AC Option?

[Ronmar]

One thing they are touting in their advertisements is the 15KBTU unit, and the other ”commercial” models is that they are built and tested to be more rugged(Shaker table testing). They also make two 12V models(4KBTU and 6.8KBTU) and they are marketing these three units toward the trucking market. Funny they don’t offer a 24V model... Yet...

Truck Air Conditioners

The widest selection of truck air conditioners! 25 years of experience with premium automotive brands ✅ Design & Brand awarded.

www.dometic.com

 

[Third From Texas]

one thing to consider after insulate, insulate, insulate..... is to not be so concerned with cooling the cab space...... but the occupants. A cooled poncho via a small 24v liquid chiller or even a fish tank chiller and inverter could do it likely. Chill vest, shirt or suit.... heck even a chilled hat.... much of the human "radiator" is in the head... cool the head and the cooled blood circulates

I got some supplies for adding this... but it is way down the list. Heck finding a new mechanic is taking a year.. (Might found one finally... will see)

Chillers aren't all that effective in +80% humidity (year round except Feb which is our winter in S. TX). LOL

But yeah, I rode Harleys most of my life. Wet bandanas can safe your life in the heat!

 

[Third From Texas]

One thing they are touting in their advertisements is the 15KBTU unit, and the other ”commercial” models is that they are built and tested to be more rugged(Shaker table testing). They also make two 12V models(4KBTU and 6.8KBTU) and they are marketing these three units toward the trucking market. Funny they don’t offer a 24V model... Yet...

Truck Air Conditioners

The widest selection of truck air conditioners! 25 years of experience with premium automotive brands ✅ Design & Brand awarded.

www.dometic.com

Rgr that.

I've found them for $970.48 at one store, so +$220.

Glad you mentioned that because I searched for the commercial and Amazon dropped that part I see.

 

[Third From Texas]

Funny they don’t offer a 24V model... Yet...

While not ideal, still viable. The cost of the inverter drops quite a bit and selections jumps way up when switching to 12V.

 

[Ronmar]

While not ideal, still viable. The cost of the inverter drops quite a bit and selections jumps way up when switching to 12V.

Yep, 12V are more common and less expensive than 24’s, but at least it is better than it used to be 10-12 years ogo...

Because of the way they designed the Neihoff alternators, I am really loath to add any additional 12V load, especially considering that is where most of it already is when the lights are turned on. The alternator output is controlled by the application of field current and the regulator controls that by monitoring and maintaining the 28V Just like any alternator does. The reg switches the 12V output on and off with SCR’s to regulate that voltage like a switching power supply. You must however have the base energy available(provided by the field) to switch so you can maintain 12V under load. I could see a situation where you might not be able to provide for a very large 12v load if the 24V side was not also loaded enough to drive the field...

 

[coachgeo]

Chillers aren't all that effective in +80% humidity (year round except Feb which is our winter in S. TX). LOL

But yeah, I rode Harleys most of my life. Wet bandanas can safe your life in the heat!

sure you are not mixing up surface cooling with evaporation cooling.? Not speaking of evaporation cooling at all.....speaking of actual cooled liquid on surface of body AND insulated from heat outside (thus not evaporating)... A motorcycle skull cap bandanna is evaporation cooling.. a bomb disposal tech, race car or tank driver's cool suit is entirely different and this is what I was referring too.

 

[Third From Texas]

Yes, we used run desert cars (I still own two prerunners). I'm quite familiar with the systems you refer to. We ran Fast Cooler suits years ago (nothing really inexpensive about the units). But it's absolutely not something I wish to invest in to drive my truck around town, to the beach, or across county.

So I know the difference. The reference to the bandana was just another form of cooling (yes, evaporation). And I can attest to the fact that the big outdoor chiller fans that mist water into the air (also evap) are worthless down here is +80% humidity.

In any event, neither are something I wish to incorporate into the cab of my daily driver. But they do get the job done in a race car or on a bike (two different types of cooling)..

