How long will a 12v battery hold its charge?

BugsBunnyBoater

Petty Officer 2nd Class
Joined
May 11, 2009
Messages
165
My plan is to move one of my 12v batteries from the rear to the center console. I need to know how long this batter if fully charged power my vhf radio and and gps.
My boat is a 1975 Mako with 112 Johnson outboard. I cant see pulling wires from the motor to the console to charge the battery.
At best my trips will last 4 to 5 hrs.

My plan is to charge the battery as soon as I get off the water.
 

Fl_Richard

Lieutenant
Joined
Jan 21, 2005
Messages
1,428
Re: How long will a 12v battery hold its charge?

If it's an automotive type battery it will last for at least that long.
 

BugsBunnyBoater

Petty Officer 2nd Class
Joined
May 11, 2009
Messages
165
Re: How long will a 12v battery hold its charge?

Its a marine battery.
My new to me used Mako had a new battery in it and I had just bought a new marine battery for a project boat I was building.
 

flargin

Chief Petty Officer
Joined
Aug 13, 2008
Messages
540
Re: How long will a 12v battery hold its charge?

on an average battery, you will be able to run your GPS and radio for a long time (all day would not be out of the equation).

I would try to figure out how to run a pair of 10 or 12 gauge wire to it, add a battery isolator to it, with a fuse, and you will never have to move the batteries again...

Remember batteries are heavy and they have acid in them. Just ask my wife as a new pair of jeans now have a hole in the leg... it will do the same to vinyl seats etc.

Additionally, you might be able to tap into the existing wires, but you would have to have a battery isolator there to prevent backfeeding.
 

Boatist

Rear Admiral
Joined
Apr 22, 2002
Messages
4,552
Re: How long will a 12v battery hold its charge?

Even a small group 24 battery would run your GPS for 2 weeks. The VHF will draw about 3 amps Max in the 25 Watt mode so if your talking all day it should still last at least a day. In the one watt mode or if you talk very little I would expect a week. Important to charge as soon as you can when you get home, leaving it run down will shorten the battery life.

If I were you I would leave battery where it is and buy a 12 guage extension cord to run up to the center console. Put a breaker on the battery end and wire the console end to a fuse box with enough circuits for everything in the console area.
 
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