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Author Topic:   Downrigger wiring
Hoop posted 08-30-2005 12:01 AM ET (US)   Profile for Hoop   Send Email to Hoop  
[Re-posting from another, now-closed, thread:]

I'm installing a used Cannon Mag-10 downrigger on my Montauk, and I've not decided on how to do it.

Manual says 10-gauge wire from the downrigger to the battery, and then a 25 or 30 amp fuse on the positive wire, or a circuit breaker.

Installing a circuit breaker instead of the fuse, or wiring through an accessory switch with the fuse, would seem to be the way to go, I think. This would allow turning off the juice when the cable / downrigger are not in use.

What have people done? There is an extra accessory swith on my 2000 Montauk panel; can I use that, I wonder?


Hoop (Jim)


Reply from John W Mayo:


I just installed the same thing on mine, Cannon Mag-20 downriggers on my Revenge 19.

With the wiring I did use #10 awg. I ran the wires to a buss, connecting both downriggers to the buss. From there, I ran a #10 wires to the battery switch and battery. Just prior to the positive connection, I added an inline 30 amp fuse. This way I can turn off the power when I shut everything down.

An extra accessory swith would work provided that it is a high enought amperage switch. Also, if you connect from a common bus with many other items, your wire size may be to small that is already there leading from the battery to that buss and switch.

The Mag-20 pulls a lot more current than a light or fishfinder. I would (and did) use #10 /30amp fuese / a seperate bus / and probably not use the switch unless I knew the amp ratting.

Mounting is another story. I mounted mine on the rail and was just not satisfied with how much stress that would be put on the gunnels on the rail, just took them off. I am still looking at the options, but will probably mount them directly on the gunnels or possible some other way. I have consider the rod holder mount, but do not want to go that route to much.

Good luck.


My reply to John:

Thanks, John. Very helpful.

- Hoop

jimh posted 08-30-2005 12:14 AM ET (US)     Profile for jimh  Send Email to jimh     
I would not use the helm mounted accessory switch to control a 30-AMP load. They are probably not rated for that much current. My guess is they are good for about 10-AMP maximum, if that.

You might also consider isolating this load from the starting battery. If you run the down rigger motors a lot, you may pull down the starting battery. If the main engine is running all the while you are trolling with the down rigger, it won't be as much of a concern.

Using 10-AWG wire is generally good for 30-AMP if the runs are not too long. Where is the battery in your boat, stern or console?

Some circuit breakers are also rated for use as a switch to control the load. Others are not, and are rated only for a certain number of trips to OFF. Check the device you select. It would be handier to have a circuit breaker than a fuse.

JOHN W MAYO posted 08-30-2005 12:50 AM ET (US)     Profile for JOHN W MAYO  Send Email to JOHN W MAYO     
I agree with jimh, isolating this load from the starting battery otherwise you may try to crank your engine and nothing happens. Check your manual and it will will give a good idea how to wire the unit and the current it will use.
bsmotril posted 08-30-2005 08:34 AM ET (US)     Profile for bsmotril  Send Email to bsmotril     
I've fished the same downrigger for seven years. They draw about the same current as a hiqh quality high flow baitwell pump. I had mine hooked to the accessory switch on my Conquest with no problems whatsoever. Unless your catching a fish every five minutes, you are not going to draw down the battery much. Remember, you are trolling and charging the battery at the same time you are using the downrigger. Even with optimax motors which are notorious for drawing a lot of juice at idle, I trolled and used the downriggers for many an 8 hour fishing day without any battery problems at all. BillS
Hoop posted 08-30-2005 07:18 PM ET (US)     Profile for Hoop  Send Email to Hoop     
Thanks everyone.

I have two batteries located in the console, with a Perko battery switch.

I like the idea of using a circuit breaker/switch. That would allow me to turn off power to the downriggers when not in use or not connected. I have looked for a waterproof circuit breaker/switch, but can't tell if what West Marine carries would be suitable for a console mount in-the-open application.

Regarding run length, the manual says 10 gauge for 0 to 15 feet; 8 gauge for 15 to 25 feet. I figure I am under 15 feet. Mag 10 is rated at 7 amps full load 12 volts D.C.; Mag 20 is rated at 16 amps full load 12 volts D.C.

