AC power

[Time2Tow]

We are cosidering buying a Rockwood 8296SS. Is the 13,500 btu AC enough or should we upgrade to the 15,000 btu? We live and camp in FL.
Thanks

[DAISY BOYKIN]

For what little it cost between the 13.5 BTU and the 15K BTU, upgrade.
If you are coming to Florida (I live here) UPGRADE, UPGRADE, UPGRADE !!!!!! I promise you that you will not be sorry.


Sid & HRH DAISY

[Time2Tow]

Originally Posted by DAISY BOYKIN

For what little it cost between the 13.5 BTU and the 15K BTU, upgrade.
If you are coming to Florida (I live here) UPGRADE, UPGRADE, UPGRADE !!!!!! I promise you that you will not be sorry.


Sid & HRH DAISY

Thank you for the input. We also live in FL, (Lutz which borders Tampa) and we were pretty sure that was the right way to go. Stay cool!

[Iggy]

Originally Posted by Thomas Kolessar

We are cosidering buying a Rockwood 8296SS. Is the 13,500 btu AC enough or should we upgrade to the 15,000 btu? We live and camp in FL.
Thanks

Yes the 15,000 BTU AC is a must!

[NWJeeper]

YES, upgrade. Beter to have it and not need it than not have it and wished you had.

We only ordered one AC on our rig when new as we do 90% of our camping in conditions that require heat and I didn't want to carry the weight or spend the money on a 2nd AC. After our maiden voyage to Arizona and Utah I was wishing I had gotten the 2nd one.

Go with the bigger AC, every time!

[Time2Tow]

Originally Posted by NWJeeper

YES, upgrade. Beter to have it and not need it than not have it and wished you had.

We only ordered one AC on our rig when new as we do 90% of our camping in conditions that require heat and I didn't want to carry the weight or spend the money on a 2nd AC. After our maiden voyage to Arizona and Utah I was wishing I had gotten the 2nd one.

Go with the bigger AC, every time!

I appreciate the advice. The decision has been made to go with the 15,000.
Thanks

[2manytoyz]

Too late, but I would have recommended the 13,500. Reason being, the 15K A/C unit requires a larger generator to run it. This may not ever be a concern for you if you don't boondock.

The Yamaha EF2400iS is the lightest, quiet series generator, capable of reliably running a 13,500 BTU A/C unit. The next sized generator, a 3KW, DOUBLEs the weight (70 lbs vs 140 lbs), and is still too small for the 15K A/C unit! Many have reported a 3.5KW generator is also too small.

I'm in FL also, and our camper is part of our evacuation plan, as is the generator.

2manytoyz - Yamaha EF2400iS Generator

[Iggy]

Originally Posted by 2manytoyz

Too late, but I would have recommended the 13,500. Reason being, the 15K A/C unit requires a larger generator to run it. This may not ever be a concern for you if you don't boondock.

The Yamaha EF2400iS is the lightest, quiet series generator, capable of reliably running a 13,500 BTU A/C unit. The next sized generator, a 3KW, DOUBLEs the weight (70 lbs vs 140 lbs), and is still too small for the 15K A/C unit! Many have reported a 3.5KW generator is also too small.

I'm in FL also, and our camper is part of our evacuation plan, as is the generator.

2manytoyz - Yamaha EF2400iS Generator

You are true that the 15K will draw more current but it is not much.
The NEW 15K pulls 16 amps and the 13.5K about an amp less. That is minor but if you have a generator close to max load already yes it is an issue. I predict that all roof AC on RV will be 15K soon.

[Time2Tow]

Thanks for the additional information. I do not use a generator when camping but I appreciate bringing this into the discussion. Getting different viewpoints is why I like these forums. Living in FL and having been through some close calls with hurricanes and losing power for a few days, I do now have a generator but never considered it and my camper as part of an evacuation plan. I actually considered it more of my back-up plan for a place to stay if the house got damaged. Since my generator is still in the box, I think I will check it for it'spower output. It is the peek of hurricane season.

[2manytoyz]

It's not about the running current, but rather the starting current. It takes upwards of 5 times the running current to start the compressor.

Most Ammeters are too slow to measure this. I purchased a Fluke meter, with an "In-Rush" feature.

Here's the actual startup current for my 13,500 BTU A/C unit:



Here's the running current once started:



Here's the tricky part, the generator manufacturers don't give you all the specs. But neither do the folks that make the products that plug into the generators.

My generator is 2400 Watts. 2400W for how long? 2000 Watts continuous. Hayes Equipment put a load on the generator, and reported it can handle a 3000W load for 10 seconds. How much can it handle for the split second needed to spin a motor? FWIW, the 2400W, 2800W, and 3000W Yamaha generators all use the same sized motor.

From my testing, my generator can handle a 50A load, but not a 53.8A load (my air compressor rated at 15A):



So it's already very near its limit. In that split second, the RPMs bump on the generator, the A/C EASILY starts, and the RPMs settle down to about 2/3 throttle. But when trying to start the air compressor, the compressor slowly rolls over, the generator grunts for 10 seconds, then finally indicates "overload".

