12V A/C anyone?

My Pioneer 120V 9k btu mini splits have a max current on a/c of 750W. The inverter will handle it fine, but has a "floating neutral" that is (an unlikely) hazard. Google that to learn more and decide.

If you install a 120V mini-split or similar, the Tripac should start up when needed to keep the batteries charged. Of course if you set it on a/c it will be running all the time anyway. Although you may want to look into an alternator upgrade for it. The originals are only 37A if memory serves.

 

I think all you need for right now is a Vornado air circulator. Point up and towards the rear of your sleeper. It takes about 15 minutes for the Vornado to circulate the air, but since most APU tie the air outlets into the vents, it’s not circulating the air properly. Heat rises and tends to stay up top. This is good during colder weather but bad during warmer weather. Make sure to get the Vornado that is good for 100sq feet. Also, make sure you have heat shields on all windows up front.

APU’s do work, but the problem many of us have had, and decided to seek alternative options, is when they break. I paid $12,000 for my APU and it last for maybe a year. Then no one could fix the dang thing. At one point, I was in the shop every week trying to get the thing to work again. That’s when I threw in the towel and gave up.

I still have my Vornado but since I now have a mini split installed and the evaporator is mounted up top, I don’t have that hot spot up there. The swing function does a great job of moving the air throughout my truck. In 100+ degree weather, I was able to keep my truck in the low 70’s. I freeze myself out at night. This is with my batteries being a complete mess right now. I’m fighting to get them replaced under warranty through Freightliner. I have a 5 year warranty but Freightliner doesn’t want to honor their warranty.

 

It’s been well documented for years that the Tripac doesn’t cool double bunk sleepers well at all. Only a few people here have said the opposite. My company issued trucks did poorly during a normal summer. I would have probably used blankets or sheets to block off as much of the top as possible, even though that would have been a PIA.

Others have said it makes a difference to get the air venting up higher and not at floor level. How much that helps I don’t know.

 

When I drove for USA Truck (which I did enjoy) my sleeper was a double bunk but I ran solo. The APU a/c vented into the sleeper from under my bed. So about 10" off the floor. I got a 9" fan and taped some cardboard to it like the bill of a hat. I flipped the fan so it blew air upward. I placed the fan on the floor right in front of the vent. The cardboard was now vertical so it could stop the cold a/c air right on top of the blades. Made a huge difference and rather quickly too.

 

Thanks you three (and all), working on this angle is what I'll try next. It's interesting that since I bought my APU about two years ago, I see that now Thermo King is offering an option that they call an "Air Tower". So this problem indeed has likely been well documented.

BTW - I had already purchased a set of custom fitted window reflectors. They do help, but the issue still remains.

 

The air tower. That’s it. I was trying to think of that not long ago trying to help someone else out. Thanks for posting. Sorry you are having issues.

 

Although the air tower seems to be a good idea of getting more air into the cab, the initial problem still remains which is moving the cool air up when you have an ultra loft truck.

Most trucks have one tower already built into the cabinets but I have found that the issue is the way these towers are positioned. The towers are built facing the back of the cab instead of facing the front of the cab so that air is blown out and forward.

I no longer have this issue because my evaporator is mounted up top and facing forward which blows cool air out and forwards. This cool air then cools the top and flows downward.

As heat rises and cool air likes to stay low, my entire inside truck has a consistent temperature. I’ve eliminated hot spots and when I sit in the driver’s seat you can feel the air. I’ve cut up paper into strands and place them around my truck to make sure I can see how the air flows. The is blow out from up top towards the front top, this air then gets sent back into the lower bunk creating a cool breeze.

The only problem I now have is that the top, no one can sleep in because they would freeze. But there was only one person I watched on YouTube who mounted the evaporator over the driver/passenger seat and this required extensive customization of the coolant lines. And, you lose that overhead space.

If budget is not an issue, the only solution that I have found is this for $5,000 not including all parts and installation;

HD-12L - 12 Volt DC Mini Split System Air Conditioner

All together, you’re looking at $6,000 to $7,000 for complete system that installs directly into your ducts like an APU. It will take up under bunk space and still need space for batteries.

Budget wise, I think these truck mini splits are the cheapest route right now if you own your truck and can customize it. Heck, if you don’t want to run it off batteries you can run it off a gas generator for about $500. Total cost is only $1,500. Way cheaper than any APU and way less maintenance costs.

 

Update:

I ordered a 300ah LIfepo4 battery and 40amp DC to DC Renogy charger to be installed under my bunk. I later canceled the order because I’m still not understanding if this will work as expected.

As mentioned earlier, I have IdleSmart and I prefer to continue to use it as I can lock my truck and be away from my truck while the ignition is off and keys are out of the truck, IdleSmart will monitor my truck while I’m away. If the interior temperature gets too hot or cold (Temperature is set by me), batteries get too low ( I can set voltage levels), cold start guard ( I can set temperature), IdleSmart will start and stop the engine ( I can set for how long the engine will idle for). I have compete control of my truck. I don’t want to lose this feature.

Having tested my mini split in Texas heat wave these past weeks, it has faired nicely. IdleSmart data shows that it started my truck most days 4 to 5 times a night. That’s 4 to 5 gallons of fuel per night. During days that I did not run, IdleSmart started my truck anywhere from 7 to 10 times in 24 hours. That’s 7 to 10 gallons in 24 hours depending upon temperatures.

This by far is no comparison to a diesel powered APU. However, in contrast to an APU, my savings isn’t in the fuel, it’s in the maintenance, efficiency, ROI, and longevity of the unit itself. In terms of ROI, I’ve almost recouped my investment (counting how much my former APU cost and maintenance costs).

As far as batteries are concerned, I’m still not fully understanding if the additional purchase cost and installation costs will increase functionality of my unit. Can it shorten the number of cycling needed for cabin comfort? This is where the true benefits come into play for me. From my understanding, adding additional batteries increases the need for upgrades to the alternator to handle the additional batteries. Yet, the benefit of having 2 or 3 less cycles on the battery, is it worth the cost?

I rather just replace my old AGM’s with 4 new X2 power batteries ($2,300) which would costs less than upgrading the alternator and installing LIfepo4 batteries with the need of a DC to DC charger costing well over $4k just to get 2 or 3 less cycling on the batteries. In addition, I’m understanding that during idling, the batteries aren’t getting much of a charge and could end up harming the LIfepo4 batteries as they would continue to discharge below recommended levels. The same is true for AGM/SLA/GEL batteries. The work around would be solar panels. Correct me if I’m wrong here. At least with solar panels, the batteries would get some form of charge between cycles. May not be much, but some.

I’ll have to start researching solar panels for semi trucks now. As it stands, I think I’ll stick with my mini split running off my starting batteries, upgrade the starting batteries to X2 powers ( I need new batteries anyway), and continue to watch the data from my IdleSmart to see if there is any benefits.