View Full Version : Dual Battery Switch

09-20-2008, 01:55 AM
My Supra 21V comes with the Dual Battery option. I understand the 1, 1/2, and 2 positions of the switch. But what does the off position do?


09-20-2008, 07:32 AM
Huh???? off= off


09-20-2008, 12:20 PM
I don't think ours is wired right. what works when you switch yours around?
I can use any accessory when it's set at anything but off, and the motor only works when it's set for either 1 or 1&2.
sound right?

09-20-2008, 01:15 PM
I haven't done alot of playing with it but I switched it to off and I could still turn on the radio. I was hoping/thinking it would stop everything from drawing from the batteries...

09-22-2008, 03:48 PM
Mine is the same way I can switch my batt to off and still run the ballast. It should kill everything but it doesn't.

09-22-2008, 04:14 PM
Trace your wires from your batteries. Lots of people jump off the battery straight to a device. If this is the case the off position will not kill them. I wire mine in to kill the entire boat. This saves the battery in case something gets left on, like stereo. The only problem with killing the entire boat is most of your saved information disappears. Stuff like clock in radio, presets and possibly perfect pass settings that are saved.

09-22-2008, 04:41 PM
make sure your auto bilge pump will work even with the switch in the off position, even if the boat is not stored in the water, was looking at a new boat that was covered up with the plug in and and had water up over the top of the seats--- i did not buy that boat.

09-22-2008, 11:12 PM
Oh, good call Moombadaze!

09-23-2008, 12:02 AM
That would really suck to open your boat after the winter to find it fill of water. So would it make since to pull the plug for a just in case or does that let the cold air flow into the engine compartment?

09-23-2008, 12:05 AM
That would really suck to open your boat after the winter to find it fill of water. So would it make since to pull the plug for a just in case or does that let the cold air flow into the engine compartment? Also anything that is wired direct to the battery will still work if the switch is off. I think that in my boat everything except the engine is hooked directly to the battery.

09-23-2008, 09:07 PM
yea, mine is too. kinda negates the dual switch in my mind, but maybe I don't really understand it's real useage. I would think that I could switch it to 1 or 2 when parked on the lake and listening to tunes, and if that battery goes dead, I could still switch to the other and start the boat. mine is the same in that the boat won't start if you move the switch, but everything else works, even in the off position, and it was wired by skiers choice, not an aftermarket...

09-24-2008, 12:49 AM
The 2 batteries are wired to the switch and from there back to the motor. The selector on the switch should only effect which battery or both are used to start the motor and are charged while the motor is running. The rest of the accessory panel is wired directly to one of the batteries. If you want to totally disconnect the power, turn the switch to off and then press the button on the breaker which should be located on the side of the storage compartment just next to the batteries.

09-24-2008, 04:48 PM
Lowdrag has it right. The switch is used for charging and starting Typically battery one is your main battery to start your boat, battery two is used for your accessories. Some of the better switches monitor the battery drain to ensure you always have enough to crank the motor. Again to truly cutoff power from the battery the switch needs to be in the off position and the breaker needs to be tripped. Just remember if you do need to pull the batteries out, label all the wires as it can get confusing hooking them back up. Especially if you have a long winter.

09-24-2008, 09:31 PM
For my 2008 LS, the recommended position is #1. This makes the sensed battery #1 (engine starting battery) which will ensure this battery if fully charged. Battery 2 will not be charged until battery 1 is ully charged. battery 2 is for the accessories.
If you use postion #2 the opposite would be true and the starting battery possibly could not get recharged if there is a high drain on battery 2.

09-25-2008, 02:11 PM
Sounds like you've got a voltage sensitive relay on your '08. Who makes the ones that they're using on the new boats? I may upgrade from my switch to one of these so I don't have to worry about it.

09-25-2008, 05:29 PM
So i was looking over my owners book and noticed the dual battery setup. Please look on the 08 book page 57. This shows you how it is hooked up and why the dash power is not turned off with the off switch.

09-25-2008, 09:43 PM
My boat is 500 miles away so I can't get a look at who makes the switch. Maybe you can contact skiers choice.