Chinook RV

How many watts and Amps does the Concourse's 13,500 BTU need to start up and continue running. I don't have manual but read somewhere Dometic recommends 3500 watt to run? Would this mean you would need minimum 3500 watt inverter to try to get running off battery bank?

I believe these came with 600 watt inverters which seem low in this day and age.....but I m sure in 2000 it was great.

The installation manual states it requires a minimum of a 3500 Watt generator and a 20 Amp time-delay fuse on the AC circuit. Both of these are because it has Compressor Locked Rotor Amps of 50 amp (for the model 630215.421 or 620215.421, which is what mine is, or the 630215.321/620315.321 has 60 amp). The locked rotor amps is the high surge that happens when a motor starts up - if the generator or inverter can't handle that large a surge, it will drop out (generator will struggle and die, inverter will scream and fuses may blow).

You really can't run A/C very long on an inverter, unless you have something like the gonewiththewynns.com, who have a bus with enormous solar installed (www.gonewiththewynns.com/off-grid-solar ... nditioning), and a large battery bank (preferably Lithium, since it will be a high draw running, maybe 80-90 amps, which lowers the AH of other types of batteries but doesn't bother Lithium).

If you do want to try anyway, you should probably get an EasyStart soft start, which they mention. It installs inside the A/C shroud up top (they say it fits) and will provide a 4-part ramp up to the AC as it starts up. This way the generator/inverter never sees a large jump to 50 or 60 amps (that is AC, at 110v DC it is more like 500-600 amps!). It also means the A/C starts up a little slower and smoother, rather than the kind of bang (well, big woosh, maybe) it does normally - that tends to startle me sometimes if I'm dozing and have the fan on automatic.

I am getting an EasyStart for my current in-progress electrical upgrade, but more to make the A/C smoother and save wear and tear on the generator, rather than running on inverter. My new system will have 400AH Lithium batteries and Victron 3000 inverter (2500 watts), like the Wynns above, so I may try running A/C on inverter a few times for kicks, but I doubt I'd do it often as I will have only 400 watts solar, which means my batteries would last at best a few hours running A/C (and then I'd have to run the generator to charge them, so that hardly seems worth it). But if I'm dying of heat/humidity at a campsite late at night and am not allowed to run the generator during quiet hours, then maybe I could see myself running A/C on the inverter for a while to cool down, and then charge the next day. Have to wait and see.

Bob

I'd say just the same as Bob in terms of running A/C from inverter. It's possible nowadays, but you still have to have a really big system, lithium batteries, AND a way to put the power back. For example I know some people who could run A/C for a meaningful number of hours (occasionally) but they have (IIRC) 1600 watts of solar and a 1000ah lithium battery bank (plus a 3000w inverter/charger). Probably similar to what the Wynns had (tho I didn't read the link in detail).

There are some commercially made Class B's that can run the A/C while parked, but at least the ones I know of have a sophisticated system wherein the vehicle engine (with its modern gigantic alternator) will start automatically to help take up the slack. That's probably more practical than the above huge system on a Chinook, but would still require some tinkering (probably our alternators are not up to the task and would the engine stay cool while just sitting like that?).

For some years it was impossible to run AC from anything but shore power or a generator. Now it's possible but still somewhat heroic. In future....?

I even half considered putting a new A/C on my Chinook this summer. Luckily I was able to escape the heat (and more importantly, the smoke) enough to make that unnecessary. I was looking at the Polar Cub that is around 9,000 btu. It still has a high locked rotor amp draw, but as Bob says that can be worked around. From what I read 9,000 btu can be run from a single Honda 2000 watt generator or similar. Let's hope it doesn't come to that (for me) because I'd have to be about 50 miles from anyone to do that comfortably (given how many evenings I've had to listen to "quiet" Honda generators rumbling along and the relief when they are shut off and you can hear nature again). That said, there have been times in recent years when it might have been nice to go someplace, plug in, and run an A/C. Cause it seems to be hotter and smokier than I remember from the past, and there have been periods of time where I was doing something that required being with my Chinook in a specific area regardless of the conditions.

Anyway, if you were designing a large system to run an AC, maybe the smaller btu model would make it slightly more doable. The Polar Cub is also quite a bit less tall than the stock model, so it would shade solar panels less (it's still 29" wide tho).

Thanks Blu and Bob. My rig has been laid up for going on three weeks for just new Power Stop Brakes and MorRyde Shear Springs, repair place broke two porta-power things trying to compress Morryde Springs, tomorrow they are getting much heavier duty one so hopefully it finally works. Once done I'll do write-up it.

Once MorRyde & brakes finished I need to make final decision on Action Van or WeldTec lift and get installed, I may do TruTrac locker but will wait to see if I need it. However, my next need, OK maybe a "want", is to run A/C off battery pack for 2 - 3 hours. My time with Chinook will be spent here in mid-Atlantic and S.E. I don't want to run generator when people around, but as Bob mentions it would be nice to get few hours from A/C off the batteries with out waking neighbors.

Basically, what I am looking to do is a "Earthroamer lite" type electrical system. In the $1.5mm Earthroamer, they have a 2100 watt solar system with 2000 watt hour Lithium battery bank. The A/C can run about 6 hours on the battery bank, once the batteries get down to 30% level a QuickCharge system automatically starts engine and they have 3 giant alternators producing 26,000 watts which can recharge the battery bank in 30 minutes.

Obviously cost is major limiting factor, but I am thinking I could get a few hours for modest budget and certainly not looking for quick 3 hr full recharge.

I am trying to sketch out now and if cost with pain threshold will look to do before next summer.

It's popular now to mount a smaller 6,000 BTU window unit (either temporarily in a window, or in a cutout below say a dinette seat) instead of trying to power a roof RV a/c.

That cuts the running 12VDC power requirement down to 50A instead of 150A.

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Personally I've often thought of installing a rear van HVAC unit, running off the engine a/c and heat. Chinook engines idle a lot quieter than a generator motor.