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Old 30-05-2012, 08:06   #16
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Re: Lifeline AGM's Fully Charged Voltage?

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Originally Posted by hellosailor View Post
frank-
"Some other Lifeline AGM owners have spoken of full resting voltages "
Unless those folks are using calibrated volt meters, an error of up to .3-.4 volts has to be assumed in whatever numbers they are reading for voltages.

Fancy monitors and controllers are more likely to be more accurate, if they are using those.

So don't worry about vague field reports, use the voltages and temperatures provided by Lifeline.
True, enough, about both relying upon others accuracy in their readings and need to stay with manufacturers recommendations.

I have gotten some really good additional insights here, though, and for that I thank all who responded.
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Old 31-05-2012, 00:18   #17
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Re: Lifeline AGM's Fully Charged Voltage?

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Originally Posted by hellosailor View Post
......Unless those folks are using calibrated volt meters, an error of up to .3-.4 volts has to be assumed in whatever numbers they are reading for voltages.......
The difference between fully charged - 12.8 volts - and empty - 12.2 volts is only 0.6 volts, so you MUST have an accurate digital voltmeter.
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Old 31-05-2012, 07:45   #18
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Re: Lifeline AGM's Fully Charged Voltage?

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The difference between fully charged - 12.8 volts - and empty - 12.2 volts is only 0.6 volts, so you MUST have an accurate digital voltmeter.
Yes, essential, and why I'd spent the bigger bucks for a Fluke 179. Also, used it to determine and put correction factors taped onto my other two cheap meters.
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Old 31-05-2012, 08:07   #19
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Re: Lifeline AGM's Fully Charged Voltage?

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Originally Posted by frankson View Post
For anyone with Lifeline AGM's, when new and you thought they were truly 100% fully charged,
what was your voltage, after they'd settled down for a number of hours with no load or charge?

I've got an OutBack FM80 charge controller with a lot of tweaking options and am trying to see
what might be highest resting voltage to be aiming for beyond Lifelines overly general standard
claim that "12.8V or more" is 100% SOC.

Thanks for any input!
When we set our system up, with solar and wind, I contacted Lifeline as to the algorithms of the batteries for charging through a TS 45 from morningstar, and the wheres to set the "dip" switches.. we have 10 each 4ds aboard.. we were told the battery was fully charged when resting voltage was 12.8 and at 50% when at 12.2.. ours have never dropped below 12.6
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Old 31-05-2012, 08:15   #20
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Re: Lifeline AGM's Fully Charged Voltage?

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Originally Posted by Randyonr3 View Post
When we set our system up, with solar and wind, I contacted Lifeline as to the algorithms of the batteries for charging through a TS 45 from morningstar, and the wheres to set the "dip" switches.. we have 10 each 4ds aboard.. we were told the battery was fully charged when resting voltage was 12.8 and at 50% when at 12.2.. ours have never dropped below 12.6
My god, Randy, you have "10 each 4ds aboard"?

That's 2,100 AH capacity on a Beneteau First 42!

What are you doing aboard to need that much capacity??? Is she converted to electric power?

Bill
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Old 31-05-2012, 08:19   #21
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Re: Lifeline AGM's Fully Charged Voltage?

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Originally Posted by frankson View Post
Yes, essential, and why I'd spent the bigger bucks for a Fluke 179. Also, used it to determine and put correction factors taped onto my other two cheap meters.
Frank,

I use my Fluke 189 to calibrate my other cheap voltmeters (usually the Velleman's which cost $15-20 new). I just open them up, apply a 12V source, and tweak the internal pots to read exactly the same as the Fluke.

I've found that they actually retain this "12V accuracy" for a long time.

Avoids the need for a correction table :-)

And, I often give them to customers who -- horror of horrors -- don't even have a multimeter aboard.

Bill
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Old 31-05-2012, 08:30   #22
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Re: Lifeline AGM's Fully Charged Voltage?

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My god, Randy, you have "10 each 4ds aboard"?

That's 2,100 AH capacity on a Beneteau First 42!

What are you doing aboard to need that much capacity??? Is she converted to electric power?

Bill
no electric power.. but figuring the 2000 amp hours, there is only a portion of that , that is usable, and there is a method to my madness..
we started with 4 each.. but I burnt my windless motor .. found that with 40 feet of cable running from the house bank to the windless, the voltage dropped to about 9 volts, and you know what low voltage does to a motor.. so we added 2 each 4ds under the windless forward and tied in parallel using the windless cable..
then added the watermaker where the forward head once was, and mounted two more under the unit
and at last I added two more in the rear quarter to opperate the inverter system for any 110 I happen to need...
they all charge from a parallel line for charging.. and its been working fine for 9 years now.. totally off the grid..
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Old 31-05-2012, 08:36   #23
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Re: Lifeline AGM's Fully Charged Voltage?

