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Wiring dual batteries

Posted: February 23rd, 2010, 9:37 am
by screaminseamen
I am going to install a 2 battery system with a switch that has 1, 2 , all and off in my boat. i had a couple of questions if any one knows the answer it would be great. I want to keep my bilge pump hard wired so that even if the batteries are off it can still kick on if needed, would this cause problems? also i want the electronics to go off when i switch the batteries off because my stereo drains some of my battery, would this be a wiring nightmare?

Re: Wiring dual batteries

Posted: February 23rd, 2010, 9:44 am
by FHC
wire bilge to battery wire radio to switch

Re: Wiring dual batteries

Posted: February 23rd, 2010, 10:18 am
by wevans
What he said :-D bilge strait to the battery and all other hot wires through the switch :thumbup:

PS: This means that your bilge will depend on only one of the two batteries for all of it's power :smt012 unless you throw the switch to ALL, then it will pull from both :smt004 :beer:

Re: Wiring dual batteries

Posted: February 23rd, 2010, 8:08 pm
by robbankston
wevans wrote:What he said :-D bilge strait to the battery and all other hot wires through the switch :thumbup:

PS: This means that your bilge will depend on only one of the two batteries for all of it's power :smt012 unless you throw the switch to ALL, then it will pull from both :smt004 :beer:

I guess if you didn't want to worry about forgetting to turn it to all, then you could install 2 bilge pumps. One wired to one battery and one wired to the other. That would be cheap insurance, at least for folks like me with bad CRS :D .

Re: Wiring dual batteries

Posted: February 23rd, 2010, 8:12 pm
by wevans
If I installed 2, I would have one set about 2 inches higher than the other so that it only kicked in if the other one failed or could not keep up :-D that way you don't drain both batteries at the same time :beer:

Re: Wiring dual batteries

Posted: February 23rd, 2010, 11:27 pm
by screaminseamen
Well its in a small boat so i think 2 bilge pumps would be overkill. but thanks 4 the advice

Re: Wiring dual batteries

Posted: February 23rd, 2010, 11:30 pm
by tin can
If it's an automatic bilge pump it has 3 wires. One to the switch on the console, a ground, and the third goes directly to a battery.

Re: Wiring dual batteries

Posted: February 24th, 2010, 9:14 am
by MudDucker
It is not good to wire two bilge pumps with one to each battery. That leaves you with the very real possibility that you have two dead batteries and no way to crank. While that is not a bad thing on shore, should you get offshore, it could be a very bad thing.

Re: Wiring dual batteries

Posted: February 24th, 2010, 10:34 am
by wevans
If it takes two bilges ta keep up with the water "with one being two inches higher than the other", you got bigger worries than dead batteries :smt004 if the boat aint already running and headed fer the hill, yer a crazy person :-D :beer:

Re: Wiring dual batteries

Posted: February 24th, 2010, 10:19 pm
by robbankston
I hear ya fellas. The only thing I am saying is if I got a bilge wired to one battery and I can't remember to throw it on ALL I don't want to worry about it while I'm docked. I come in from fishing and have a few :beer: I may not remember to turn the switch. :smt010 During the day when I'm out I'm more likely to remember the switch. 8)