Using existing switch for power

[George in Spokane]

It's probably old news to most people but I came up with a way to get accessory power with minimal cutting of wires.

I needed 12V to run my new sprayer. I could have spliced but I ended up just disconnecting one rear light at the plug and crimping on a connector for each wire. The wires were easy to get to since the underside of the fender is exposed. I never go off my land so I do not need rear lights.

This way I can use my headlight switch to control the sprayer. Somehow it feels more "stock". It is also a very short run to the 3pt implement.

 

[kennyd]

I think that's a bad idea. You may very well burn-up the switch, it was designed to turn a light on&off, not a pump motor. It would be best to add a new circuit from the battery through a heavy duty switch or a relay.

 

[Thumper & Buttercup]

Fleet Farm sells a in line switch to run a FEMCO Sprayer. I got one for my tractor, it plugs into the cig lighter and the pump pigtail, there is enough wire to go from the tractor seat to the drivers seat to the pump.

 

[George in Spokane]

I think that's a bad idea. You may very well burn-up the switch, it was designed to turn a light on&off, not a pump motor. It would be best to add a new circuit from the battery through a heavy duty switch or a relay.

Thanks for the warning but the pump only draws 9.3 amps. I disconnected the headlamps so I imagine the pump draws less than the two front lamps and the one rear light.

 

[RWolf]

For running current you're right on the edge. Assuming 2 55w headlamps they will draw 9.1A at 12V. Your pump is 9.3A so in that aspect you're ok. However what's the stall current of the pump. Hopefully your fuse will blow before damaging the switch. Other than that I don't see any major problem.

 

[AndyMA]

For running current you're right on the edge. Assuming 2 55w headlamps they will draw 9.1A at 12V. Your pump is 9.3A so in that aspect you're ok. However what's the stall current of the pump. Hopefully your fuse will blow before damaging the switch. Other than that I don't see any major problem.

Not just the stall current, a bigger problem may be the starting current which can be several times the running current. Also remember DC is much tougher on switches than AC (arcing).

Andy

 

[6sunset6]

I have been running a sprayer pump on my headlite switch for 15 years on two different tractors. Never had a problem.

But then again I guess it depends on the pump.

 

[RWolf]

That is the jist of it "depends on the pump". Another is the quality of switch. I think that a switch made 15 years ago will be a much better quality than the cheap ones made nowdays.