Dual batteries and Perko switch

**OC Boater** · 03-07-2010, 09:17 AM

I’m a newbie when it comes to this stuff. I had a 2nd battery installed along with a Perko switch to run my amplifier for my stereo a while back. I just had a second amp installed to run my highs and the guy that installed this amp is telling me that he believes that the perko switch setup was installed incorrectly. We checked the batteries when he finished installing the new amp and one was showing about 13 volts and the other about 9 volts. The original guy that installed the switch told me that I only had to charge one of the batteries and both would get charged. He also told me that it didn’t matter what setting I had the perko switch on that I could start the boat and listen to my music with no problem. This didn’t seem correct because I would think that position 1 is to start, 2 is if I want to park the boat and listen to music or all is if I want to drive around listening to music. Here are some pictures of my wiring setup. The diagram seems kinda easy to follow but that only has one wire to the battery and one wire to the switch. As you might be able to tell from the pictures i have several wires to the battery and several wires to the switch. The first 3 pictures were the original setup and the last pictures was the new amp install to the battery.
I know this is a lot but can someone explain or preferably give diagram or picture of setup. Thank you.

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**STV_Keith** · 03-07-2010, 10:37 AM

Well, those pics don't show a whole lot of the wiring. I can see that there is an ACR (Automatic Charging Relay) wired in. Theoretically, that will allow the "house" or stereo battery to be charged even if the Perko switch is in the #1 battery setting.

My guess is that your setup is wired so that:
Perko set to OFF - motor won't start, no power to harness or boat functions, stereo still work as it appears to be drawn DIRECTLY from battery 2.
Perko set to #1 - motor and boat runs off battery 1, stereo runs from battery 2. Battery 2 is charged via ACR.
Perko set to #2 - motor/boat and stereo run off battery 2, battery 1 out of the loop completely (will not get used or charged).
Perko set to ALL - both batteries combined and used for all power requirements.

If your house battery was down to 9v, that indicates you may have a constant draw on that battery, since it's direct wired to the stereo. This setup wouldn't be bad...but I would personally run another ON/OFF switch that disconnects the stereo/house battery from all loads. There is also a main circuit breaker in the stereo line just to the left of the switch. If the stereo cable got cut/abraided anywhere, this would pop before burning the boat to the water line. If you turn the perko off, you also turn the house off, so no battery can be drained by any remaining power draws.

Here's my setup...it's for twin motors. Each motor has it's own switch for engine/boat harness power - Battery 1 only, battery2 only or both. Either engine can draw/charge either battery or both. Those are the red switches. The gray on/off switch is for the house/stereo battery. Look above the switches, I have two ACR's...each motor feeds the ACR, when the engine battery is up to charge, it feeds and charges the house battery.

**OC Boater** · 03-10-2010, 01:12 PM

I have no clue how the guy wired it stereo system to the batteries. I tried moving the switch to the different settings to see where the stereo works or doesn't work and i found the it all works on 1 and both but when i put it to 2 both amps turn on but only sound is coming out of sub which was the original setup.

**OC Boater** · 03-10-2010, 06:47 PM

I actually charged the batteries and now the stereo works with the switch on either 1, 2 or both. I don't understand why it would work this way because isn't the switch to isolate the starting battery so i could run the stereo without having a problem to start boat? Could it be working this way because of the ACR?

**STV_Keith** · 03-11-2010, 03:27 PM

Sounds like the stereo is wired off the COM post of the Perko? That would not be my choice.

See the Perko wiring schematic on the other thread. I'd wire it like the top picture, THEN, wire the ACR isolator from the COM post directly to the second (stereo/house) battery. If it were me, I would then put in a direct ON/OFF switch JUST for the stereo wiring and have it come off the second battery...that way you can turn off any house draw when you're not using the boat. You can see my battery switches, including my stereo ON/OFF switch in the picture above.

**hobo** · 03-26-2010, 05:48 PM

hello. I'm new to the thread and somewhat new to boat wiring. in attempt to clean up and simplify my pilot house trawler's wiring, I ended in failure. I have the classic Perko switch, Off, 1, both and 2, with it wired up the way in the attached link, I have power to all 12v systems coming from the fuses block and the positive bank while in the "Off" position. Switching it to any other position doesn't change a thing.

wiring diagram

http://danimal.myphotoalbum.com/view...wiring_diagram

after messing around with different combinations I found that if I moved the positive wires coming from the fuse bank and the positive bank to the common terminal on the switch that it all turned off when I moved the switch to the off position. my goal is to in the
"Off" position have no power at all(except for the hard wired bilge on a float).

"#1" position only be able to start my boat's engine w/ no power to 12v accessories.

