I am always fantasizing about having a energy efficient air conditioner for van life, anyone seen any concepts in tech news or anything?

So i have that 8k midea and while that pic doesn’t list a starting watts, as far as i can tell from watching on a power meter there is NO start ‘surge’ or at least not one that goes over the normal max running watts. I assume this is the case on mini splits as well and have been considering that to be one of the major advantages of running an incerter ac.. off of an inverter. ? You dont have to size the inverter for a peak load that only happens 1% of the time.

Also, down here in south texas where it has hit 108f so far, i saw my midea 8k hit 1000w at times. I rarely run it on highest settings but it makes sense that inverter units would be no better or slightly worse efficiency at max output since more conversions are happening.

Vigo said:

So i have that 8k midea and while that pic doesn’t list a starting watts, as far as i can tell from watching on a power meter there is NO start ‘surge’ or at least not one that goes over the normal max running watts. I assume this is the case on mini splits as well and have been considering that to be one of the major advantages of running an incerter ac.. off of an inverter. ? You dont have to size the inverter for a peak load that only happens 1% of the time.

Also, down here in south texas where it has hit 108f so far, i saw my midea 8k hit 1000w at times. I rarely run it on highest settings but it makes sense that inverter units would be no better or slightly worse efficiency at max output since more conversions are happening.

Click to expand...

Where are you running the midea ac? Just curious does it stay running the whole time? Even after it reaches temperature?

Vanconversion21 said:

So I've got a portable, I'm in Florida and like it chilled inside. 74 degrees during the day and 67 at night. My setup is on the first page.

My whynter exhausts the heat outside and right now we don't have the air input hose connected because I didn't want to cut another 6 inch vent hole I might not need in the side just to run hot and humid air from Florida through the system.

I read all the arm chair physicists posts that this was awful and wasted time, energy and whatever. I tried it out and it works just fine.

When the unit is running you notice the doors are a fair bit harder to open, obviously due to pressure differences but there is no noticeable air leakage at the door seals nor the fantastic fan vent or anywhere else for that matter. Yes, I know there's is air leakage, yes I know the rules of physics apply to my van what I'm telling you is the same is true for every structure, every vehicle etc and in the case of cooling the inside of my van it hasn't impacted performance at all. Much less to the degree that people stress about it.

We spray foamed the crap out of our van so we don't have a ton of gaps and cracks exposed so besides our seals the only other place air comes in is probably from the vent where it's already venting and where I would have placed the return vent anyway. That cabinet is a good spot because the air conditioner is there and it tends to over cool the area in its vicinity so we insulated the output to the vans inside and the minimal amount of air leakage from that cabinet isn't noticable even when looking for it. Even in the rear near the vent and the heat of the unit, there isn't noticeable temp, humidity difference nor is there noticeable air flow from the outside via the exterior vent.

Regardless, real world, venting that second hose hasn't mattered one bit.

Ymmv.

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This is a non analytical observation. You tried it one way only, and thus declare the other way isnt necessary or significant because of the results of the one way you tried.
There are a lot of reviews and tests out there that show dual hose portables are far more effective than single, as if common sense and a good grasp of thermodynamics isnt enough.
Single hose portables give you something cold to sit in front of. Dual hose units will actually lower the temperature of a room.
Many single hose units can be converted to dual hose use with a little ingenuity if you dont mind a little more bulk and hassle. Some have so many gaps within the case that to isolate that section youd have to disassemble the unit and re engineer it with adhesive and foam most people wouldnt consider it.
I would just for the challenge.

Q-Dog said:

Finally, someone gets it.

Yes, the unit would have to be modifired to work in a van. It is not designed to draw condenser air from outside the room.

The intake air side.
View attachment 44526

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Youd have to cover that intake with something like a roof vent flashing out of galvanized steel, then attach a hose to it. Thats provided there arent gaps in the cabinet that render the filter nothing more than window dressing. Ive seen portables like that, sad.
But what is that, 2k BTU?
I have heard that most oem auto air conditioners have an output equal to about 12k btu, to cool a glass and steel box.
Sounds about right.
I put a portable ge rated at 5k/7k in my honda odyssey last year, converted it to dual hose using the method described above. I insulated the exhaust hose fully with foam tape over the hose and an aluminum rigid duct over that. Both hoses were mounted to a plywood window filler mounted to the drivers side rear door window, sufficiently spaced apart, and had rubber seals to keep it relatively a closed system. It worked, although performance was disappointing. It lowered the temp but not like Id hoped. Probably needed about 12k. I picked the GE because it was very small.
I powered it with a generator of course.

