Battery group 24? 27? deep cell?

[raycarlson]

just to clarify, the walmart garrantee isnt prorated, its 100% 3 year free replacement, and yes of course keep your reciept thats a no brainer!

[DaveB]

I put in 2 House batteries Walmart 27 Marine deep cycle two years ago and done many 4-5 day trips without any recharge and come back with 12.2-12.4 charge and thats useing TV CD movies,and all the elect. needs on my boat including chargeing Items with inverter.
I only toped the batteries once with acid and just cked them after a year and fluid is still were it should be. I cruise year round in SW FL.
Batteries are still good as new and no sulfation.
For $80 I see no problem, I also liked the Golf Cart Trojan 6 volt batteries, they lasted more than 6 years before I sold the boat and close to same cost as walmart per battery.
Dave

I personally have never had a wet cell go bad in less than 5 years(on a boat).But the wonderful thing about the Walmart batterys is their 3 yr no question asked full refund on any of the 75.00 battery's(24,27,29 all the same price).I'm sure any of us could think of a way to induce total failure of a battery at about 2yrs and 11months into the warranty period.The sales associate at the counter knows nothing about batteries, other then how to load test (Twice I have had them not even test the battery,they just told me to grab a new one(car battery).If your battery somehow can't pass the load test,grab a brand new one off the shelf and your on your way out the door with another three year warranteed battery.

[opie]

DaveB,

I am guessing that you are leaving out the "rest of the story" (as the radio great guy used to say.)

What I mean is, I bet that you put the batteries on a good charger at your dock when you return from your trip. "Of course," you probably are thinking, but newbies out there my not get it.

My thinking is that many of the battery failures that occur are due to improper charging. Take your example. If someone was to take a 4-5 day trip and run the batteries down to 12.2 volts and the trip destination was only 2 hours away and then they just charged the batteries with the outboard on the way back and then they moored the boat without a 115v dock charger, the result would be that the undercharged battery(s) would sulfate quickly. And if they did this often, the battery(s) would last less than a year.

Using a rough guess, if you had 2 group 24, 75 AH batteries, and you used the batteries down to 12.2, that would be 50%. So you used 50% of 75AH x 2 or 75AH total. To charge them back to 100% takes roughly 150% of what went out, so you need 112AH back in. If you had a 50 HP motor with a 10amp output (like my Honda 50), then it would take 11 hours to recharge the batteries to 100%. If you ran the motor less time than that coming back, then you would be undercharged. Many newbies probably do not know that storing batteries that are undercharged is death to batteries due to unreversible sulfation (or sulphation).

And while I am on my soapbox, newbies should invest in a hydrometer (less than $10 for the clear plastic new ones that are temperature compensated) so that you can be sure that the SG has stopped rising at the 1.270++ level. A battery can register 12.7+v without being fully charged. The specific gravity is the best way to determine charge IMHO.

[Navy DOC]

So, after reading through this thread, I'm tending towards purchasing two identical deep cycle batteries to replace the batteries that are currently sitting "dead" in my garage (Both are >6 yrs old and neither holds a charge).

My question is this:

I have no access to shore power where I store my boat. (boat on trailer, in boat yard at marina). Short of removing the batteries after every sail (awkward/time consuming) to place on a charger at home in my garage, what else can I do to keep my batteries healthy? My battery power usage is extremely limited, since I use mostly portable electronics (GPS/Radio/etc).

Thanks!

[Uncle Jim]

You could install a solar cell of around 30 watts to add a trickle charge to the battery. You will need a charge controller if you use anything above about 10 watts to protect the battery. it will also protect against discharge after dark. I've been running a small 7watt panel that worked great until the fuse blew out on the power point I had it plugged in to But that's another story.