View Full Version : Boat Dual Battery Setup

03-22-2004, 12:27 AM
I want to run two batteries in my Outback LS. Besides two batteries, what else will I need and how should I hook everything up? I want to have the main battery for the boat and all its accessories besides the radio. I want the second battery for the radio, amps, speakers, subs, etc. I was thinking by running two batteries, I would never be stuck out in the middle of a lake with a dead battery because I played my stereo too long while just chillin'. Any help would be great. Thanks.

Brian Raymond
03-22-2004, 11:24 PM
JNA. Contact; techservice@skierschoice.com, they have the illustations and voltage sensor relay (standard on the Gravity SSV), to meet your needs. Brian Raymond

03-24-2004, 11:28 PM

I was at our local Moomba dealer today and I asked there parts department for the Voltage sensor relay. They said I needed a Battery Isolater. Is this the same thing?


03-25-2004, 10:03 AM
I came across this page discussing a battery isolator for an RV: http://www.geocities.com/harald_nancy/isolator.htm
This would allow running accessories from only one battery but would let the other (starting) battery kick in when required. Both batteries would receive a charge from the alternator.

I am not suggesting using this particular product however I felt there was some good information there.

I also recall reading about a voltage sensor to be used on single battery systems. It would shut down completely if the battery was getting low enough to risk not starting. I will do some more homework on this.

Having two batteries would seem like the ideal solution. However batteries are a high maintenance/failure items in the marine setting. Two batteries means you now have two to service/replace.

03-25-2004, 03:12 PM
I had another battery and selector switch installed on my 02 LS last season with a 650 watt 4 channel amp and tower speakers. I have a total of nine speakers one of which is a 10" sub under the drivers console. I have found that running the stereo almost all day will not completly drain the battery and my amp will stop working if it gets too low. The way I discovered it was purely by accident as my stereo would come on but there was no sound. This was after I had started the boat on the same battery, so there is enough juice to start the boat, just not enough for the amp. If one gets low, I just throw the switch to the other one, but the momentary loss of power erases my presets and gain.


03-25-2004, 05:32 PM
Hey Medic151,

Is there anyway you can take a picture of your setup and email it to me explaining everything? Email is: jsmith@sppkg.com or you could just post everything here. Thanks

03-25-2004, 05:39 PM
I'll see if I can get a digital camera and send those to you. Mine is on the blink currently, but I'll see if I can do it over the weekend. I'll let you know something.


03-25-2004, 07:03 PM
Go to Costco and purchase their largest marine battery for $122. It has about 35% more power than the stock one. I am running 12 speakers. Two are powered bazooka tubes and an amp for my four tower speakers plus a six light bar. Never have had a problem. I can run the sound system all day. Never have had a problem.

03-26-2004, 07:11 AM
Take a look at WestMarine.com, they sell a battery combiner "model 143268" Cost $80.00. It is a simple combiner with a couple of leads but it will take over the monitoring of your batteries. It will combine the two for charging and isolate them when the voltage drops from running your stereo. They also have a great diagram in the package for a triple on/off switch setup. This is just another way of many that you can run dual batteries. If you are interested I can email you more details.

03-28-2004, 12:13 PM
I still am working on getting the pic's of my setup. I am at work today and won't be off till 0700 monday. I'll see if I can get them them.


03-28-2004, 02:59 PM
Thanks for all the info and different thoughts . Much appriciated.


05-12-2004, 05:07 PM
For anyone considering going to a two battery setup. It was a easy job. I contacted Anthony Cooper at Skierschoice and he sent everything needed. I got the voltage sensor relay, battery box,all needed battery cables,tags( to place on each wire so their would be no questions on what went back where if you disconnected your batteries in the futher) and a wiring diagram.

I'll probably never really need it, but I sure dont want to be caught in the middle of the lake with a dead battery.

My boat is a 2004 Outback.I mounted the battery box just forward of the stock one and placed the voltage sensor on the small wall above the master reset switch. I had it done within a hour.

If any one has a questions or needs pictures of my installation Email me at


Thanks to Brian & Anthony for your help.

05-13-2004, 04:53 PM
I have 10 speakers (3 way) and 1 12" sub. woofer. 1 1200 watt amp and a 5 channel 500 watt amp. The amps have a low voltage cut-off built in that will shut the amps down when voltage begins to get low. When it gets to this point, I start the boat and charge the battery for awile. This very seldoms happens, I usually get approx. 2hrs. play time before having to run the engine. I also have a rechargable battery booster I carry with me all the time. It charges with 120v ac or 12v dc. The battery is upgraded as well.

01-10-2006, 12:56 PM
I know this is an old thread but does anyone have the wiring diagram for this setup. Thanks.