Smart RV

Having voice-controlled lights, outlets, and stuff at the house, the wife wanted to be able to do the same in the RV. I found (from my friend AB5KT--THANKS Brian !! )the Shelly smart relays that will work on 12VDC, so I bought and added to the RV. Its somewhat simple and not all that expensive.

This will work IF there is wifi and internet available in the RV. If none is available (really roughing it !) The original switches will still work.

Wire strippers, Crimpers, jewelers flathead screwdriver, cap crimps, Voltmeter, and of course the Shelly 12VDC capable smart relay. It MUST be the Shelly 1 Plus that can be powered by 12 volts DC, usually around US$20 each at current time. I have labelled the connections used, the last one on the right will not be used.

Prepare the smart relay by cutting and inserting wires as shown, you will need 2 wires for the + 12VDC (shown here in red), a wire to connect to the original switch with female spade lug on the other end, and a wire for the -Ground (other end stripped bare). Use the flathead screwdriver to firmly tighten the connectors for each wire. Also cut another jumper wire that will go from the main -Ground wire(s) to the switch with a female spade lug on one end and stripped bare on the other (not shown). Again, the farthest right connection will not be used.

Using the flathead screwdriver, gently work it around the bottom edge of the switch face plate, it should pop loose, revealing the switch body and the 2 screws holding it in.

There are 2 screws top and bottom holding the switch body to the wall. Depending on who installed it, they may have drilled a hole just big enough for the wires to pass through, or they may have cut a larger opening. You may need to modify the opening to allow the smart relay to fit inside the wall. BE CAREFUL about nicking or cutting the wires inside the wall if you have to widen the hole.

If you are working on switches in the main control panel, you will need to figure out how to get to the switch backs and wiring. In my case, my OCD kicked in and I had to do MAJOR cable management, adding terminal blocks and lots of tie-wraps. Do what you are comfortable with.

Depending on how the switch was originally installed, you may find one of the 3 shown here. This will determine how to proceed, and if you will need to figure out which is the +12VDC supply wire.

1: If you have 1 wire to 1 lug and 2 wires combined to the other lug, the 2-wire is usually your +12V supply. Skip the next step.

2: If you have multiple switches in the same housing, the wire with the jumper between the 2 switches will usually be the +12VDC. Skip the next step.

3: 1 wire to each lug: will need to use a meter to determine the hot wire. See Next Step to diagnose.

When you pull out the switch, you may find just 2 wires going to the switch. If you dig around inside the wall, you may feel and find the -Ground wire looped past the switch. Pull out the loop and either strip some of the insulation off or cut the loop and strip 1/4 to 1/2 inch of the insulation off both ends (you will need this later anyways).

BE VERY CAREFUL when dealing with stripped wires and bare metal contacts--If a +12VDC wire comes into contact with a -Ground wire, it will short, spark, and blow the fuse. If you are concerned, find and unplug the fuse for the circuit you are working on. 12volts is usually not enough to cause a shock, but shorts will cause you to waste a fuse and maybe cause a scare...

Using a multimeter in DC Voltage mode, and with the switch OFF, carefully attach the black meter lead to the ground wires you just stripped. VERY CAREFULLY touch the red meter lead to each of the lugs on the switch. One of the lugs will show almost 0 volts, while the other will show 12-14volts. THIS is your hot lead. Mark it with marker or electrical tape, etc.

Locate the "load" wire on your switch. This is the other wire connected to the switch that is NOT the +12VDC determined earlier.

Wiggle the female spade lug and gently pull at the same time to remove the lug from the switch. Snip off the crimped lug and strip back about an 1/8-3/16" of the insulation. Twist the wires neatly and tight, insert into the LOAD connection on the relay and tighten the connection with the flathead. Take the wire on the relay in the SWITCH position and push the female spade lug onto the switch where you just removed the wire from.

Wiggle and remove the 12VDC lug from the switch. Cut off the lug and strip back 1/4-1/2" insulation from the wire(s). Bring them together with the 2 12VDC wires on the relay, twist together tightly, insert the wires into a crimpable cap and crimp firmly. Tug each wire to make sure they are not loose in the connection.

Find the ground wire(s) from the RV (sometimes a small bundle already with a cap crimp). Cut off any cap or if just a loop (as in step 4) cut the loop, strip back 1/4 - 1/2" of insulation from all wires. Bring them all together evenly with the Ground wire from the relay and the other female-lug-and-stripped wire, twist tightly, insert into cap and crimp. Tug all wires to check none are loose. Plug the Ground female spade lug onto the other spade on the switch.

At this point, the smart relay should be active.

If you have not previously set it up on your network and the app, do so now. Before putting it all back in the wall, it is best to test that everything works.

Flipping the switch should turn the light/etc on and off. Using the Shelly app should also turn it on/off. Using voice commands (alexa/googlehome/etc) should also now work.

Here is where the fun comes in... Getting it to fit in the wall.

If they had originally cut a large enough hole (as shown here), gently work the wires and relay into the wall, allowing the relay to drop down a little to give room for the back of the switch.

If they only did a hole big enough for the wires to poke through, you will need to gently and carefully open the hole big enough. I suggest holding the relay on the wall over the hole, centering it on the screw holes, so that the switch and plate will cover it, and mark the outline with a pencil. Then with a knife or other cutting tools on hand, gently cut the wall to the minimal size needed to fit the relay in. BE VERY CAREFUL TO NOT NICK OR CUT THE WIRES IN THE WALL !

Screw the switch back the wall with the 2 original screws and snap the face plate back on.

If you are working the main control panel, reassemble anything you had taken apart.