 

[ramdough]

Yep, 12V are more common and less expensive than 24’s, but at least it is better than it used to be 10-12 years ogo...

Because of the way they designed the Neihoff alternators, I am really loath to add any additional 12V load, especially considering that is where most of it already is when the lights are turned on. The alternator output is controlled by the application of field current and the regulator controls that by monitoring and maintaining the 28V Just like any alternator does. The reg switches the 12V output on and off with SCR’s to regulate that voltage like a switching power supply. You must however have the base energy available(provided by the field) to switch so you can maintain 12V under load. I could see a situation where you might not be able to provide for a very large 12v load if the 24V side was not also loaded enough to drive the field...

Why not get a battery balancer that is rated for 100a, make the alternator just push 24v (remove all 12v loads from the alternator side), then draw all of your 12v off of the balancer?

Not sure if I said that right, but hopefully you get the question that I meant to ask.


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[coachgeo]

Yes, we used run desert cars (I still own two prerunners). I'm quite familiar ..... But it's absolutely not something I wish to invest in to drive my truck around town, to the beach, or across county.
....

In any event, neither are something I wish to incorporate into the cab of my daily driver. But they do get the job done in a race car or on a bike (two different types of cooling)..

yeah in normal configuration they.. as in a suit, would not work as you say.... that is why I was thinking poncho-ish and not "suit" Could even be a shaw/blanket-ish... kind of thing attached to the seat belt. So as you pull your belt over yourself; it literally pulls right along over ya.. at the same time. no fuss .... in and out in a jiffy.

 

[Third From Texas]

I actually have a Bussmann 21100E00 still in the box. I was going to install it as a balancer but I can get another one to run as a converter.

You have better ideas on this than I do. I haven't put much thought into the concept of this yet, but that is exactly why I picked up the Bussman originally (I got it for my first A0 truck and was going to use a 24v alt and the converter to step down the 12v side. Then I got the A1R and it's planned use shifted to balance (I have a 12v leak that is beyond just the trans but damned if I can trace it). .

 

[Third From Texas]

yeah in normal configuration they.. as in a suit, would not work as you say.... that is why I was thinking poncho-ish and not "suit" Could even be a shaw/blanket-ish... kind of thing attached to the seat belt. So as you pull your belt over yourself; it literally pulls right along over ya.. at the same time. no fuss .... in and out in a jiffy.

I follow. But the Fast Cooler box was like $1500 back in the day. No idea what they run these days. I'd love to have one for the full day runs down Padre to Port Mansfield jetties in the prerunner but not very practical. .

Still, I'm looking at AC options for the truck...not so much alternatives.

Thanks for mentioning it, it brought back some fond memories...

 

[Ronmar]

Why not get a battery balancer that is rated for 100a, make the alternator just push 24v (remove all 12v loads from the alternator side), then draw all of your 12v off of the balancer?

Not sure if I said that right, but hopefully you get the question that I meant to ask.


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That is exactly what you should do, except you have to also change the alternator I plan on shifting to a straight 24V alt and equalizer if/when my 24/12 alt fails... not necessarilly because of the way the alt works, but because of the VERY high cost of the 24/12 neihoff’s compared to the commercially available 24V alts and equalizers.

The 24/12 Neihoff regulator is designed to charge AND balance series wired 12V batteries. Its regulator is looking for that 12V buried within the 24V series string, and will keep the alternator offline if it doesn’t see it(Discovered this trying to separate and measure actual electrical loads/power needs)

In the case of the 100A Neihoff, 24V@ 50A is 1200W. 12V@ 50A is 600W for a total of 1800W output. If you could stop using the 12V output, your available output/supply would drop by 1/3.

