Anything learned from battery use on a boat that is not really out there cruising is…well, not very useful. Cruising is different, and much harder on batteries than most other uses. And so much of what you read about sailboat battery life is theory based on…well, not a lot.
So it was great to get an interesting comment from AAC member Rick Salsman, relating his real-world, real-cruising, battery experience.
Over to Rick:
I have just replaced my four old 4D East Pen(EP) AGMs with Lifeline AGMs.
These EPs lasted me from 2006 until the spring of 2013. I was not near a facility to bench test the remaining capacity, but I had noticed a continual decline in the time a reasonable charge could be held. I might have gotten one more year out of them, maybe.
We have lived aboard anywhere from 4-6 months per year since 2007. We use about 200+ amp hours per day while at anchor, running computers, fridge, etc.
Our primary charge source is our 125 amp alternator plus a little from a Superwind wind generator. Cruising in the Mediterranean, with light to no winds in many areas, we do a lot of powering.
We typically charge up to about 85% to 90% battery capacity with the alternator unless a longer passage is underway…
…I have also used a desulfator from Pulsetech, that has run over that whole period.
Do you or your readers have any experience with these desulfators? I wonder how much it contributed to the 7+ year life of the EP batteries.
I was unaware of the ability of AGMs to accept an equalization charge. I am also trying to decide if I should also equalize these Lifeline Batteries when I did not do so with the EPs?
Do you have some thoughts on my battery program, and why I have seemed to get a longer than normal life out of my old batteries and if I should now equalize monthly with the new?
Rick asked some interesting questions. Here are my thoughts.
Longer Than Normal Life?
On the life you got out of the old East Pen AGM batteries, while you say that it was “longer than normal”, and you are probably right (taking into account your use), my thinking is that, given that they only lasted for 3 to 3-1/2 years of actual cruising, this highlights a fundamental problem: real cruising use sulphates lead-acid (all types) batteries and results in a pretty expensive lifecycle.
There are a lot of variables here, but comparing your experience to ours and other reliable second hand evidence, I would guess (and it is just that) that the PulseTech desulfator did make some difference and probably extended the life of your batteries, perhaps as much as 50%.
While monthly equalization is not without its downsides, which I discuss in this chapter of our Battery Installation and Maintenance Online Book, I would suggest that you add monthly equalization to your regime.
I base this recommendation on our own experience with our current set of LifeLine AGM batteries that:
- Have 2-1/2 full years of out-of-marina cruising on them.
- Have been equalized once a month, while cruising, with one exception where they went two months.
- Discharge testing shows they still have over 90% of their capacity left.
- Our use is even tougher than yours: 250-350 amp hours a day out of just two 8Ds.
If you have real-world, out there cruising, battery life-cycle experience, please share it in a comment. However, please take a page from Rick’s book and make sure you include your usage and charging profile. Comments that say things like “my batteries have lasted 10 years” without that information are simply useless—years mean nothing, it’s cycles, their depth, and how much, and how the batteries were recharged that matter.
We would also be interested in any further real-world experience with desulfators.
If you want to comment on, or ask questions about, subjects such as equalization, please do so on the appropriate chapter in our Battery Installation and Maintenance Online Book. And yes, that will require you to become a member, if you are not one already.
And that brings up another subject. This post, and the last but two, answered questions and brought to the fore (to solicit input in the comments) challenges that two of our members were facing. This is part of our commitment to go the extra mile for those who have contributed to the site.