jjrbus Posted August 29, 2015 Share Posted August 29, 2015 Got around to trying the Dometic 11,000 BTu Roof air on the Honda EU2000i. The roof air is an older Dometic model #57912.602 it is an R22 unit that has an LRA of 48.3 and 5.8 running amps. This is similar to the most efficent unit out there the Mach 1 PS It is 92° out with 68% humidity and I am on a hill so about 9 feet elevation. The Honda would start and run this AC in cooler weather and the unit works well on shore power. The Honda will start and run the AC for about 10 minutes then goes into overload, did that 3 times. I have already added a soft start capacitor. Not sure IF I should think the roof air is old and not that efficent or if it is old and more efficent than new ones?? I do not have the equipment nor the knowledge to run any tests. Need to pursue other options, just not sure whcih way to go? Any thoughts, ideas, links, information, suggestions or wisecraks greatly appreciated. Jim Broiling in SW FL Quote Link to comment Share on other sites More sharing options...
zero Posted August 29, 2015 Share Posted August 29, 2015 I wouldn't expect a 1600 watt generator to run an AC unit like that (but I've wrong before). Even with the cap-kit I bet you it draws 25 amps at first start. That's 3000 watts and near twice what your generator has for a momentary surge rating. And note that's 25 amps IF the voltage stays at 120. If it dips to let's say 110 - the amps get up to 27-28 amps. Probably the cheapest way to diagnose what is going on is to go to Walmart and buy a Killowatt meter. It will tell you how much surge the AC unit is pulling and how much voltage the little Honda generator is maintaining. Handy and cheap unit to have - even if you don't have an AC problem. Quote Link to comment Share on other sites More sharing options...
Totem Posted August 29, 2015 Share Posted August 29, 2015 I warned you on the Honda... unless eu3000 the lower rated ones can't hack it for long. My cousins would only even start it when out of economy mode.... Quote Link to comment Share on other sites More sharing options...
PapaFred Posted August 29, 2015 Share Posted August 29, 2015 Tried running 13.5btu ac today with champion 3100 on Eco mode. It started it and ran it! Couldn't believe it. Would have lost that bet! Quote Link to comment Share on other sites More sharing options...
jjrbus Posted August 30, 2015 Author Share Posted August 30, 2015 Trying to sort through it all and choose the best option. On my last motorhome I could start and run a 13.5K BTU roof AC with a EU2000i. Not in the summer in FL! Should not work but it did. I do not see anyplace to put a 3K Honda on my toy or 2 2000K. Other than a back hitch mount which eliminates the advantage of a 21' home. A 9K mini split seems like an answer, but I do not see any feasible way to mount and install it? I am still pursuing the 8000 btu window AC to roof air mod. Will attempt that if I can find a cheap one to experiment with. Thanks for the input Jim SW FL Quote Link to comment Share on other sites More sharing options...
zero Posted August 30, 2015 Share Posted August 30, 2015 Seems to me you're kind of "pissing into the wind" until you ascertain which component is guilty. Is the AC drawing more then that Honda could ever possibly handle, or is the Honda genset putting out less then it should? A quick check with that cheap Killowatt meter will give you the answer. Quote Link to comment Share on other sites More sharing options...
WME Posted August 30, 2015 Share Posted August 30, 2015 FYI. My Escaper has a Onan 2800. I live around 5000 ft. A generator LOSES about 3.5% of its power rating for each 1000 ft above 500 ft. It loses about 1% per 10 degrees above 85 degree. So a 100 degree day at this altitude I'm down about 500 w. My 2800 would not reliable run the 13.5k AC. It would after I installed the starting cap booster. At my favorite 9000 ft fishing lake nope no deal. So based on this I would say you need at least 2500w for a stock 13.5k AC near sea level. On a vacaton here in the Rockies fer get about it with your under 3000w generator. i Quote Link to comment Share on other sites More sharing options...
