M923 air conditioning a/c install project

[Mike929]

For those considering AC installation in their M939s, be aware that the alternator will need to be upgraded to a 100 amp or >unit. I've suffered multiple electrical system faults due to alternator not liking the additional load. So far I've replaced the ABS ECU, the fail safe module, and the alternator. I might also need to replace the PCB due to recent symptoms. I am currently in the process of acquiring a 200 amp alt to power my M923A2. Good luck to all.
The AC works flawlessly and cools well. However, after a 10 min drive, the 60 amp alternator goes in to an overvoltage condition which will/has damaged electrical components. My Hawker batts are in good shape, so alternator voltage dump doesn't seem to be the case.
Any electrical experts on here care to shine light on this issue?

I've gone through two voltage regulators and had two gauges blow out and my ABS burn out (hopefully that is all) using the military alternators. I am planning to switch to a commercial bull dozer 24v/60amp big bearing/brushless alternator.

Beyond a new Alternator, what else are you changing to support the 24v/200 amp solution? i.e., will the PCB handle 200 amps at 24v?

 

[jetjockB747]

Haven't received the new alt yet, but I plan on upgrading the wires to lower gage. The pcb should handle the higher amperage....I hope. This Neihoff 4/28 200 amp alternator should drop in to the existing mount. I'll keep you guys posted.

 

[jetjockB747]

Dupe post.

 

[Mike929]

TMs should cover an upgrade to 100 amp and may give you some clue to what may need to be changed.

After having two of the military alternators die and do its best to burn down my truck, I'm going to look into much less expensive commercial alternators that can handle a low battery and die more peacefully. I.e. not blowing out gauges and ABS cards.

 

[Over]

After seeing all the problems I am still at a loss at what it is happening to a couple of members. I know Kenway makes the brackets for the M923A0 and the A2 for a military contract, past or present. This would indicate the military installed similar units (The RedDot units are pretty generic and utilize all the same base components) but I have not seen anything in kit form or mention in any TM in regard to upping the alternator output. I've driven around with zero issues and even when working on the interior of the truck when it's 115 degrees fired up the truck and AC just to make it nicer to get the work done. Of course on the "Patrol" no buzzer has ever worked (will get around to figuring that out). I only have 2 of the military batteries hooked up as one bounced around and shorted on the previous owner. But that shouldn't matter as draw is draw. Main power is direct from the batts and sensor power is a plug dangling under the dash, either a light or heater power, only on when main power switch is on. Note: All the above doesn't mean I'm saying there isn't a problem, I am just at a loss at what the problem is for a few of these installs. When I get a chance I'll hook up a clamp on meter on the condenser fans and see what kind of amps are being pulled and I'll do the same thing for the unit inside the cab. What the compressor pulls is inconsequential. That should be a good starting point in what's going on.

 

[Suprman]

I have seen 5-tons with AC military installed and it appeared to have a stock electrical system. I can see a bit if power loss from the engine driving the compressor but the system should not draw enough power to cause electrical issues. I could see it bringing out issues like a weak alternator regulator that was on its way out already. If the sense line to the alternator has a bad connection that would make things go a bit haywire.

 

[machinist75]

TMs should cover an upgrade to 100 amp and may give you some clue to what may need to be changed.

After having two of the military alternators die and do its best to burn down my truck, I'm going to look into much less expensive commercial alternators that can handle a low battery and die more peacefully. I.e. not blowing out gauges and ABS cards.

Hey mike try these guys. Put one in the deuce and it was a direct replacement. Tell them your on steel soldiers, they gave me a discount. http://wolverinetechnologiesllc.com/M925Alternator.html

 

[Artisan]

I have details on the 24V RD-2-4617-0(p) system if it helps.
It is very close I think.


Condensor Fans = 6.2Amps EACH = 12.4AMPS
Evaporator Blower Motor = 14.5AMPS
Compressor Clutch = 1.7AMPS

If you look on the PS of the evap box you see a 30AMP 24V breaker.

Now the equililant motors in 12V flavor, meaning if I wanted to
swap my 24V fans, blower for 12V =


Condensor Fan 12.4 Amps EACH = 24.8Amps
Evaporator Blower Motor@ = 31.0 Amps
Compressor Clutch = N/A

 

[Mike929]

Hey mike try these guys. Put one in the deuce and it was a direct replacement. Tell them your on steel soldiers, they gave me a discount. http://wolverinetechnologiesllc.com/M925Alternator.html

Thanks for the link. It looks like they are using a car sized alternator, which should be fine. I was looking at the bull dozer, big bearing/brushless alternator at about the same price, with me having to do the leg work to set it up correctly. (Shop needs me to pull mine, I assume so they can determine pulley size, etc., for the new alt.)

I want to see what it would take to mount the bigger bulldozer alt, but glad to have options if I run into any road blocks.

 

[74M35A2]

A brushless alternator will not have as high of electrical current output at idle as compared to an equivalent frame size brush type alternator.

 

[Over]

M923A2 Kenway bracket kit. KIT P/N RD-9-10043-0

Had 6/Sold 2/Need 3. Looks like I have 1 more left.
I just received a bracket kit from Kenway and need to sell it at what it cost me. $751.95+$16 ship=$767.95. Add $15 to ship to you. They have a 6 week lead time and same price if you were to order now. Can ship anytime just pm me. I had to order 2 more of the model for the M923A0 which are only $200! Good reason for the old NHC250! I was going to do my M923A2 but will wait and finish up the A0's. Here are some pics off a fleabay seller that a guy here picked up that are no longer available but is what I have.
Here are the install instructions for the M923A2 (M939A2) kit that I am selling. I also have some RedDot M915A0/A1 kits that can be used on the M923 that are identical to the kit I used in this thread on my truck. Or if you have a M915A0/A1 it's a direct bolt up. Almost forgot I have 4 PLS AC kits also. Gotta stay off of you know what, ended up with more than I needed.
View attachment M939 mounting compressor.pdf

 

[Csm Davis]

Okay the military did run ac in the uparmored 939 A2s and the condenser was in front of the radiator and the evaporator was on the floor in between the seats under a console the gunners stood on. So red dot probably makes a bracket for an 8.3 has anyone checked?

 

[Suprman]

I have the proper condensers and the Kenway kit pictured above is what Red Dot rebadged and sold to the military. There is a group buy in a thread somewhere.

 

[Artisan]

I have the proper condensers and the Kenway kit pictured above is what Red Dot rebadged and sold to the military. There is a group buy in a thread somewhere.

Where dat?

 

[Suprman]

There is a group buy for the 8.3 mount and drive kit from Kenway. I believe it is 500 per kit if 20 are sold. As opposed to the 7xx dollars plus shipping price.

 

[Mike929]

Yes the group was up to 10 or 11, myself being one of them.

http://www.steelsoldiers.com/showthread.php?127635-M939A2-Red-Dot-Compressor-Mount-Kit-Group-Buy

 

[Over]

I have 4 of the M915A1 Red Dot kits available. Same as the one I used here but has front adjustable vents. $600 a piece, local pick up in North Phoenix. PM me if interested.

 

[Tacticalhummer]

Do you have a picture of just the compressor bracket by utself?

 

[Over]

Do you have a picture of just the compressor bracket by utself?

I think somewhere in this thread I posted the pdf instructions. Been 2 years. Don't have anymore available.

 

[Tacticalhummer]

Thanks for the reply on a dated post.