Hi,
I'm curious about how often my fellow blue water cruisers change their service batteries. We use marinized lead-acid batteries, which I have to change every 2 years, even though we are very careful. Is it just us ?
Michel on Velvet.

Hi Michel,
That is really an impossible question to answer as it depends on so many obvious and not so obvious variables. I can tell you that when full time living aboard I go 5-7 years out of my good quality gel cells. Now that I am 6 months on and 6 months off, I do not expect to get more years, but we shall see.
At 2 years replacement rate, I would definitely be looking at all the variables in expectation that I would not need to replace so often. Feel free to share your thinking/plans here for feedback.
Dick Stevenson, s/v Alchemy

[quote=Michel.Tabusse]Hi,
I'm curious about how often my fellow blue water cruisers change their service batteries. We use marinized lead-acid batteries, which I have to change every 2 years, even though we are very careful. Is it just us ?
Michel on Velvet.[/quote]

No, it's not just you!
I used to get about two years out of "leisure deep-cycle" lead acid batteries. Then a battery supplier suggested that I change to a pair of 6V wet golf cart batteries, as he was supplying them to commercial yachts with good results. I got eight years out of a pair of Trojan T105 golf cart batteries, and then only changed them because I was headed out across the Pacific, and didn't know where the next pair were going to come from. The second pair, a different brand but the same size, lasted a similar length of time, and were not near to failing when I sold the boat. I think that golf cart batteries are the cost-effective way to go, so long as you don't intend to invert or flood your boat (!), and so long as you don't mind checking the electrolyte levels at suitable intervals.

I'd say that 2 years is really poor performance. Many people claim 8 - 10 years - normally I get about 5 - 6. Questions I would have:
[ul][li]How big is your battery bank?[/li][li]How much do you draw per day?[/li][li]What's your charging capacity?[/li][li]Are you routinely discharging to 50% or more?[/li][li]Are you charging to full on a regular basis? At all?[/li][li]Do you ever equalize the batteries?[/li][/ul]
John Harries (Morgan's Cloud) has done several articles about batteries - including this recent one - https://www.morganscloud.com/2018/06/29/reducing-ac-generator-run-time/ - and would be a very good place to sort out what's going wrong.


Hope you get to the bottom of this!

Bill Balme

Hi Michel,
I second Bill's recommendation of John Harries series of articles on battery management. the best I have ever seen. It is slanted towards AGM's, but there is lots of good info. Dick Stevenson, s/v Alchemy

Hi all,
Thanks for your replies. My apologies for not getting back earlier.
After several changes of thought, I decided to leave lead acid a last chance. I renewed the service bank as it was before : 6*Vetus 105Ah, based on the following :
- we have left tropical latitudes so the conditions should be easier
- we may have just been unlucky with the previous banks, especially when one of the batteries overheated (short circuit ?) and damaged the other ones
- from now on, I will make sure I recharge the park before it gets down to 80% (previous iterations were in the 92-100% range, might not be enough "exercice" ...) 
Cheers, Michel.