Using AC is worse then Winter Driving

[Oman]

I tried to find a definitive answer to this in the tech manual, but so far nothing. As far as any HVAC folks I can talk to know, compressors don't work well at variable speed. They are either on or off and cycle based on temperature at the evaporator. But from the evidence in the load display on the dash it sure seems that the compressor does not cycle but rather ramps up with the main blower fan speed. Curious minds would like to know...

 

What I can say for sure is that A/C on with a low fan speed doesn't sap much power and keeps the cabin pretty comfy. The power drain ramps up exponentially though as you drop the temperature. I think that dehumidification is somewhat more important than actual temperature (at least until it gets real hot).

 

Jon

 

 

 

 

hmm, Well, i have my ac on auto and set to 71, and get about what you are getting, tonifan...but i noticed on cooler, less humid days, like today, i was getting 43...

The outside weather does play a big role in it..

 

As long as i'm getting 40+ in the DC area, i'll keep my ac where it is and keep doing what i'm doing, since after all, 44 mile commute, i'm not going to go without ac during the summer

[FFHdriver]

I tried to find a definitive answer to this in the tech manual, but so far nothing. As far as any HVAC folks I can talk to know, compressors don't work well at variable speed. They are either on or off and cycle based on temperature at the evaporator. But from the evidence in the load display on the dash it sure seems that the compressor does not cycle but rather ramps up with the main blower fan speed. Curious minds would like to know...

 

What I can say for sure is that A/C on with a low fan speed doesn't sap much power and keeps the cabin pretty comfy. The power drain ramps up exponentially though as you drop the temperature. I think that dehumidification is somewhat more important than actual temperature (at least until it gets real hot).

 

Jon

Okay it's time for someone to get a chair and a couple of beers and turn on the AC and watch the compressor to see what it does. lol I'm not volunteering.

[lolder]

Okay it's time for someone to get a chair and a couple of beers and turn on the AC and watch the compressor to see what it does. lol I'm not volunteering.

I can't hear it cycling on and off, I can't feel the load on the vehicle and I can't see the Accessory load cycling.

[cgul]

I can't hear it cycling on and off, I can't feel the load on the vehicle and I can't see the Accessory load cycling.

 

From a FFH manual I bought on ebay.

 

When the ACCM receives the A/C demand message, it will engage. Instead of cycling ON and OFF like a

traditional A/C compressor, the PCM monitors the evaporator discharge temperature from the HVAC module

to raise or lower the electric A/C compressor speed as required. When the HVAC module is OFF or not

requiring A/C operation, the electric A/C compressor will be OFF.

 

Charles

[lolder]

From a FFH manual I bought on ebay.

 

When the ACCM receives the A/C demand message, it will engage. Instead of cycling ON and OFF like a

traditional A/C compressor, the PCM monitors the evaporator discharge temperature from the HVAC module

to raise or lower the electric A/C compressor speed as required. When the HVAC module is OFF or not

requiring A/C operation, the electric A/C compressor will be OFF.

 

Charles

Thanks. It's probably a synchronous ac motor like the rest. I believe the inverter is built into it. It's probably exorbitantly expensive.