Posted: 6/25/2026 1:52:23 PM EDT
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Has anybody done 12v electric AC? Any input beyond what google can provide? There's tons of interweb stuff, but everything I can find is worthless youtube videos where they install it and say "Yup, the air is cold" or forums where people say they did it but provide no useful details. I'm looking at this for an old mid-engine car with an engine swap that makes a belt driven compressor a PITA and $$$. The AC parts (minus compressor) are all still in the car. The lines run through the front trunk so it would be easy to put an electric compressor there. The battery is also in the front trunk so the current carrying wires would just be 1-2 feet long. The cabin volume of the car is quite small and it doesn't sit in the sun, so huge amounts of cooling capacity aren't needed. I don't expect the car to be a refrigerator, I just want to take the edge off the summer heat/humidity. Looking at a compressor like this one. My only real concern is the current draw. The instructions say to use a 70a fuse. I've googled around and can only find vague references to current draw like "40-100a" or "you need an 870 amp alternator". Anybody actually know a current draw figure for one of these? |
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On the web page it says it needs a 140amp alternator. Only issue is, does that include the power needed to run the vehicle and the lights, charge the battery etc? I’d guess you’ll need a 220 amp alternator at least. Then you gotta figure out how to mount the condenser, route the hoses, and how to set up the evaporator and ducts. Seems like a lot of work for low gain to me. |
"It behooves every man to remember that the work of the critic is of altogether secondary importance, and that, in the end, progress is accomplished by the man who does things."
Theodore Roosevelt
Theodore Roosevelt
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Originally Posted By ColtRifle: On the web page it says it needs a 140amp alternator. Only issue is, does that include the power needed to run the vehicle and the lights, charge the battery etc? I’d guess you’ll need a 220 amp alternator at least. Then you gotta figure out how to mount the condenser, route the hoses, and how to set up the evaporator and ducts. Seems like a lot of work for low gain to me. Reading is fundamental. |
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What mid engine car? I have an MR2 I’m looking to do this to after the engine swap is complete. I found a couple of vids that were more useful than most, but they weren’t the top searches. One guy put it in a Chevelle IIRC. No personal numbers, but the fusing might be a simple “oversized” to cover the inrush on start vs using something like a slo-blo or other spike tolerant fusing. Keeps costs down on the kit and what some people might consider “complications” simplified. Like electric fans it’s not going to be pulling 50 amps continuously. |
Wake up, wake up and smell the ashes.
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Originally Posted By Morgan321: They say 140a alternator but they recommend a 70a fuse. Either/both of those numbers vary among the various resellers for what appears to be the same physical compressor also. That's why I'm looking for actual numbers from somebody who has used it or a similar compressor. Reading is fundamental. Well, I took the time to check with a friend of mine who has worked with those (custom car guy) and knows what it takes to make it work but since you want to act like a douche, I guess you can figure it out for yourself. Good luck. |
"It behooves every man to remember that the work of the critic is of altogether secondary importance, and that, in the end, progress is accomplished by the man who does things."
Theodore Roosevelt
Theodore Roosevelt
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Originally Posted By Agilt: What mid engine car? I have an MR2 I’m looking to do this to after the engine swap is complete. Alternator for the engine I have is 100a. The car doesn’t use much electricity except for the steering which peaks as high as 40a but averages much lower. The engine stuff is just under 20a total. I’m considering trying it and if it’s too much power I can easily wire it to turn off steering power when the AC is on. Even if it works OK with the steering in the daytime I’m assuming the lights at night will be too much for the alternator. I found a couple mr2 using them, but one had manual steering and the other had an engine with readily available higher current alternators so he installed one. |