Air Conditioning On Generator

[uncle_bob]

Hi

Backing off a bit, generators are rated in terms of surge and in terms of constant run power. They also have rated ability to handle power factor. When a motor is starting up (like the AC compressor) it's not a constant run sort of load. The 2.8 KW is close enough to 3 to do the job just fine. it's the 2.5 that isn't quite up to the task.

Bob

[3bcamper]

Originally Posted by Boxster1971

Yes - there is a 3,000 Watt diesel generator that will fit under the Sprinters. It is made by Power Tech Generators in Leesburg, FL:
https://www.powertechgenerators.com/...ter-van-rv-3kw

Here is a company selling them in Colorado for about $6,000, plus $2,000 to install it:
http://sprintergenerator.com/

They are a little larger than the Onan LP generators installed by Airstream in the Interstate vans.

The phone apps do tell you which sub-forum your are responding to, but it doesn't jump out at your. The slightly off-topic comments we get from trailer and larger motorhome owners usually come because they use the "Unread" feature on phone apps or the "New Posts" featured on the Air Forums web page.

I like the idea of the diesel and additional wattage, but $8,000 for an additional 500 watts? Holy schneikies! Would one get more torque with the diesel gen? Also, it seems that if one did that upgrade, the the propane tank could be downsized substantially. Why haul around such a large tank?

[Boxster1971]

Originally Posted by uncle_bob

Hi

Backing off a bit, generators are rated in terms of surge and in terms of constant run power. They also have rated ability to handle power factor. When a motor is starting up (like the AC compressor) it's not a constant run sort of load. The 2.8 KW is close enough to 3 to do the job just fine. it's the 2.5 that isn't quite up to the task.

Bob

... and the Onan LP generator on the Airstream Interstate and many other B-vans is only rated at 2.0 KW. However the surge capacity on these generators is enough to start the A/C compressor, but there is no margin for anything else. Plus Airstream installs the Power Control System (PCS) that will not allow you to utilize the power that the generator can make. Thus this creates the power cycling mode that many Interstate owners, including myself, have experienced. The PCS is a good thing as it avoids tripping circuit breaker, but the setting for “GEN” mode does not match the generator they install.

[Boxster1971]

Since we are back into a HOT summer I thought I'd add once again that if you are having trouble running Air Conditioning (A/C) on the generator the problem might not be the generator or the A/C unit.

Some have suggested adding an "Eazy Start" mod to the A/C unit. That is expensive, requires climbing on roof and may not be needed.

The Aistream installed Power Control System (PCS) may be the real issue.

Yesterday in 99degF temps I once again determined that the problem, at least on my Interstate, is the PCS . I started the generator and ran the A/C for over 30 minutes with no issues during grandson's Little League baseball game. This worked because I disabled the PCS, it can be disabled by turning off the 120VAC circuit beakers for the Microwave and Receptacles. Turning off those breakers causes the PCS panel to go blank and no longer control 120VAC power distribution.

Just before I turned off the A/C and generator I turned the PCS back on. It briefly displayed a 15A load and then immediately shut down the A/C. The generator can put out 20+Amps and can easily handle the A/C load variations.

Just another lesson learned in the never ending saga of RV ownership.

[UKDUDE]

Here’s another issue I’ve recently discovered while we’re on this cross-country and top to bottom trip:
Whilst dry parked for the night and having inevitably used some of the battery capacity, my wife often asks to use the microwave; so I start the generator and find that it’s taking perhaps 7-8 amps to bulk charge the batteries, with not enough generator capacity to run the microwave; it could be a 30 minute wait before it moves to absorb mode and she can run the microwave!

[Pahaska]

UKDude ... set the Magnum charge rate at 50% rather than the default 100%. That cuts the charger draw in half. I leave it at 50% all the time unless I really pull my batteries down and need a quick charge.

You can even cut it down to 10% temporarily.

[Boxster1971]

Originally Posted by Pahaska

UKDude ... set the Magnum charge rate at 50% rather than the default 100%. That cuts the charger draw in half. I leave it at 50% all the time unless I really pull my batteries down and need a quick charge.

You can even cut it down to 10% temporarily.

It might be easier to just put the Magnum into "Charger Standby" mode. Here is Manual page how to do it.

[Titus]

Boxster,
Thanks for the reminder about charger standby - much easier than temporarily decreasing the charge %.

Can you please explain more about the PCS solution. Is the PCS the same as what the AI OM calls the EMS? I understand how tripping the breakers removes the potential AC loads of the microwave, receptacles (and water heater), but how does that blank out the PCS (EMS?) panel? Aren't those beakers downstream of the panel, and how would the panel know if they are on or off? Fortunately, I have never had a problem running the AC with the breakers on (but without any loads besides the AC)

[UKDUDE]

Originally Posted by Boxster1971

It might be easier to just put the Magnum into "Charger Standby" mode. Here is Manual page how to do it.

Thank you Boxster, I hadn’t spotted “Charger Standby” mode in the manual and since I’m not relying on the generator to top up the batteries on this trip - we’re driving most days - then it’s perfect for running the microwave or AC on the spot as needed.

