Upgrade from 13.5k to 15k Coleman A/C units

time_to_go_now wrote:
I just checked out the spec sheets on the Mach 3 (13.5k) and the Mach 15 (15k). They both say max usage is 1900 watts. They are identical, even down to the 1/3 horse fan motor. Undoubtedly the SAME fan motor.

Replacing two 13.5 units with two 15k units should use the same power.

Thanks Jim, that's good to know.

Bill

I just checked out the spec sheets on the Mach 3 (13.5k) and the Mach 15 (15k). They both say max usage is 1900 watts. They are identical, even down to the 1/3 horse fan motor. Undoubtedly the SAME fan motor.

Replacing two 13.5 units with two 15k units should use the same power.

The chances of them both starting their compressors at the same time are pretty low.

If I were to give you a hundred dollars to get both compressors to start at the exact same time do you think you'd collect it?

And if Doug says it's OK, then it's OK. He knows his stuff.

time_to_go_now wrote:
I am looking at replacing my two 2008 vintage 13.5k air conditioners with new Coleman Mach 8 15k units. I have a 6,000 watt generator. My questions is can my 6,000 watt generator run both these units?

When I look at the specs for the 15k unit, it requires 2017 watts while running with the compressor on, fan on high speed, on a 100 degree day. That is 16.8 amps. I called the support line, and they said to expect 2 1/2 times the running load on start up. That would be a momentary hit of 42 amps! That means to me there is no way a 6,000 watt generator could handle TWO of these 15k units at the same time.

But, I was wondering if anyone has some real world data to support one way or the other.

Thanks.

Your surge amp start up----They ALL do that for a millisecond. That will not affect the power of a 6k onan. Even a 5.0 or 5.5 k onan will start and run 2 units. The Mach 8 pulls 15.9 amps at 95 degrees. At 105 it will pull 16.9 and at 115 degrees will pull 17.9 amps. Do NOT worry about running wattage. A 6500 Onan is rated at 55 amps and a 5500 is rated at 46 amps. 5k and up have never had a problem starting 2 RV AC units. I base MY statements on 36 years as a RV Tech and remember when almost ALL the class a Gas motorhomes in the 70's/80's and 90's had 5500 Onans/Kohlers or larger and never had problems staring 2 AC units. Remember, back then there were oinly 30 amp Motorhomes and the Rear AC was wired direct to the Genset and you had to have the Genset running to run BOTH front and Rear and they were capable of doing it. Doug

10forty2 wrote:
I've got a 15K in the front a 13.5K in the bedroom. My genset is an Onan 5.5KW. It runs both units and the fridge and the lights with no problem. I suspect you'll be fine.

That was my fall back plan. Put a 15k in the living room and a power saving 13.5k in the bedroom.

When I go to Onan website and look up the RV6000 diesel generator, it says right there that it can run two 15k AC units. I just don't see how based on what the Tech said.

Thanks.

I've got a 15K in the front a 13.5K in the bedroom. My genset is an Onan 5.5KW. It runs both units and the fridge and the lights with no problem. I suspect you'll be fine.

My Kipor runs both of my 15k units but I dont run microwave and water heater on electric at that time, and for the AC I start one and let it get going then start the other one and have one set at 70 and the other at 73 so they dont try and start at the same time. you can give a bigger range to be safe but it will run them.
good luck

According to the power panel, my draw when running the two 15K A/C units is 23 - 24 amps in hot weather using the generator. I have an Onan 7.5KW generator. I don't think you'll have a problem, but you might check to see how much of a draw your battery charger takes when the batteries are down.

In other words - if you're out boondocking and haven't run the generator to charge the batteries in a while, then the next day around noon when it's getting hot, you decide to start the generator and both air conditioners AND the battery charger kick on at the same time. Our generator can handle it, I don't know about a 6,000 watt generator.

Run your house batteries down to about 60%, then start the generator and see what the amp draw is on your power panel.

Bill

Both could RUN.....both could NOT start at same time