Expected Lifespan of Lifeline AGM's

[sailinglegend]

Originally Posted by CaptRory

... It's a 440 AH bank being charged with a 40 amp, three stage smart charger at the dock and a pair of 185 watt solar panels....

Firstly Lifeline AGMs require a minimum of 20% of the total Capacity (C20) - so your 40 amp charger should be 100 amps.

My five 4D Lifelines are now 12 years old after 10 years as a Liveaboard. Last year I performed a 20 hour discharge test on each one in turn. This only took about 11.5 hours because their capacity was well depleted. Lifeline say replace when down to 50%. They were all exactly the same - I plotted the voltage on graph paper.

They lasted all season and I will do the tests again in a couple of months but fear I will have to replace them this year. They get fully charged on shore power every 2-3 weeks and equalised twice a year.

One reason they have lasted so well is because the bank was very large so they only get discharged lightly before being recharged. I only have 140 watts of solar, 120 amp shore power charger and 100 alternator. My 280 amp DC genny does a better job.

Remember not all AGMs are created equal!!!!!

[john61ct]

Originally Posted by sailinglegend

Firstly Lifeline AGMs require a minimum of 20% of the total Capacity (C20)

nitpick - .2C

[J Clark H356]

I have 2 4d lifelines. Got 7 years out of the first set but other than when winterized for 3 months, they are regularly charged and never get anywhere close to 50% discharge because I use my generator full time when off the dock. I have 5 years on the current set and will be starting year 6 this spring and they are going strong. If I hadn't been going on a long cruise in 2013 I would have gone another year and think they would have, possibly longer.

[PaulinOz]

Lifeline 6 x 2 volt 900 amp/hr. Lasted 4 1/2 years in a Bare Boat charter cat think totally abused 220 days a year.

[waterman46]

My first set of 2 4D Lifelines new in 1997 lasted through a 5 month off-the-grid cruise and 10 more years of 2 week long cruises and some weekend use. Next pair I got in 2007, one of them was apparently weaker than the other (slower to charge, quicker to discharge) when used either in parallel or individually, and I just nursed them along until 2016, when I replaced both again. This time, same problem, I'm getting good performance out of one of them but the other just takes forever to charge but discharges faster when in parallel. I need them in parallel to run my Glacier Bay freezer/refrig that takes 32A to cool the plates, otherwise the voltage will fall below 12V after about 30% discharge (-60 AH on these 220AH batteries). I do intend to see if Lifeline will make good on their one-year warranty.

So my experience is that process and quality controls at Lifeline are not as good as they used to be.

[StuM]

Originally Posted by john61ct

0.2Cnitpick - .2C

It's worth noting that the Lifeline technical manual actually says:
For repetitive deep cycling applications (deeper than 50% DOD) chargers should have an output current of at least 0.2C.

With less deep cycling and solar topping up, that 0.2C doesn't necessarily apply.

[a64pilot]

.2C is tough, and pretty much requires a generator or shore power.
I believe unless deeply discharge they would not stay at .2C for very long

[StuM]

Originally Posted by waterman46

My first set of 2 4D Lifelines new in 1997 lasted through a 5 month off-the-grid cruise and 10 more years of 2 week long cruises and some weekend use. Next pair I got in 2007, one of them was apparently weaker than the other (slower to charge, quicker to discharge) when used either in parallel or individually, and I just nursed them along until 2016, when I replaced both again. This time, same problem, I'm getting good performance out of one of them but the other just takes forever to charge but discharges faster when in parallel. I need them in parallel to run my Glacier Bay freezer/refrig that takes 32A to cool the plates, otherwise the voltage will fall below 12V after about 30% discharge (-60 AH on these 220AH batteries). I do intend to see if Lifeline will make good on their one-year warranty.

So my experience is that process and quality controls at Lifeline are not as good as they used to be.

With consecutive pairs of batteries failing in the same way, I'd be looking at how they are wired together and testing current flows on all connections with a clamp meter before I started blaming the manufacturer.

[john61ct]

Originally Posted by PaulinOz

Lifeline 6 x 2 volt 900 amp/hr. Lasted 4 1/2 years in a Bare Boat charter cat think totally abused 220 days a year.

now that's impressive. No LVD?

[john61ct]

Originally Posted by StuM

It's worth noting that the Lifeline technical manual actually says:
For repetitive deep cycling applications (deeper than 50% DOD) chargers should have an output current of at least 0.2C.

With less deep cycling and solar topping up, that 0.2C doesn't necessarily apply.

So more like the common-sense: don't let them stay down in the nether regions "too long"?

More than two theory-hours to go bulk from 40-80% is very long in practice anyway, since the required-often last long tail 80-100% will be what 8 times that?

Makes sense, if you're only dipping 10-15% each cycle, the max available amps becomes irrelevant.

At which point it starts to look logical - assuming consistent use patterns - to say "if your charge source is very limited (solar only), grow the bank AH big enough to ensure you're not discharging deep".

But then better be * sure * you don't dig a hole takes you a month to get back out of 8-)

[roland stockham]

AGM is a very low water system with nor reserve and no way of topping up so basically your battery is dead when it runs out of water. Fast charging with kill them but also leaving them on trickle charge for long periods can use water. 6 years probably puts them in 'dodge' territory but many will live longer. This applies to all sealed /maintainance free batteries, a good analogy is sealed bearings, the grease is guaranteed for life ie when the grease is gone the bearing is at the end of its life!

[Shrew]

I'm going on my 9th season with 2 x Group 31 AGM lifeline batteries for the house bank. They are connected to shorepower Mon . - Fri. Only used on weekends and a couple of week long vacations. My season is also only 6 months long.

[macman4190]

Originally Posted by Suijin

My Lifelines are four years old, live aboard and use them year round, no solar, and were doing great. Winter of 15/16 the boat was hauled and I left it for for four months, and some *$% disconnected the shore power cord and when I returned they were dead.

Lifelines manual says the self discharge rate is 1-3%. If the negative cable, or positive cables are removed from the battery, they would not be expected to be discharged after four months, especially in cold weather. That could be another option if it is possible for someone to unplug your charger.

[ranger58sb]

Originally Posted by CaptRory

So now, I'm getting ready to head out into the keys and Bahamas... I don't want to throw away money, but I'm considering replacing what appear to be good batteries based on their age because replacing the starting battery and charger will have the whole system out on the deck...

Probably more expensive and maybe not as easily available in the Bahamas... but how hard can it be to come up with replacements in the Keys if you decided you need to?

FWIW, our oldest bank of dual-purpose AGMs (different, respected brand) will get replaced sometime this next season... after 11 full seasons of use. The symptom is that we now have to use the genset to charge 3x/day at anchor -- mostly to service both fridges. Not really a catastrophic problem... IOW, I can time the replacement easily enough. (fingers crossed, of course)

-Chris

[waterman46]

Originally Posted by StuM

With consecutive pairs of batteries failing in the same way, I'd be looking at how they are wired together and testing current flows on all connections with a clamp meter before I started blaming the manufacturer.

Yes, good point. However the first time this happened it was the battery #1 in my system that degraded, if I recall correctly. This time its #2. Well, I guess I can also switch them around just for fun, then if you are right I'll have two crappy batteries to prove it! Anyway thanks for reminding me to use a clamp ammeter - my measurements are all from the Link 2000 with it's low resistance shunts, and an independent measurement would be well worth it.