Im thinking next I will try a double window fan mounted in a thin plywood frame, dropped into the power sunroof. The kind you can switch from intake to exhaust. It wont have to be a full seal but should be sealed enough to force cool air in.

eXodus said:

Interesting thought:

Just replace the engine driven Compressor on the Van with an Electric one - and use the onboard A/C components to run cooling ?

Click to expand...

Almost any automotive application I can imagine ties the HVAC into multiple aspects of the cars operation. The compressor is definitely connected to the ecm, youll have to power up the car to use the blower... The amount of re engineering would be staggering.
Thats an end your marriage project.

Some guys might be looking for that, I know I would if she was still around.

(I just thought of that after seeing a hot rod video on youtube, he said it cost him $200k, twenty years, and two wives. Then they took it for a ride, the brakes failed and he wrecked it!)

Ase Master tech here. Up until somewhat recently most cars had no electrical connection to the ac compressor other than a circuit to activate the clutch. Of course there are many variable displacement compressors in use now. But many vehicles wouldnt know or care if there was even anything plugged into that clutch connector.

Of course many cars do several other things like idle control and condenser fan etc when the ac is ‘on’, but all those commends come from the ecu.

So what i’m saying is there are plenty of cars where if you replaced the engine driven compressor with an electrically driven compressor, the rest of the system would function normally.

Moltensurf said:

Where are you running the midea ac? Just curious does it stay running the whole time? Even after it reaches temperature?

Click to expand...

In my bedroom, roughly 160-180sq ft.

It has an eco mode which will allow it to ‘turn off’ when it reaches the set temperature and then run briefly every 10 minutes to see if more cooling is needed (it seems without airflow, the interior temp sensors of window units in general don’t sense actual room temp). Sometimes when i begin to wake up in the morning at 5-6 (waking up is not GETTING up, lol) the unit is ‘off’ in eco mode, and other times it’s running continuously, but that doesn’t mean it never turned off earlier while i slept.

So i dont have precise info on what it does when i sleep, but i know my house uses roughly 2kwh while i sleep, and i believe the midea is most of that, with the fridge a distant 2nd.

Vigo said:

Ase Master tech here. Up until somewhat recently most cars had no electrical connection to the ac compressor other than a circuit to activate the clutch. Of course there are many variable displacement compressors in use now. But many vehicles wouldnt know or care if there was even anything plugged into that clutch connector.

Of course many cars do several other things like idle control and condenser fan etc when the ac is ‘on’, but all those commends come from the ecu.

So what i’m saying is there are plenty of cars where if you replaced the engine driven compressor with an electrically driven compressor, the rest of the system would function normally.

Click to expand...

Since nobody here is actually gonna do this its probably a hypothetical debate, but my C4 Corvette (1986) had a connection from the high pressure head sensor(think that is the term)of the AC system to the ECU. It sensed when the AC was working hard, and caused the main cooling fan to turn on provided: the coolant temp was above 160f, and the car was below 35 mph.
I knew that because of some tips in a TPI tuning manual I had bought. GM liked to run these cars at about 224f, for emissions reasons if you could keep it about 160f and used a recalibrated and relocated MAT sensor you could exploit the timing advance and gain at least 10% more power in some conditions. Since my AC was long broken anyway I just hooked up a switch to that wire and the cooling fan ran up till 35mph, and it stayed around 160-165f on all but the hottest days.
You did have to replace the fan motor every coupla years, it was a whole $27 from the dealer. An added bonus was without all the excess underhood heat the stock wire harness only had to be replaced once.

I mistakenly overcharged the system in a 1995 honda passport (isuzu rodeo) I owned, when the system went into overpressure on a near 100f day, it shut the engine down. Wouldnt run until I bled some refrigerant out. So there was some sensors in there too that tied into the ECU and that was a very primitive vehicle.

And thank goodness Isuzu pulled out of north america. They were the bottom feeders of japanese cars. Maybe because GM owned 49%? I think they were the model for that michael keaton movie "gung ho".

