Idling engine to power AC or heater

[wallyflint]

Converting my high roof Ford transit short wheel base cargo van into camper van and hitting the road! Yay! Can't wait!

Thinking of using a portable air conditioner with a 5,000 BTU rating -

https://www.midea.com/us/air-condit...se-3-in-1-portable-air-conditioner-map05r1wwt
This unit draws 824 watts. I am planning to idle the vehicle to power the AC. My inverter is 1500 watts, and my alternator is a 250 amp alternator. At 12 volts, 824 watts is 69 amps. This would seem to be well within the range of what my alternator can supply continuously... or is it? Are my calculations accurate? Is my thinking correct?

Thanks in advance for any help!

 

[bullfrog !]

In my opinion running a huge engine to run an expensive oversized alternator to power an overpriced poorly performing air conditioner even one that can be vented properly at todays fuel prices in not a good idea. Many large RV owners try to save money by running their generator and roof air conditioners rather than using their vehicle engines power to run their air conditioning in order to cut down fuel and maintenance costs. Take a look at the maintenance and fuel costs for some ambulances that do that. A simple 2500 watt dual fuel inverter generator and an efficient 5,000 btu window air conditioner will do the job for much less with little wear and tear on you primary vehicle. Most of those generators require an oil change of 20 oz of oil every 100 hours and are a diy easily done. Not so with your primary vehicle I bet! Will it work? Probably, but not well ( ducts and vents are not very well insulated and are required for those units to work well ) or cheaply after you consider the costs of wear and tear and upkeep of your vehicle’s motor, drive belts, cooling system and alternator.

 

[Overland One]

https://www.walmart.com/ip/seot/966...e6-438c-b443-0fbcba1341ea&listRegistryType=WL Here is a link to the window AC unit (Keystone KSTAWO5CE) I am installing in my Dodge van. It is a 5,000 BTU unit but, it only draws 446 watts. I did a lot of research before deciding to get this one. I agree with bullfrog, while I have 720 watts of solar that I can run the ac from, I also have a champion 2000 watt inverter generator for after sunset and cloudy days. that will run for up to 11 hours on a tank (1 gal. ) of gas. My van has a 135 amp alternator but I would not even think about using it to run the ac unit. Most vehicles, unless they were specifically designed for long idling times like Police cars, would not do very well being at idle for extended periods. This puts stress on many components of the vehicle and can shorten the life of catalytic converters too. If you think about the life of your engine being measured in hours instead of miles, you can see that you would be shortening the potential miles your vehicle will go before it dies. In other words, instead of driving 70 miles in a hour, you idle for an hour so that's 70 less miles (not exactly but you get my point) that your vehicle will be able to travel in its lifetime. That can really add up over time. If you think about it, my generator engine is 80cc (4.88 cubic inches) as opposed to my van's engine which is 318 cubic inches, does it not make more sense for me to use the 80cc engine? When that wears out, I can buy another one for about $350. (Probably cheaper than replacing your alternator) I don't even want to think about what it would cost to replace the 318.

 

[eDJ_]

You may search this site for window air conditioners as this has been discussed here for some time now. One desirable feature mentioned frequently is the EZ-Start or Soft-Start compressor which requires less power to begin the cooling cycles. Thus less load on a generator.

 

[Spaceman Spiff]

Ford Transit V6 takes about 0.6 gallons of gas to idle for 1 hour. You should get about 1/2 rated output from an alternator at idle.
A Honda EU2000 will take about 0.2 gallons/hour to produce 824W.

Standard vehicle alternators are not designed to run at idle for hours on end. They need air flow from moving to keep cool in high ambient temperatures (emergency vehicles, et.al. use special alternators designed to run at idle). You can mitigate that somewhat by keeping your hood open.

As mentioned above: you will need to keep track and do engine maintenance based on hours run, not milage.

 

[wallyflint]

https://www.walmart.com/ip/seot/966...e6-438c-b443-0fbcba1341ea&listRegistryType=WL Here is a link to the window AC unit (Keystone KSTAWO5CE) I am installing in my Dodge van. It is a 5,000 BTU unit but, it only draws 446 watts. I did a lot of research before deciding to get this one. I agree with bullfrog, while I have 720 watts of solar that I can run the ac from, I also have a champion 2000 watt inverter generator for after sunset and cloudy days. that will run for up to 11 hours on a tank (1 gal. ) of gas. My van has a 135 amp alternator but I would not even think about using it to run the ac unit. Most vehicles, unless they were specifically designed for long idling times like Police cars, would not do very well being at idle for extended periods. This puts stress on many components of the vehicle and can shorten the life of catalytic converters too. If you think about the life of your engine being measured in hours instead of miles, you can see that you would be shortening the potential miles your vehicle will go before it dies. In other words, instead of driving 70 miles in a hour, you idle for an hour so that's 70 less miles (not exactly but you get my point) that your vehicle will be able to travel in its lifetime. That can really add up over time. If you think about it, my generator engine is 80cc (4.88 cubic inches) as opposed to my van's engine which is 318 cubic inches, does it not make more sense for me to use the 80cc engine? When that wears out, I can buy another one for about $350. (Probably cheaper than replacing your alternator) I don't even want to think about what it would cost to replace the 318.

Thanks for your advice overland. Will definitely take it into consideration.

 

[wallyflint]

Ford Transit V6 takes about 0.6 gallons of gas to idle for 1 hour. You should get about 1/2 rated output from an alternator at idle.
A Honda EU2000 will take about 0.2 gallons/hour to produce 824W.

