Dual Battery Set Up

[Dano1]

Hi all,

Just wanting to install a second battery on my boat was wondering if any one has done so and if so how is it set up!! I want to be able to run the bait pump over night, sounder etc.. and be confident she's going to kick over in the morning.

As the outboard charges the battery while running i thought i could have a swithable link between the 2 batterys

thanks for any help

Dan.

[livo]

Hi all,

Just wanting to install a second battery on my boat was wondering if any one has done so and if so how is it set up!! I want to be able to run the bait pump over night, sounder etc.. and be confident she's going to kick over in the morning.

As the outboard charges the battery while running i thought i could have a swithable link between the 2 batterys

thanks for any help

Dan.

For about $30.00 you can buy a switch that allows you to run your main boat circuit off either BAT 1 or BAT 2 or BOTH. The fourth position is ALL OFF. You will also need some extra Battery Cable and connectors plus another battery mount / clamp. Easy to do and well worth the effort.

With this setup you can run other devices like Livie tank, lights etc from one battery and keep the other for starting the motor. Once under power flick the switch to the other one or both and recharge as you go. Works a treat.

Edited March 17, 2007 by livo

[dangles]

For about $30.00 you can buy a switch that allows you to run your main boat circuit off either BAT 1 or BAT 2 or BOTH. The fourth position is ALL OFF. You will also need some extra Battery Cable and connectors plus another battery mount / clamp. Easy to do and well worth the effort.

With this setup you can run other devices like Livie tank, lights etc from one battery and keep the other for starting the motor. Once under power flick the switch to the other one or both and recharge as you go. Works a treat.

could also go a battery isolation setup like on 4x4's

[fishingrod]

For about $30.00 you can buy a switch that allows you to run your main boat circuit off either BAT 1 or BAT 2 or BOTH

Thats people used to do years ago (and still do mind you) There is nothing worng with them at all.

Its the most simple and economical way, but relies a bit on you remembering to switch between batteries at different stages of the trip.

IE: BOTH on the way out to charge both up, then back to 1 or 2 when stopped so you dont drain the other battery with pumps etc, and then back to BOTH on the way home. (that what i consider the ideal way)

could also go a battery isolation setup like on 4x4's

These are getting more and more common in marine applications. There is a VSR (voltage sensitive relay or voltage switching relay) with 4 position battery combo/package available. They are about $180 at the chanderlies. With these you switch to use BOTH, 1 or 2.

When on BOTH you are using both batteries at the same time and theVSR really does nothing.

When you are on 1, everything runs off battery 1, as this battery gets close to being fully charged, (say 13.8v) the VSR kicks in and some of the charge is diverted to battery 2. So both batteries get charged when your engine is running. When you switch off your engine, the VSR cuts out and isolates battery 2. Then all your electronics run off battery 1. But you have piece of mind that battery 2 has been topped up as you were driving along. (and it all works vice-versa too) Its good if you have a bad memory and forget to switch the old fashioned $30 switch over during the day.

When i need to upgrade switches i will definatly be using a VSR style set up like this.

Some people talk about having a house battery to run accessories and a dedicated starting battery for the engine. If one dies or goes flat, you can "jumper" or link across between them to start the motor or run accessories. In my opinion this is good on a overnighting cruiser that might have 3 batteries and 2 different battery switches. It also works well if you have an electric trolling motor as these draw a fair bit of juice and need a dedicated deep cycle house battery.

But for a typical trailer boat (without an electric motor) the $30 switch and/or VSR is the way to go. (mated with two reasonable size starting grade batteries)

With the price of copper now, you will be suprised how much the good thick starting grade cables are per meter. Try to get them with tinned (silver coloured) copper. Its less likely to corrode than the normal copper stuff in a marine enviornment. Dont skimp and go too thin to save money. You end up with voltage loss and extra heat during extended cranking.

Its easy to do yourself, but if you are paying someone to do it, make sure up front they are going to use good quality components and that all the connections are sealed/protected in some way.

cheers

Rod

[Dano1]

Thanks for all the help guys will look into both methods! i think for now i might use the $30.00 switch.

Thanks,

Dan.

[livo]

Thats people used to do years ago (and still do mind you) There is nothing worng with them at all.

Its the most simple and economical way, but relies a bit on you remembering to switch between batteries at different stages of the trip.

IE: BOTH on the way out to charge both up, then back to 1 or 2 when stopped so you dont drain the other battery with pumps etc, and then back to BOTH on the way home. (that what i consider the ideal way)

These are getting more and more common in marine applications. There is a VSR (voltage sensitive relay or voltage switching relay) with 4 position battery combo/package available. They are about $180 at the chanderlies. With these you switch to use BOTH, 1 or 2.

When on BOTH you are using both batteries at the same time and theVSR really does nothing.

When you are on 1, everything runs off battery 1, as this battery gets close to being fully charged, (say 13.8v) the VSR kicks in and some of the charge is diverted to battery 2. So both batteries get charged when your engine is running. When you switch off your engine, the VSR cuts out and isolates battery 2. Then all your electronics run off battery 1. But you have piece of mind that battery 2 has been topped up as you were driving along. (and it all works vice-versa too) Its good if you have a bad memory and forget to switch the old fashioned $30 switch over during the day.

When i need to upgrade switches i will definatly be using a VSR style set up like this.

Some people talk about having a house battery to run accessories and a dedicated starting battery for the engine. If one dies or goes flat, you can "jumper" or link across between them to start the motor or run accessories. In my opinion this is good on a overnighting cruiser that might have 3 batteries and 2 different battery switches. It also works well if you have an electric trolling motor as these draw a fair bit of juice and need a dedicated deep cycle house battery.

But for a typical trailer boat (without an electric motor) the $30 switch and/or VSR is the way to go. (mated with two reasonable size starting grade batteries)

With the price of copper now, you will be suprised how much the good thick starting grade cables are per meter. Try to get them with tinned (silver coloured) copper. Its less likely to corrode than the normal copper stuff in a marine enviornment. Dont skimp and go too thin to save money. You end up with voltage loss and extra heat during extended cranking.

Its easy to do yourself, but if you are paying someone to do it, make sure up front they are going to use good quality components and that all the connections are sealed/protected in some way.

cheers

Rod

I agree with everything you have said here, especially about using quality cable and sealing everything up. I am also a firm believer in soldering and heat shrinking all marine wiring. I never rely on crimped fittings.