Remaining powered without shore power

[PotatoAddict]

Hi all. How do you manage to stay powered when you're away from shore power and you're at sea, at anchor, at a mooring, etc.?

I made my first trip to Catalina Island and moored at Avalon Harbor for 3 nights. It was a lot of fun. However, a major concern of mine was battery power. I have lots of appliances that relied on them: 3 refrigerators, lights, stereo, TV, etc. My boat has 2 x group 29s (house, port engine) and 1 x group 29 plus 1 x group 27 (starboard engine, generator).

I do have a generator and I ran that a couple of hours a day while cooking and showering (for the hot water heater). I also figured the 30 amp battery charger would also have the opportunity to recharge the batteries a bit. However, during the last day, my batteries were really running low: the lights got dimmer, etc. Apparently 2 hours a day of generator usage was not enough to keep my batteries up to charge. Should I have let it run longer? Or perhaps is my 30 amp battery charger just too slow/weak? Would have running both engines at idle and allowing the alternators been better (they're both rated at 65 amps each, but I know that at idle the output is less, plus I'm concerned about adding extra hours to the engines).

What would you have done and how do you manage to keep your own vessel powered? Thanks for your thoughts!

 

[Mischief Managed]

Re: Remaining powered without shore power

You need to calculate/measure your current draw and offset it with generator power. If you you are drawing 10 amps per hour off the batteries and you can only put 30 amps per hour back into them with the generator, you need to run the generator 8 hours per day to keep up with demands.

This excludes losses due to inefficiencies of charging batteries.

 

[JoLin]

Re: Remaining powered without shore power

What Mischief said. You have several factors to be balanced-

1. Your rate of consumption

2. The amount of energy you can store on board (batteries)

3. The amount of energy you can generate via generator and/or engine alternator

Look first at consumption, as that pays the biggest dividend. How/how often are you using all those appliances and accessories? Do you really need to run 3 refrigerators at anchor? Block ice in a good cooler lasts for days. Interior and anchor light incandescent bulbs can be replaced with LED's, etc. I don't have a genny, so energy conservation is critical. Energy you DON'T use doesn't deplete the battery.

As a general observation, a single house battery is pretty light for all that stuff you have aboard. I'd add another- if space is a concern, maybe 'lose' one of the engine starting batteries and wire in a second house battery, instead... but that's only one of several ways you could redistribute your batteries.

To be perfectly honest with you, a bunch of boats at anchor, all running their gennys for hours at a time, is annoying. If that was the environment I wanted when I 'get away from it all', I'd pitch a tent on the side of the highway. It'd be a helluva lot cheaper than owning a boat!

My .02

 

[shrew]

Re: Remaining powered without shore power

1 Group 29 House battery and three fridges. This sounds woefully underpowered. Yes, you have a genny, but as stated, look at your AMp Hour consumption rate and compare to amp hour capacity. I would think you would be better suited for an 8D. I would also be looking at how to reduce amp hour draw. Turn fridges down when on battery. Use only as many lights as is absolutely necessary, and turn off those in areas not being occurpied. Consider upgrading 12 v light bulbs to LED, which draw up to 1/10th the amp hours. do you NEED the ice maker while on the hook? Do you need the electronics running? For example, if I leave my chartplotter on, the radar is also on, even if it isn't on the screen. I have to go in and specifically shut down the radar. Look at a 40 amp battery charger if possible, for faster charging. Consider running hte genny longer, for example a few hours in the morning and a few hours in the evening.