Not sure what the breakdown for the OP’s 260A alternator is, but this isn’t really an issue as long as he keep the 24V side adequately loaded, which is why I brought up the subject. The Neihoff reg does a pretty good job of balancing the batteries. I think the biggest cause of issues with the LMTV electrical system was the pairing of the 100A alt with the grossly oversized battery bank. This leads to regular occurrences of partial battery charge(usually 12V) and near constant alternator overload and failure... I think that is why the A1R got the 260A alt. Thats the alt the A0 should have gotten

 

[Third From Texas]

That is exactly what you should do, except you have to also change the alternator I plan on shifting to a straight 24V alt and equalizer if/when my 24/12 alt fails... not necessarilly because of the way the alt works, but because of the VERY high cost of the 24/12 neihoff’s compared to the commercially available 24V alts and equalizers.

The 24/12 Neihoff regulator is designed to charge AND balance series wired 12V batteries. Its regulator is looking for that 12V buried within the 24V series string, and will keep the alternator offline if it doesn’t see it(Discovered this trying to separate and measure actual electrical loads/power needs)

In the case of the 100A Neihoff, 24V@ 50A is 1200W. 12V@ 50A is 600W for a total of 1800W output. If you could stop using the 12V output, your available output/supply would drop by 1/3.

Not sure what the breakdown for the OP’s 260A alternator is, but this isn’t really an issue as long as he keep the 24V side adequately loaded, which is why I brought up the subject. The Neihoff reg does a pretty good job of balancing the batteries. I think the biggest cause of issues with the LMTV electrical system was the pairing of the 100A alt with the grossly oversized battery bank. This leads to regular occurrences of partial battery charge(usually 12V) and near constant alternator overload and failure... I think that is why the A1R got the 260A alt. Thats the alt the A0 should have gotten

Yeah, I should have been more clear about swapping the alt. I think Sean Fulner was the first I ever saw mention it a couple years back but he went to a 200a Niehoff out of a HMMWV instead. That was when I snagged the Bussman, though. As I said, it was when I still had my 100a A0 (I'm the OP and I have the 260a alt on my A1R) . Like you, if my Niehoff ever takes a dump, that's the plan. I even know one person who actually did this (Alex from ACELA who works with Seth up in Siberia...err, Montana). Heh

 

[Third From Texas]

I would like more info on the 260a Niehoff. There is so little out there on the A1R trucks (especially electrical) and I honestly had no idea it even came with the 260a until I got it home.

 

[Third From Texas]

Hmmm

May have to do some cypherin'

Product Code:	N1224-1
NSN:	2920015592715
Voltage:	28/14
Output (Amps):	260/140
Dual Voltage:	Yes
Mounting Configuration:	Hinge Mount
Regulator Options:	N3221
Regulator Configuration:	External

 

[ramdough]

That is exactly what you should do, except you have to also change the alternator I plan on shifting to a straight 24V alt and equalizer if/when my 24/12 alt fails... not necessarilly because of the way the alt works, but because of the VERY high cost of the 24/12 neihoff’s compared to the commercially available 24V alts and equalizers.

The 24/12 Neihoff regulator is designed to charge AND balance series wired 12V batteries. Its regulator is looking for that 12V buried within the 24V series string, and will keep the alternator offline if it doesn’t see it(Discovered this trying to separate and measure actual electrical loads/power needs)

In the case of the 100A Neihoff, 24V@ 50A is 1200W. 12V@ 50A is 600W for a total of 1800W output. If you could stop using the 12V output, your available output/supply would drop by 1/3.

Not sure what the breakdown for the OP’s 260A alternator is, but this isn’t really an issue as long as he keep the 24V side adequately loaded, which is why I brought up the subject. The Neihoff reg does a pretty good job of balancing the batteries. I think the biggest cause of issues with the LMTV electrical system was the pairing of the 100A alt with the grossly oversized battery bank. This leads to regular occurrences of partial battery charge(usually 12V) and near constant alternator overload and failure... I think that is why the A1R got the 260A alt. Thats the alt the A0 should have gotten

Ronmar,

In almost every case, I just assume you know more about trucks than I do, but I thought their construction was different. Please correct my thoughts below.

