If you were me, and all else was equal(ized)

[S/V Alchemy]

Originally Posted by jr_spyder

I have 3 pairs of 6v gels and had a pair fail last year. It was great that I could disconnect that pair and continue operation and then patiently shop for a purchase the optimal replacements. I wouldn't do it any other way, but your priorities may be different.

No, they probably similar. So you actually had the failure that suggests pairs of 6VDCs are a good choice. Interesting.

Thanks to all the posters here for a stimulating discussion. 90% of boats have a pair of Group 27s 12 VDCs and maybe a start battery, so I didn't expect this much response.

[TeddyDiver]

Originally Posted by jr_spyder

I have 3 pairs of 6v gels and had a pair fail last year. It was great that I could disconnect that pair and continue operation and then patiently shop for a purchase the optimal replacements. I wouldn't do it any other way, but your priorities may be different.

Caveat emptor.. That's the dilemma with paralled banks, one eventually fails and finally you have a single bank which is just a tad smallish. But like you said, priorities..

[S/V Alchemy]

Originally Posted by TeddyDiver

Caveat emptor.. That's the dilemma with paralled banks, one eventually fails and finally you have a single bank which is just a tad smallish. But like you said, priorities..

And yet it's stories like this that are putting me in the "pairs of 6Vs" camp as I weigh "robust" versus "available" and "still gives me 2/3rds at 13.2 VDC".

[TeddyDiver]

Originally Posted by S/V Alchemy

And yet it's stories like this that are putting me in the "pairs of 6Vs" camp as I weigh "robust" versus "available" and "still gives me 2/3rds at 13.2 VDC".

That's just the very reason why they fail. Like having a marriage to help solving all the problems you never encountered being single..
With AGM's it's inevitable, flooded are a more forgiving if maintained properly.
http://solarprofessional.com/article...-battery-banks

[a64pilot]

Originally Posted by S/V Alchemy

I'm in Canada and Honda never bothered to have their "Companion" models certified for here, so I just have the one Honda 2000. I use it frequently for power tools (except it dies when I use my 10 amp Makita circular saw and hit a knot...). I also use it to lay a charge on my boat that overwinters in an unpowered yard. I am very pleased with it...it will keep a small chest freezer and a fridge going in a blackout.

But the "real deal" for me is the Honda "Companion" model plus an American-sourced "regular" Honda 2000 are able to sync up their outputs to provide 3200 watts continuously and 4000 watts at surge, so read 23-30 amps of 120VAC. That's enough to run my 12000 BTU heat pump, which has a 17 amp "kick" on the March pump. That's enough to charge my banks should my alternators fail. That's enough (and you may see where I'm going here) to power my welder (it's a steel boat).

So if I can get a pair for, say, $1,400 U.S., I have a portable 3.2 kW gen set I can take ashore to build the native chief a house and never lack for taro and roast pig again!

I paid right at 2K for my pair, the Companion is nice in that your shore power cable plugs directly into it. To start my 16K BTU AC both need to not be on eco, but once running you can turn them down to eco and they are much quieter and vibrate much less and of course burn less fuel. Eventually I'll get that invertor / charger that will allow me to keep them on eco all the time regardless.
Main thing is two running on eco is much quieter than one running hard even if you don't need the increased output, plus of course there is redundancy if you have two.

[mcarling]

Any lead-acid acid battery will eventually fail, even if treated perfectly and it will fail with about ten years in the best of cases. Anyone wanting a battery that can last for decades (only if properly treated, of course) will need to choose another battery technology, such as LiFePO4.

[S/V Alchemy]

Originally Posted by a64pilot

I paid right at 2K for my pair, the Companion is nice in that your shore power cable plugs directly into it. To start my 16K BTU AC both need to not be on eco, but once running you can turn them down to eco and they are much quieter and vibrate much less and of course burn less fuel. Eventually I'll get that invertor / charger that will allow me to keep them on eco all the time regardless.
Main thing is two running on eco is much quieter than one running hard even if you don't need the increased output, plus of course there is redundancy if you have two.

That's very much our logic: we plan on having windscoops, fans and dorades and so on for most of the time, but if we really need an off-deck sleep or we have guests, it would be great to lay down a couple of rubber mats to leeward and to have A/C for the evening for a couple of cups of gasoline. I use the eco setting most of the time unless it's a hefty power tool I'm operating. For instance, eco will run a compressor for air tools just fine, and that's not something I'd bother running through the inverter.

[S/V Alchemy]

Originally Posted by mcarling

Any lead-acid acid battery will eventually fail, even if treated perfectly and it will fail with about ten years in the best of cases. Anyone wanting a battery that can last for decades (only if properly treated, of course) will need to choose another battery technology, such as LiFePO4.

Actually, I'd be happy with five or six. I get six or seven out of the crap consumer grade Group 27s I run on my 33 footer (bought with only saving money in mind) with a spring and fall hydrometer check and service, clean terminals and lugs and most of the time spend on shore power. So I don't think I'm being unrealistic to assume that six L16s kept cool(ish, or at least out of the engine room), temperature monitored and properly watered and never likely below 60% SOC should last at the more durable end of the timeframe.