In case you don’t know there are two ways to power devices in your recreational vehicle. There are batteries for running battery powered devices such as your lights, water pump, awning, and 12 volt TV if you have one of those. Then there is the AC power cord that plugs into the electrical service at the RV park. This runs basically two devices in my trailer: the microwave and the air conditioner. Since we do most of our camping primarily in the western US, we need an air conditioner! This limits us to camping where electricity is readily available.
But there’s another option, a generator! You can plug your trailer’s AC connection into a generator and run your air conditioner that way. There’s just one problem. You have to make sure that the generator has enough power to start the air conditioner, once the air conditioner is started, it uses far less power. It’s just that initial start. This is where the soft start module comes up. You see inside the air conditioner is an electrical motor that basically runs the pump that pumps all the freon around your air conditioner. When motors start, they generally use a ton of electrical current to get them going, and then once started, they use much less current. That initial kick of electrical current is called inrush current and will bog a generator down as the generator struggles to supple enough electrical current to meet the demand. Many smaller generators will just blow their breakers or shut themselves down.
But what if you could limit that inrush current to a manageable level that the smaller generator could keep up with? Then you wouldn’t have to buy that bigger more expensive generator. This is what the SoftStart module does.
Imagine electrical current as water. When you flip a switch to turn on your AC, it’s like turning your water faucet on full blast. When you flip the switch off, it’s like turning the faucet completely off. But what if you could just turn that faucet on slowly until it reaches full blast? This is what the Soft Start does. When you turn your air conditioner on, the fan comes on, and then a few seconds later the compressor comes on with a loud “thunk”. This is the motor responding to a full blast of electrical current, like the water faucet being turned on full blast, and the motor is trying to respond to that full blast of current. It’s hard on the motor and uses a lot of electrical current to FORCE that motor to start running at full speed almost instantly!
So the Soft Start ramps up the electrical current slowly so that the compressor’s motor comes on more slowly, thus using less electrical current and also being gentler on the motor and associated components. THIS means you can use a smaller generator than you normally would because it doesn’t have to supply as much current to start your air conditioner.
(For my sister, you can tell our brother than this device OBVIOUSLY uses TRIACS to limit the inrush current)
Installation was pretty easy. They have detailed instructions for every model of RV air conditioner out there complete with pictures. It’s a matter of mounting your Soft Start module inside the AC unit, finding the electrical box, and start wiring it in. All the wires are color coded and there are only 4 of them to connect so it’s hard to go wrong.
I used strong, double-sided tape to mount it out of the air flow in my AC unit. I then routed the grey cable containing all the wiring over to the electrical box. I forgot to take pictures of my wiring but I’ll include a sample from the instruction manual.
This was all the wiring that was necessary. Connect a white wire where the other white wires are connected, connect an orange wire where all the red wires are connected. Connect the brown wire to the white wire going back to the compressor, then cut the blue wire (not the red wire, never the red wire) and splice the black wire into the middle. Tuck all the wiring away nicely. Remember you’re afraid of heights. Don’t fall off the trailer.
After it’s all connected up it’s time to “teach” the Soft Start device about your air conditioner. You do this by turning the AC on, wait until the compressor comes on, let it run for 30 seconds, then adjust the temp so that the compressor turns back off, adjust the temp again to make it come back on (it will make you wait 3 minutes before it turns back on but be patient, it will turn back on.) And then repeat this 2 more times. That’s it. The Soft Start module has now learned your AC’s inrush current particulars. You will notice that the compressor no longer “klunks” on. You just hear a gentle humming begin. Very nice.
Then it was just a matter of closing the AC back up and taking a nap! Now to shop for a generator.
2 thoughts on “Installing A SoftStart On The Air Conditioner”
You did a great job! How clever 🙂
That’s because I have some great support!