Run AC from inverter in truck?

naturist wrote:
The roughly 2,000 - 2,500 watts needed to start the AC translate to 17-21 amps at 120 volts, or 167 to 250 amps at 12 volts. And that will require your engine to be running at highway rpm. So the short answer is no, bad idea, won't work.

The somewhat longer answer is that your truck's engine used as a generator is a horribly inefficient and extremely expensive way to run an air conditioner. If you want to run that AC, frankly, the only practical power sources are shore power at a campground with hookups or a dedicated generator of at least 3,000 watts capacity. At this point in the universe of modern technology, virtually all other schemes for ways to avoid those two power sources fall into the classification of "hair-brained schemes."

Good answer - no need to read this thread any further.

"Hair-brained" it is!..:R..:S

(Exactly what is a "Hair Brain"?)

BTW -
You should have mentioned....
all the new "friends" the OP will make doing that..:B

~

Assuming the engine is running, at operating temp, the batteries should be fully charged. With the alternator propping up the battery voltage, and decent wires (whatever the inverter recommends) you should be able to start the AC. The auto batteries are designed for high cranking amps (which look the same as startup surge on an inverter). Runtime is another thing, as at idle you may be barely able to charge the batteries with the lights and trucks fan on - without the inverter in the picture. Most factory (even the upgraded ones) put 20-40% rated output at idle, less when hot. Aftermarket alternators (I like Mean Green) out put far more at idle, and if big enough can support the AC when running down the road.

Most likely it will never even start the compressor. Get a 3,000 watt generator.

Hi,

The high torque motors on refrigerators and air conditioners require a pure sine wave inverter. I know someone who had a MCI bus with a 200 amp 12 volt and 200 amp 24 volt alternators. (The engine started on 24 volts). He had a 12 volt inverter but had to change to a 4,000 watt 24 volt inverter to run his rooftop A/C unit.

Your 160 amp alternator is rated at 160 amps while it is cold, and the engine RPM is over 2,500 RPM. Get the alternator warm, and the amp rating drops to less than 100 amps. This is about 1,400 watts (assuming it is putting out 14 - 14.5 volts) and still not enough to run the A/C very long, as it will be constantly discharging the battery.

Also the load on the alternator fan belt and alternator bearings will be excessive, leading to pre-mature wear on the alternator and belt.

Once I had left my inverter on, and the refrigerator on electric. This is a 3.5 amp 120 volt load, or about 35 amps on the alternator. It was enough to make my alternator belt squeal! It was really noisy, and I had to stop and turn off the inverter, switch the refrigerator from 120 to gas only.

Good luck,

Fred.

Even if the truck has to be running for whatever reason, a generator in the bed is the way to go to run the air conditioner.

naturist wrote:
The roughly 2,000 - 2,500 watts needed to start the AC translate to 17-21 amps at 120 volts, or 167 to 250 amps at 12 volts.

...and it's probably more amperage than that. Some airs can suck 3-5x their running amps when starting.

sfpcservice wrote:
Just wondering if a 160 amp alternator can handle running an AC unit through an inverter? Also would a modified sine wave run it or would it need to be pure sine wave?

I'm not sure if the AC is a 13.5 or 15k btu, I know that will make a difference.

Let's assume that a generator is not an option and the truck will be running.

There is a notice on my son-in-law's 2010 Tacoma that says that there is a 400w limit on the factory inverter while the engine is NOT RUNNING, but only 100w while the engine is RUNNING.

Lyle

For all practical purposes I say no. Better to get a 3000w generator.

The roughly 2,000 - 2,500 watts needed to start the AC translate to 17-21 amps at 120 volts, or 167 to 250 amps at 12 volts. And that will require your engine to be running at highway rpm. So the short answer is no, bad idea, won't work.

The somewhat longer answer is that your truck's engine used as a generator is a horribly inefficient and extremely expensive way to run an air conditioner. If you want to run that AC, frankly, the only practical power sources are shore power at a campground with hookups or a dedicated generator of at least 3,000 watts capacity. At this point in the universe of modern technology, virtually all other schemes for ways to avoid those two power sources fall into the classification of "hair-brained schemes."

I think an invertor the size you'll need, plus cabling, will cost more than a generator from Costco. I don't think the idea is worthwhile.

Bill