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Jonny H Jonny H is offline
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Join Date: Jul 2013
Location: South East England
Posts: 1,710
Quote:
Originally Posted by 47silver View Post
An engine driven ac porsche from what i read uses 7+ hp. That = 17000 Btu’s.
If the electric one is equivalent that would = 433 amos to run it.
Apparently electric ones get by with 6500 btu’s. But that is still 155 amos at 12volts. You need lights and spark do figure a 300 amp alternator so it lasts more than a summer

Not quite. Compressor 101 - the COP rating (Coefficient of Performance) means that the cooling capacity is greater than the input power. Our compressor COP is around 3

We typically run 75A input power at 13.5 volts which is 1012 Watts. With a COP of 3 that yields a cooling capacity of 3 x 1012 = 3036W which is 10,360 BTU.

Our alternators are rated 175A.

We have power management in our ECU which reduces the compressor speed in relation to cooling demand and alternator output. This reduces the amp draw at idle to save the battery from draining.

We have well over 2000 systems in operation, 70% of them in hot climates.

Here's a video which just came out today of a guy driving the length of Portugal in 37 degree C / 100F conditions. This car runs our AC.

https://www.youtube.com/watch?v=nM6uFhMyFMU

Note:

1) the guy has the windows closed and has a passenger - he is not sweaty.

2) when he stops for gas (21:44 in the video) and shows the engine there is no compressor on the engine.
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Old 08-04-2025, 03:58 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #9 (permalink)