Gotcha, we're on the same page, I misread. I think I've decided to wire the new batteries in parallel to increase the amp hours. I have one of those car jumper packs I will bring as a backup starting battery until I can install a real starting battery in the fall (probably one of those small PWC ones will work).
Regarding the alternator, my off the cuff calculations are as follows. Two 79AH group 24 batteries = 158 amp hours total. Since we'd never drop below 50% of those amp hours, the max that would be needed to put back into the batteries is 79. We have a 55amp alternator on our Yanmar. Since AGMs can draw as much as 75% of the needed amp hours, that really only leaves us with a 4 amp larger draw than the alternator is capable of providing (59 vs 55). I figure 50% would even be excessive so I think we're safe. Time will tell if I'm right. Thank you everyone for the help and comments, much appreciated! Mike --- In [email protected], "Phil Agur" <pja...@...> wrote: > > Mike, > > > > I just used the generator to crank the diesel and then stowed it to get > underway again. But you're right if I stayed in the anchorage with the > generator running until I saw my charge current fall off to a safe level > then everything would have been fine. This was probably a dozen boat raft-up > so when it's time to go, it's time. > > > > It's a twenty amp Charles Marine "bulk" charger so it only gets used to for > jump starting. It's fine to bring a battery back from the brink but I have a > portable smart charger that really takes care of conditioning the batteries. > > > > Phil Agur > <http://www.catalina27.org/public_pages/profile270.htm> s/v Wing Tip > C270 LE #184 MMSI 366901790 > > > > > > From: [email protected] [mailto:[email protected]] On Behalf Of > mkeller23173 > Sent: Tuesday, June 29, 2010 12:01 PM > To: [email protected] > Subject: [IC27A] Re: AGM Batteries > > > > > > Phil, > > I don't quite get that. If you're charging both batteries with the honda > generator, then run home under power using both batteries, wouldn't that > alleviate alternator issues? If the batteries are fully charged, then they > wouldn't pull very much juice and overheat the alternator right? > > Also, what AC charger do you have installed? I have a feeling the Charles > marine one that came factory is NOT a three stage charger and also does not > have an AGM setting . . . > > Thanks, > > mike > > --- In [email protected] <mailto:IC27A%40yahoogroups.com> , "Phil Agur" > <pjagur@> wrote: > > > > Your alternator can only stand to put out 50% its rated load for any > > extended run time. Any time you are charging into a discharged deep cycle > of > > any type there is some risk to the alternator. > > > > > > > > On a long weekend, as long as I bring my Honda 1000i generator, I can > treat > > both batteries as house batteries since the Honda adapted to my shore > power > > inlet will jump start the diesel via the bulk shore power charger. > > > > > > > > However if you then motor back in and set the A-B switch to both your > local > > alternator rebuild shop will gladly school you on what not to do next > time. > > > > > > > > Phil Agur > > <http://www.catalina27.org/public_pages/profile270.htm> s/v Wing Tip > > C270 LE #184 MMSI 366901790 > > > > > > > > > > > > From: [email protected] <mailto:IC27A%40yahoogroups.com> > [mailto:[email protected] <mailto:IC27A%40yahoogroups.com> ] On Behalf > Of > > mkeller23173 > > Sent: Tuesday, June 29, 2010 9:59 AM > > To: [email protected] <mailto:IC27A%40yahoogroups.com> > > Subject: [IC27A] Re: AGM Batteries > > > > > > > > > > > > Thanks gentlemen, > > > > Did any of you change your alternators when you made the switch to AGM? > I've > > read that AGMs can burn up alternators since they pull up to 75% of their > > rated amp hours when charging. > > > > Mike > > >