I thought the alternators had two sets of coils that were in series. Take one coil and you get 12volts when you add in the second coil you get 24volts. So, all amps are flowing through the first coil. I thought the first coil limited the amps because all amps for both voltages went through that coil. So, if you lowered the 12v amps, you could raise the 24v amps. If this were true, I could leave a small draw on 12v so the alternator brains thinks everything is ok, then pull everything else off 24v.

Is my logic all wrong?


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[coachgeo]

unnecessary fluff..... moderator feel free to delete.

 

[Ronmar]

Ronmar,

In almost every case, I just assume you know more about trucks than I do, but I thought their construction was different. Please correct my thoughts below.

I thought the alternators had two sets of coils that were in series. Take one coil and you get 12volts when you add in the second coil you get 24volts. So, all amps are flowing through the first coil. I thought the first coil limited the amps because all amps for both voltages went through that coil. So, if you lowered the 12v amps, you could raise the 24v amps. If this were true, I could leave a small draw on 12v so the alternator brains thinks everything is ok, then pull everything else off 24v.

Is my logic all wrong?


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I made some assumptions based on the only drawing I have seen that the windings were in parallel, but the idea of them being in series is interesting and makes sense on a couple of levels. Regulate the field current to maintain the desired combined series winding 28V output. Tap the junction between the two series windings and switch that output with SCR’s to regulate it. The same 12V current limitations would apply as you still need field excitation and that comes from 24V but pulling the 12V load out of the series would effect the 24V output and help provide for some of that and provide a little better for mismatched loads, but using only half the windings would still limit 12V output to around half the combined output...

A typical alternator is a “Y” configuration. putting two in series I believe would basically form 2 delta’s which is what the drawing shows... The drawing is also missing a ground off of the SCR “rectifier” to complete a 12V circuit, so wired in series makes sense there as well

Thats funny, our discussion last night got me thinking about how to convert a dual volt to single volt without loss, you would not want a 12V load on the alt, but I think the regulator could be fooled into operation by sending just the regulator 12V(14V) sense line a signal from the middle of your balanced battery bank. If the windings are in series, you would simply disconnect the 12V side and take the total output off the 24V side, providing the rectifier is equipped to handle that much load.

If the windings were in parallel, and more importantly were similar in composition, and with the regulator fooled as above, you could send a steady DC voltage to the SCR’s effectively turning them into diodes. Then you would tie the 12V output to the 24V output and let the regulator control the field to regulate the combined output...

Series wound would be easier provided the rectifier bank can handle the added output...

in the end probably cheaper and time better spent getting a larger already configured single volt alt... you could sell a working 100A dual volt and probably buy 2 of them

My Apologies to Third From Texas for turning an interesting A/C discussion into an alternator discussion...

 

[simp5782]

Some alternators simply use a transformer to change 12v to 24v. These are the ones you don't want. It's always a small 24v voltage

24v alternators are cheap in the 100amp to 200amp range from Delco. They also have remote sense alternators available. I have ran a standard 24v alternator on 12/24 trucks for a bit using the Eaton 100amp Equalizers. They run a 36amp blower unit in my 915. I drew directly from the 12v on the battery so that the remote sense would kick on when the draw from the AC was present. Rather than it being pulled from the equalizer or its control solenoids.. Upgrading your alternator feed wire would be great as 4awg is rated to 90 amps. I ran 1/0

Equalizer systems require either a 12v switch side solenoid or 24 and 12. I run both

 

[Third From Texas]

My Apologies to Third From Texas from turning an interesting A/C discussion into an alternator discussion...

I hate you ! ;p

Seriously, this is part of the equation for one option so it is important. Most owners are running the 100a alt, so an alt swap would be in order. And given the dual voltage Niehoffs do tend to fail (and are *grossly* underpowered for our trucks) swapping to a 24v and then stepping down some for 12v can be done for $500-600 makes it a desirable option (compared to the $2000 for a refurb).