[UKDUDE]

Originally Posted by Pahaska

UKDude ... set the Magnum charge rate at 50% rather than the default 100%. That cuts the charger draw in half. I leave it at 50% all the time unless I really pull my batteries down and need a quick charge.

You can even cut it down to 10% temporarily.

Thanks Pahaska. It used to be set at 50% - I think that setting came from Airstream - but Lew set it to 100% when he upgraded my batteries a while back.

[Boxster1971]

Originally Posted by Titus

Boxster,
Thanks for the reminder about charger standby - much easier than temporarily decreasing the charge %.

Can you please explain more about the PCS solution. Is the PCS the same as what the AI OM calls the EMS? I understand how tripping the breakers removes the potential AC loads of the microwave, receptacles (and water heater), but how does that blank out the PCS (EMS?) panel? Aren't those beakers downstream of the panel, and how would the panel know if they are on or off? Fortunately, I have never had a problem running the AC with the breakers on (but without any loads besides the AC)

Yes - Airstream calls it the Energy Management System (EMS) in the manual. The control panel is clearly marked as Power Control System (PCS). Just another attempt by Airstream to further confuse the owners. Copy of 2015 manual page attached for info as it much better than the useless 2013 manual.

If you are not having any issues running the A/C off the generator then I wouldn't recommend doing anything. As the manual says the EMS/PCS prevents you from overloading the generator and tripping the circuit breaker on generator. Resetting that requires climbing under the van - not easy. You could overload the generator as it can only power the A/C and little else.

The breakers I first mentioned provide power to the EMS and when they are off the EMS is disabled. I only do this when I need the A/C on generator power. The generator can safely provide 20A, but my EMS shuts down the A/C when the displayed generator load is 15-18A. I researched the EMS/PCS technical documentation on the Precision Circuits Inc web site and found the the generator setting are made at the factory for various types of generators. Maybe mine is set wrong? I just know it doesn't work right when using the generator.

[Alex AVI]

Originally Posted by Boxster1971

Yes - Airstream calls it the Energy Management System (EMS) in the manual. The control panel is clearly marked as Power Control System (PCS). Just another attempt by Airstream to further confuse the owners.

The breakers I first mentioned provide power to the EMS and when they are off the EMS is disabled.

MIKE - so true on the confusing terminologies. So frustrating. While I am not having issues running A/C on my gen, thank you for the tip about the ckt breaker. One can never tell when it may come in handy. In my case, I often take the AI to elevation above 8,000ft. And generators are known to hate thin air, so if it compensates the power demand and draw higher current, your tip may come in handy. Of course, at 8,000 ft. I rarely have to use the A/C even when the Las Vegas valley is boiling at 110, so hopefully will not need to execute this workaround.

[Boxster1971]

Resurrecting an old thread.... I just installed a Micro-Air EasyStart on my Interstate. It helps reduce the A/C startup current draw on shore power. But now on generator it shuts down the A/C compressor shortly after it starts. The generator could run the A/C OK before I installed the EasyStart. Very disappointing.

I'm working with Micro-Air customer support now to try to get it working.

Any Interstate owner's out there who have installed the EasyStart device and had it work with generator on their Interstate?

[Al and Missy]

The Easy Start "learns" the combination of your AC and the power you are using. It may be that the power from your generator is different enough that you need to "teach" your easy start on the generator.


I don't have an Interstate, but my unit trained on shore power and worked fine on my Honda 2000.


Al




Al

[NavyCorpsman]

Watch the voltage. Prolonged running at LESS than 110 volts will kill the compressor. Another case where bigger is better. Genset and extension wiring.

[Boxster1971]

Originally Posted by Al and Missy

The Easy Start "learns" the combination of your AC and the power you are using. It may be that the power from your generator is different enough that you need to "teach" your easy start on the generator.

I don't have an Interstate, but my unit trained on shore power and worked fine on my Honda 2000.

Al

Today I ran the A/C using a rented Honda EU2000i generator, as recommended by Micro-Air for troubleshooting. It ran fine, but since I had to plug generator into normal shore power plug the Mini-PCS (Power Control System) treated this external generator as an external shore power source.

Airstream Interstate Sprinter vans have this Mini-PCS that is designed to prevent tripping circuit breakers.

https://precisioncircuitsinc.com/pro...-wh-ac-2-ac-1/

The power from generator is not much different than shore power, but it is handled differently by the Mini-PCS.

I suspect the Mini-PCS is interfering with running the A/C on the generator. I had some trouble with this before I installed the EasyStart. Before installing the EasyStart the A/C would pull about 40A momentarily on compressor start, then the Mini-PCS would just dump the whole load and initiate a restart delay of 2 minutes. Then I would disables the Mini-PCS and A/C ran OK.

