Dual Battery Connection

tholmes3

Cadet
Joined
Dec 4, 2005
Messages
18
Re: Dual Battery Connection

Thats fine. The sole purpose of them is to bring and keep the batteries at a full charge once they are trailered/docked. If there were to be a dead battery situation, then I would connect a 10-20 amp charger.
 

tholmes3

Cadet
Joined
Dec 4, 2005
Messages
18
Re: Dual Battery Connection

Also, I went to the hardware store to purchase 24+ inch battery cables. There were two different guages of wire, both were pretty thick. What would you suggest? (Something at least as thick as what is the terminal leads from the boat?)
 

tholmes3

Cadet
Joined
Dec 4, 2005
Messages
18
Re: Dual Battery Connection

Could I connect one charger to the common connection and when the boat is off, leave the switch on "both"? Isn't this the same as a small alternator charging both batteries?
 

Reel Poor

Vice Admiral
Joined
Jan 29, 2005
Messages
5,522
Re: Dual Battery Connection

Yes its the same. With the switch in the both position you could also hook the battery charger to either battery positive post.<br /><br />Here is the ideal way to set up dual batteries for a single engine set up. <br /><br />I would rcommend using an isolator. They control battery charging and will keep the alternator from over charging or under charging batteries.<br /><br />Connect your onboard 2 bank charger wires to the #1 and #2 terminals on the battery switch. If using a single bank charger, connect it to the isolators alternator input terminal. Wired like this both batteries will charge with selector switch in the on or off position.<br /><br />Connect the fuse block +lead wire to the common terminal on the switch. Be sure to fuse the 12 volt +lead to the fuse block. Connect the fuse block -lead to the ground buss bar. <br /><br />Wire all accessories from fuse block.<br /><br />Do not connect the batteries negative terminals directly together. Use a remote, common buss bar and connect each battery negative lead to the bar. Then use this bar for all of your ground leads including accessories and engine.<br /><br />
Battery4.jpg
 

ed/il

Petty Officer 3rd Class
Joined
Nov 24, 2004
Messages
80
Re: Dual Battery Connection

Run the motor on battery one, next time out run motor on battery two. To play it safe you could start on one battery let it warm up, turn it off and start on the other battery. Now you know both batteries will start motor. If you do not use the boat for long periods of time use your charger one battery at a time. I do not charge my bateries unless the boat has not been used for several weeks. I do not run my motor with selector switch on both.
 
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