Join Date: Oct 2000
Location: Portland, OR
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An AGM battery comment, although not quite germaine to the question... but perhaps a data point all the same.
We are on our second AGM 12 volt "starting/emergency" battery. The first one was a Trojan and died too soon. Present one is a spiral-cell and must be about four+ years old. House bank is a pair of Trojan GC batts, flooded technology.
Reason for the odd battery technology in the "emergency" position was that the only good location for it on our boat was back under the aft cabin berth and there was no practical way to service a flooded battery there.
I also like the way I can charge it off the stock alternator for about 30 minutes, about three or four times a season, and it stays fully charged for long periods of time (i.e. self-discharge is very low for this type).
I just used/tested it for the first time this year to start the diesel a few days ago. Engine had not been run since I winterized it in early December. Glow plug and starting worked without a hitch.
As others have pointed out, most any 12 volt battery will start a small diesel, and it's just nice to know that we do have enough spare power available.
All of rest of the time we run everything off of the "house" bank, which is about 235 to 250 AH, depending on which edition of the Trojan brochure you look at. We have actually anchored out for two full days with the fridge running full time, and easily started up the three-cyl. diesel when we decided to leave.
Last edited by olson34; 04-20-2014 at 12:56 AM.
Reason: wrong battery info