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mlibkind 09-12-2019 19:27

Batteries don't hold charge
I have 4 Lifeline 125 ah AGM batteries that are 3 years old. Prior to getting very sick 2 years ago, my solar and wind generator was sufficient to keep them charged. Only one time did I have to run the engine to charge them due to extended cloudiness.

I got very sick, was removed from my boat on a stretcher, and over 18 months it got very little attention. Certainly for the first 6 months it was left in a state of disarray until a friend flew to the Bahamas to take care of it and move it to the US. I do not know what occurred over that time w.r.t. the batteries' charge state.

I'm now sailing again, and my batteries will not hold a charge. Lifeline says to equalize at 15 volts for 8 hours. My Magnum charger/inverter will do an equalize at about 14.5 volts for 4 hours. I spoke to them and they said the reduced voltage is probably due to increased temperature though I don't think that there is a temperature sensor on the batteries.

So far that is all I have done. Using a Honda generator, I charge them to where the charger says they are float charging in the evening (usually 12.7 or 12.8 volts when the charger is turned off), and by morning they barely have 12.3 volts. The only things running during the night are two small refrigerators that are not opened during the night, status lights on panels, and maybe a cell phone charger or two. This is small to what in the past the batteries could handle ... refrigerators, chartplotter, autopilot and radar.

I'm in Nassau and the two large marine stores do not have AGM deep cell batteries. I have one more place to try, but do not have much hope of buying new ones.

Tomorrow I will equalize them again; I may do it twice to get the recommended 8 hours, but I can't increase the voltage to 15 as Lifeline suggests.

I would appreciate any suggestions you have as to what might be wrong and if there is a way to rectify the problem.

CassidyNZ 09-12-2019 19:32

Re: Batteries don't hold charge
Switch off all know appliances then take a terminal off the battery. If you get a spark, you have parasitic drain that isn’t showing on your instruments. If no spark, have the batteries load tested.

Anyway, that’s where I would start.

john61ct 09-12-2019 19:58

Re: Batteries don't hold charge
That's a long time to expect batteries to survived without attention.

I don't know if it's even worth having them load tested, 98% sure they need replacing.

Even higher if there was any load on them.

a64pilot 09-12-2019 20:57

Re: Batteries don't hold charge
A few things first your voltages are wrong. You charge at 14.3 plus or minus .1 so 14.5 isnít even close to an equalization charge thatís 15.5V

Then float voltage is 13.3 V. Fully charged resting is about 13, but can be lower if any load at all.

But you must first do as they say, equalize after a full charge for 8 hours at 15.5V.

But your not fully charged until you get to .5% of the rated capacity when holding 14.3V.
Set you Magnum to hold 14.3V and keep it there until your acceptance rate is .5%.
Then set it to hold 15.5V for 8 hours, you May have to equalize more than once, maybe 2 or 3 times. That is I believe straight out of the manual.

a64pilot 09-12-2019 21:00

Batteries don't hold charge
You canít load test deep cycle batteries, that is a car starter battery thing. You have to capacity test deep cycle, but that is pointless until after I would say at least two Conditioning charges, Lifeline calls it Conditioning charge, everybody else equalizing, but itís the same, just brought that up so the manual makes sense.
Speaking of which download that and read the section on charging carefully.

a64pilot 09-12-2019 21:02

Batteries don't hold charge
My Magnum will easily go past 15v.
How are you setting yours? Do you have the remote? If you donít get 15.5V your not accomplishing anything.

You set equalization voltage and duration under battery type. Iíd select custom if I were you and set absorption to 14.3 and float to 13.3 max charge time to say 8 hours
Equalization voltage at 15.5 and duration 8 hours.

Then do you know how to get the charger into equalization mode?
You hold the on/off button down for a stupid long time, itís at least 30 sec maybe longer and it will go into equalization.

acem 09-12-2019 21:11

Re: Batteries don't hold charge
Try this too.

Charge the battery bank. Then remove ALL the cables from ALL the batteries. Allow it to set for at least 8 hours then check the voltage of each battery. You might get lucky and have one battery with a short and be able to use the rest of the bank with it unhooked.

