What count as a cycle (battery life)

[mikereed100]

[QUOTE=a64pilot;2645199
I’ve never yet met a cruiser that really understands a battery bank, not one.
[/QUOTE]

Nor have I, and I include myself in that number. Sure, I understand about acceptance, Peukert effect, actual amp hours as opposed to manufacturer's data etc. But really, what is the sense of going deeper? I know in my heart of hearts that I will never run a 20 hour discharge test on each of my batteries yearly to establish the true amp hours. I know that when my monitor says the bank is at 100% but the batteries are still accepting 10 amps on a 400 amp bank, that the monitor is not being entirely honest. My solar truly charges to 100% only rarely, particularly on passage when the wind is good and the panels are shaded by the sails. But I am rarely inclined to pull out the generator and put up with the noise in order to top off the batteries. To be honest, I would rather swap out the batteries every few years than listen to my generator every day and I think many cruisers are of the same mind. I think most of us try our best not to assassinate our batteries, but the reality is that, if one is actively cruising, this is not always possible.

[a64pilot]

You understand far more than most, and likely know all you need to, to make an informed decision.
Usage of course varies, I use my generator to make water at least once a week and if I run it in the morning, I get to 100% SOC at least once a week.
However many never get to 100% SOC, but think they do, they think they are taking care of their bank cause the green light is on by noon, and as you say, their monitor says 100%. They have two source to verify fully charged, so they are getting there every day before noon.
Most seem to run the little Honda in the afternoon too.
I think if they knew better, they may do differently is all.

However short cycling batteries is a lot like not changing the oil in your car, it may take a long time before the damage is apparent, so many think frequent oil changes and babying their batteries is silly and unnecessary.
You can’t convince them otherwise either.
Yesterday as I was carrying my two gls of RV antifreeze back to the boat to pickle the Watermaker, I was asked what it was for. I said I’m pickling my Watermaker. I was told we just flush ours every now and again, I forget how often your supposed to.

Think maybe, their membranes don’t last long?

There are three types of boat maintenance that I have seen.
1. fix stuff when it breaks
2. Call someone to fix stuff when it breaks
3. Preventative maintenance

My belief is that my meager funds will stretch longer and I will spend less time fixing broken stuff if I maintain it.

Nothing wrong with waiting until something breaks until you do something about it, that is your call, it’s your Boat.

[john61ct]

The key requirement for those truly cruising, far from home for long periods, is predictability.

You want to replace your bank long before there is much risk of an "unexpected failure".

Knowing what you're doing gives you that knowledge, even if you consciously choose to "abuse" your bank to some extent.

No surprises!

[MagnusS]

For Lead-Acid battery aging when used in boats, mobile homes etc. Cycles are hard to translate into battery life. IN reality, the aging can be visualized by this illustration, where the blue area of not fully charged level is the cause of aging.

[Ike]

Maine Sail, that is excellent info.

[Pete7]

Interesting article on batteries, shame he chose such a deep discharge voltage. A 12 or 12.2 volt would have produced a different results, still interesting.

https://www.youtube.com/watch?v=jR34QF3xcCc

[a64pilot]

Interesting, but of course does cycling a battery to 0 SOC each time tell you much?
I’d like to see the same test cycled to 50% SOC, take 6 months I guess

[Pete7]

I guess he is replicating caravans and small run around boats or day types. Yes a 50% test run would be good.

[a64pilot]

My gut feeling is he was trying to make a point, and it was best made by repeatedly killing the LA batteries stone dead, every cycle.
I’d suspect that if you did the same cycling to 50% for six months, there wouldn’t be much of a drop off, and the point wouldn’t be made.

He wasn’t being dishonest at all though, I am not suggesting that

[john61ct]

Charles has always been a great engineer, but as a marketeer tends to go a bit over top sometimes.

His fancy "one bank at a time" VSRs are a great example, solution in search of a problem.

His charger designs are unsurpassed though, especially the mains ProCharge Ultra and DCDC BB series

[geoffschultz]

Originally Posted by Maine Sail

• Size your charging or alternator for a bare minimum of at least 20% of bank capacity. Bigger is better with AGM but 20% of "C" should be the bare minimum for AGM's. eg: A 400Ah bank should ideally have an alternator capable of at least 100A so that when hot it will still hit the 20% minimum.. Odyssey AGM's (Also Die Hard Platinum which are re-branded Odyssey) want to see a minimum of a .4C charge rate. This is 40A for a 100Ah battery. High charge rates for AGM batteries are yet another piece of the cycle life puzzle than should not be omitted. FDC batteries can be charged at .15C to .3C depending upon brand.

Sorry for being so late to the conversation, but I've been off cruising and just go finished storing my boat in Guatemala for hurricane season.

Anyhow, almost all of my charging of my 2 Lifeline 8D AGMs is done via solar and wind at a relatively low charge rate (10-20A). Most mornings the batteries start out at 12.8 and by noon are at 13.2 via just solar. If the wind is blowing, my Morningstar Tristar controller brings them up to 14.2 (average temp 85F).

I'm trying to understand Maine Sail's comment about high charging rates. Is this slow charging rate detrimental to the longevity of the batteries? I guess that I had always believed that slow charging was preferable to fast (hot) charging.

-- Geoff

[a64pilot]

Trickle charging was considered the best, safest way when I was growing up. However I think that was back in the day when chargers were not well controlled and a little one just wasn’t as likely to wreck a battery with high voltage cause it couldn’t get high voltage, it was just too small.
However if you read Lifeline’s Manual I believe it recommends a high charge rate whenever possible.
Of course with Solar it’s not likely possible.
http://lifelinebatteries.com/wp-cont...cal-Manual.pdf

[john61ct]

Yes in recent years the top AGM makers have learned that longevity is improved by higher charging rates.

.4C is the minimum Odyssey recommends, Lifeline and the others more conservative at .2C.

Of course most alt energy sources can't get there, so do the best you can when on shore power or charging off dino juice.

FLA usually can't accept much over .2C, at least not for long.

[geoffschultz]

Based upon what I read in the LifeLine Manual: "The charging current during the Bulk state should be set as high as practical; higher current means faster charging and less time for the plates to become sulfated", doesn't tell me much about what the effects of a low charging rate has on AGM batteries are, but it's something to think about. However, it's not going to change most people's charging schemes.

[john61ct]

Think of the higher rate being ideal, rather than the lower rate causing harm.

Certainly not nearly as critical as getting back to 100% Full, nor refraining from discharging too deeply.