jjrbus Posted August 30, 2015 Author Share Posted August 30, 2015 It is rather trying to sort through this. Most people do not include any details when they say something works. Elevation, tempature, humidity, brand of AC age of AC. I am going to try a 8000 btu window AC wed, it will be over 90° with high humidity. I would like to sort this out before the hot humid weather ends in a few weeks! I might pick up a Kilawatt meter in the meantime and tinker with that. I am hesitant to try it on my Honda and roof air again as I am concerned about damageing the Honda. I am also watching for a 2.8K genny, I would not be a happy camper with it but it may be the best option?? Thanks for the input. Jim Quote Link to comment Share on other sites More sharing options...
fred heath Posted August 30, 2015 Share Posted August 30, 2015 Jim, If my memory serves me correctly, your generator compartment is configured for the Microlite 2800. That may be the way to go. Quote Link to comment Share on other sites More sharing options...
zero Posted August 30, 2015 Share Posted August 30, 2015 FYI. My Escaper has a Onan 2800. I live around 5000 ft. A generator LOSES about 3.5% of its power rating for each 1000 ft above 500 ft. I wonder if that is true with all portable generators? Seems to be it would not always be the case. Any gas or diesel engine loses that much power as altitude climbs IF it has no supercharger on it (exhaust or mechanically driven). But the generator head works the same IF it can turn the rated speed. Seems to me power loss depends on what engine is matched to what generator head. If an engine is running at absolute max power output to make max watts - then yes. But if it has more engine then they needed it can afford to lose 10-15% engine power and still make rated wattage. At least the big ones. With portables or small ones - I don't know. With something like a Honda inverter unit - I don't even know what RPM it is supposed to run make max power since RPM is not needed to make the 60 Hz sine wave. I know some of the gensets I've had are either slightly underpowered or overpowered. I tend to rate them by watts per ccs of engine. The lower the number, the more reserve power usually. I have an older Coleman Pulse 1850 that has more power then it needs and I don't think it would suffer much at a high elevation. Look at the numbers and you can see why. Very noisy though. Honda (old) EM650 - 7.2 watts per cc Honda EU2000i - 16.1 watts per cc Hyundai 2000i - 16 watts per cc ETQ inverter 1800 - 16.1 watts per cc Onan Microlite 2.8 - 14.2 watts per cc Champion inverter 2000 - 21.2 watts per cc Coleman Pulse 1850 - 11.8 watts per cc Quote Link to comment Share on other sites More sharing options...
WME Posted August 30, 2015 Share Posted August 30, 2015 Like you said ALL NA engines lose power at altitude. What happens is that the generator rated output is matched closely to the engine HP. If you lose HP then the engine won't pull full rpm at rated load and the generator loses RPM and voltage Quote Link to comment Share on other sites More sharing options...
DanAatTheCape Posted August 30, 2015 Share Posted August 30, 2015 my 2000 will start and run a newer 13.5k ac at sea level. I do not run it more than 30 minutes as per my math it is drawing nearly the full 2000watts and after 30 minutes the 2000i derates to 1600 watts. It grunts and the overload light flashes but it does it. I do not do it too often either. My gen has about 800 hours on it now - still going strong. If i was going to make it a habit I would get a 9000btu with a strong start capicator Quote Link to comment Share on other sites More sharing options...
jjrbus Posted August 30, 2015 Author Share Posted August 30, 2015 The 11K Mach one is more efficient than the 9K! Will pull 1000 watts on low. Quote Link to comment Share on other sites More sharing options...
