When I bought Amelia in 2017 I replaced the Onan. I spent about two months with no genset and there was no list. As soon as the new genset was installed we listed to port.

I also bought new Lifeline AGMs.

Still going 100%. I wanted Firefly at the time  but availability was the problem.

I understand the attractions of Lithium, but carbon foam AGM batteries are also very attractive. Firefly brand is the best but expensive and not available in the U.K.

Pure lead carbon AGM by Leoch are available in the U.K. £239 inc delivery. I am sure you could get a discount for 12. I have no personal experience with these batteries.

I currently use my boat for about 5 months per year. I have solar and wind. For the other seven months the solar keeps the batteries 100% charged. Whilst cruising I run the genset to make water, do the laundry etc for about 3 hrs per week. Call it 75 hours per year. So about 115 litres of diesel, one oil change and an oil filter pa.

I anticipate that my battery bank will last quite a long time...but who knows.

Now if I was to do it again now, that is buy a boat with the generator seized and dead.

I would not replace the generator.

I would go Lithium and big inverter and big solar and big alternator.

The boat would have less weight and no list and it would have saved money.

The thing is, you:

Have a good generator

Only use the boat six months pa

Not sure Lithium is worth the trouble and expense unless you are cruising full time.

If you had solar you would prolong the life of your AGM bank.

All the best and looking forward to rolling out effective vaccines so we can get back on track.

Nick 

S/Y Amelia Leros Gr

AML54-019