It is the first properly hot afternoon of the trip, somebody puts a plate in the microwave while the air conditioner is running, and the pedestal breaker goes. You reset it in flip flops, and for the rest of the week you run the microwave and the air conditioner in shifts.
The air conditioner is not really the greedy one. It runs on about 13 amps, which nothing in your rig objects to, and then for roughly one second when the compressor kicks in it asks for something closer to five times that. Almost everything annoying about RV air conditioning comes out of that one second: the pedestal tripping with the microwave on, and, more surprisingly, a generator rated comfortably above your running load stalling anyway. The fix is not a bigger generator.
What a soft start actually changes
A compressor motor starting from rest is close to a short circuit for a moment. It has no back-EMF to oppose the supply until it is turning, so it draws locked rotor current until it gets moving. That spike, not the running load, is what your breaker and your generator both have to survive.
A soft start module sits between the thermostat and the compressor and brings it up over a few hundred milliseconds instead of instantly. The compressor is unchanged, the running current is unchanged, and the peak comes down dramatically. What that buys you, roughly in the order people notice:
- The 30 amp pedestal stops tripping when something else is running.
- A smaller generator becomes viable. This is the reason most people buy one.
- Two air conditioners can start without fighting each other, if you have them.
- Dimming lights stop. Cosmetic, but it is the same problem.
It only fixes the first second. A soft start changes the startup surge and does nothing to the running load. If your air conditioner is tripping the breaker after it has been running happily for ten minutes, this is the wrong purchase and you have a different problem.
There are three ways people deal with this, and the first one does not involve a soft start at all.
Buying a bigger generator instead
It works, and it is what most people try first. A larger inverter generator has the surge headroom to swallow the spike with no soft start anywhere in the picture. Nothing gets wired and nothing gets installed; you buy the bigger box.
Then you live with it. You carry the weight every mile, hear the noise every evening, feed it more fuel, give up storage space you were already short of, and usually spend more than the soft start would have cost, all for a problem that lasts one second at a time. It also does nothing for the campground pedestal, which is where most people actually trip a breaker.
If you were buying a generator anyway and the next size up is marginal, size up. Buying one specifically to brute-force the startup surge is a bad trade.
A plain soft start module
The entry level of the category. It wires into the air conditioner, reduces the startup surge, and that is the whole feature list. Installation is a handful of connections at the unit, within reach of anyone comfortable working on a rooftop unit with the power off.
What you do not get is any sense of how it is doing. It either works or it does not, and you find out it has stopped by the breaker tripping again. No reading to look at, no fault code, nothing to tell you the unit is short cycling before short cycling turns into a compressor failure. Some of the cheaper modules are also fixed-profile rather than adaptive, so they apply the same ramp regardless of what that particular compressor needs.
None of which makes it a bad buy. If you want the problem gone and no further involvement from you, this is the thing to buy.
A soft start that reports what it is doing
The Micro-Air EasyStart is the one we support, and the reason is that it broadcasts over Bluetooth rather than sitting up there silently. Four things come off that broadcast, listed here and in the compatibility database with the caveats attached:
- Status code, so you know what state the unit is in
- Current, the running draw
- Peak start current, which is the number the whole product exists to reduce
- Short-cycle protection delay, so a compressor being protected from itself is visible rather than mysterious
Peak start current is the one we actually watch. It measures directly whether the thing is still doing its job, and it drifts before it fails. A soft start that used to hold the surge down and no longer quite does is a repair you schedule rather than a breakdown handed to you in August.
The EasyStart costs more than a plain module, and the readings only matter if you are the sort of person who will look at them. Plenty of people are not, and there is nothing wrong with that. If you would never open a dashboard, you are paying for a feature you will not use, and the plain module is the honest recommendation.
Which one
- You want to run the air conditioner off a small generator. Soft start, any of them. This is the case the category was invented for.
- The pedestal trips when you use the microwave. Soft start. A bigger generator does nothing here.
- You are already monitoring your rig, or plan to. The EasyStart, because peak start current is genuinely worth watching.
- You have two air conditioners. Soft starts on both. Two compressors starting at once is the hardest case there is.
Where to get one
The reporting version, which is the one this guide is about.
Micro-Air EasyStart
The soft starter that lets a generator or a 30 A pedestal run the roof air. RoamVitals reads its live current, last-start inrush, and fault and start counters.
We may earn a commission if you buy through this link. It does not change your price.
One thing worth saying plainly
This is a 120 volt AC circuit inside a rooftop appliance. It is well within reach of a confident DIYer with the breaker off and the manual open, and it is also a completely reasonable thing to pay an RV tech an hour to do. Honestly, if you are quietly unsure which of those two people you are, you are the second one, and that is not a criticism. Either way the compressor gets its gentle second, and the pedestal stops arguing with you about the microwave.
