What count as a cycle (battery life)

[john61ct]

Originally Posted by Paul L

What claim have I made that you think I need to support?

That they manufacture their AGM themselves.

[john61ct]

Originally Posted by Paul L

Can you at least point to the hearsay?

Many forums over the years, just use the site: keyword googling

http://www.google.com/search?q=site%...R+surrette+agm

[john61ct]

And note, I am in no way claiming that doing so is a negative.

Deka is a fantastic quality manufacturer, but I would only buy their AGM if I found out they'd switched to outsourcing that line.

[mako]

Originally Posted by Maine Sail

What ever DOD you discharge to then back to 100% would be a cycle as a battery manufacturer defines it in a lab. You can have shallow cycles or deep cycles, most have a mix plus PSOC use..

That’s not what Apple has to say about the lithium batteries when I was researching for my MacBook:

https://support.apple.com/en-us/HT201585

[john61ct]

Apple is just explaining how **its software** is counting cycles. So users understand when their batt needs replacing. Variation of total-AH counting, rather than counting actual cycles.

And the batteries used in House banks are a completely different chemistry from those used in electronic gadgets

[Paul L]

Originally Posted by john61ct

That they manufacture their AGM themselves.

Nice try, but I never said I knew who manufactured the Rolls AGM. I just asked you what your evidence was that it isn't Surrette.

[kmacdonald]

Originally Posted by Dockhead

It's commonly said that you shouldn't discharge lead-acid batteries below 50%, but if you look at the DOD vs cycle life charts, I think it's hard to discern any reason why not. Cycle life does not fall off a cliff, but declines proportionately all the way to 20% or so (80% DOD). I realize this contradicts what Stu said about 40% and maybe I'm missing something, but it sure looks to me, from reading all those charts, that you will be using your batteries more economically, especially if you are charging with a generator, if you discharge them further than 50%

I have consistently said it is good to discharge to 80% DOD. The loss in cycle life tapers off past 50% DOD. Recharging becomes more efficient. A smaller battery bank is needed. A smaller charger is needed. What's not to like?

[a64pilot]

Originally Posted by kmacdonald

I have consistently said it is good to discharge to 80% DOD. The loss in cycle life tapers off past 50% DOD. Recharging becomes more efficient. A smaller battery bank is needed. A smaller charger is needed. What's not to like?

The actual use evidence that points to premature death. I suspect it’s from PSOC, but either way the deeper you discharge the bank, the shorter the lifespan, and the major manufacturers recommend not discharging deeper than 50%.

[ranger58sb]

Originally Posted by john61ct

Some say they outsource to Full River, I dunno.

Originally Posted by Paul L

I just asked you what your evidence was that it isn't Surrette.

Geez, the ping pong is getting old.

Paul, see post 62: John said "some say..." and the "I dunno" part suggested he hasn't seen evidence either. Later, in response to your request, he supplied a keyword search argument pointing to related hearsay (see post 92).

He made no claims, he didn't disparage Rolls, he didn't disparage Full River...

-Chris

[kmacdonald]

Originally Posted by a64pilot

The actual use evidence that points to premature death. I suspect it’s from PSOC, but either way the deeper you discharge the bank, the shorter the lifespan, and the major manufacturers recommend not discharging deeper than 50%.

Sure, the deeper the discharge the shorter the cycle life but you need lees capacity so you are buying less or smaller batteries. As DOD increases the cycle life curve flattens out and therefore it is cost efficient to deep discharge the batteries. PSOC cycling is the killer, not deep discharging. Huge capacity banks encourage PSOC cycling.

[a64pilot]

Originally Posted by kmacdonald

Sure, the deeper the discharge the shorter the cycle life but you need lees capacity so you are buying less or smaller batteries. As DOD increases the cycle life curve flattens out and therefore it is cost efficient to deep discharge the batteries. PSOC cycling is the killer, not deep discharging. Huge capacity banks encourage PSOC cycling.

I’d say actually small banks deeply discharged encourage PSOC.
My line of reasoning is it takes longer to charge to 100% from 40% than from 80%, plus I bet on average the average egg timer based charger drops into float at a much lower SOC when started out in a low SOC.
Just about everyone I meet thinks the battery bank is full, when the green light or other such indicator is on. You start talking about acceptance rate at absorption voltage being .5% of rated capacity and they look at you like you have something growing out of your head.
When you try to tell them otherwise, they smile and say they have been doing it this way for years and it’s always worked.

It’s like maintaining a car, I try to get people to flush the radiator, flush brake fluid, change the transmission fluid and differential etc., and they look at me like I’m crazy and tell me they have never done that before. Of course they buy a new car every few years, doesn’t everybody?
Last guy I worked for had dirty fuel injectors in his Ford pickup cause he bought crap gas, dealership told him when that started the engine was about to go, he had better buy a new truck, so he did, and thanked them for taking care of him I’m sure.

IF a bank is properly recharged, then taking it down to 40% isn’t likely all that bad, but you can’t recharge from that low on Solar, it’s tough to do that from 80%, and the average person is sure their bank is full before noon, and that is why a small bank deeply discharged will live a short life, cause average people don’t know or care how to eek the most life out of a bank.
I’ve never yet met a cruiser that really understands a battery bank, not one.
I’ve not met all that many, and I don’t walk around the clubhouse trying to start that conversation, but you would think I would have met at least one.

[kmacdonald]

a64pilot, I agree, most boater don't know much about batteries or charging. Service providers take complete advantage of that fact and are able to sell battery and charge systems that maximize profits. I guess it's the same in all service industries now. It's actually comical to hear people buy $1000 Lifelines and ruin them the first year of service. Then they spend $2500 for a new charge system and another $1000 Lifeline to correct the problem and the same thing happens. Then they complain about chasing their tail. You can't tell those people anything, they already know it all.

[john61ct]

Let others squander their investments in batteries. Those of us better informed, given the tools, can 99% of the time prevent PSOC abuse on our own banks.

If the amps are high enough compared to bank size, 80% of the charge time is for the last 10%.

Going to a lower SoC, will not increase charge time to 100% by more than say 20min.

[kmacdonald]

Originally Posted by john61ct

Let others squander their investments in batteries. Those of us better informed, given the tools, can 99% of the time prevent PSOC abuse on our own banks.

If the amps are high enough compared to bank size, 80% of the charge time is for the last 10%.

Going to a lower SoC, will not increase charge time to 100% by more than say 20min.

Exactly.

[sailinglegend]

Originally Posted by a64pilot

......Just about everyone I meet thinks the battery bank is full, when the green light or other such indicator is on. You start talking about acceptance rate at absorption voltage being .5% of rated capacity and they look at you like you have something growing out of your head.....

Bingo!!!!!

This is the only thing boat owners really need to understand about their batteries. But why should they believe this Forum when ALL manufacturers tell them their batteries are fully charged when in Float. How many tell them about sulfation due to PSOC?