Maineah Posted August 31, 2015 Share Posted August 31, 2015 As the ambient temp increases the compressor head pressure rises making it even harder to start the AC unit. Be advised the Killawatt meters are only rated for 1800 watts. Quote Link to comment Share on other sites More sharing options...
zero Posted August 31, 2015 Share Posted August 31, 2015 As the ambient temp increases the compressor head pressure rises making it even harder to start the AC unit. Be advised the Killawatt meters are only rated for 1800 watts. I "killed" my Killowatt meter once but it took 30 amps over a full second of time. Has a little slow blow fuse inside. It won't read 20 amps but can carry it. Not the greatest tool when trying to ascertain if the gen or the AC is the culprit though. This one is just as cheap and handles over 200 amps of current. Quote Link to comment Share on other sites More sharing options...
davidtan Posted September 1, 2015 Share Posted September 1, 2015 My Atwood 13.5 AC unit arrived today. It is advertised by Atwood that it is designed to run on a 2000 watt generator. I bought the champion 3100 and also found that there is no place to store it. I will have the ac installed this week and pick up the Honda EU2000i and let everyone know the result.... pretty stoked to see it all work Quote Link to comment Share on other sites More sharing options...
jjrbus Posted September 2, 2015 Author Share Posted September 2, 2015 What is your model # Only one I can find shows 63 LRA. Quote Link to comment Share on other sites More sharing options...
jjrbus Posted September 2, 2015 Author Share Posted September 2, 2015 ???? 16,000 BTU on a 2000 watt genset??? I am skeptical at best. But here is the link. http://www.atwoodmobile.com/images/air-conditioners-brochure.pdf There is a little disclaimer there of 16,000 BTU equivalent, what ever that means? Quote Link to comment Share on other sites More sharing options...
Totem Posted September 2, 2015 Share Posted September 2, 2015 what was the price on that baby>? (atwood) Quote Link to comment Share on other sites More sharing options...
davidtan Posted September 3, 2015 Share Posted September 3, 2015 525 with the coach vent and remote + 45 bucks for shipping (got it on my12voltstore). They are installing right now. I should test it on Saturday and let everyone know. I was skeptical too , but its on their website and that is that their selling point Quote Link to comment Share on other sites More sharing options...
shibs Posted September 3, 2015 Share Posted September 3, 2015 525 with the coach vent and remote + 45 bucks for shipping (got it on my12voltstore). They are installing right now. I should test it on Saturday and let everyone know. I was skeptical too , but its on their website and that is that their selling point link pls. Thanks, Quote Link to comment Share on other sites More sharing options...
jjrbus Posted September 3, 2015 Author Share Posted September 3, 2015 I will be patiently waiting and looking forward to the results. Jim Quote Link to comment Share on other sites More sharing options...
zero Posted September 3, 2015 Share Posted September 3, 2015 ???? 16,000 BTU on a 2000 watt genset??? I am skeptical at best. But here is the link. http://www.atwoodmobile.com/images/air-conditioners-brochure.pdf There is a little disclaimer there of 16,000 BTU equivalent, what ever that means? I'm curious to see what happens. Honda 2000i is NOT a 2000 watt generator though. So if it doesn't work, guess you can't blame Honda? Quote Link to comment Share on other sites More sharing options...
jjrbus Posted September 3, 2015 Author Share Posted September 3, 2015 I have been surfing the net and can not find one person that tried to run this unit on 2⃥0⃥0⃥0⃥ opps 1600 watt Honda. Good point on the Honda not being a 2000 watt genset, went right over my head! Also Atwood is not being real open with the spec's on this unit. The only LRA rating I could find was 63, which cannot be right. Super great price on the unit from my12Vstore, the only local ones here are almost $800 from camping world and a 1 year old one for $600. I played with a 10k btu window unit yesterday, the little Honda will start and run it with no issues, it was 92 yesterday with high humidity. It does idle up when the compressor starts. My concern with the window units is the CFM, most are rated around 200 cfm and most roof airs are around 300. I believe where this would only be an issue in the initial cool down. Also roof airs do not list moisture removal, so cannot compare. I though about running the Toy with the AC on with the small AC for initial cool down Harbor Freight has a clamp on ammeter for under $20, now just need to go buy it, wondering if they will show LRA and not just running amps? Jim Quote Link to comment Share on other sites More sharing options...
