# dual battery switch questions



## LJackson (Apr 28, 2018)

I an going to add a second battery to my boat. I see several switches on the web. What have you used that has been dependable and long lasting? The third one has a choice of alternator field disconnect or not. I'm not sure why you would want that? I did read in a post here that someone had problems with the perko and the blue seas was recommended as a replacement.

Here are 3 I am considering.

https://www.ezacdc.com/boat-wiring-products/battery-switch-systems/manual-battery-switch-systems/ 

https://www.bluesea.com/products/6007/m-Series_Mini_Selector_Battery_Switch_-_Red 

https://www.westmarine.com/buy/perko--battery-switches--P009_272_004_007?recordNum=1


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## gnappi (May 12, 2018)

Since I wanted the batteries totally isolated from each other I used two of the blue sea (6007 RED and 6007200 Black) four position (1, 2, 1+2, and off) on my boat. I like the dimunitive size of them compared to others. 

The thing that niggles at me is why the bottom is open and the sides have slots making them kinda sorta open to the elements more so than if only the bottom was open. They work fine though. 

On my other boats the Perko did not fare well, but to be fair the boats were kept in the water and I had a pool nearby and the salt / chlorine air contaminants may have been a contributing factor. The new one with a lock to me is just adding another possible failure point.

Here's a pic of my stern with the switches mounted.


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## Crazyboat (May 13, 2018)

I can only speak for #3, I've used it for over 10 years now, the first lasted me over 7 of those years on the salt. I have no problem saying it's a good product.


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## bcbouy (May 29, 2018)

i just went thru this same dilemma.i ended up going with a single battery shut off for the rear starting battery that has some sort of a parasitic draw, and kept the 2 front trolling motor batteries separate from the entire system and added a minn kota single bank alternator charger that is wired to the dash switch.it charges the starter batt then switches to the trollers at the flick of the switch.works fantastic and no dead batteries so far.


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## DaleH (May 29, 2018)

LJackson said:


> The third one has a choice of alternator field disconnect or not. I'm not sure why you would want that?


Those are for inboard engines where you don't want to fry anything when switching between batteries if/when the motor was running.

FWIW I always used Guest marine switches in my saltwater boats and never had an issue.

Nowadays I like the concept of the BEP Marine switch clusters. But even there if you want to truly make them saltwater-environment-proof, you'd need to upgrade their wiring, as they use std crimp connectors - not those heat-shrink sealed.

If both batteries will be the same and for same use, a good tip to equalize their use is to head out and fish half the trip on battery 1, then switch to battery 2 for the remainder of the day. The BOTH position should only be used for emergency starting - don't run on it.


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