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Originally Posted by Randyonr3 View Post
no electric power.. but figuring the 2000 amp hours, there is only a portion of that , that is usable, and there is a method to my madness..
we started with 4 each.. but I burnt my windless motor .. found that with 40 feet of cable running from the house bank to the windless, the voltage dropped to about 9 volts, and you know what low voltage does to a motor.. so we added 2 each 4ds under the windless forward and tied in parallel using the windless cable..
then added the watermaker where the forward head once was, and mounted two more under the unit
and at last I added two more in the rear quarter to opperate the inverter system for any 110 I happen to need...
they all charge from a parallel line for charging.. and its been working fine for 9 years now.. totally off the grid..
I understand your reasoning, Randy. Thanks for the explanation.

I hope they work for another nine years, because the $4,000 to $5,000 price for new batteries when the need arises ain't gonna be very pleasant, not to mention the back-breaking labor of removing and installing 10 4-D's :-)

Bill
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Old 10-10-2018, 00:12   #24
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Re: Lifeline AGM's Fully Charged Voltage?

I run a 780 amp agm house bank that is charged by 700 watts of solar plus our genset. Overnight we normally use approx 120 amps which is recovered via a breakfast genset session which takes us over 700 then topped up with the solar panels. To ensure tbe batteries are fully charged when we are sitting at anchor for a few days I normally set the solar regulator to a 14.4 float as I find it drops into float well before we are showing a full bank. On a good day tbe solar will generate close to 3 kw.
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Old 10-10-2018, 07:05   #25
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Re: Lifeline AGM's Fully Charged Voltage?

Thanks for this info -- also interested!
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Old 10-10-2018, 17:46   #26
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Re: Lifeline AGM's Fully Charged Voltage?

I have 660 AH of Lifelines, and a kilowatt of Solar. I leave the outback 80 set for 14.3 V in absorb and float and run the generator twice a week.
I donít quite get to a true 100% SOC without a generator run, so Iím only truly 100% fully charged twice a week and the other five days in the high 90ís%.
Now I have a little Honda too, and will run it once or twice a week, just to get a jump on battery charging, that should get me to fully charged four days a week.
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Old 10-10-2018, 18:01   #27
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Re: Lifeline AGM's Fully Charged Voltage?

Trojan recommends a maximum absorption time of 4 hours. Some chargers use the 4 hour time limit.
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Old 10-10-2018, 19:05   #28
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Re: Lifeline AGM's Fully Charged Voltage?

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Trojan recommends a maximum absorption time of 4 hours. Some chargers use the 4 hour time limit.


See thatís the thing.
It makes as much sense as saying Island Packet recommends putting 30 gls into the tank whenever you refill. How about if you only used 10? What if you used 50?
Then to further confuse things the 4 hour time limit doesnít know how big your charger is, so depth of discharge, and actually house loads and charger size can change that 4 hours.
You need to watch your trailing Amps and determine for yourself, what your bank, with your charge source and your usage is.
Or your just shooting in the dark and hoping to get it right, which with four hours, is unlikely.
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Old 11-10-2018, 00:46   #29
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Re: Lifeline AGM's Fully Charged Voltage?

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..... so Iím only truly 100% fully charged twice a week and the other five days in the high 90ís%.....
I've just replaced my 210Ah Lifelines and their instructions now say:

"It is recommended that batteries be recharged to 100% at least every 5-10 cycles."

That seems to mean every 5- 10 days as a minimum?

They define 100%:"...when the current drops to below 0.5% of the battery's rated capacity..."

I've always recharged fully with shore power every two weeks - and they have lasted 14 years.
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Old 11-10-2018, 01:11   #30
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Re: Lifeline AGM's Fully Charged Voltage?

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I've always recharged fully with shore power every two weeks - and they have lasted 14 years.

Glad to hear that ! For a64pilot I am a battery murderer a he says, I think he is an extremist



I can now see that Maine Sail suggest "Ideally you'd go into float at "full" or somewhere below 2% acceptance at absorption voltage" which is pretty much what my Victron MPPT have been doing for the last 30 months.


Honestly a64, if you can get 10+ years with very little attention, why would you spend so much time & energy to reach true 100% every 2 days ??
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