Maineah Posted September 3, 2015 Share Posted September 3, 2015 Check the little * in the specs for the AC unit. I have been surfing the net and can not find one person that tried to run this unit on 2⃥0⃥0⃥0⃥ opps 1600 watt Honda. Good point on the Honda not being a 2000 watt genset, went right over my head! Also Atwood is not being real open with the spec's on this unit. The only LRA rating I could find was 63, which cannot be right. Super great price on the unit from my12Vstore, the only local ones here are almost $800 from camping world and a 1 year old one for $600. I played with a 10k btu window unit yesterday, the little Honda will start and run it with no issues, it was 92 yesterday with high humidity. It does idle up when the compressor starts. My concern with the window units is the CFM, most are rated around 200 cfm and most roof airs are around 300. I believe where this would only be an issue in the initial cool down. Also roof airs do not list moisture removal, so cannot compare. I though about running the Toy with the AC on with the small AC for initial cool down Harbor Freight has a clamp on ammeter for under $20, now just need to go buy it, wondering if they will show LRA and not just running amps? Jim No cheap clamp meter will not read inrush with any accuracy if at all. Mine is a Fluke 374 (around $300) I don't know about the AC unit you are looking at but maybe a good guess on a generator would be the MOP rating at least that is what can happen. Quote Link to comment Share on other sites More sharing options...
zero Posted September 3, 2015 Share Posted September 3, 2015 I have been surfing the net and can not find one person that tried to run this unit on 2⃥0⃥0⃥0⃥ opps 1600 watt Honda. Good point on the Honda not being a 2000 watt genset, went right over my head! Also Atwood is not being real open with the spec's on this unit. The only LRA rating I could find was 63, which cannot be right. Super great price on the unit from my12Vstore, the only local ones here are almost $800 from camping world and a 1 year old one for $600. I played with a 10k btu window unit yesterday, the little Honda will start and run it with no issues, it was 92 yesterday with high humidity. It does idle up when the compressor starts. My concern with the window units is the CFM, most are rated around 200 cfm and most roof airs are around 300. I believe where this would only be an issue in the initial cool down. Also roof airs do not list moisture removal, so cannot compare. I though about running the Toy with the AC on with the small AC for initial cool down Harbor Freight has a clamp on ammeter for under $20, now just need to go buy it, wondering if they will show LRA and not just running amps? Jim I've got three cheap clamp-meter . Mine are analog which I prefer. All were in the $20 price range and all show any amps flowing. No matter if it's from a running motor, a starting motor, or a locked motor. It's all about response time. I tried a few digital meters a few years back and their read-response time was too slow to read a high surge that only lasted a fraction of a second. Maybe now they've gotten better? Some of the better units have a function that records the highest reading which is a nice feature. The drawback to clamp-on meters is you need a way to just clamp onto one conductor. If you just clamp it over a power-cord with two conductors - you get no reading. Easy work-around is just make yourself a short extension cord and separate the conductors in one spot. Quote Link to comment Share on other sites More sharing options...
zero Posted September 3, 2015 Share Posted September 3, 2015 Check the little * in the specs for the AC unit. No cheap clamp meter will not read inrush with any accuracy if at all. Mine is a Fluke 374 (around $300) I don't know about the AC unit you are looking at but maybe a good guess on a generator would be the MOP rating at least that is what can happen. MY $20 analog meter reads in-rush current just as well as my $200 Klien digital. That with normal house current from the power company. Now - if I was messing with power from a portable generator or an inverter - I'd trust my Klien more. That because the el-cheapo meters use an "average RMS" reading, where as my pricey Klien uses "true RMS" and is more accurate when measuring voltage or current with "imperfect" sine-waves. In fact - my $4 voltmeter from Harbor Freight will read a 92 volt output on my 3000 watt inverter (so-called "true sine wave" although it is not). My Klien or my Extech RMS meters read that same output as 120 volts. Again - biggest problem I have reading surge current is the response time of the meter. Cheap digitals are usually way to slow. Never had that problem with a cheap analog. Quote Link to comment Share on other sites More sharing options...
