Battery life

[Talmine]

We have a traditional 36' cruising yacht with a modest 12 volt system. A 100 amp hour starting/back up wet cell battery very light use. And for the domestics two 110 amp hour Agm batteries. We manage our consumption pretty well with led lights, a small fridge and charging mobile phones laptop etc. at anchor and on our mooring, as the main use. We have 2 forty watt solar panels that keep batteries topped up whilst the boat is unoccupied and help out when we are on board. My question is how long is it reasonable to expect the batteries to last before replacement. At the moment everything is fine with the engine having to be run for a couple of hours every third day. The batteries get a fair amount of use with us spending 4 months on board each year and we have lived full time aboard for 2 years. The agm's are nearly 7 years old and we are planning on live aboard cruising for the next 3 years or so so I'm trying to decide wether to replace now, whilst the boat is in the uk or wait until they pack in and replace when required. I don't like junking kit that's working but have experienced the pain and expense of replacing kit abroad. Any experience or views on a reasonable life expectancy for the agm's?
Jim

 

[superheat6k]

If they are working then stick with them but perhaps source best place to locate replacements. Exercising them as described sounds like excellent practice. You will find a basic lead acid more or less anywhere. How about a small suitcase generator for the charging ?

 

[temptress]

If they are working then stick with them but perhaps source best place to locate replacements. Exercising them as described sounds like excellent practice. You will find a basic lead acid more or less anywhere. How about a small suitcase generator for the charging ?

+1 Batteries are available everywhere.

 

[duncan99210]

I'd replace them now and add to the capacity if space is available. I bought AGMs before we set out and paid about 50% more for them than wet cell batteries in UK. I had to replace them this year in Greece and had to make do with sealed batteries rather than AGMs as the cost of them was about 3 times what I paid in UK. The sealed cells weren't cheap either!

The real problem of waiting until they fail is that you'll then be stuck with whatever you can lay your hands on at the price the locals think that they can charge you, which will be a nasty shock to the system. Replace now where you've got a wide choice of suppliers and competiton keeping the prices down.

 

[RAP77]

I have 4 Lifeline AGM 100Ah batteries. 12 years old
I plan to replace this year as they MUST be near the end of useful life.

 

[Talmine]

Thanks all for your thoughts and opinions which pretty much reflect my internal dilemma. Keep going and sort out when I need too or pre- empt failure and replace now. Having experienced buying abroad I guess the extra costs are just about offset by the extra use I might get out of the existing set, as long as they don't pack in too soon! Ah we'll a bit more thinking to do.
Jim

 

[TQA]

Normal 50% cycling with the odd deeper cycle - 4 years

Say 30% cycling with long dormant periods - 7 years

Anything after that is bonus time IMHO.

 

[sailinglegend420]

...I had to replace them this year in Greece and had to make do with sealed batteries rather than AGMs as the cost of them was about 3 times what I paid in UK. The sealed cells weren't cheap either.......

Because AGMs are non hazardous you can order them from the UK and ship to Greece for only maybe 20% extra, not 300%.

 

[KellysEye]

If you are going long distance sailing I would replace them you don't want battery failures in the middle of Biscay or the Atlantic. If you are living aboard in a Marina no need to change them. Our batteries lasted 5 years but that was using them 24x7x365.

 

[Talmine]

We're wintering in a marina and I've pretty much decided to replace in the spring. Thanks for thoughts and advice
Jim

 

[duncan99210]

Because AGMs are non hazardous you can order them from the UK and ship to Greece for only maybe 20% extra, not 300%.

Yes in theory. Two problems: most courier companies take one look, see lead acid batteries and say hazardous and go no further. Secondly, when cruising you have no address to send them to and have no choice but to buy what is available on the shelf locally. That's why I said to the OP to buy new ones now in UK. A further point is that 220 AH is, IMO, too small a bank and could do with being bigger. Better to do that now with all new batteries than trying to fix it in the Med.

 

[sailinglegend420]

Yes in theory. Two problems: most courier companies take one look, see lead acid batteries and say hazardous and go no further. Secondly, when cruising you have no address to send them to.....

Any company that sells AGMs will have a courier that accepts them -if not go to sales@merlinequipment.com
They used to have a calculator in the checkout for overseas delivery @ power-store.com but that link doesn't work now.

I had stuff delivered to an agency in Rhodes - A1 Yachting. They charge 30 euros handling and storage charge. Any marina will probably accept deliveries if you stay one night.

 

[alteredoutlook]

Batteries are available everywhere but consider where you are going cruising - the cost of replacement in a out of the way place could be exorbitant!

 

[Habebty]

Good original question,my AGMs are nearly ten years old,and was wondering how much longer they are going to last. Boat is marina based and a smart charger keeps them topped up all year round.
Based on my experience, I would go with AGMs again.