Air conditioner hard start capacitor [broken off from another thread]

[Padgett]

Is that black square at the top the PCTR (Positive Temperature Coefficient Resistor) ? Am not certain which is better so ordered one of each (PCTR and Relay). If one is there already do you think it should be replaced or the new one placed in parallel ?

There is a very good writeup here.

ps am surprised you didn't hear a BANG when that went. In my school daze we used to blow caps in the lab.

[tentcamper]

I wonder if you need the hard start cap, or if it was added by a PO that was trying to get the AC to run with an EU2000i.

[Padgett]

That is why I plan to take a good look at the generator step-up, my eu2000 would start the ac in my tests but had to really grunt & the Pred is rated 500 watts higher than the Honda. When the pred works, It starts almost instantly and when it doesn't I see the voltage drop to 50-60v for several seconds. If I leave there (about 5 seconds) long enough, the gen will stall.

Hard to tell since after each try I gave it 5-10 minutes to equalize. Not sure if needed since it didn't start.

[Bill]

I'm still wavering on this hard-start idea. In the article that Padgett linked, the author has a different air conditioner than we have on our TMs. For his air conditioner, the electrical diagram shows that the START capacitor is optional (dotted line), and if desired, you can add a START cap and PTCR, a combination that is referred to as a hard-start cap.

In our TM air conditioners, the situation is different. The electrical diagram (first link in post #6) shows that the START cap is not optional, but is part of the basic wiring. Since there is a PTCR with it, does this constitute a built-in hard start cap? And if so, would it be wise to put a second hard-start cap in parallel with it?

I'm not convinced. Too much start current could damage the compressor motor. If it were my unit, I would simply replace what is there, and button it up. Unless someone gets a different answer from RV Comfort. Has anyone actually done this? Padgett, I look forward to hearing your conclusions.

Bill

[Padgett]

OK, am still in the information and parts gathering mode. Is possible my problem may be the governor in the generator and not the start cap at all.

Was pointing out that generic caps from Amazon may be better and half the price of the OEM. Also need to figure out the difference between PCTR and relay controlled units.

[tentcamper]

I think you may get it to work with a hard start cap. But I think you will have issues when temps get high and you have higher static head pressure to overcome at compressor startup.

Other things you could try along with the hard stop cap. before compressor start up; Turn off the circuit breaker to the converter and any other circuit using power. Add a switch for the AC blower fan and turn it off before starting up the compressor and turn it back on after the compressor startup surge. Also, you can get a little more out of the generator by changing the oil to synthetic oil.

But with all these changes, I don't think you will have a reliable solution for the EU2000i to power the AC unit.

Let us know your results. Thanks.

[Padgett]

I agree, the EU2000i (2000W surge/1650W steady, 97cc engine) is underpowered for AC use and why I bought the Predator (2500W surge/2200W steady, 125cc engine) being the largest I can lift and fit into the rear compartment - those two requirements are why I didn't just buy a 3000W portable.

The rationale was that if the EU2000 was marginal starting the AC, 25% more power should be "enough" even for Florida summers. That said I have seen reports of a sticking governer not allowing it to amp up on a sudden demend.

Agree with the direct circuit but not sure how much would be gained by seperating the fan since I run on HI blower for a minute before switching to LO Cool so no startup surge for the fan.

Also if I need to turn the fan off first, it won't be able to cycle at night (though I wish there was a lower fan setting).

Do wonder if the failing coach battery was having an effect and whether adding a 1000W inverter to the two new GC2s could provide some extra surge capacity..

Simplest things first. Synthetic oil may be a good idea but also need to get solar panels on (if hot day is factor that is when solar should work best) & another 150-200W can't hurt.

[tentcamper]

My bad, I thought you had an eu2000.

I think you should be fine. I bet with that dead battery, which sounded like one cell was near shorted. I would think the converter was sending a lot of amps to the battery to try to keep it at 13+ volts.

[Padgett]

Except it also had some trouble with the battery disconnected. I am getting conflicting information. Now that am home I need to run some load tests and see how it acts. I have seen some reports of a sticking governor.

ps think the confusion is that I do have an EU2000i which I use as a baseline for comparison of sound level (little difference under load) and capability.

but first I need to get the solar panels installed which is going to require a platform. Now that I have retired, I've never been busier.

[rickst29]

within "electrcial", I'm strongly recommending the add-on "hard start kit" with the included "additional" timing circuit. Lots more "oomph" when needed, and it goes away properly.