Dual batteries

[Kimtown]

Sparkies at work said they will happily set up dual batteries for me, what else do I need besides the obvious (a battery lol)

Already have the 2 way isolator switch.

[smile0784]

Battery box.
Battery cable.
Terminal ends.

[Kimtown]

Battery box.
Battery cable.
Terminal ends.

Just enough cable to reach from each terminal to the other battery terminals, or will it have to reach to the isolator?

[rb85]

Battery selector switch/vdr

[smile0784]

Is it a isolator switch that had a round knob that switches between battery 1 or 2 or both?
Or a simple swith with a red key that can be removed?

Either way set up is almost the same.

From memory i think the 2 negative need to go together and the 2 positives go to the different povit terminals switch.

Depending how far switch is from the switch is from battery depends how long these need to be.

Also you probably need 6mm wire to join from isolator switch to your fuse pannel and earth board instead of existing battery.

[skronkman]

There are many variations to how you can setup dual batteries depending on what you want to achieve. Do some research on the options using google. Any questions you have, people here will be happy to help. I do think a VSR is a good option to have in addition to the battery selector switch. For the wiring between the selector and all batteries be sure it is of a gauge no less than what is used on your motors existing starter wire (the thick one).

Cheers

[purple5ive]

second battery is generally used as a backup incase the first one fails.
because lets face it, theres no way you can get a jump start from another boat if your battery is flat. (unless somehow theres a battery pack on board)
but as mentioned earlier, few others ways to use a second battery and the setup all depends on what you want the second battery to do.

[barra mick]

There are many variations to how you can setup dual batteries depending on what you want to achieve. Do some research on the options using google. Any questions you have, people here will be happy to help. I do think a VSR is a good option to have in addition to the battery selector switch. For the wiring between the selector and all batteries be sure it is of a gauge no less than what is used on your motors existing starter wire (the thick one).

Cheers

Listen to skonkernon. ...thats my advice. I used his knowledge in my boat.

I knew a fair bit but hes pretty switched on with the finer details.

bm

[Kimtown]

Is it a isolator switch that had a round knob that switches between battery 1 or 2 or both?
Or a simple swith with a red key that can be removed?

Either way set up is almost the same.

From memory i think the 2 negative need to go together and the 2 positives go to the different povit terminals switch.

Depending how far switch is from the switch is from battery depends how long these need to be.

Also you probably need 6mm wire to join from isolator switch to your fuse pannel and earth board instead of existing battery.

Yes, the boat already has a selector/isolator switch for batteries 1 & 2 so that's one thing I won't need.

I want it so my electronics like radio, stereo, winch, lights, sounder etc. are all ran off battery 1, and so if it goes dead flat battery 2 should still have full charge to turn the boat over and charge up battery 1 again. I don't want any accessories ran off battery 2, it's primary purpose is for a backup, like mentioned in an early post.

I assume this is possible as a lot of 4WD's are set up like this.

[skronkman]

Is it a isolator switch that had a round knob that switches between battery 1 or 2 or both?
Or a simple swith with a red key that can be removed?

Either way set up is almost the same.

From memory i think the 2 negative need to go together and the 2 positives go to the different povit terminals switch.

Depending how far switch is from the switch is from battery depends how long these need to be.

Also you probably need 6mm wire to join from isolator switch to your fuse pannel and earth board instead of existing battery.

Yes, the boat already has a selector/isolator switch for batteries 1 & 2 so that's one thing I won't need.

I want it so my electronics like radio, stereo, winch, lights, sounder etc. are all ran off battery 1, and so if it goes dead flat battery 2 should still have full charge to turn the boat over and charge up battery 1 again. I don't want any accessories ran off battery 2, it's primary purpose is for a backup, like mentioned in an early post.

I assume this is possible as a lot of 4WD's are set up like this.

It's possible. You could hard wire your auxiliary electronics to battery one and then your motor connects to the selector switch so you can choose which battery you start from. This is a decent setup as long as you remember to keep battery 2 charged up as it will never get a feed from the alternator/coil while the selector switch is set to battery 1. This is where a VSR comes in handy, it will feed a charge to the second battery when the first battery is fully charged without you needing to change the selector switch. It will likey add another $50-$100 to your setup but it's worth it.

In this scenario, just use your boat normally on selector switch set to battery 1. In case of a flat battery you can switch to battery 2 for starting. Once started you can switch back to battery 1 (via the 1&2 option, not the Off position) and the motor will charge battery 1 again and your electronics will function.

My preferred option in this scenario is to wire your AUX electronic load to battery 2 and run your motor off battery 1. This way the only load on batter 1 is starting the motor and it always gets the primary charge feed from the motor. This way, even if you run your battery 2 flat (by running your deck lights for example) you can still start without doing any switching and after the engine is running and fully charges battery 1 the VSR will charge battery 2 automatically.