There are typically pressure sensors but they are rarely mounted directly to the conpressor and so would still function normally if some other compressor was making that pressure.

As far as not running while overcharged, many small 4 cyls can be stalled by an ac compressor trying to make 500psi because they dont have the excess power at idle to do that, and the idle control system back in the cable throttle days didn’t habe the range of authority to throttle the engine up enough to compensate. Old ‘dumb’ systems would activate the compressor clutch any time the key was on and the button was pressed (you can hear the compressor clutch clunking on some older cars with key on engine off and hotting the ac button) so the car would attempt to start with an engaged compressor even if there were a bunch of pressure on the high side. Even $120 window units are technically a lottle smarter than that. Most cars had low pressure cutoff switches only and could not monitor high side pressure at all. The only safety mechanisms they had in that regard is they would often disallow compressor operation over 4000rpm or so, and had an actual popoff valve set to ~500psi or so, which is maybe a little better design than a ‘total loss oiling system’ but not much better! High side pressure monitoring even when it was there was often a simple pressure switch to either raise idle speed or turn on the condenser fan. Actual pressure transducers that could measure the pressure across a range were not common until somewhat recently.

The ac system on cars really was ‘dumb’ in most regards even into the 2000s and if you put an electric compressor on it it mostly wouldnt know or care on those systems. But yes for the most part noones doing it anyway.. lol

Vigo said:

So i have that 8k midea and while that pic doesn’t list a starting watts, as far as i can tell from watching on a power meter there is NO start ‘surge’ or at least not one that goes over the normal max running watts. I assume this is the case on mini splits as well and have been considering that to be one of the major advantages of running an incerter ac.. off of an inverter. ? You dont have to size the inverter for a peak load that only happens 1% of the time.

Also, down here in south texas where it has hit 108f so far, i saw my midea 8k hit 1000w at times. I rarely run it on highest settings but it makes sense that inverter units would be no better or slightly worse efficiency at max output since more conversions are happening.

Click to expand...

Real inverter units compressors are three phase and constantly optimize voltage/current phase for load. Very little wasted power.

Batvette said:

Since nobody here is actually gonna do this its probably a hypothetical debate, but my C4 Corvette (1986) had a connection from the high pressure head sensor(think that is the term)of the AC system to the ECU. It sensed when the AC was working hard, and caused the main cooling fan to turn on provided: the coolant temp was above 160f, and the car was below 35 mph.
I knew that because of some tips in a TPI tuning manual I had bought. GM liked to run these cars at about 224f, for emissions reasons if you could keep it about 160f and used a recalibrated and relocated MAT sensor you could exploit the timing advance and gain at least 10% more power in some conditions. Since my AC was long broken anyway I just hooked up a switch to that wire and the cooling fan ran up till 35mph, and it stayed around 160-165f on all but the hottest days.
You did have to replace the fan motor every coupla years, it was a whole $27 from the dealer. An added bonus was without all the excess underhood heat the stock wire harness only had to be replaced once.

Click to expand...

Most people think one can simply install an electric compressor and run the ac system and that would be the power draw. It would require a cooling fan at the condenser and blower on the evaporator which will probably draw as many watts as the compressor and both would run basically non stop.

The best ac units for use in a stationary vehicle is an inverter mini split. I researched the 12V and 24V units and the COP was not there compared to an inverter mini split.

Batvette said:

I mistakenly overcharged the system in a 1995 honda passport (isuzu rodeo) I owned, when the system went into overpressure on a near 100f day, it shut the engine down. Wouldnt run until I bled some refrigerant out. So there was some sensors in there too that tied into the ECU and that was a very primitive vehicle.

Click to expand...

Most likely the engine couldn't handle the load. The PT Cruiser was known to have engine cooling fan issues, when the fans failed and head pressure was high, the vehicle engine would stall at stop signs.

There should have been a high pressure cutoff switch in the Honda as high head pressures are common when a vehicle is first started with a high interior heat load and a high ambient temp with high humidity. Having the engine shut down due to high head pressure would be dangerous while driving in slow traffic as power steering and even the power brakes would be affected.

Batvette said:

And thank goodness Isuzu pulled out of north america. They were the bottom feeders of japanese cars. Maybe because GM owned 49%? I think they were the model for that michael keaton movie "gung ho".

Click to expand...

