Generator A/C question

[InterBlog]

Originally Posted by Amg

Yes temperature alert. Their website is www.temperaturealert.com

Nice. This has come up before in the context of cellular security cameras coupled with a similar device. I believe it's the Wendlands who use a dual-purpose device - it alerts them if the temp gets too high (they have a dog that they keep in their Roadtrek CS) but it also streams pics of the inside of the van and alerts their cell phone if there is a break-in.

I've looked at the products currently on the market and IMO, none of them are ideal for an Interstate application. Most still require shore power whereas my biggest break-in concern would be while boondocking or stopped in a parking lot for lunch (= the scenario in which the Wendlands got broken-into, and if I'm remembering correctly, one Interstate owner on Air Forums got broken into while daytime-parked near the St. Louis Gateway Arch). We have not yet gotten into the issue of how one might be adapted to run on its own battery or 12V. That's lower down on our current priority list and I'm hoping that the market will produce more choices before we even get to it.

The other limitation is that some of the security devices would be triggered by movement of our 45 pound dog if she were left inside the vehicle, such as during lunch. The manufacturers seem to have solved that issue on the conventional fixed residential side, but not with the more portable devices.

[Amg]

For security I have a Compustar coupled with a dronemobile. I set the inside motion detector to compensate for my dog so the alarm will not go off. I get notified by email and text message of any issues. I can set or unset alarm anywhere there is cellular. It has GPS tracking It also has a temperature monitor but it is not as accurate as the temperature alert. I heard some people have coupled video to the device off of Facetime.

[K9CarCrate]

Amg, I had an A/C problem much like you described. I'm not sure of the year of your AI--mine is a 2014. There was a resistor in the Dometic A/C roof unit that was defective and requiring too much current so it would not start up and only the fan would work. It got progressively worse. Eventually "Lewster" warrantied out the defective A/C unit. I hope this information helps.


Sent from my iPhone using Airstream Forums

[LB_3]

If the fan comes on but the compressor won't, could it be a mis-wired thermostat?

[lewster]

Originally Posted by LB_3

If the fan comes on but the compressor won't, could it be a mis-wired thermostat?

It is almost impossible to 'miswire' a Dometic t/stat as they use 4 conductor phone cable with rj-11 jacks on either end. They simply plug in at the t/stat and control board.

It is highly likely that you have either a blown start capacitor, PTCR motor start device or both. If either is burnt, BOTH should be replaced.

If neither is defective, problem would most likely be the control board not energizing the K-5 relay which is responsible for sending 120VAC to the compressor. This requires a board replacement. The final option is a bad t/stat. Any competently trained and experienced RV tech with Dometic certification should be able to diagnose the problem in less than 15 minutes!

[Amg]

Thanks for help.

I did follow advice to wait until all the lights were lit on generator panel and everything has been fine since. When LEW gets back to Florida I plan on having lithium batteries installed with upgraded solar panels. Hoping to being able to get a few hours use of A/C without running generator to keep my dog cool. What a life she has!

[lewster]

Originally Posted by Amg

Thanks for help.

I did follow advice to wait until all the lights were lit on generator panel and everything has been fine since. When LEW gets back to Florida I plan on having lithium batteries installed with upgraded solar panels. Hoping to being able to get a few hours use of A/C without running generator to keep my dog cool. What a life she has!

You sure won't be the first Interstate owner who has put in a large lithium bank and hybrid inverter with solar for the sole purpose of keeping their pooches cool and comfy!! They also don't seem to like it when the generator is running either!!

[Boxster1971]

Originally Posted by Amg

Something strange is happening with A/C. I turn on my generator (control located above front cabinet). I then walk to the rear on turn on the A/C. The unit will come on. I know I have to wait for the generator to be ready to turn on the compressor. It normally takes a few minutes. Lately the compressor never comes on. I notice all the lights on the generator are lit showing the A/C is being powered. However if I then turn the A/C off and then on the unit will cycle properly with the compressor. I keep a dog in the van and am concerned that the compressor will not turn on properly. Is something wrong or am I doing something wrong? Thanks

After saying back in May that I haven't had this sort of problem - I now have to eat my words. Yesterday I tried to use the A/C with generator power and it wouldn't work properly. I waited until the PCS panel was properly lite after the generator was running for about 2 minutes. Then I turned on the A/C and it started normally. But once the compressor started it overloaded the PCS and all power was shed by the PCS. Then the PCS went through another 2 minute delay before restoring power. It did this repeatedly about five times before I gave up to try something different. So I switched off the Magnum inverter/charger circuit breaker on the AC distribution panel. That seemed to work and the A/C functioned normally on the generator. I'm inclined to think the 120VAC load of the larger MS-2000 inverter/charger I installed last fall is just enough to overload the 20 A limit of the PCS Generator mode when running the A/C. This larger charger does draw more power than the original 1,000 watt Magnum inverter/charger.

This was the first time I tried running the A/C off the generator since I installed the larger inverter. I'll have to investigate further to be sure this is the problem. I've been using the A/C every day without issues while plugged in for the last few days on our trip through the hot Midwest.

More details on the problem once I get back home in July.


- - Mike
2013 Interstate Lounge EXT on 2012 Sprinter

[Boxster1971]

Following up on my post of June 22nd when I said the A/C would not run off the generator on my AI. I tried it today in my driveway at home and it worked fine. Ran the A/C for an hour on the generator without missing a beat. Now I'm really confused by the problem I had back in June. Back in June I was at the Kickapoo SP in Illinois, with temps in mid 90's and high humidity. Today in Maryland the temps was about 85 DegF with 65% humidity.

For now there are no issued on my rig as it all worked, but I'll have to watch for this problem again in the future.

- - Mike

[lewster]

Originally Posted by Boxster1971

Following up on my post of June 22nd when I said the A/C would not run off the generator on my AI. I tried it today in my driveway at home and it worked fine. Ran the A/C for an hour on the generator without missing a beat. Now I'm really confused by the problem I had back in June. Back in June I was at the Kickapoo SP in Illinois, with temps in mid 90's and high humidity. Today in Maryland the temps was about 85 DegF with 65% humidity.

For now there are no issued on my rig as it all worked, but I'll have to watch for this problem again in the future.

- - Mike

Mike,

Higher ambient temperatures and especially high humidity cause the A/C compressor to run at a higher amperage. That might have been your problem, but the 2400 watt Onan that comes in the Interstate shouldbe able to handle the A/C load, assuming that you're actually getting that 20 amps of output.

If it happens again I would take it to Onan for a performance test.

[Boxster1971]

Originally Posted by lewster

Mike,

Higher ambient temperatures and especially high humidity cause the A/C compressor to run at a higher amperage. That might have been your problem, but the 2400 watt Onan that comes in the Interstate shouldbe able to handle the A/C load, assuming that you're actually getting that 20 amps of output.

If it happens again I would take it to Onan for a performance test.

Thanks Lew. I definitely saw higher current spikes when the compressor started during the hot June problem. I saw one spike at 29A in June, but none higher than 19A this week. I guess I'll need to be careful when using the generator powered A/C in really hot humid conditions. In June I was able to keep the A/C running of generator by turning off the 120VAC inverter circuit breaker. I figured the increased load from the larger battery charger in Magnum 2000 watt inverter/charger was just enough to trip the EMS 20A load limit during those hot/humid conditions in June.


- - Mike
2013 Lounge EXT on 2012 Sprinter

[73shark]

On really hot days (>90*), I turn the inverter to charge only to reduce the current draw.