Typical power consumption


Petty Officer 2nd Class
Apr 23, 2002
I was curious as to what the typical drain from a battery would be with minimal equipment being used. I would use only my GPS, marine radio, and all navigation and cabin lights would be LED lights. I don't see the need to spend the night at a marina when I have all I need on board. Would an average deep cycle battery last me a weekend of sailing or do I really need to get a slip and recharge?


Petty Officer 1st Class
Oct 6, 2012
You could recharge w/solar or wind. other than that it would be hard to say not knowing what kind of boat, is it electric head? and so


Supreme Mariner
Sep 22, 2003
The only way to determine for certain that you can make it through a weekend at anchor without charging capabilities is to add up the maximum current draw of each accessory you are running. Since none of the things you list will likely run continuously, you can factor the approximate run time into the calculation. Once you come up with an AHr (amp/hr) number you will look at the label on the battery and see if there is enough capacity. There is no such thing as an "average" deep cycle battery. Deep cycle batteries are rated in either AHr or Reserve Capacity. Reserve capacity is an industry standard and uses a 23 or 25 amp current draw to come up with reserve capacity called reserve minutes. If the label on your battery says 175 minutes, that means the battery can supply 23 or 25 amps continuous for 175 minutes. Hopefully your load will be nowhere near that so if you used a 5 amp continuous load, the battery could supply 5 amps for five times the 175 minutes which would come out to 14.5 hours of continuous operation. Still not enough for a weekend but again, you should not have a continuous 5 amp load during the day, but it would likely be more than that at night. Unless you have a sizable boat, you need a fairly large capacity solar panel to keep the battery charged.Same for wind power. If your boat is an I/O or has a big outboard with high output alternator you could charge the deep cycle from it via a dual battery switch or ACR.

Scott Danforth

Grumpy old guy who plays with boats
Jul 23, 2011
one or two batteries on board?

your house loads should be separate from the engine starting load.