New 12V outlet = dead battery

[Sethic]

OP update:

Charged the battery overnight to no avail. Returned battery to Walmart where they honored the warranty (I was still in the pro-rated period as the battery is only 18 mos old). New batter was only $53. Installed new battery. Depthfinder is working properly again, reading 6' in my slip rather than 900' or so as previous. Depthfinder voltage reads normal at 12.5V or so with the motor off and 14 or so with it running.

Looks like the battery failure and the 12V receptacle install were unrelated.

Nagging issue to me is why the battery failed in the first place, at only 18 months old (Everstart 24P-4 marine battery). I don't know much about marine batteries but from my experience with car batteries that's pretty unusual. The PO didn't run the motor much as his marina was on good sailing waters which was all he was interested in with this boat. I think I've run the motor in the last 3 mos as much as he has in 10 years.

I'm curious as to whether the coroded contacts from the motor might have led to the battery not being charged properly during operation of the motor (a Honda 9.9 electric start, with alternator)? That would seem logical to me. I may consider replacing the contacts with new ones as the current are pretty coroded despite my efforts at cleaning them with a wire brush.

Or maybe I just got a shi**y Walmart battery!

 

[Bill Roosa]

Ah-Ha! the other side of the story

I certainly believe that using a Wal-Mart battery in deep cycle mode is going to result in it failing in short order. Car batteries are not designed for that type of use and literally come apart inside when taken to 50% discharge more than a few times. An "everstart" battery is a starting battery not a deep cycle one.
99.44% of all electrical problems on boats are corroded terminals. If your alternator can't push the current into the bat due to corrosion then you are going to have a dead battery in short order no matter what type.
Just because the outside of the terminal looks nice and clean does not mean the current carrying part is. You HAVE to take it apart to clean it properly. I find a generous mitten full of lithium grease a cheap means of keeping corrosion down over time.

 

[isaksp00]

I bought a marine battery from Walmart - they do carry deep cycle marine batteries - is this what you got, or is it a "normal" starting battery? If it is marine as you posted, 18 mos seems pretty short, and the fact that you had to pay $53 even with the prorating seems high. What is the total period over which they prorate? I'd have thought 5 yrs or so.

I ended up removing most all the connectors when I bought my boat, and putting in new crimp connectors - corrosion was bad, also in the nav light receptacles. Including the wire from the outboard to the battery, and I installed new in-line fuse holders (old were pretty bad).

I have tested my setup in my basement, with outboard in water, and ammeter to battery. At idle it generates essentially no current, at higher RPMs if I recall maybe an amp or two? So mine (8HP Honda) would only provide any kind of recharging at more like cruising speed, and it is weak even at that. My load is only nav and interior lights, which are rarely used, so it ought to be OK for me. I accidentally tipped the anchoring light switch and it was one for like a week, draining the battery. Had to bring it home to recharge - outboard would have taken hours if at all.

 

[Sethic]

Excellent idea. Hadn't thought of greasing the terminals. PO installed the motor in 2002, but I have every reason to believe those cables going from the battery to the motor are from earlier... meaning the terminals may be almost 30 years old(!). They certainly look it. New project: replace and grease terminal connections.

The battery I purchased is a 'marine' battery for 'starting and trolling'. It's not labeled as a deep cycle battery. I think my usage will primarily be for starting the motor (although charging a phone or powering a handheld spotlight are not out of the question). I'll wait to see how the new one manages after I install new terminals before I go hunting for a deep cycle battery. Motor has a pull-start as an alternative. Really only useful if it's already warmed up though...

Thanks for the input!

 

[Sethic]

The battery is a 24P-4 'marine' battery, labeled uses are 'starting and trolling'. I have a 9.9hp Honda, and have not hooked an ammeter to it as you have. That's not very encouraging!

Warranty period for this battery was total within 1 year, prorated for an additional year.

Sounds like the moral of the story is that I shouldn't get grand ideas about what I can power from my new receptacle.

 

[isaksp00]

If it is rated for trolling, I would think that it is more like the deep cycle type. Trolling normally would involve discharging it more deeply than you would in a car starter. I was told by a AAA mechanic recently, when asking if we could use my trolling battery to help start a friend's car, that they can produce high amps for starting, so the fact that yours says it is also for starting probably doesn't mean it isn't also a deep cycle type.

That said, 2 yrs warranty is 2 yrs - pretty poor, I guess we get what we pay for when at Walmart.

 

[soling42]

Just replaced both of my deep cycle batts that were 3yr group 27 rated. one was 4 1/2 y/o and one was right at 3yrs. Averaged at about the rated lifespan so I'm satisfied. Yours were most certainly deep cycle and just old.

As for cranking amps we're talking about a 9hp ob on a sailboat not a cold hearted Cummings diesel in frozen Iowa. If I was racing and weight conscious or just day sailing I'd like to think I'd be carrying a 5lb motorcycle battery in my small boat instead of spending $200(or more) and carrying 100lbs+ of fussy caustic lead. So instead I carry what we need for staying over a few days at a time with our small solar panel and alternator backing us up.

Good luck, Mike