RV Air Conditioner Soft Starts

What does an AC soft start kit do on an RV air conditioner?

When a rooftop AC compressor starts, it draws a short spike of current (locked rotor amps) several times higher than its running draw. An AC soft start kit ramps that startup so the spike is smaller. The Coleman Mach Soft Start Kit, for example, is rated to reduce inrush current by up to 75%. The result is fewer breaker trips on 30A shore power and less startup stress on the compressor. A soft start does not protect your RV from campground voltage drops or surges. That job belongs to a surge protector such as the Southwire Surge Guard RV surge protectors.

Can a soft start kit for an RV air conditioner let me run it on a smaller generator?

Yes, and this is the most common reason owners install one. Lowering the startup spike lets many 13,500 BTU rooftop units start on a 2,000 to 2,200 watt inverter generator that would otherwise trip or stall. Results depend on your AC's BTU rating, the generator model, altitude, outside temperature, and what else is drawing power when the compressor starts. Test with other loads like the microwave and water heater turned off first.

Will an AC unit soft start kit fit my RV air conditioner?

Most soft start kits work with rooftop units that use a single-phase fixed-speed compressor, which covers most units from Dometic and the Coleman RV air conditioner line. Before ordering, check the model number on your unit's data plate and confirm the compressor type. Inverter and variable-speed units, such as the Furrion Chill Cube, already ramp compressor speed at startup and do not need a soft start. For those units, browse Furrion RV air conditioner parts and accessories instead.

How hard is an RV AC soft start installation?

An RV AC soft start installation is a manageable DIY job for owners comfortable with basic wiring. The module mounts under the AC shroud or in the control box and connects to the compressor leads and run capacitor. Most installs take one to two hours with hand tools and a multimeter. Disconnect shore power and the generator first, and discharge the capacitor before touching it, because it can hold a charge after power is off. Many kits run a short learning sequence over the first several compressor starts, so expect startup to improve after those starts.

Can I return an RV soft start if it doesn't work with my AC?

Please note: we cannot accept returns on electrical items, and an RV soft start is an electrical item. Confirm your AC model number, compressor type, and voltage before ordering. Our team at United RV Parts is here to help you find the right soft start. Text or call 817-984-1852 with the make and model number of your air conditioner and we'll make sure you get exactly what you need the first time.