ac start capacitor

rsbamafan · 09-21-2013, 05:29 AM

My 4000/3500 watt champion is having trouble starting the ac on my 2012 outback 15000 btu coleman.I have heard that some didn't come with as start cap.Thinking about installing a boost start cap.Any thoughts?

jtyphoid · 09-21-2013, 07:13 AM

Some say they help, others say they don't, and a very few claim that the extra current through the motor windings will shorten the life of the compressor motor.

Before putting one on, I recommend checking your existing capacitors and make certain that your blower fan motor bearings are not going out.

pjhansman · 09-21-2013, 10:16 AM

Seems to me a 4000/3500 watt champion should produce as much as a 30 amp breaker on shore power. That should be more than enough to run your AC.

Try running it on 30 amp shore power. If that is OK, you might want to check the actual output of your generator.

MarkS · 09-21-2013, 11:38 AM

I have run my 15000 Dometic on my 3500/4000 Champion. Without the capacitor. Not a lot. And it was a close thing. My champion has trouble going from no load to full load in zero seconds. I found turning the fan on first helped.

Adding the cap is on my todo list. We only dry camp where we need the AC, a couple of times a year. So, not high on my todo list.

mikell · 09-21-2013, 03:55 PM

The caps only about 20$ and the hard starting one is a few more go ahead and replace it

Bob Landry · 09-22-2013, 05:28 AM

I would be suspicious of the generator. If the AC starts and runs OK on shore power, leave it alone and start looking at the gennie. There seems to be a misconception that a hard start kit is the cure all for AC problems. it is not. While it can be beneficial for old units that are beginning to have problems starting, it's not necessary on newer ACs. If they need start components, they will come rom he factory with them.

SAD · 09-22-2013, 05:37 AM

Quote:

Originally Posted by pjhansman

Seems to me a 4000/3500 watt champion should produce as much as a 30 amp breaker on shore power. That should be more than enough to run your AC.

Try running it on 30 amp shore power. If that is OK, you might want to check the actual output of your generator.

Quote:

Originally Posted by Bob Landry

I would be suspicious of the generator. If the AC starts and runs OK on shore power, leave it alone and start looking at the gennie. There seems to be a misconception that a hard start kit is the cure all for AC problems. it is not. While it can be beneficial for old units that are beginning to have problems starting, it's not necessary on newer ACs. If they need start components, they will come rom he factory with them.

I'd like to address these two statements which imply that the generator is the same as the utility/shore power.

In a perfect world, they are... However we do not live in a perfect world.

Running amps they should behave the same... However it's the surge. The utility has the ability to respond to the compressor startup amp surge with nearly unlimited resources... The generator does not. The generator has a very finite ability to respond to the startup amps.

In this respect, comparing the two power sources is apples and oranges.

Bob Landry · 09-22-2013, 05:51 AM

Quote:

Originally Posted by SAD

I'd like to address these two statements which imply that the generator is the same as the utility/shore power.

In a perfect world, they are... However we do not live in a perfect world.

Running amps they should behave the same... However it's the surge. The utility has the ability to respond to the compressor startup amp surge with nearly unlimited resources... The generator does not. The generator has a very finite ability to respond to the startup amps.

In this respect, comparing the two power sources is apples and oranges.

The startup amperage of the compressor , AKA Locked Rotor Amps, is considerable, however, it has such a short duration, generally a fraction of a second. It's transparent to a power source, or at least it should be. Otherwise, a breaker would trip every time it attempted to start. My marine 16KBTU units start and run fine on 20A breakers. At any rate, a 3500-4000 generator should have no problem starting a RV air conditioner.

SAD · 09-22-2013, 07:09 AM

Quote:

Originally Posted by Bob Landry

The startup amperage of the compressor , AKA Locked Rotor Amps, is considerable, however, it has such a short duration, generally a fraction of a second. It's transparent to a power source, or at least it should be. Otherwise, a breaker would trip every time it attempted to start.

Correct... For example, a household 20 amp breaker can withstand 100 amp "burst" (i.e. LRA). And the utility has no problem supplying the demanded surge.

This is the key difference between the utility and a generator. If the burst is outside of the generator's ability, it may fail.

Quote:

Originally Posted by Bob Landry

...My marine 16KBTU units start and run fine on 20A breakers. At any rate, a 3500-4000 generator should have no problem starting a RV air conditioner.

I agree with the above. However, without a hard start kit, the generator may struggle.

pjhansman · 09-22-2013, 09:23 AM

My 3000 watt Yamaha has no issues starting a 15k btu AC.....

but there could well be a problem if the hot water heater and/or fridge were set to electric, and the batteries were low so the charger was running, or if the DW was running the microwave.....

or even if the genny wasn't running properly.

rsbamafan · 09-27-2013, 02:52 AM

Wanted to give an update on my start cap install.I installed a Supco spp6e and it did wonders.My champion now starts the ac with ease.My honda 2000i will even start it with eco mode off.Install was fast and easy.I would highly recomend doing this.Your Gen will love you for it.

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