Installing a "master" switch inline with batteries Installing a "master" switch inline with batteries
Bass Fishing Home PageTM    Boats and Motors  


Boating Equip.
Tackle Shops
Fishing Acc.


Fishing Reports
BFHP Articles
Fishing News
Fishing Tactics
Places to Fish
Boat Ramp Stories
Other Topics
Other Fishing Topics
Swap/Sell (no boats)
Props 4 Sale

Boats 4 Sale
Saltwater Fishing
Striped Bass
Lure Making
OBX Wildlife Photos
More Politics

Boats and Motors

    Installing a "master" switch inline with batteries
from MikeM (  
1/7/2005 4:09:00 PM


 I'd like to install a master switch inline with my batteries for a couple reasons:

1) it's easier to turn a switch to disconnect my TM batteries before I plug in the charger.

2) I'd like a way to disconnect power to the bilge/live well/trim pumps so kids won't leave em running. (had that happen on my last boat, and burned a pump.
I figure it will take a couple switches at least. I know it might be easier to disconnect or put the switch on the ground leads, but I'd rather not go that route.
Also, I have a Merc Opti with the smart guages, does disconnecting power to these units have any effect, like losing a calibration or something like that?

Looking at using Perko battery switches. Anyone have any tips I should know about before doing this?


Rate this message:
1 Star

2 Star

3 Star

4 Star

5 Star

   Perko Switch from pmgoffjr (  1/7/2005 6:06:00 PM
It's easy to install. Go for it.

   Switch from Ron1  1/7/2005 6:09:00 PM
I did what you are suggesting by mounting 1 master switch. I ran the grounds from the 3 batteries to the switch and then to ground. Worked like a champ. I bought the switch from Northern Tool I believe, it was 6 years ago. You might check with Cabelas also, it was a rotory switch with a mounting bracket, about $ 25 I think.

   Question? from Lucky Al  1/7/2005 9:02:00 PM
Is there a reason to switch the ground rather than the positive side?

   switch from Mike (  1/7/2005 10:36:00 PM
You really should put the switch on the positive side,if you post how many batteries I tell you how to wire. The bilge pump should always run directly off a battery for safety.

   well, Lucky Al... from MikeM (  1/8/2005 12:18:00 AM
fiogf49gjkf0d's more a desire to cut off power to all the elements of the electrical system than anything else. One of the more basic elements of electrical design is to put all power switches/disconnects on the +(possitive) side, thus cutting power to the various recievers of that power down stream of the switch. If it takes me wiring a buss bar, so be it.

My current setup is 1 cranking battery for the Opti and accessories, and 2 batteries for the 24V TM. The grounds are not connected.

I'm pretty sure a lot of folks just use the ground wire for switching cuz its a whole lot easier to do it that way....but it violates everything I was taught, and have observed in 20yrs working in electronics/ high tech.

My main concern is cutting power to the Opti and smart guages, and thus causeing a loss of calibrations...if that is the net effect.

   Battery Cutoff from pmgoffjr (  1/8/2005 7:55:00 AM
Most, if not all saltwater rigs will have a battery cutoff or multiple switches. Normal procedure.

You won't hurt anything cutting power off to your engine, they are built for it.

It's a good idea, and you can actually rig it to wire your TM batteries to a multiple switch to provide emergency starting power if you ever needed it.

   Positive side from Uncle Pauper (  1/8/2005 10:49:00 AM
Instructions that come with the switch are to put it on the positive. The ground should always be there because that's how your boat's electrical system is designed to work in the first place. Also, if you disconnect the ground you compromise the static discharge connection on the built-in tank.

   What I did... from SurFishaLot (  1/8/2005 11:14:00 AM
I use a Perko rotary switch for disconnect on my cranking / accessory battery. I use a Blue Sea Systems #7100 (50 Amp) circuit breaker/disconnect switch for my 36V Troller wiring. I have my trolling batteries connected in series, so I only need 1 breaker at the batteries to protect all of the TM wiring. If you need breakers for each battery the price of the Blue Seas would start to add up. (about $40/each)

I have everything switched/fused/breakered on the positive sides. There are some theoretical reasons for using the ground side, but I prefer to stick with automotive conventions and use the positives. It's much easier to diagnose problems when everything is uniform.

   BlueSea Disconnect from Chaz (  1/8/2005 11:23:00 AM
I used a BlueSea disconnect switch. They are ultra high quality products.

   There should be a switch in every boat from leaky (  1/8/2005 5:22:00 PM
Yes, it's easy and every boat *should* have one (or more) installed; it just doesn't make any sense to keep the electrical system "hot" unless you are using the boat.

As far as this statement:

"You won't hurt anything cutting power off to your engine, they are built for it."

That's fine if the engine isn't running, and I think that is what was meant, BUT NEVER CUT POWER TO A RUNNING ENGINE. That will burn out your charging system unless there is some additional safety mechanism installed.

I like the west marine on/off switches. They are simple, compact, reasonably priced, and have a luminous lable so you can read them in the dark. You can also get ones with a removable key to prevent accidental switching.

Each battery should have it's own on/off switch. Mike is correct in saying that you can cut the system ground, but that is fine only if every single electrical device has it's ground cut, if any single item has a path to ground other things can find ground through it - then that accesory will appear "on" when the switch is actually off. Very strange things happen. That is why in most systems we switch only the "positive" side.

As far as bilge pumps. It is more failsafe having them directly wired to the battery, but in a boat that is trailered and not left in the water 24/7 it's not really neccesary.




Can't remember your password? Click here!
Email Address:

Users with subscriptions can attach pictures to their comments by using the form at"




Advertising/Sponsor Information

Register to post messages and reports


Subscribers don't receive these ads

Fishing Reports
BFHP Articles
Fishing News
Upcoming Events
Rally Page
BFHP Surveys
Fishing Tactics
Places to Fish
Other Topics
Product Evaluations

Boat Ramp Stories
Trailers & Towing
Boats For Sale
Tournament Tactics
Striped Bass

Fly Fishing
Saltwater Fishing
Non-Fishing 2
Political Hook
Tall Tales, Fiction & Legend
Complete Listing of Boards
Copyright © WMI, Inc. 1995-2017. All rights reserved.
This message board created and maintained by: WebMasters International, Inc. (WMI) address mail to

WMI disclaimer
Privacy Statement