My website is one of the very few that has actual testing of the Yamaha EF2400iS (I make nothing for this!). I've talked to literally thousands of people on this topic. Many I've talked with have tried unsuccessfully to run a 15K A/C unit with generators. Zero have had success with a 3KW or smaller generator.

[NWJeeper]

One Dometic owners manual I found showed a start up load for a 13.5K AC at 54 amps and for the 15K unit 71 amps. Running amps were very close however, less than 2 amps.

[2manytoyz]

Originally Posted by Time2Tow

Thanks for the additional information. I do not use a generator when camping but I appreciate bringing this into the discussion. Getting different viewpoints is why I like these forums. Living in FL and having been through some close calls with hurricanes and losing power for a few days, I do now have a generator but never considered it and my camper as part of an evacuation plan. I actually considered it more of my back-up plan for a place to stay if the house got damaged. Since my generator is still in the box, I think I will check it for it'spower output. It is the peek of hurricane season.

I learned my lesson in 1995. Hurricane Erin, a lowly Cat 1 storm, thumped us. No power for 3 days, trashed all my trees.



Then in 2004, Frances and Jeanne thumped us 3 weeks apart. We evacuated in our MH (had a 36' Class A back then) to GA, then returned afterwards. It ripped shingles off the roof, but the paper was still intact. The roof was temporarily patched, then Jeanne showed up 3 weeks later. We stayed for that one. The patch held, but more shingles ripped off, pouring water into the master bedroom. I patched the damage the next day. No power, so we stayed in the MH for a few days, running the generator, living in comfort.

Coworkers in the nearby area, were without power for 18 days. One had a conventional generator, which consumes about 1.5 gallons per hour. The other had a Honda 2KW, which consumes about 1 gallon every 8 hours. Mine present generator consumes about 1.5 gallons every 8 hours or 4.5 gallons per day (1/4 load). A little math...

18 days x 24 hours x 1.5 gallons = 648 gallons!

18 days, x 4.5 gallons per day (Yamaha) = 81 gallons.

A conventional generator runs at a constant speed to make 60Hz. An inverter type generator makes 60Hz electronically from idle. The motor only runs as fast as the load demands, which can significantly reduce the fuel consumption.

During an outage at home, I will run 2 refrigerators, and a 5000 BTU A/C unit (window shaker) to cool one room. Not enough resources to cool an entire house. But I can make a single room 72 degrees, even in the middle of a FL Summer!

Measured #s:

Each fridge running ~140W-150W, defrost cycle ~600W
5000 BTU A/C unit running ~600W

So for the most part, my generator runs my critical loads from idle (1/4 throttle). Whisper quiet at 53 dB, very thrifty on resources. When storms approach, I fill ten 5 gallon gas cans. If those run out, we leave!

I tell you the story of my two coworkers as that was the lesson that convinced me to part ways with conventional generators (I had a Coleman 4200W), and now have the smaller Yamaha EF2400iS. It not only takes care of the camper, but also emergency power at home.

Didn't want to hijack the thread, but thought you might find the info useful.

[Iggy]

Why are you bring up electrical theory when all was asked if he should get a 13.5K AC unit or a 15K unit. I have a electrical degree and have been in the business for over 42 years so please it is not necessary to explain starting amp and running amps to me.
Thanks for a great demo with pictures.

[NWJeeper]

Thanks Robert and your story brings a good point to light about buying generators. The difference in cost of gas over a period of time will pay for that more expensive Yamaha or Honda generator vs buying an auto parts store cheapo (loud) generator which are usually not any where near the same quality either.

[2manytoyz]

Originally Posted by NWJeeper

One Dometic owners manual I found showed a start up load for a 13.5K AC at 54 amps and for the 15K unit 71 amps. Running amps were very close however, less than 2 amps.

That's great, some useful (to me) numbers! I couldn't find anything on the 15K unit, so I appreciate the info.

A hard start kit will help spin an A/C unit that's marginal by phase shifting, but wouldn't help with the 15K unit. That's a big difference in start up current!

[2manytoyz]

Originally Posted by Iggy

Why are you bring up electrical theory when all was asked if he should get a 13.5K AC unit or a 15K unit. I have a electrical degree and have been in the business for over 42 years so please it is not necessary to explain starting amp and running amps to me.
Thanks for a great demo with pictures.

I bring it up because you said: "You are true that the 15K will draw more current but it is not much. The NEW 15K pulls 16 amps and the 13.5K about an amp less. That is minor but if you have a generator close to max load already yes it is an issue."

Again, running current isn't the issue. Starting current is. If he ever plans on running his A/C unit on a generator, the size of the A/C unit matters!

I didn't bring up theory, I showed you ACTUAL numbers. That's the problem with most discussions, lots of theories, very few facts.

There's no telling who the audience is, nor who the person talking is. I've been in the business a while too. And 'twasn't a lesson for you, but rather the OP, or anyone else considering a 13.5K vs 15K. The idea of getting a tad more cooling now sounds great. But having to lug around a $2K generator @ 200 lbs, might be an issue later if wanting to visit BLM land, or having to bail out during storm.