Wiring solenoid valve

[Welder Dave]

Was hoping someone could post a simple diagram how to wire a rocker switch to operate a 12 volt solenoid valve with 2 solenoids, one for raise and one for lower? Coils have 2 wires coming out and would like to hook directly from the battery. Valve is on a former plow truck that has a ton of wires and electronics that most has been chopped off and/or disconnected. Box works trouble free with jumper wires from the battery but is a pain having to get out to operate the hoist. Old system was intermittent and then stopped working all together. Instead of messing with a jungle of wires crammed into the control box would like to bypass the old system and just have a rocker switch (or 2 separate switches) in the cab for the dump box.

 

[Nige]

Depending on how much current the solenoids require to activate it's possible you may require to power each of them via a relay. On machine electrics most solenoid valves are powered via relays.
Running high current through a rocker (or any other) switch is probably not a good idea.

 

[Welder Dave]

The wires coming out of the solenoids are pretty small. I'd guess 18 gauge or maybe smaller. The valve is just on and off and not proportional. From what I can find the solenoids are 14.4 watts.

 

[Bootheal]

This could work...if I can figure out how to post a picture!

 

[Bootheal]

Inline fuse is a great idea also.

 

[Welder Dave]

Thank you for the diagram. Yes, I could install an inline fuse. I wasn't sure if the ground should be common or the pos. should be common or if it really matters. Polarity doesn't matter on the solenoids. I'll have another look at the existing wiring just in case I missed something obvious but there's a lot of electronics in the control box.

 

[kshansen]

Polarity doesn't matter on the solenoids.

That might be true for 99% of the solenoid valves but years ago we got caught by some that for some reason were polarity sensitive.

These were the group of solenoid valves that controlled the shifting in an Allison CLBT5860 transmission. We discovered the problem when I believe we installed a shift valve body from a Euclid(negative ground machine) and installed it in an Off-Highway Mack(positive ground machine). These small solenoids had just one wire to connect them and got their ground from the mounting flange so there was no way to swap the wires. The original valves were not polarity sensitive but the updated ones were! As I recalled it took a good amount of digging and questioning the dealer to finally find a service bulletin to get the correct part numbers. All I can guess is the plunger in the updated ones had small magnets as part of the plunger instead of just being steel possibly to make the action stronger but if wired for the wrong polarity they would repel when they should attract the coils?

Could be the only time one would find a polarity sensitive valve!

 

[kshansen]

I know this may be a bit OT for this thread but thought I'd post it here as it does regard polarity and solenoids.

There is a Service letter that explains a little but not why they are this way. If anyone is interested I did find a copy of that SIL.

 

[Welder Dave]

It's for a Rexroth valve on a Compu-Spread system.

 

[Cmark]

Whether you drive them through a switch or through a relay, it's important to wire a diode in parallel with each coil. It suppresses arcing at the contacts.

 

[Welder Dave]

I talked to a place that deals with these systems and got it working. There was even a plastic plug in a precut hole to mount another rocker switch and the hoist up and down labels also popped out and could be moved to the new location. It works but I couldn't finish the installation because the inline fuse holder I got doesn't come with a fuse. It says 20 amp and has the cap on in the package. Not sure why it doesn't come with a fuse or least a note saying a fuse is also required.

https://www.grote.com/fuse-circuit-protection/fuse-holders/miniatm-fuse-holders/82-2208/

 

[Cmark]

20 amp will be the maximum current for the holder. It's up to the installer to choose the correct fuse for the application.

 

[Welder Dave]

I picked up some 10 amp fuses. Figured if I had a short it would still blow pretty easily. Fuse is just for an extra safety measure. The tiny wires on the solenoid would probably melt before anything else was damaged. I could see someone getting a little annoyed if they had to drive a long way to fix something only to discover it didn't at least come with a 20 amp (demo) fuse. Kind of like batteries, some things don't even tell you what type they take so you figure maybe they come with batteries installed. Nope. I bought an electronic TENS device like this. Nothing on the package and no way to open it at the store to check. Brought it home and had to open it to see what it took. Luckily had some batteries to fit.