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AC and generators.

grizz272
Explorer
Explorer
The new fifth-wheel has a 15K btu AC on it. What size generator do I need to run that thing when we are boondocking?
16 REPLIES 16

ktmrfs
Explorer
Explorer
Atlee wrote:
This is why I have 2 2K Hondas. Together, they will power the AC and micro. If I don't need AC, I only have to run one. And I can handle one 2k genny at a time. However, I could never move the 3k machine alone.

Ltrip wrote:
I just went through this decision process. Your priorities may be different than mine.
I considered the 3500W units and 2 2000W units.
At age 68 I was concerned about moving the 3500W unit. Also, there are times when you don;t need to run the air, so the 3500W is overkill for other uses.
I opted for 2 Champion 2000W units. I can carry the 49 lb unit pretty easily and it pairs up to create a 4000W unit, enough to run the AC.
Upon receipt, 1 of them started and ran perfectly. The other is in the shop for a warrantee fix of leaking gas. I have not used them yet on a camping trip. But soon!!!


me also on the honda 2000's.

Actually, one of the 2000's is going to our son, and I've got a 2200 on order, should be here middle of March.

The honda 2000 with the micro air easy start will easily run the AC unit we have up to about 3500ft. 4500ft on a hot day and it eventually kicks out. expectation is that the extra 200W on the 2200 will get me over the hump at higher altitudes and let me get by with one generator 95% of the time.
2011 Keystone Outback 295RE
2004 14' bikehauler with full living quarters
2015.5 Denali 4x4 CC/SB Duramax/Allison
2004.5 Silverado 4x4 CC/SB Duramax/Allison passed on to our Son!

Atlee
Explorer II
Explorer II
This is why I have 2 2K Hondas. Together, they will power the AC and micro. If I don't need AC, I only have to run one. And I can handle one 2k genny at a time. However, I could never move the 3k machine alone.

Ltrip wrote:
I just went through this decision process. Your priorities may be different than mine.
I considered the 3500W units and 2 2000W units.
At age 68 I was concerned about moving the 3500W unit. Also, there are times when you don;t need to run the air, so the 3500W is overkill for other uses.
I opted for 2 Champion 2000W units. I can carry the 49 lb unit pretty easily and it pairs up to create a 4000W unit, enough to run the AC.
Upon receipt, 1 of them started and ran perfectly. The other is in the shop for a warrantee fix of leaking gas. I have not used them yet on a camping trip. But soon!!!
Erroll, Mary
2021 Coachmen Freedom Express 20SE
2014 F150 Supercab 4x4 w/ 8' box, Ecoboost & HD Pkg
Equal-i-zer Hitch

Ltrip
Explorer
Explorer
I just went through this decision process. Your priorities may be different than mine.
I considered the 3500W units and 2 2000W units.
At age 68 I was concerned about moving the 3500W unit. Also, there are times when you don;t need to run the air, so the 3500W is overkill for other uses.
I opted for 2 Champion 2000W units. I can carry the 49 lb unit pretty easily and it pairs up to create a 4000W unit, enough to run the AC.
Upon receipt, 1 of them started and ran perfectly. The other is in the shop for a warrantee fix of leaking gas. I have not used them yet on a camping trip. But soon!!!
Larie Trippet Reno/Tahoe region
2018 Ford F250 Lariat Ultimate CC SB 4X4 diesel
2018 Arctic Fox 25Y
2019 BMW R1250RT

ktmrfs
Explorer
Explorer
jamesroadking wrote:
Power measured in Watts is the Question. The Formula is P over I E.
Power Over I Current measured in Amps (30 amps) times E Volts (120 volts)
30 amps X 120 volts = is 3600 watts, to run your RV. Now to run just your A/C by it self (mine is on a 20 amp breaker, so 20 amps times 120 volts equal 2400 watts.
I've ran a 4000 watt non inverter Champion Generator for the last 6 years. It cost me about $250 in 2012. It's run flawlessly, all I've ever had to do is change the electric start battery once and change the oil a couple of times. In stock form the Champion generator runs at 68 decibels, and to further quiet it down I routed the exhaust through a stock HD Electra Glides stock quiet muffler. That did the trick, now I can stand right next to it and have a normal conversation. Total cost about $300 bucks.


