battery switch wiring (2 batteries)

OC Rider

Seaman Apprentice
Joined
Mar 14, 2008
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31
I have two batteries on my boat with a Perko battery switch. I don't know much about this stuff so I had someone install for me but I don't know if it's correct. I'm able to start the boat with the switch on 1 or 2 and use the accessories such as stereo and lights. I thought that the switch needed to be placed to the designated starting battery in order for the boat to start? Is it ok to switch between 1,2, or both while engine running and will that charge both batteries? Does it matter what battery the accessories and stereo is wired to?
 

PondTunes

Petty Officer 1st Class
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Jun 7, 2007
Messages
387
Re: battery switch wiring (2 batteries)

Your accessories *might* be wired to just one battery but I bet everything is connected to the common post of the perko switch. Typical operation of a system like this would be to crank the boat with battery #1, drive out to wherever you were going to fish/swim/anchor then switch to battery #2... If battery #2 goes dead you can always crank the boat with battery #1, charge battery #2 on the way back in or with a charger once you get home.
 

Randy169

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Mar 25, 2008
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48
Re: battery switch wiring (2 batteries)

The most important question is:

Do you have beer? :confused:

Opps. Wrong thought.

Do your accessories work on both 1 and 2?
They shouldn't.
You should be able to start on either switch position. (It's more important to get home than to listen to tunes.)

There should be an isolator which allows both batteries to be charged at the same time when the switch is on both. Either through the alternator or a charger.

It's not really good for the equipment to move the switch when things are running. :(
 

PondTunes

Petty Officer 1st Class
Joined
Jun 7, 2007
Messages
387
Re: battery switch wiring (2 batteries)

Do your accessories work on both 1 and 2?
They shouldn't.
They probably work on either or and he can start from either or....

There should be an isolator which allows both batteries to be charged at the same time when the switch is on both. Either through the alternator or a charger.
He doesn't have an isolator he only has a 1-2-off-both switch he can move it to 1 or 2 for crank/charge or to both to charge both batteries at once....

It's not really good for the equipment to move the switch when things are running.
According to perko's website: Selector switches are designed with a ?make before break? feature. This allows switching between the ?1?, the ?all? and the ?2? positions while the engine is running. Thus it won't hurt your charging system or anything else to move between them...
 

Silvertip

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Joined
Sep 22, 2003
Messages
28,771
Re: battery switch wiring (2 batteries)

Every accessory on the boat except an automatic bilge pump should be wired to the COM terminal on the switch -- not directly to either battery. The beauty of the switch is its flexibility. You can start on BAT 1 OR BAT 2 OR BOTH if need be. On BOTH, both batteries charge. On BAT 1 just BAT 1 charges and on BAT 2 just battery 2 charges. You can't get more versatile than that. Yes -- it is ok to switch batteries under way. You DO NOT ever switch to OFF with the engine running. Switching to BAT 2 when at anchor protects BAT 1 (typically the start battery) from being discharged by whatever you are running.
 

OC Rider

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Joined
Mar 14, 2008
Messages
31
Re: battery switch wiring (2 batteries)

I'm able to use my accessories such as my stereo with the switch on either 1, 2 or both. I don't have my boat with me but If i'm not mistaken the accessories are directly conected to the battery post and not the COM terminal on the switch.

I was also wondering if the boat is ancored for a few hours than i start it up to drive around should i put the switch on both to charge both batteries or will both batteries charge automatically with switch on 1. When charging battery when the boat is out of the water in what position should the switch be in?
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: battery switch wiring (2 batteries)

Think about it! If the accessories are all wired to one of the battery posts the switch position won't make a bit of difference because the accessories are getting juice directly from the battery. The purpose of the switch is let YOU decide which battery the juice comes from. It's wired wrong.
 

fishrdan

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Jan 25, 2008
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6,989
Re: battery switch wiring (2 batteries)

Yup, wired wrong as Silvertip said. When the switch is off nothing on the boat should work and only the heavy wires from the battery switch should be connected to the + terminal of the batteries. Well,,, except the bilge pump in my opinion, I have it direct wired to the battery since I'd rather kill a battery than swamp the boat.

Everything should go through the common post and then you can select which battery(s) you want to run off or charge. I start the engine on #1, switch to ALL while running to charge both batteries, then switch to #2 for accessory power when the engine is off. On occasion, switching to ALL for starting the engine because the engine start battery was low.

If anything (except bilge pump) works on the boat when the switch is off, it's not wired correctly.
 

drewpster

Commander
Joined
Oct 17, 2006
Messages
2,059
Re: battery switch wiring (2 batteries)

It is important to note here that a battery switch is used as an isolator as well as a means of keeping a fresh battery. The switch should be placed so that it can isolate the battery or batteries from ALL loads. Wired correctly, the switch can be used to turn all the power off if there is an electrical fire on board.
 

Boatist

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Apr 22, 2002
Messages
4,552
Re: battery switch wiring (2 batteries)

OC Rider
Welcome to the board.
There is no right or wrong way to wire your boat it is personal prefrence.
The way you have it wired if fine.
The way they want you to wire it to protect your starting battery you need to be changing the switch every time you start or stop.

The way you have it You do not need to change the switch at all unless you need to charge battery 2. That is the way I would wire it also with a few changes.

My prefrence is no switch at all or if have a switch only switch if battery one is dead.

I would set up where the common post has the starter and all the electrical needed to run the boat. Mostly all the gear that came with the boat. Bilge blower, Navigation lights, Dash Lites, Wiper. Horn, Compass Light.

All the gear added later can go to battery 2 and not wired to the common post. This way you leave the switch in postion 1 unless for some reason battery one is dead and you need to start off battery 2, or you want to charge both battery while engine is running.
Battery one should not run down as all the gear connected to battery one is only use while under way. If running the navigation lights all day you can switch to postion 2 but usually even if run all day will not run battery down enough that you can not start the boat.

One thing I would do different than you is Instead of hooking direct to the battery I would hook a fuse box up to post 2 on you switch. Then I would run all my gear off the fuse box. This just keeps it nice and neat and if a wire or some device short out it blows the fuse instead of catching fire.

My 1980 boat I do not have a switch at all. Instead I use a battery isolator.
I have wired like you in that the stuff needed to run the boat is wired to my starting battery. All the added gear is wired to battery 2 thru a Fuse box.

When I start my boat off battery one it charges both batteries thru my battery isolator. You could do this also or later put in a battery combiner to charge both batteries without having to play with a switch.

They are right about never turning your switch thru off with the motor running as it will destroy your charging system.

I may add a Switch some day but really see no need.

Anyway there is no right or wrong way do it your way.
 

OC Rider

Seaman Apprentice
Joined
Mar 14, 2008
Messages
31
Re: battery switch wiring (2 batteries)

I haven't had a chance to do anything with the wiring of my batteries since my boat isn't stored at my house. As I mentioned at the beginning of this thread, I don?t know much about boats or wiring batteries. I just remembered that the guy that installed the battery switch for me also installed a BatteryLink ACR PN7600 by Blue Sea Systems. Not sure if this makes a difference for the responses I received earlier or if the wiring would be the same and the function of my setup. Again, thank you for your responses and help.
 
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