Trying to keep my cool

[1stimerver]

you could call soft start and ask them if your ac using their device would start with the generator you plan to use. They told me that adding a soft start to my unit would not work with my generator, due to its limited surge capacity.
I respect their straightforwardness.

 

[woof-n]

you could call soft start and ask them if your ac using their device would start with the generator you plan to use. They told me that adding a soft start to my unit would not work with my generator, due to its limited surge capacity.
I respect their straightforwardness.

I just reached out to an old colleague of mine who is an industrial HVAC control expert. He was surprised that my generator would even start the AC. ( To get my AC to start, I turned the converter breaker off. I then turned the blower to run on continuous low, after a few minutes, I started the compressor.) He said the soft starts are basically a start relay with capacitors. When the AC is called to start. The relay pulls in to use the capacitors help the compressor start. Once started, the relay falls out, and the soft starter is done until the next start. He went on to say that compressor amps will continue to go up to as the unit builds up heat and head pressure, etc.. After your first initial start, the RLA, (run load amps) are the lowest you will ever see. A soft start will not help me. I can start but not continue to run. The best solution is to get a larger generator. But if I hate off grid camping then I would have a much larger generator to keep, my smaller generator company that I don't use. I like the idea of having a plan B, option, if Plan A camper AC fails. It may also work as an off-gird plan B solution. Just as you did before vacation when your AC failed. It is not just camping; it is an adventure and opportunity to tell new campfire stories.

 

[Kirk]

Your buddy knows what he is talking about. Soft start kits are exactly what they say. The lower the starting current requirements. Any motor has a far higher current draw for a very brief time as it goes from standing start up to operating RPM. It is that starting surge that the capacitors help to supply.

 

[1stimerver]

In the end I just got a bigger generator. The cost was a bit more than purchasing a soft start, but i couldn't be more pleased with the current set up.
Safe travels and all the best.

 

[Gary RV_Wizard]

That's the ideal solution and a choice you won't regret (except maybe when you have to lift it!).

However, I didn't understand why you thought you could start once but not continue to run. Yes, the starting amps will climb a bit, but probably not more than a soft-start boost can handle. And the actual running amps are easily within your 2200W genset capacity (running load is about 1400w). a few RVers are able to use their a/c nicely with 2200W or even run from a 15A (1800W) shore source and most can operate well from 2400W (20A). Usually the a/c branch circuit is a 20A breaker.

 

[Gr8bawana]

I've always felt that RV AC manufacturers were a bit behind the bubble when it came to developing a 12 volt air conditioner for RVs. I have no personal experience with this unit, but I think it's a step in the right direction - especially for boondockers. If it's durable, I think it will make strong inroads with RVers. (in time) 12V/24V/48V VELIT 2000R Rooftop Air Conditioner

Kev

That 12v unit might work if it was on a van in Norway where it doesn't get hot.
Try one of those units in the southwest on a 100°+ day and it would be like an oven inside.

 

[woof-n]

However, I didn't understand why you thought you could start once but not continue to run. Yes, the starting amps will climb a bit, but probably not more than a soft-start boost can handle.

Think of it as three separate things.
Step 1:
Starting the compressor is often expressed in the in rush current or the amps required to start the compressor, condenser fan, blower and move the refrigerant. This where the soft start helps. Instead of using just the power source amps to start the compressor. A soft start will use a start relay and capacitors to assist the power source in starting the AC unit. I am not smart enough to know what real mix is but let say for example, its maybe 75% power source and 25% soft start. Once running, the soft start is done. Soft start would be like hitting the electric start on a lawn mower and pulling the pull cord at the same time. Once it is started the soft start or pull rope is done. In rush current is like a choke on a lawn mower. It is always more very short-term fuel or amps to get everything moving than what's need to run.
Step 2:
Now that the unit is running. It is operating on minimum run load amps or RLA or in the case of our lawn mower, it is running on the minimal amount of gas idling.
Step 3:
The compressor is now seeing the load, compressing the refrigerant and releasing it into a cold vapor in the evaporator. The evaporator absorbs the heat from what the blower is bring to the evaporator. The evaporator transfers the heat to the refrigerant gas. The hot refrigerant gas from the evaporator goes to the condenser where it is returned to a liquid. As this work is being done it requires more amps from the power source, because it is doing more work than when it is first running. The RLA has to go up because it is doing more work. Same thing is true on a lawn mower. When you first start it. It only uses a little fuel but when you push it to cut grass it uses more fuel to cut the grass. If you push the lawn mower faster, it will use even more fuel because it has to do more work in less time.

FLA is full load amps, that is the max amps this unit should ever see. Most of the time RLA is 10 to 25% less than the FLA depending on the load. If The RLA is above FLA expect trouble, . I hope this helps. I apologize for the long explanation. It's the only way I know how to explain it.

 

[Adventurous Traveler]

Woof, great job with putting things in simple terms, especially with the lawn mower comparison.

Another Forum Expert on the job!

 

[Kirk]

It's the only way I know how to explain it.

It is a fairly reasonable explanation, at least for amateurs but it makes me wonder why you asked the question at all? Gary has an electrical background as do I, but I'll not get into a discussion of theory.