Isuzu makes the Duramax diesel engine and I can tell you I own 2 trucks with the Duramax. I have found the engine is reliable and a very well built unit provided it isn't abused.

Vigo said:

Ase Master tech here. Up until somewhat recently most cars had no electrical connection to the ac compressor other than a circuit to activate the clutch. Of course there are many variable displacement compressors in use now. But many vehicles wouldnt know or care if there was even anything plugged into that clutch connector.

Of course many cars do several other things like idle control and condenser fan etc when the ac is ‘on’, but all those commends come from the ecu.

So what i’m saying is there are plenty of cars where if you replaced the engine driven compressor with an electrically driven compressor, the rest of the system would function normally.

Click to expand...

I was thinking about this on my ram promaster. The ac system is really cold. It would be nice to run it on solar

Vigo said:

There are typically pressure sensors but they are rarely mounted directly to the conpressor and so would still function normally if some other compressor was making that pressure.

As far as not running while overcharged, many small 4 cyls can be stalled by an ac compressor trying to make 500psi because they dont have the excess power at idle to do that, and the idle control system back in the cable throttle days didn’t habe the range of authority to throttle the engine up enough to compensate. Old ‘dumb’ systems would activate the compressor clutch any time the key was on and the button was pressed (you can hear the compressor clutch clunking on some older cars with key on engine off and hotting the ac button) so the car would attempt to start with an engaged compressor even if there were a bunch of pressure on the high side. Even $120 window units are technically a lottle smarter than that. Most cars had low pressure cutoff switches only and could not monitor high side pressure at all. The only safety mechanisms they had in that regard is they would often disallow compressor operation over 4000rpm or so, and had an actual popoff valve set to ~500psi or so, which is maybe a little better design than a ‘total loss oiling system’ but not much better! High side pressure monitoring even when it was there was often a simple pressure switch to either raise idle speed or turn on the condenser fan. Actual pressure transducers that could measure the pressure across a range were not common until somewhat recently.

The ac system on cars really was ‘dumb’ in most regards even into the 2000s and if you put an electric compressor on it it mostly wouldnt know or care on those systems. But yes for the most part noones doing it anyway.. lol

Click to expand...

The rodeos are all V6s but hardly overpowered so what youre saying makes sense. I think it was 1994 model that dropped the GM V6 and went to their own SOHC 6VD1 powerplant.

Zwy said:

Isuzu makes the Duramax diesel engine and I can tell you I own 2 trucks with the Duramax. I have found the engine is reliable and a very well built unit provided it isn't abused.

Click to expand...

We are going off topic so I will be brief. Isuzu being primarily a truck company it doesnt surprise me they get diesel engines right. The issues with their gas engine SUVs in North America were well documented, including premature frame rust, what killed them was an issue with their V6 redesigned around '98. It would run a little low on oil, like less than a qt... Then starve #1 cylinder of any lubrication and seize. Isuzus response was to blame the customer. When the cause was proven to be faulty design they didnt apologize and do a campaign, they just kept blaming customers and charging them.. That coupled with criticisms from auto media that their designs were all years behind competitors and GM divesting their interests (causing the loss of much of their dealer network) caused sales to plummet to a few hundred units a year in the 00s till they quit altogether.
I was a frequent poster at planet isuzu forums, they do have their faithful and were top of their class in off road driving. Most admit they only own them because they got them cheap, as did I.
The passport/rodeo I owned for 8 years was 8 years old when I got it. I put about 70k miles on it. The engine ran when I sold it but was on its last legs leaked a qt of coolant every mile, lifters ticked like mad, the tranny had a fierce howling noise. It had substantial numbers of repairs required compared to other japanese branded SUVs, to be fair it was assembled in the US with many US sourced parts as GM was a partner to ISUZU. The engines were GM until 94, but the Isuzu V6 that replaced it was not an improvement. I would summarize my criticism of "bottom feeder of japanese brands" with a comparison to a friends Toyota 4 runner of the same year. It was a bad joke compared to the Toyota in every aspect. The rodeo might seem viable if youve never driven a 4 runner.
Strangely enough in those 70k miles not once did it break and leave me stuck.

Enough of off topic, what does everyone think of this little gem:


Looks impressive. Is it $2300 with battery impressive? There are reviews on youtube, positive but not quite giddy about it.
The price wouldnt scare me if I knew for sure it worked. Well.
A bonus is that it seems it can charge off 12v, if not outright run on it.

