New Coleman Soft Start Option vs Microair

Wow to both Otrfun and Ktmrfs, that is some valuable information and a solid validation as well :) - Thanks for adding to the conversation!

3 tons

otrfun wrote:

jjrbus wrote:
I have been watching this for some time. It would be nice to see some actual LRA numbers for the Coleman "soft start" vs no soft start. I suspect if they were impressive numbers that Coleman would publish them. I do not see them anyplace unless I am missing something?

I've made a number of inrush/LRA current measurements over the last few years after installing a few Micro-Air Easy Starts ($250-$300) and hard/soft start cap kits ($20-$30). The Micro Air typically reduces the 55-65a inrush/LRA current found on a typical 13.5 BTU RV a/c as much as 35-45a (down to 20-25a), sometimes even lower. This is a dramatic, 50-75% reduction in inrush/LRA current.

A hard/soft start cap kit *may* net you a small 2-4a (<5%) reduction in inrush/LRA current. If you have a generator that's right on the edge of starting your a/c, a hard/soft cap kit can nudge your generator into successfully starting your a/c compressor. However, as soon as ambient temps rise (along with your inrush/LRA current) you may find your generator unable to start the a/c again.

Bottom line, the Micro Air Easy Start dramatically outperforms any hard/soft start cap kit.

I had similar results.

I installed the micro air on our Coleman Mach III 13.5K AC unit a few years ago. After the "learning sequence" I measured the peak inrush current using a NIST traceable current probe that would capture peaks as short as 10ms. (e.g. < 1 cycle of 60 hz) The peak current on start up measured over 5 start cycles was less than 20A, meanwhile peak inrush current before the install was a consistent 45A.

with the micro air, my honda 2000 in eco mode would easily start the Mach III with a very smooth ramp up in rpm on the honda.

I will mention that a honda 2000 is likely to have trouble running a Mach III above about 3000-4000 ft w/o tripping the micro air overload sensor. Gave one honda 2000 to our son when the 2200 came out and the 2200 will consistently run the MachIII at 7,000ft all day long.

jjrbus wrote:
I have been watching this for some time. It would be nice to see some actual LRA numbers for the Coleman "soft start" vs no soft start. I suspect if they were impressive numbers that Coleman would publish them. I do not see them anyplace unless I am missing something?

I've made a number of inrush/LRA current measurements over the last few years after installing a few Micro-Air Easy Starts ($250-$300) and hard/soft start cap kits ($20-$30). The Micro Air typically reduces the 55-65a inrush/LRA current found on a typical 13.5 BTU RV a/c as much as 35-45a (down to 20-25a), sometimes even lower. This is a dramatic, 50-75% reduction in inrush/LRA current.

A hard/soft start cap kit *may* net you a small 2-4a (<5%) reduction in inrush/LRA current. If you have a generator that's right on the edge of starting your a/c, a hard/soft cap kit can nudge your generator into successfully starting your a/c compressor. However, as soon as ambient temps rise (along with your inrush/LRA current) you may find your generator unable to start the a/c again.

Bottom line, the Micro Air Easy Start dramatically outperforms any hard/soft start cap kit.

jjrbus wrote:
I have been watching this for some time. It would be nice to see some actual LRA numbers for the Coleman "soft start" vs no soft start. I suspect if they were impressive numbers that Coleman would publish them. I do not see them anyplace unless I am missing something?

what is most important is not just the peak LRA, but a graph of the current vs. time. Even a 2000VA generator can supply pretty good peak currents for a second or less IF the current drops to within generator running current limits quickly. If the current peaks at say 50A and takes seconds to drop to 15A or so, another story. A starting cap may not reduce LRA but will get the current down sooner. The area under the curve probably doesn't change, but the shape will. Regardless of what is done, the total energy needed to start the motor doesn't change. You can change the peak energy.

IIRC when I was looking at different AC units, some of the smaller high efficiency units, like a coleman power cub had LRA in the 30A range and my honda 2000 easily and consistently starts the polar cub even in eco mode. And I think some of the newer dometic and coleman high efficiency units not only have lower running current, but lower LRA as well.

I have been watching this for some time. It would be nice to see some actual LRA numbers for the Coleman "soft start" vs no soft start. I suspect if they were impressive numbers that Coleman would publish them. I do not see them anyplace unless I am missing something?

chuckbear wrote:
As you said, "to help boost marginal voltage/amps with a special capacitor or appliance to help get the compressor going." While a soft start system reduces the start-up demand allowing less stress on the compressor and lets the AC units start up easier using a generator or in situations where the RV is already using a heavier load. So these are polar opposites, so if we are using the same name for both, we need to stop doing that so as not to confuse people and have them go out and buy the wrong system. This is from Mike Sokol...

"Sadly, no matter how much we all wish it were true, a hard start capacitor won’t help start an air conditioner compressor using a small generator.

I know that these aftermarket soft start controllers cost a lot of money, especially compared to a $10 Supco hard-start capacitor. But they aren’t the same thing at all. Hard start capacitors are really only useful on a capacitor start induction motor connected to low-voltage utility power."

Chuck

Well, after 42 years I have seen and installed Hard Start capacitors that do indeed work for marginal smaller Gensets and lower than correct 30 amp service line voltage. Over the years I have installed them on older RV AC units instead of replacing the compressor or the complete upper units and have saved my customers lots of dollars. I have even installed them on my 3 and 4 ton home residential units to start a marginal old compressor, that would not start occasionally and still working after 10 years. Saved me from either replacing the outdoor unit or the Compressor. Doug

PS, I still maintain this discussion is about starting on marginal Gensets or Line voltage which both appliances will do the job:)

As you said, "to help boost marginal voltage/amps with a special capacitor or appliance to help get the compressor going." While a soft start system reduces the start-up demand allowing less stress on the compressor and lets the AC units start up easier using a generator or in situations where the RV is already using a heavier load. So these are polar opposites, so if we are using the same name for both, we need to stop doing that so as not to confuse people and have them go out and buy the wrong system. This is from Mike Sokol...

"Sadly, no matter how much we all wish it were true, a hard start capacitor won’t help start an air conditioner compressor using a small generator.

I know that these aftermarket soft start controllers cost a lot of money, especially compared to a $10 Supco hard-start capacitor. But they aren’t the same thing at all. Hard start capacitors are really only useful on a capacitor start induction motor connected to low-voltage utility power."

Chuck

chuckbear wrote:
Hard start and soft start are not the same. Chuck

I think for this discussion, we are talking about the same problem and solution. I have 42 years as a RV tech and have never really heard the term soft start. It has always been called Hard Start, to help boost marginal voltage/amps with a special capacitor or appliance to help get the compressor going. Doug


Hard starters typically cost less than soft starters. However, the forcefulness of a hard start can cause compressor parts to deteriorate faster. ... An electronic soft starter is designed to reduce the starting current of the compressor by actively controlling the current in both the run and start windings.

Hard start and soft start are not the same. Chuck

if your using 30A shore power, stay with the coleman soft start. if your using a <3500VA generator, then use the micro air.

the coleman "soft start" is just a starting cap for the motor, helps but still have a very high surge current need, (w/o it you have an outrageously high surge current)

Micro air will keep the peak starting current less than 20A.