3000 watt inverter.

[davidjsimons]

I have a 3000 watt inverter that I can wire to my truck. The truck is a 2012 Ram 3500 6.7 Cummins. I believe the stock alternator is 160 amp. Will this set up provide me enough current to run the blower on the furnace for my gas heat in a roadside emergency? I realize this would require leaving the engine running. If not, I suppose I could sleep in the truck as I regularly do already. This is more about if I have my family with me.


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[SAD]

You should not need an inverter at all to run your furnace. The furnace blower is 12v and with the on-board batteries, should easily last a full night... Of course it depends on the number of batteries you have (1 or 2), outside air temp, thermostat setting.

If you DID run your RV batteries down, you could run your truck and the trickle charge through the umbilical cord would provide enough "life line" to run the blower.

[davidjsimons]

Thanks, I didn't realize the furnace blower was on twelve volt. I hadn't tried to run it that way. Second question, would it produce enough power to run my a/c unit?


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[SAD]

Originally Posted by davidjsimons

Thanks, I didn't realize the furnace blower was on twelve volt. I hadn't tried to run it that way. Second question, would it produce enough power to run my a/c unit?


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You will probably never find a consumer grade inverter/battery bank sufficient to run an RV a/c for any reasonable length of time.

[tanman32225]

I dont know about your 2012 Ram but my Ford will only run a short while then cut off on its own. There are no extended idles unless you wish to keep restarting the motor. Yours may be different.
I agree with the others. Another battery aboard may be sufficient to keep your furnace motor operating. No need for an inverter.

[Festus2]

As others have already stated, simply use your in-house battery (ies) to operate your furnace. If they are fully-charged and in good condition, the furnace should be able to be used during the night to keep you warm enough inside.
Not sure about your present battery set-up, but having 2 6-volts is something I'd recommend.

[JRTJH]

The Dometic 13.5K BTU a/c is rated for 12.4 Amps compressor and 2.5 Amps Fan. That's a power requirement of 14.9 Amps at 120 VAC for a total of 1790 watts. It will use significantly more wattage to start the compressor and depending on the temperature, will most likely remain at or near the maximum operating power most of the time.

A 3000 watt inverter, if it is capable of handling the start load of the a/c should provide temporary power to run it. But as SAD said, very few inverters are rated at continuous power. There is some internal loss of power in any inverter system (cooling fans, transformer loss, etc) that make it a power drain requiring more watts to run than it is capable of producing, so an input of 1900 watts would most likely give an output of less than 1500 watts.

The 160 AMP @ 12 VDC alternator in your truck is capable of producing 1920 watts maximum output. I don't think any automotive alternator is rated to produce maximum power continuously. However, even if it were, depending on the power required to maintain the truck systems, there most likely wouldn't be enough power generated by the alternator to run the a/c for any extended period of time. My guess is that to maintain the computer and other electrical systems in the truck, you'd need at least 1000 watts (that's a SWAG) so realistically, you could provide around 900 watts to run the inverter. The remaining power to maintain the inverter output to the air conditioner would then be provided by the truck batteries. After a time (who knows how long) the system would not be capable of maintaining battery charge on the truck and it would fail. Even if the truck charging system cuts out to maintain the power needed to run the engine systems, once you turned off the ignition and then attempted to restart, I'm guessing you'd be in for a rude awakening (dead batteries)

I'm of the opinion that your idea is a good one, but the truck's alternator just isn't strong enough to maintain that kind of load for very long. After a while, probalby 2 or 3 hours, you'd be discharging the truck's batteries so much that maintaining the 120 VAC load would put you in a "no start" condition.

[Javi]

Honda Genset...

[SAABDOCTOR]

JOHN you are right about the alternators running at full power constantly. soon after it gets very hot and shreads the belt and then there are no amps watts volts and bearings with out grease!

[davidjsimons]

Originally Posted by tanman32225

I dont know about your 2012 Ram but my Ford will only run a short while then cut off on its own. There are no extended idles unless you wish to keep restarting the motor. Yours may be different.
I agree with the others. Another battery aboard may be sufficient to keep your furnace motor operating. No need for an inverter.

The truck has no idle limitations. On some job sites, I have slept in the back seat for up to five hour. I just set my engine speed at about 1500 rpm's. I appreciate all of the input. It was just a thought in the back of my mind that I did not know enough about to decide. I'm still going to wire it up but not with that heavy of use in mind. Again, thanks for the insight and knowledge.


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[mhs4771]

A quick cal based on an 1800 watt load would require approx 150 amps from the 12 volt supply and for that amount of current you better have pretty big cables. I personally don't think it's practical.

[davidjsimons]

Four, four gauge.


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