Soft start capacitors

mntnflyr4fun wrote:
I recently installed a "hard start" capacitor and an AC fan delay circuit to my Coleman Mach III 13,500 AC unit.

As I was investigating the AC starting load requirements, I realized that to get the most performance (ie: max reduction in load to my generator) I needed to not only have more power available, but I could also reduce the total load at startup by delaying the fan for a couple seconds which is another motor being started at the same time as the compressor motor.

Amazing difference in performance. Prior to the install (which took about 20 min.) my Honda EU2000i would choke out trying to start the AC unit due to the very high load required at startup. In fact last summer on a trip to Louisiana, I tried to start the AC with my gen. and blew both Capacitors in the AC due to low current during startup.

Not only is the generator trying to start the AC motor, it is also trying to start the fan at the same time along with any added loads like maybe your converter trying to charge a battery etc. and 2000 watts was nowhere close to enough.

By installing the hard start capacitor to increase the available starting current AND by delaying the start up of the fan by a couple seconds, as if by magic the AC starts and runs with no trouble and my EU2000i doesn't seem to be struggling to run it after it has started. I am sure I don't have alot of extra power to do much else with from my 2000watts, but on a hot day, a little AC can be just what the Dr. ordered.

Amazing what a little booster and a smart delay circuit can do for about $100 bucks and 20 min. on top of the RV with a couple hand tools. Both parts installed in the AC unit on top of the RV with minimal effort or technical proficiency needed.

I bought the RV Coleman Dometic Duo-Therm A/C Compressor Hard Start Kit + tips +instructions and the RV-AC Starter prevents Generator Stalls, Overload trips at Air Conditioner Start on Ebay.

Cheap upgrade, simple to install and I immediately called my brother and told him he should purchase as well. Living in Oregon, we don't get much call for the AC when dry campingbu so we both run undersized suitcase generators and this little mod. was a game changer.

Now I can sell one of my EU2000i generators and use the money for a solar kit....seems like a great value to me.

Yes, delaying the start of the fan motor can make a noticeable difference in starting the AC from a generator. your phasing in the inrush currents, and reducing the load. I had a 30 second delay between the compressor and fan. It helped and along with the supco kit let me start the AC at lower altitude and moderate temps. However at over about 1500ft and 90F I still ended up with a not start condition.

BTW the micro air does this time delay trick as well. However they swap the sequence, start the fan FIRST then the AC. starting the fan first gets the generator to start off the eco mode low rpm and start ramping up the RPM before they hit it with the compressor load.