I've got mounting settled: I have a Cannon rail mount bracket at the stern end of one of the side railings, with the downrigger mounted directly aft and in line with the railings. The downrigger boom is pointed aft over the transom and directly above the rail, just where the rail goes down for mounting. A friend of mine has had his Cannon downriggers mounted in this fashion on his Montauk for well over 10 years with no problems.

Thanks again.


andygere posted 08-31-2005 01:30 AM ET (US)     Profile for andygere  Send Email to andygere     
When I re-wired my Outrage this year, I did the downriggers as well. They were originally wired directly to the batteries, with an in-line fuse on each one. Now they get power directly from the "house" battery switch, and ground to the nearest battery. This allows me to shut off power to the plugs when the boat is not in use. I've kept the 30 amp in-line fuses in the system very close to the battery switch. I used 10 gauge wire, and Ancor wire connectors with heat shrink jackets to water proof them. With the old setup, there was a lot of electrolysis and resulting corrosion.

I was not happy with the aftermarket plugs in the existing system, which relied on tiny brass set screws to make contact with the wire. These were always green with oxidation, and let me down more than once. After a lot of searching, I settled on some trolling motor plug connectors that had nice rubber caps, and were rated for a lot of amps. I made some teak settings for these, which I fit beneath the coaming boards. These plugs are potted, and had pigtails extending out of them. I made the connections with the Anchor heat shrink connectors, and so far it is all holding up nicely.

Here's a photo of the finished job:

bsmotril posted 08-31-2005 10:00 AM ET (US)     Profile for bsmotril  Send Email to bsmotril     
Who makes those battery swtiches that you used? I'm looking for something like that, which looks to be a lot smaller than the perko switches.
andygere posted 08-31-2005 11:20 AM ET (US)     Profile for andygere  Send Email to andygere     
The switches are made by BEP marine:

What I actually have is what they call a VSR Battery Distribution Cluster. It consists of an On-Off switch for the start battery, an On-Off switch for the house battery, an emergency paralleling switch and a voltage sensing relay (VSR). The only load (and charge) on my start battery is the 200 hp Outboard. Everything else is on the house battery. The way the system works is the start and house batteries are isolated by the VSR. When the main Outboard is running, and has charged the start battery to a voltage of 13.7 volts, the relay closes and the house battery begins to charge as well. When the main motor is shut down, and the start battery drops to 12.7 volts, the relay opens and automatically isolates the house battery from the start battery. The emergency parallel switch can be used to "jump start" the boat off the house battery if the start battery should somehow lose it's charge. I'm very pleased with this system, which is very simple to operate. When I get down to the boat, I simply turn on the house and start swicthes, and forget about my battery system for the rest of the day.

I purchased my cluster directly from BEP, by calling their US offices in Georgia. They gave me good technical support over the phone as well.

Hoop posted 08-31-2005 12:57 PM ET (US)     Profile for Hoop  Send Email to Hoop     
Andy, great insight to use trolling motor plug connectors. Thanks. Hoop
andygere posted 08-31-2005 02:22 PM ET (US)     Profile for andygere  Send Email to andygere     
I think the connectors were Sierra brand, but I'm not positive. I ordered them from Bass Pro Shops, but I've also seen them at Boater's World and similar stores.
JOHN W MAYO posted 09-01-2005 12:11 PM ET (US)     Profile for JOHN W MAYO  Send Email to JOHN W MAYO     

Great looking job,.....looks good on your Whaler.
You have me thinking about changing my battery swicth, nice.
Have got an idea what the cost of your project was with the switch, etc.

If anyone need assistance from Cannon, I had instance response from them with my inquiries and a manual in the mail in 3 days. Good customer sevice.

andygere posted 09-01-2005 08:48 PM ET (US)     Profile for andygere  Send Email to andygere     
Ah....what did it cost? Well, I didn't add it all up, but here's a few items I do remember. The switch cluster was about $150 all told, those little Anchor 4 AWG lugs cost about $5 per pair and there's a lot of them in this project. The tool to crimp the lugs was about $40. I used at least 25 feet of 4 AWG tinned cable, and misc. smaller sized wire, connectors, heat shrink tubing, stainless screws, etc. I'm sure it all adds up to...well, it wasn't cheap, but it sure turned out nice. My rationale is it was cheaper than a tow, and I won't have any ruined weekends because of dead batteries or mysterious electrical problems. Next winter: the console wiring!

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