Power is VxA ONLY for the case of a pure resistive load. which an AC motor is NOT. what you care about with a generator is Volt Amps, which is what most generators are rated at. Now, with a Air conditioner motor, VA draw is fortunetely only about 10% more than calculated based on watts. so it's not a bad approximation.

where it falls apart is with things like microwave ovens and most chargers built into an RV. In those cases current draw can be 30% more than what is calculated based on the power (watts) draw.
2011 Keystone Outback 295RE
2004 14' bikehauler with full living quarters
2015.5 Denali 4x4 CC/SB Duramax/Allison
2004.5 Silverado 4x4 CC/SB Duramax/Allison passed on to our Son!

jamesroadking
Explorer
Explorer
Power measured in Watts is the Question. The Formula is P over I E.
Power Over I Current measured in Amps (30 amps) times E Volts (120 volts)
30 amps X 120 volts = is 3600 watts, to run your RV. Now to run just your A/C by it self (mine is on a 20 amp breaker, so 20 amps times 120 volts equal 2400 watts.
I've ran a 4000 watt non inverter Champion Generator for the last 6 years. It cost me about $250 in 2012. It's run flawlessly, all I've ever had to do is change the electric start battery once and change the oil a couple of times. In stock form the Champion generator runs at 68 decibels, and to further quiet it down I routed the exhaust through a stock HD Electra Glides stock quiet muffler. That did the trick, now I can stand right next to it and have a normal conversation. Total cost about $300 bucks.

pnichols
Explorer II
Explorer II
Isaac-1 wrote:
Keep in mind it also depends on where you will be using it, engines loose power at altitude, so if you will plan on using air conditioning at high elevations you need a larger one. My Onan 4,000 will power my air conditioner and microwave oven at the same time with no problem here in Louisiana, but when I tried running them both at 7,000+ ft elevations last August in Wyoming the engine would bog down.


How modern is your Onan generator model?

The Onan in our 2005 Itasca Class C has a convenient knob right on it to turn and set to the altitude it's going to be used at. It supposedly will run much better at high altitudes if you remember to set this knob to the altitude you want to run it at.

Some RV owners may not be aware that their Onan generators have this easy adjustment to make them run stronger and smoother at high altitudes.
2005 E450 Itasca 24V Class C

grizz272
Explorer
Explorer
Isaac-1 wrote:
Keep in mind it also depends on where you will be using it, engines loose power at altitude, so if you will plan on using air conditioning at high elevations you need a larger one. My Onan 4,000 will power my air conditioner and microwave oven at the same time with no problem here in Louisiana, but when I tried running them both at 7,000+ ft elevations last August in Wyoming the engine would bog down.


Never thought of the elevation factor. We generally boondock on an island in the middle of the Mississippi in June. That is were we would be using it. We all know what teh best generator is. It is a Honda why buy anything else?

Isaac-1
Explorer
Explorer
Keep in mind it also depends on where you will be using it, engines loose power at altitude, so if you will plan on using air conditioning at high elevations you need a larger one. My Onan 4,000 will power my air conditioner and microwave oven at the same time with no problem here in Louisiana, but when I tried running them both at 7,000+ ft elevations last August in Wyoming the engine would bog down.

352
Explorer
Explorer
azrving wrote:
2oldman wrote:
Oh, no, I'm not suckering for another generator thread. ๐Ÿ™‚


Come on, just tell us which brand is best. ๐Ÿ™‚


I really want to know. Please
The manatees of Halls river Homosassa Springs Fl

1985 Chevy Silverado c10. 454 stroker / 495 CI = 675 HP. 650lb of torque. Turb0 400 tranny. 3000 stall converter. Aluminum heads. 3 inch exhaust flowmasters. 2 inch headers. Heat and air. Tubed.

SidecarFlip
Explorer III
Explorer III
2oldman wrote:
Oh, no, I'm not suckering for another generator thread. ๐Ÿ™‚


You are no fun.....:p
2015 Backpack SS1500
1997 Ford 7.3 OBS 4x4 CC LB

Sandia_Man
Explorer II
Explorer II
Anything over 3K watts, I'll add another vote for the Champion remote start inverter genny mentioned above, our unit easily runs our rig's AC and does so at over 8K' elevation. The newer Harbor Freight 3K watt plus inverter generator appears to have a good following thus far and is certainly a good deal if they prove to be built for the long haul. Of course the Yamaha and Honda 3K watts units or pairing 2 of their 2K inverter units would do the job nicely. It boils down to how much you are willing to spend to get the job done, we wanted reliability and simplicity as provided by our onboard Onan.

TurnThePage
Explorer
Explorer
pianotuna wrote:
Add a soft start system such as the one from Microair Easy Start.

I'd choose the Champion 3400 watt with remote electric start.

X2 on both accounts! I have that very generator and love it.
2015 Ram 1500
2022 Grand Design Imagine XLS 22RBE

kerrlakeRoo
Explorer
Explorer
To put it simply in answer to your question, anything offering over 2800 watts continuous, will operate most ac units,
Folks in here will almost universally recommend inverter based units for noise reasons.
Beyond that you have numerous brands available ranging in prices from about $649 to $1999.
There are passionate believers in all.

azrving
Explorer
Explorer
2oldman wrote:
Oh, no, I'm not suckering for another generator thread. ๐Ÿ™‚


Come on, just tell us which brand is best. ๐Ÿ™‚