How long should one expect a marine battery to last.?

[bluefin59]

My batteries where installed in my bluefin in may 04 and they are both still working fine , but I have probably just put the knocker on myself ... Matt

[bar raider]

I got 7~8 years out of the battery in my bar raider with 75 2st merc, never charged and sporadically/rarely used, I'm talking 2~3 months between uses fairly often and only 150 hours in that 7-8 year period.

[deckie]

Some just keep on going and others shit themselves if you dont treat them like a princess. I dont pretend to know why, all i know is that its the #1 safety feature on the boat...everything begins with some plastic encased lead. The motor can be just a useless ornament without a battery. Nobody ever seems to practice a pull start these days either.
On the basis that all my boating fun (and safety) begins with the batteries i dont mind spending a bit extra on them, and maintaining them better than i once did. I used to charge them only during winter months and even then maybe once every 2 mths at best. Often even a good deep cycle less than 1-2yrs old would shit itself over a winter.
Best battery i ever had was stolen at a well known boat racknstack in Syd...was about 4-5yrs old. Yepp they will even steal your bloody batteries. Normally i;d replace after 3-4yrs for a normal deep cycle marine...currently running 2 agms, one a Optima and the other an Odyssey which come with 4 yr guarantees and a general expected life of 8-10yrs.
All depends on proper charging regime, not draining a deep cycle too low, and ability to keep vibration and shock to a minimum i reckon. I start thinking about turning unnecessary's off if i drain the house batt past about 40% on a longish night fishing, have good rubber vibration matting under each, then connect up a 10A multi/float charger when home.
Normal DeepCycle marine batteries i reckon an average would be about 3-4yrs life before replacing for safety reasons, but could likely extend that to 6ish expectancy with a good charger and not allowing them to drain too low.

[buck66]

Feral top advice! I always use a multistage charger before heading out to make sure as best you can that your batteries are fully charged, especially when heading out a long way. Several years ago I had one lead acid battery drop a cell while underway while running both batteries in parallel and it stopped my previous DF90 cold (as well as my heart). Fortunately I was able to switch to the good battery and get home, batteries were 4 years old and were both replaced before the next trip. I now have a different rig and have been running dual AGM Optima's for 2 years and so far they have been great, would have Odyssey's if I could afford them.

regards

[fisho8]

The battery I had on my boat lasted 3 years it may have lasted longer but a certain dealer who is now broke did some work on my boat and left a light on in the cabin and ran the battery dead flat it must have dropped a cell as it would not charge after that needless to say they denied it and I had to go out and buy a new one at my own expense. The one I have now I have had for about a year cost me $160.00 so far so good.

[PADDLES]

yep littleskipper, i use a 7A ctek and our biggest battery is a 150Ah wet cell that we use to run the fridge. our boat has 3 batteries so i just one of the ctek disconnect plug things on each battery and plug the charger in from battery to battery every week or so and leave the charger permanently on. the things i have described should give you the maximum battery life.

[trueblue]

I get about 4 years out of my boat batteries

they are still working and reliable when I replace them and usually end up in a car for another couple of years.

I change them when they don't charge as well as they used to

I can tell from the amperage on the battery charger when they need changing, the minimum amperage load on my charger (after charging the battery) goes up a bit when the battery gets on a bit - time to change the battery

even though I have 2 x 720 marine pro batteries, I don't wait for them to die

[LittleSkipper]

yep littleskipper, i use a 7A ctek and our biggest battery is a 150Ah wet cell that we use to run the fridge. our boat has 3 batteries so i just one of the ctek disconnect plug things on each battery and plug the charger in from battery to battery every week or so and leave the charger permanently on. the things i have described should give you the maximum battery life.

Thanks for that info PADDLES, I was also interested in the CTEK 7A. I think this little unit will be suffice for my charging needs!

[paulp]

Seamaster M70 on boat 8 years never once charged and now 2 years on camper trailer and still going strong
Total 10 years

[Fed]

How long should one expect a marine battery to last.?

Expect it to last until the next time you hit the key, other than that drive it til it drops. That's what having a 2nd battery is all about.