Dinger65 acutally brought this thread to my attention. Very good thread.
Searching out equipment that would mount with the best ease of install for the boxes on the 109's a system with a mounted compressor was searched - kept going back to the Red Dot system.
For the 12v charging issue in the 109's for the 12v battery bank of 4-105 ah deep cycle AGM batteries we went with this system for charging - it is the 66-100 from the list:
http://www.vanner.com/client/images/manual_Battery_Equalizer.pdf
This charges the 24v system from the OEM system - it as well charges the 12v battery bank whenever the engine is ran.
The inverter/charger as well can put the 12v batteries back to full charge from several power sources - so this covers different concepts to get the 12v system charged.
To keep this on point - I like the concept of installing the compressor to the place as pointed out - a thought would be to mount it a little more secure for vibration issues.
On the 109's I would run a/c lines up the backside of the cab securing them as best as possible (with a roof mounted condensor unit) and up and over to the unit. I have installed systems this way years ago on tractors.
I am curious as to the volume of freon in this install from M35Tom - I am guessing around 2 or 2.5 lbs. Also is this a R134 system.
Running lines appears to have been the easiest to figure out as far as components.
If this style of system would have been utilized to the M109's Dinger65 and I would have had to run the frame - leaving some flex room and up the nose of the box and across the top to the condensor - then calculate the freon.
If you get time please update with completed system as I am intersted and possibly others are as well. Good Thread