12V A/C anyone?

Mounting to the chain rack is preferable anyway, vibration directly on the back of the cab when it cycles is quite the annoyance. (My headache rack is an unenclosed chain only rack, sorta wish id put it down bellow the rack or mounted to backside of chainrack)

Thats virtually the same model i have, be curious what amount of refrigerant you used. Pretty sure i slightly overfilled at the 600 grams they say (22 oz.)
the high/low readings dont seem to be good indicators for as high as im used to on other ac systems.

 

I bought my truck with a Nite system under the bunk. Guessing it was installed around 2008, so I didn't even expect it to work, but I got 4 years out of it until recently the compressor fails to come on. Haven't had a chance to take a look, but parts availability seems to be non-existant. I've looked at those little mini splits and was wondering for the guys with the setup, is there any condensation issues with the low pressure line? Something about having them exposed just seems like it would create a moisture issue.

 

Outside, it doesnt matter, inside, there can be SOME on the insulated (rubber) hose, but really only in excessive humidity situations,best to simply leave them exposed so you can wipe it off if they stay wet, if you wrap it, that can create a place for mold to grow and you wont see it till far later than you want

 

I’ve had mine installed and running for the past 3 weeks and have not experienced any moisture issues just yet. I’ve tested mine down in Texas 110F degree heat and worked perfectly for me. My AGM batteries are very weak currently, but I have the unit wired to them. My IdleSmart keeps them from dying completely and I have it set to run for 1 hour to get voltage back above 12.5v. At night and below 80f degrees, my truck starts maybe 3 times. I really don’t know because I’m asleep but IdleSmart keeps track of how many times my truck restarts and my reports say my truck is restarting 3 to 4 times a day. During 34 hour resets, my truck restarts about 12 times. Again, that’s because of my weak AGM’s and the fact that 1 hour charges isn’t enough to recharge them fully. That’s still good given that during a 34 hour reset, I’m using 12 gallons instead of 34 gallons of fuel.

I’m going to install a 400ah LIfepo4 with DC to DC charger, upgrade my alternator to 300a, and eventually get solar panels installed for trickle charging. My goal is to reach only having my truck restart once in a 10 hour rest period and 2 to 3 times in a 34 hour reset. If Maxswell still made their module, I would get rid of AGM’s and run straight LIfepo4’s upgrading to 700ah to 1100ah. Until then, I’ll run 400ah lifepo4/400ah AGM’s totaling 800ah with possible upgrade to 1600ah (2x400ah run in parallel/400ah AGM’s) based upon further testing.

 

I bought 4 Lifepo batteries before I did enough research on them. I'd have to either use a thermostat to not let them charge under 32F, or buy some type of heater for them, and then use a DC/DC charger for them since just having a voltage sense relay from my start bank would probably either overload wiring or my little alternator. Currently using 4 AGM's as my starting bank, and 4 regular old flooded lead acid deep cycles for the A/C with a 180 amp alternator and everything works. If anyone wants the adventure, I'll give you a good deal on these since I missed my return window: https://www.amazon.com/gp/product/B09CPXJVRD/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

 

Id be interested. I have a bunk heater so low temp charging isnt a problem for me. I had been thinking 2x 230ah but looks close to same list price

 

Are

Are you mounting these on your frame rail in a battery box? I plan on building under my bunk where temperatures are within range. My mini split is wired so that everything is under my bunk, not on the outside of my truck. The only portion of my AC outside is the compressor unit and it’s mounted on back of my cab. Everything else is inside my truck just as they have in RV’s.
I did see in the RV forums that there are heating pads if your LIfepo4’s don’t have a built in heater. For my application, I don’t need a heater.

100a BMS seems a little low for my liking. Also, I rather have one battery versus having 4. One 400ah battery will fit under the bunk perfectly. Yeah you lose space under the bunk. But a tool box in place of a 400lb APU on my side rail is much better and makes up for lost space. There are 500ah lifepo4 batteries but I think it’s overkill. 400ah should be enough to get through 10 hours rest break. I heard of some using 300ah and still not fully depleting the battery overnight.

 

The way mine came, (4) deep cycle lead acids in the passenger step, and the Nite system is all in one box, mounted under the mattress in the center of the storage area (Peterbilt Unibilt sleeper). It's tied into the bunk air vents, but CFM is pathetic and only really comes out the vents on the passenger side of the sleeper. They cut a hole in the bottom of the sleeper for the condenser venting. Not something I would have ever bought, especially with their crazy pricing, but it was already there and still worked, so I figured some marine batteries was a pretty cheap investment at that point.

Seemed like I'd always have a battery or 2 go bad every 12-16 months, and thought I'd just do the Lifepo's, but like I said, I didn't do enough research into them to know I would need heated ones. Since that "house bank" also runs my Espar, without changing around wiring, I'd have to have something to protect them from cold charging. I actually bought a temp control, and relays to cut power to them, but never got far enough along to install, or buy a DC/DC charger since my current lead acids decided to last over 2 years this time around.

I figured if I bought one of those mini-split things, I'd just mount my condenser under the sleeper as well as the "air handler" and just run a couple vents up the back wall, depending on what kind of airflow they produce. Even if my batteries were in the sleeper area, I'd still need freeze charging protection of some type, since half the year since I don't typically spend more than a few nights a week in the truck..

 

Having now driven my relatively new T680 with a Tripac Evolution APU in 100+ degree heat for an extended period of time this last week, it's confirmed. The TK Tripac AC unit is not coming anywhere close to keeping my high roof sleeper survivable, let alone comfortable. And having payed $14,000 for this piece of garbage, I have to admit that thoughts of murdering a few TK dealership staff have been crossing my mind...and my poor cats, too! (/s)

I still haven't had time to properly think this through yet, but this thread popped up and I thought I'd go ahead and ask for some advice. So far my options seem to be something like this?

1) Idle the truck instead of using the APU (I can't begin to tell you how much this grates on me).

2) The APU does have an upgraded 120amp alternator and a 2,000 watt inverter, and I suppose I might try running a supplementary portable AC unit, or perhaps even better a small mini-spilt heat pump off of the electric system? I haven't had time to run the electric load numbers myself (it will be a struggle, I'm not an expert), but do you guys think I likely have the headroom to do this? Truck electrical fires make me nervous. If I went the 120v route, how dangerous is it running the snot out of an inverter like that?

 

If you are worried about electrical fire, just get a GOOD inverter that is capable of double your maximum draw and make sure the electrical cables running to it are properly sized, and make sure its ventilated. Moving dc to ac (and viceversa) involves loss in the form of heat, heat buildup = bad

Inverter death is usually from running at the absolute capacity, usually over the recommended duty cycle