Batvette said:

Almost any automotive application I can imagine ties the HVAC into multiple aspects of the cars operation. The compressor is definitely connected to the ecm, youll have to power up the car to use the blower... The amount of re engineering would be staggering.
Thats an end your marriage project.

Click to expand...

the problems is slowly solving itself with many Plugin Hybrid Vans. Their A/C compressors are usually DC driven by the high voltage battery.

So just needs a little bit of CAN-Bus hacking to get them working including the interior and exterior fans.

Vigo said:

Ase Master tech here. Up until somewhat recently most cars had no electrical connection to the ac compressor other than a circuit to activate the clutch. Of course there are many variable displacement compressors in use now. But many vehicles wouldnt know or care if there was even anything plugged into that clutch connector.

Click to expand...

that's how my Chevy RV and RAM 1500 are working. Just a stupid 12V line going to the compressor.

The ECM has no clue if that 12V would start a engine driven compressor or a relay to run a DC compressor.
It complains when I leave it unplugged (open circuit) but otherwise the ECM doesn't care.

We could build a cheap relay contraption, which allows starting a DC compressor and the Condenser and blower fans, which shuts off as soon as you start the engine.

eXodus said:

the problems is slowly solving itself with many Plugin Hybrid Vans. Their A/C compressors are usually DC driven by the high voltage battery.

So just needs a little bit of CAN-Bus hacking to get them working including the interior and exterior fans.


that's how my Chevy RV and RAM 1500 are working. Just a stupid 12V line going to the compressor.

The ECM has no clue if that 12V would start a engine driven compressor or a relay to run a DC compressor.
It complains when I leave it unplugged (open circuit) but otherwise the ECM doesn't care.

We could build a cheap relay contraption, which allows starting a DC compressor and the Condenser and blower fans, which shuts off as soon as you start the engine.

Click to expand...

What voltage do they run at though? Is it practical to adapt to a 12v system? Might only be marginally more efficient than using a 110vac AC through an inverter, and I would get a little wary about the safety of playing around with high voltage DC.

FWIW - We live in S FL and needed A/C in order to do our Promaster 3500 extended high top build-out during Covid. Van was Foam insulated by previous guy who used it as a toy hauler/dirtbikes.
Found a Coleman Mach 8 13500 btu A/C on craigslist with intent to use it for build out and then replace it with a maxfan. It is only 8-inches tall on roof and freezes us out when needed.

Thought we would only use it in "plug-in mode" at campsites (if ever) but then wife asked to be able to use her hair dryer, microwave, coffee pot, and have hot water off grid for a few days - LOL - so new plan!

We decided to leave A/C on the roof and I built a 280AH 24Volt LIFEPO4 battery (thanks all for your advice) and put an LV2424 inverter/charger/MPPT unit in it. Coming back from Maine is humid hotlanta we ran A/c for 7 hours while we slept at a cracker barrel and had 40% power left for coffee/microwave in the morning. Not bad!

Looking to add second 280AH 24v pack soon for longer stays. We have 400 watts flexible solar (but frankly it barely makes a dent in charging - flat roof van) and we have a DC-DC 12-24v 10amp doohicky that charges from alternator. When in Nova Scotia we found we need to plug in every 3-4 days w light AC use.

Bottom line is it can be done. My boat has a 12-volt marine A/C that is flakey as hell, water cooled, but kinda works half the time ;-)

" It is only 8-inches tall on roof and freezes us out when needed."

We are now starting the ~3 months where its miserable to be in a metal box in san diego. Not south FL miserable but bad enough. Humidity kicks in and every day is blazing sun. That sounds delightful.

I used to keep a 10k btu window AC running in my spare bedroom workshop 7/24, prolly cost $150 a month but gave me one room in the house of relief. I removed the door and had thick clear plastic strips with magnets so you could come and go with little cold air loss.
It was near the beach so every other year had to buy a new one because the coil fins turned to dust (unless you coated them which added a year)

Curiously LG sells the US air conditioners with bare aluminum coil fins. Go to their intl website, they sell the rest of the world with gold anodized. At least they did about 10 yrs ago.

there is a new 12-volt RV roof mount A?C but I think it is $4k - thats a lot of hotel rooms ;-)