large bow hatch that doesn't have any sort of seal other than being recessed.
 

boat1010

Senior Chief Petty Officer
Joined
Mar 10, 2009
Messages
781
Re: Battery not holding charge

Just take the battery in and have it tested. Stranger things have happed. Batteries die and it may just have picked that time to die.
 

nitro71

Cadet
Joined
Aug 18, 2009
Messages
6
Re: Battery not holding charge

Definetly take it wherever you bought it from. They can test it.

This is a battery aside as I believe your battery is bad. On your new battery you should make sure the terminals are not corroded on the cables. They get a black corrossion that won't conduct. If your cables or terminals look bad I'd replace them. Before you put your cables on your new battery spray some Permatex corrosion preventer on them and the terminals. This will help keep future corrosion from building up. Make sure you get the preventative as Permatex makes a cleaner also.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: Battery not holding charge

If a battery discharges and sits that way for a period of time, the plates sulfate. When that happens it won't take a charge again. Time for a new battery.
 

kenmyfam

Supreme Mariner
Joined
Aug 10, 2006
Messages
14,385
Re: Battery not holding charge

Battery test job #1
Replace if necessary.
 
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