"#2" position to have power to all 12v accessories and no power to engine.

how can I do this? thanx daniel

**Hass828** · 03-27-2010, 09:01 AM

Originally Posted by hobo

hello. I'm new to the thread and somewhat new to boat wiring. in attempt to clean up and simplify my pilot house trawler's wiring, I ended in failure. I have the classic Perko switch, Off, 1, both and 2, with it wired up the way in the attached link, I have power to all 12v systems coming from the fuses block and the positive bank while in the "Off" position. Switching it to any other position doesn't change a thing.

wiring diagram

http://danimal.myphotoalbum.com/view...wiring_diagram

after messing around with different combinations I found that if I moved the positive wires coming from the fuse bank and the positive bank to the common terminal on the switch that it all turned off when I moved the switch to the off position. my goal is to in the
"Off" position have no power at all(except for the hard wired bilge on a float).

"#1" position only be able to start my boat's engine w/ no power to 12v accessories.

"#2" position to have power to all 12v accessories and no power to engine.

how can I do this? thanx daniel

Your power for all of the 12v comes from a wire under the main lug on your starter. But you'll need it hot or the engine wont crank-fire.
I just did the same thing with a perko, if your wanting the ability to run your radios & stuff without killing the start battery just wire like the instructions and when you get to the beach just turn to #2 battery & run it all day then when ready to leave turn to battery #1 and it'll still be hot so you will start.
Good luck

**STV_Keith** · 03-27-2010, 11:16 AM

Originally Posted by hobo

hello. I'm new to the thread and somewhat new to boat wiring. in attempt to clean up and simplify my pilot house trawler's wiring, I ended in failure. I have the classic Perko switch, Off, 1, both and 2, with it wired up the way in the attached link, I have power to all 12v systems coming from the fuses block and the positive bank while in the "Off" position. Switching it to any other position doesn't change a thing.

Looking at your diagram, all your positive bank and fuses come from battery 2 and are NOT switched. The only thing that is switched is power to the engine. Battery 1 is completely isolated from any loads other than the engine IF the switch is set to battery 1 or both. Were you trying to switch the engine only or the rest of the boat too?

Originally Posted by hobo

after messing around with different combinations I found that if I moved the positive wires coming from the fuse bank and the positive bank to the common terminal on the switch that it all turned off

Correct.

Originally Posted by hobo

when I moved the switch to the off position. my goal is to in the
"Off" position have no power at all(except for the hard wired bilge on a float).

"#1" position only be able to start my boat's engine w/ no power to 12v accessories.

"#2" position to have power to all 12v accessories and no power to engine.

how can I do this? thanx daniel

You need a second switch. Basically that switch is for two batteries to run ONE LOAD. You have TWO LOADS (engine and boat/house). To do what you want, you need one switch for the engine and one switch for the house...then you can independently decide which battery powers which load.

One thing...I assume you are running two battery "meters" volt gauges, right? One from each battery and to the common ground buss? That's the way it needs to work.

Be aware that the engine will only charge which battery it is switched to. While running, you might want to have the engine on BOTH to ensure both batteries get charged. If you plan to run the engine predominantly on one battery, I'd recommend an automatic charging relay be connected from that battery to the other battery so that the load stays isolated, but charging will go to both batteries.

**hobo** · 03-27-2010, 12:49 PM

hey guys!! after your help and buying a digital volt meter and testing things out, I figured out how to solve my problem.

like previously mentioned I connected my positive leads from my 12v bank and 12v fuse panel to the COM on my Perko switch(NOT the #2 terminal). This way my engine will start and all my electronics will work in all positions, but I'm only drawing power from whatever battery I have the switch on. This seems like the best application for me and I'm stoked that in effort to fix the problem I now have every wire labeled and where it should be all nice and tighty! Here's the diagram for how I've got it wired. hopefully you will like it and it might even help someone else. adios. daniel

http://danimal.myphotoalbum.com/view...wiring_diagram

oh, and yes. each battery has it's own meter! I don't think I'll need a second switch, but I do like the idea of having an isolator between the batteries.. how much do they cost, and how to they wirer up? thanx

**STV_Keith** · 03-28-2010, 12:54 PM

The diagram you have now is the standard way to wire things...but doesn't give you the ability to turn the motor off and have the house power on as you originally mentioned you wanted.

Check out Blue Sea stuff for the ACR's... http://bluesea.com/category/2

**skippers WFOT** · 05-11-2010, 09:48 PM

i would not reccomend draining any battery. the surge load that the alternater has to put out to bring up a drained battery will kill an alternater. if you have amps on your stereo keep it running or moniter voltage and DO NOT go below 12v. anything lower is the danger zone for amps etc.

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