Supco Hard Start kit for window AC unit

[usmc70_14]

It appears that by adding this capacitor to an AC that is experiencing issues with inverters or generators, might be the solution.

In my scenario, my 2300 watt inverter from Ryobi will only start and run my 10k btu in normal mode. Using Eco will not start it. No big deal. But I would like to have the inverter run on Eco mode with the AC. So I decided to buy this little kit which is only 2 wires to connect ( discharge ac capacitor safely before installing the kit, failure to do so may result in shock or death ) for about $14.

My question is.... If this little device is capable of solving the problems of people not being to use the inverters with their ac due to amp surge. Then why hasn't this device been made a MUST have gadget on this or any other forum ? I mean I see lots of videos and reviews. So this product has to work.



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[flboy]

It think at best,it depends. In my case, it made the difference for my 3000W pure sinewave inverter tripping out when I start my 8000 BTU AC, but the Honda 2000 would start the same AC in ECO mode. The inverter just has a very quick to respond overload circuit. The capacitor allows the compressor to spool up quicker before the inverter overload has time to respond.

From what I can see, if the system is marginally working or almost there, the capacitor improves the start response time and makes the difference.

The sure fire best way is to purchase a soft start kit which is about $299. It is much more than a capacitor but will absolutely solve the problem if used as directed.

https://www.amazon.com/dp/B07YBMCTBC/re ... rFbMZCJR9Y


Btw.. I also have a 6000 BTU AC that won't start in ECO mode on my Honda. It appears to be because of a very fast brown out circuit in the AC..


So you can see... there is alot of variance with ACs and Generators and the associated circuits meant to protect the compressors from under voltage or the inverter from high surges.


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[bdosborn]

There are two conditions that make A/C hard to start. One is the fact that the motor has a single electrical phase and the motor poles tend to align when it spins to a stop. It has minimum starting torque when that occurs. The capacitor has an electrical phase shift, providing what is essentially another phase for additional starting torque.

The other condition is hot start. The refrigerant pressures go up as the A/C gets hot with use. This makes it harder for the motor to start when the A/C cycles on and off. The capacitor may not provide enough additional torque to overcome a hot start condition.

Let us know how it works for you; a lot of the big RV guys add the capacitor. I bought one to play with and never got around to installing it.

Bruce

P.S. The capacitor probably won't do much if you have a modified sine wave inverter (for a lot of technical reasons).

[flboy]

Nice explanation! I have had some success with the caps. I'd just say try it and if it works, be glad. If not, hold on to it for another day. Only out less than $10.00.

As you mention, there are alot of variables at play.



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[aggie79]

I’ve always wondered if you could “split out” starting the compressor and the blower motor to smooth out the peak of the initial current demand. The design of this concept is too deep for my feeble brain, however.


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[hankaye]

aggie79, Howdy;

I’ve always wondered if you could “split out” starting the compressor and the blower motor to smooth out the peak of the initial current demand. The design of this concept is too deep for my feeble brain, however.


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Interesting that you mentioned that. In my thermostat (RV Overhead A/C), I have the ability to operate
the fan only for the A/C or allow it to turn on and off with the unit. I choose to leave the fan ON all the
time. I'm a huge proponent of air flow.

hank

[usmc70_14]

I was able to install today..

It was a tight fight to get into the Frigidaire 10kbtu.

My initial impressions are that it didn't give me the results I was looking for. I'll test in some more and report back.

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[usmc70_14]

Since it was a tight fit getting the capacitor inside, I ended putting a zip tie around both cans. Will the zip tie be a fire hazard if the cans get hot?

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[flboy]

I installed mine external to the AC . Just ran the wires out into the appliance cabinet below and mounted the cap on the inside wall.

I don't think the tie wrap would be any more of a fire hazzard than anything else.

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[usmc70_14]

I originally wanted to wire on the outside. The problem with that is I built a slide out for the AC on the vnose area. The 2 brackets for the slide out I don't trust for the bouncing of the AC while traveling. So my plan is to remove the AC from the slide out before travel. I plan on re enforcing those brackets. But for now I'll make do with that.

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[flboy]

I see. Did the cap solve your issue?

[usmc70_14]

I see. Did the cap solve your issue?

My initial play time of about 20 minutes on the generator, I don't think it helped out any.

Out of the times I heard the compressor kick on eco mode, it sounded like the compressor didn't kick in. I am going to try running again on low fan speed instead of high. I don't know if that would matter or not. I just need to experiment some more.

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[flboy]

Ok, good luck. I had a 6K BTU unit that would not start on ECO and my 8K BTU does. On the 6K unit, the low voltage circuit (brown out) just tripped too fast as there is a slight drop in voltage before the Inverter Generator can respond to the surge.... Nothing I could do about that... 8K works fine with Honda, but tripped my 3KW Inverter when running off batteries and inverter. The Supco Cap fixed that problem... I could hear the compressor try to start but the inverter would trip after about 2 seconds... the Supco resolved that problem.