Now with the EasyStart installed the startup current is only about 14A and Mini-PCS keeps the power on the coach, but just stops the compress and fan keeps running. The Mini-PCS gets an input from the generator so it knows when on generator power and is designed to prevent overloading the generator. I've seen as high as 19A on the Mini-PCS display just before it shut down the compressor. This is likely close to the cutoff designed into the Mini-PCS to prevent generator overload.

[Boxster1971]

Originally Posted by NavyCorpsman

Watch the voltage. Prolonged running at LESS than 110 volts will kill the compressor. Another case where bigger is better. Genset and extension wiring.

I have a Progressive EMS to monitor the power, voltage never went below 110V.

[gypsydad]

Originally Posted by Boxster1971

Resurrecting an old thread.... I just installed a Micro-Air EasyStart on my Interstate. It helps reduce the A/C startup current draw on shore power. But now on generator it shuts down the A/C compressor shortly after it starts. The generator could run the A/C OK before I installed the EasyStart. Very disappointing.

I'm working with Micro-Air customer support now to try to get it working.

Any Interstate owner's out there who have installed the EasyStart device and had it work with generator on their Interstate?

I did not see mention of what brand/size generator you were using with the Easystart? I know my Champion 2000 would not work after talking with Mateo, so I purchased a larger DualFuel 3400 and it works fine, and no Easystart needed.It is just 90lbs.....

I believe there are Yamaha, Honda, and perhaps one or two more 2000 series that Mateo said they tried and worked fine with the Easystart. I would suspect with your Interstate, you are looking for small and lightweight generator, so the Honda or Yamaha 2200 should work fine especially with the Easystart...

I did try my friends new Honda 2200 with the propane conversion on my AC last summer without the Easystart, and the 13500 worked fine even when I cycled it, but the 1500 AC struggled.

[Boxster1971]

Originally Posted by gypsydad

I did not see mention of what brand/size generator you were using with the Easystart? I know my Champion 2000 would not work after talking with Mateo, so I purchased a larger DualFuel 3400 and it works fine, and no Easystart needed.It is just 90lbs.....

I believe there are Yamaha, Honda, and perhaps one or two more 2000 series that Mateo said they tried and worked fine with the Easystart. I would suspect with your Interstate, you are looking for small and lightweight generator, so the Honda or Yamaha 2200 should work fine especially with the Easystart...

I did try my friends new Honda 2200 with the propane conversion on my AC last summer without the Easystart, and the 13500 worked fine even when I cycled it, but the 1500 AC struggled.

Hi GYPSDAD,
I don't want to offend anyone - but Airstream trailer owners who make comments in threads inside the Sprinter and B-Van Forum need to be aware that what they think works or applies to their trailers often does not apply to the Airstream B-vans. They are Interstate Sprinters, older Ford van B-190's and the Chevrolet van Avenue.

All these Airstream B-vans have built-in generators installed by Airstream. The Ford and Chevy vans used a gasoline version of the Onan 2800 watt generators. The newer Sprinters all have the Onan LP 2500 watt generators.

The Interstate Sprinters with the Onan LP generators also have a Power Control System (PCS) that is designed to shed loads and thus avoid tripping circuit breakers when you run more than the capacity of shore power or generator. The PCS has three modes; 30A and 20A shore power, plus generator. I'm now fairly certain the problems I'm having is the PCS load shedding of the A/C compressor when the load approaches the set internal limit of 20A. I'm planning another day of testing to confirm my conclusion.

I'm working with Roger from Micro-Air and they have been fairly helpful, but they don't understand the complexity of the Airstream Interstate generator system with the load shedding PCS.

As an aside I read somewhere that Mateo is no longer at Micro-Air. The "Micro-Air" commercial member on this forum has not posted on this forum since last November.

[gypsydad]

Originally Posted by Boxster1971

Hi GYPSDAD,
I don't want to offend anyone - but Airstream trailer owners who make comments in threads inside the Sprinter and B-Van Forum need to be aware that what they think works or applies to their trailers often does not apply to the Airstream B-vans. They are Interstate Sprinters, older Ford van B-190's and the Chevrolet van Avenue.

All these Airstream B-vans have built-in generators installed by Airstream. The Ford and Chevy vans used a gasoline version of the Onan 2800 watt generators. The newer Sprinters all have the Onan LP 2500 watt generators.

The Interstate Sprinters with the Onan LP generators also have a Power Control System (PCS) that is designed to shed loads and thus avoid tripping circuit breakers when you run more than the capacity of shore power or generator. The PCS has three modes; 30A and 20A shore power, plus generator. I'm now fairly certain the problems I'm having is the PCS load shedding of the A/C compressor when the load approaches the set internal limit of 20A. I'm planning another day of testing to confirm my conclusion.

I'm working with Roger from Micro-Air and they have been fairly helpful, but they don't understand the complexity of the Airstream Interstate generator system with the load shedding PCS.

As an aside I read somewhere that Mateo is no longer at Micro-Air. The "Micro-Air" commercial member on this forum has not posted on this forum since last November.

Understand; forgot the Interstate is not a TT...Thanks for the update and comments! Mateo was pretty sharp and responsive...wish him well.