Best of luck.


CarlF 09-12-2019 22:16

Re: Batteries don't hold charge
Even with lots of care (and twice a year conditioning), my 125ah Lifelines lasted just over 3 years. This seems to be typical of people who don't plug in at a marina most nights.

The Lifeline conditioning helps a little but not much. And it only helps if you do it before the batteries are in serious trouble. Some recommend once a month.

I would sail back to the US and get new batteries. The import duty in the Bahamas makes batteries very expensive.

I replaced my last set of Lifelines with Firefly's and am glad I made the switch.

john61ct 09-12-2019 23:13

Re: Batteries don't hold charge
With deep cycling, a load test is just another name for a capacity test, also SoH or discharge testing.

Fully charge, including equalization if appropriate, and yes follow mfg specs for both.

Then feed a CC load, with lead using a 0.05C rate, and precisely time how long it takes to hit 10.5V.

Immediately start re-charging to avoid harming the batteries.

Of course this procedure has no relation to the load testing performed on automotive or other cranking type batteries.

And, as stated, I doubt it would be worth the trouble in this case.

Also, a nit pick perhaps, but standard unit terminology for current relative to capacity, in this case the endAmps stop-charge point, uses C-rate.

For Lifeline, the spec is indeed 0.005C, so with a 500Ah bank, wait during CV/Absorb cycle, for trailing current to drop to below 2.5A.

That is Full, and if at all possible, do not allow the charge source to drop voltage to Float, until that point has been reached.

Exile 10-12-2019 00:13

Re: Batteries don't hold charge

Originally Posted by john61ct (Post 3032869)
That's a long time to expect batteries to survived without attention.

I don't know if it's even worth having them load tested, 98% sure they need replacing.

Even higher if there was any load on them.

The OP stated the boat got little attention over the previous 18 months and he didn't know what happened with the batteries. But he also stated that the solar & wind generator was mostly keeping them charged prior to his departure. Finally, he stated that they were Lifelines which have a very low self-discharge rate, and don't require much if any attention other than keeping the terminals clean.

The OP's batts. are not maintaining the same voltage overnight as well as they used to, but he has yet to do a proper conditioning cycle and the voltage drop could be due to other factors. So based on the facts presented thus far, I don't see how you can be "98% sure they need replacing."

wingless 10-12-2019 00:37

Re: Batteries don't hold charge
My automotive Schumacher charger will permit overcharging the battery.

My carbon pile load will permit discharging the battery.

mark0978 10-12-2019 01:15

Re: Batteries don't hold charge
You are running refrigeration all night starting at 12.8 and ending at 12.3. Sounds like the batteries are working fine and your refrigeration is consuming the power. I've got 900AH and wake up to 12.3/12.4v in the morning on the hook. My refrigeration load consumes about 3KWh/day (Freezer and Fridge). I'm currently trying to get that load tuned with better thermostats.

roland stockham 10-12-2019 12:31

Re: Batteries don't hold charge
y is a fairly typical life for small AGM batteries, with care you can get up to 5 years but given your statement that the boat was left unattended I would assume that they have had periods of partial state of charge. With conditioning you may get some life back but I would plan on replacing them ASAP.

If you want longer life look at replacing them with something like a pair of L16 6v FLA,s or even better 3 4v batteries. Basically the bigger the battery and the lower the voltage the longer the life cycle. Lifeline rates there batteries for about 500 cycles to 50% DoD. (as a comparison the Rolls AGM at the same size is better at 1000 cycles but still not good) By comparison Rolls 4v 4CS17P 568A/hr battery is rated for 4500 cycles to 50% DoD which goes up to 7000 at 75%, that 19yrs and change for about the same price at replacement lifelines. A rolls L16 6v is about half the life of the 4v ones. They do do a 2v but only in VERY large sizes and with minimal advantage over the 4v. The 'fly in the ointment is that all these batteries are tall and wont fit under the floorboard on most boats so you may need to modify the storage.

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