davidtan Posted September 12, 2015 Share Posted September 12, 2015 So , the results are in. Installed the Atwood Command air 13.5 (they sent me 4 units - 2 broken in shipping , 1 actually working unit , and another by mistake . Wherever they are shipping out from needs to package them better. The boxes show up all ripped and banged up). I borrowed a Yamaha MZ80 2000 watt generator from a friend and tried starting it up. NO GO. The generator just kept dying whenever the compressor kicked in. So that sucked. I called a Honda generator store to see if I could test the RV ac right there in their store and said it was OK, but they said it was too small too for a 13.5 ac unit. I got to the Honda store and we plugged it in . The Atwood is kinda weird because it runs for around 3 minutes on fan only to cool down all the hear exchangers before the compressor kicks in. Then the compressor kicked in and walla , the Honda kept going. Upon reading the specs, the Honda has a 98 cc engine while the Yamaha had a 79 cc engine . Both rated at 2000 surge watts , 1600 running , but I guess the Honda has more torque to keep going on the surge. Mystery put to rest, a Honda EU2000i will start a Atwood 13.5 command air. I even tried turning on the fridge and it did not even bog. Good times Quote Link to comment Share on other sites More sharing options...
Totem Posted September 12, 2015 Share Posted September 12, 2015 So, did it run it in eco mode or non eco? Quote Link to comment Share on other sites More sharing options...
jjrbus Posted September 12, 2015 Author Share Posted September 12, 2015 I'm impressed, what was your ambient temperature and humidity? Jim Quote Link to comment Share on other sites More sharing options...
davidtan Posted September 14, 2015 Share Posted September 14, 2015 Non - eco mode, I did not try the eco mode just because the guy at store said outright that was more for light loads. You can hear the engine surge when the AC goes on and then it resumes its idle. Very quite and light genset. It was 90 degrees outside. Got the inside temp to 73 in 30 minutes. Not sure what the humidity was (NorCal). Also the noise level of the Atwood is very impressive . Very quite operation. Quote Link to comment Share on other sites More sharing options...
Totem Posted September 14, 2015 Share Posted September 14, 2015 That doesn't quite add up to me... in non eco mode the unit will go full throttle all the time; not idle. Since its running full blast in non eco it doesn't have to spool up to meet the load and risk overload mode which then shuts off the output. Eco mode is electronic throttling based on need; and on my cousins eui2000 it would not run in it. So basically, the non eco mode means you are operating in the upper bounds of the unit; and that you will need to keep the AC unit on full blast at lowest temp setting; otherwise on the next cycle the compressor and its frost covered workings will require even more power potentially (depending on humidity and elevation). Its still good to know but people should be aware that you really want a 3000 + unit to run these things proper. even my 2500 predator is underpowered. Quote Link to comment Share on other sites More sharing options...
jjrbus Posted November 18, 2015 Author Share Posted November 18, 2015 For anyone that is interested I needed to run the Honda dry today so out of curiosity hooked it up to the Toy. It is 86° out and 63% humidity, Toy is in full sun. The little Honda started and ran the AC for about 45 minutes till it ran out of gas. No strain, no hesitation, worked well. So my experience is the Honda will not run a 11K btu roof air in hot humid weather but will do fine in warm weather. I am in FL so this is at sea level. The issue here is I live in FL I do not consider 86 hot. Matter of fact when it is 60 out I am cold, this from a Buffalo boy. Jim Quote Link to comment Share on other sites More sharing options...
Derek up North Posted November 18, 2015 Share Posted November 18, 2015 86° is hot for me. Even in the Summer. Currently 37° here. Just right for cutting, splitting and stacking firewood. Heat wave tomorrow: 50° Quote Link to comment Share on other sites More sharing options...
jjrbus Posted November 18, 2015 Author Share Posted November 18, 2015 When it was 50° out in Buffalo I would be out in T shirt and shorts, washing my car Quote Link to comment Share on other sites More sharing options...
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