This discussion raises an issue I have struggled with as I have started cruising more: deciding how much battery power I have. I have 2 AGM batteries, one house, one starting and a panel voltmeter for monitoring. My batteries are now separated so I no longer have to worry about being able to start the engine if I run the house too low. The fridge is the only major power draw, so I usually am just conservative, running it only periodically to make sure I don’t overdraw the battery. So what is the most efficient way to figure out how much I can safely run the fridge? If I just watch the voltage, how do I decide if I can leave the fridge on overnight? Dave
Aries 1990 C&C 34+ New London, CT > On Feb 12, 2018, at 2:33 PM, Josh Muckley via CnC-List > <cnc-list@cnc-list.com> wrote: > > Much of your problem is a matter of battery capacity as much as a matter of > charging capacity. I have ~450 Ah of capacity on one bank, a 90 Amp > alternator that never reaches full load, and 200 watts of solar. Even > without the solar I was able to comfortably keep the the fridge running and > the lights on when cruising for ~2 weeks. The half hour to hour of engine > operation to anchor or moore in the evening and the same in the morning was > always enough to keep the batteries charged. > > Keep in mind that the battery capacity should be at least 4x of the charge > capacity for flooded lead acid and at least 2x for AGM. So a 400 Ah or 200 > Ah respectively for a 100 amp alternator. > > Josh Muckley > S/V Sea Hawk > 1989 C&C 37+ > Solomons, MD > > > > On Mon, Feb 12, 2018, 12:55 PM Damian Greene via CnC-List > <cnc-list@cnc-list.com <mailto:cnc-list@cnc-list.com>> wrote: > A question for your collective wisdom: > > I am scoping out upgrading my stock 55A alternator to a 100A Balmar, and > related upgrades to the controls. I had a very productive discussion with Rod > Collins at Compass Marine (mainesail), and we worked out the details. > Unfortunately he's booked out through the spring, so this job will wait until > next winter. > > So thinking then about keeping the batteries charged, and the fridge running > on our long summer cruise - where we may go for weeks without access to shore > power, I got wondering about using a portable generator to charge the > batteries - as an alternative to many hours of running the diesel. There are > a couple of Hondas that might do the trick 2000 Watt, weighing 47#, 1000 Watt > weighing 29#. > > Have any of you tried this? What could (would) go wrong if I plugged this > generator into my inverter, to charge the batteries? > > Regards, > > Damian > > 1986 Sabre 38 Freefall > Previously 1984 C&C 34 Ghost > Bass Harbor, Maine > _______________________________________________ > > Thanks everyone for supporting this list with your contributions. Each and > every one is greatly appreciated. If you want to support the list - use > PayPal to send contribution -- https://www.paypal.me/stumurray > <https://www.paypal.me/stumurray> > > _______________________________________________ > > Thanks everyone for supporting this list with your contributions. Each and > every one is greatly appreciated. If you want to support the list - use > PayPal to send contribution -- https://www.paypal.me/stumurray >
_______________________________________________ Thanks everyone for supporting this list with your contributions. Each and every one is greatly appreciated. If you want to support the list - use PayPal to send contribution -- https://www.paypal.me/stumurray
