Powering 5K BTU 115V Air Conditioner in Auto

[panoptic]

Folks

This is my first post to Physics Forum. I've started a project to put air conditioning into my '86 Westfalia van. The stock AC never worked and was ill-designed with huge long runs of tubing back and forth in the van, so I've removed it. I located the smallest possible 115 V AC window unit, a 5000BTU Frigidaire, only about 1 1/4 cubic ft, 40 pounds, and believe I can power it while the engine is running.

The window AC unit uses 515 watts, which would be 515/12 = 43 amps at 12 volts. The stock alternator is rated at 90 amps. Do you think I can attach a 750 watt rated inverter to the generator and have it work? How much margin do I need for the alternator and inverter?

I'm thinking to get an ammeter to test actual current flow in the AC unit, both at start-up and under load, then to test current flow from the alternator under various conditions with the engine running in the van. Suggestions where to get an AC/DC ammeter with that capacity?

Options would be to install a larger alternator, larger inverter, or maybe I could find an alternator that puts out 115V AC and install it in the engine bay where the AC compressor used to be? Is there such a thing? Would that make more sense?

Larry Burt
Portland, Oregon

 

[JGM_14]

measure the DC aperage because it takes more amperage from the battery than the AC is for example an incandescant 60 watt light bulb makes the inverter draw 5.22 amps of current but only draws 2 amps itself and some inverters cannot run an inductive load (motors, power tools, ect.)
as for the 115v alternator, they don't make them (at least i don't think they do),but certain AC motors can be converted to AC generators.

 

[oswaler]

I commend you for taking on this project and thinking about the power requirements for your air conditioning unit. It's important to consider the power needed for your AC unit, as well as the capabilities of your alternator and inverter, to ensure the system functions properly and safely.

Based on the information provided, it seems like your plan to use a 750 watt inverter should work, as long as it is rated to handle the initial surge of power when the AC unit starts up. However, I would recommend leaving some margin for safety and to avoid overloading your alternator.

To accurately measure the current flow in the AC unit and from the alternator, I suggest getting a clamp meter that can measure AC and DC currents up to at least 50 amps. This will give you a better understanding of the power requirements and capabilities of your system.

In terms of your options for a larger alternator or an alternator that outputs AC power, these may be viable solutions but would require more research and possibly additional modifications to your vehicle's electrical system. It may be worth consulting with a professional mechanic or electrician to determine the best option for your specific setup.

Overall, it's important to carefully consider the power requirements and capabilities of your AC unit, alternator, and inverter to ensure the safe and efficient operation of your air conditioning system in your van. Good luck with your project!