Standard vehicle alternators are not designed to run at idle for hours on end. They need air flow from moving to keep cool in high ambient temperatures (emergency vehicles, et.al. use special alternators designed to run at idle). You can mitigate that somewhat by keeping your hood open.

As mentioned above: you will need to keep track and do engine maintenance based on hours run, not milage.

Thanks for your advice space. Will definitely take it into consideration.

 

[wallyflint]

In my opinion running a huge engine to run an expensive oversized alternator to power an overpriced poorly performing air conditioner even one that can be vented properly at todays fuel prices in not a good idea. Many large RV owners try to save money by running their generator and roof air conditioners rather than using their vehicle engines power to run their air conditioning in order to cut down fuel and maintenance costs. Take a look at the maintenance and fuel costs for some ambulances that do that. A simple 2500 watt dual fuel inverter generator and an efficient 5,000 btu window air conditioner will do the job for much less with little wear and tear on you primary vehicle. Most of those generators require an oil change of 20 oz of oil every 100 hours and are a diy easily done. Not so with your primary vehicle I bet! Will it work? Probably, but not well ( ducts and vents are not very well insulated and are required for those units to work well ) or cheaply after you consider the costs of wear and tear and upkeep of your vehicle’s motor, drive belts, cooling system and alternator.

Thanks for your advice bullfrog. Will definitely take it into consideration.

 

[wallyflint]

https://www.walmart.com/ip/seot/966...e6-438c-b443-0fbcba1341ea&listRegistryType=WL Here is a link to the window AC unit (Keystone KSTAWO5CE) I am installing in my Dodge van. It is a 5,000 BTU unit but, it only draws 446 watts. I did a lot of research before deciding to get this one. I agree with bullfrog, while I have 720 watts of solar that I can run the ac from, I also have a champion 2000 watt inverter generator for after sunset and cloudy days. that will run for up to 11 hours on a tank (1 gal. ) of gas. My van has a 135 amp alternator but I would not even think about using it to run the ac unit. Most vehicles, unless they were specifically designed for long idling times like Police cars, would not do very well being at idle for extended periods. This puts stress on many components of the vehicle and can shorten the life of catalytic converters too. If you think about the life of your engine being measured in hours instead of miles, you can see that you would be shortening the potential miles your vehicle will go before it dies. In other words, instead of driving 70 miles in a hour, you idle for an hour so that's 70 less miles (not exactly but you get my point) that your vehicle will be able to travel in its lifetime. That can really add up over time. If you think about it, my generator engine is 80cc (4.88 cubic inches) as opposed to my van's engine which is 318 cubic inches, does it not make more sense for me to use the 80cc engine? When that wears out, I can buy another one for about $350. (Probably cheaper than replacing your alternator) I don't even want to think about what it would cost to replace the 318.

Your air conditioner link didn't work. Can you post it again? Thanks for the help overland!

 

[Overland One]

Your air conditioner link didn't work. Can you post it again? Thanks for the help overland!

I just tried the link in my post and it worked fine here and, I also tried the link in your post where you quoted me (and the link) and it worked fine here too. I am not sure what else I can do from this end? (PS I always test links before I post them just to make sure they work, just an old habit of mine left over from the old days) Do any links posted on this site work for you? Maybe your firewall is blocking them or something? You could just copy and paste the link in your browser and it will surely work for you that way I would think. You could also go to walmart's site and type in the name and model number of the ac unit in the search area and it will come up. Amazon sells that same unit on their site too. Sorry I do not have any more suggestions.

 

[bullfrog !]

I just tried it and it worked for me $219.

 

[wayne49]

The link contained more than just the product code, same as links to Amazon do.

The rest of the link is tracking info related to the person, and their browser, who posted the link.

This is all that is needed to connect to the product page:

"https://www.walmart.com/ip/seot/966150851"

 

[Overland One]

The link contained more than just the product code, same as links to Amazon do.

The rest of the link is tracking info related to the person, and their browser, who posted the link.

This is all that is needed to connect to the product page:

"https://www.walmart.com/ip/seot/966150851"

Yes, I usually remove everything beyond the "?" because it is not needed. It was a short link so I decided not to. It still should have worked for him as it was though? (Maybe the tracking code set off something in his security software?) Thanks for pointing this out.

 

[afblangley]

It cost less than $1000 to buy a 120V portable AC and a generator to run it. If that’s acceptable, it’s the cheapest solution by far. My RV as traditional rooftop ACs powered by a built in generator. That works well, but that solution is not congruent with the use case scenario for my van. As summer approaches, I find myself contemplating the best options for my van.

The first option is a battery powered portable AC (Zero Breeze, EcoFlow, BougeRV, generic Chinese). A few YT van lifers (eg. Ryan Twomey, Travel Snacks, Bibia Bus) use them and have given honest, long term reviews on the Zero Breeze. There are fewer reviews on EcoFlow Wave/Wave 2, but it seems more powerful and more energy efficient. EcoFlow launches new products at discounted pricing. Right now, the Wave 2 costs $1600 with a detachable battery, that reportedly last 6-8 hours under reasonable conditions. Or I could buy the Wave 2 standalone for $1000 and power it with my current Delta Pro, which would double those hours (or cool better in more extreme conditions). Although I’ve never seen it done, it should be possible to power these 12V ACs with a cheap LiFePO4 battery. I’d rather spend $600 on a 200Ah Chins than a generator. The problem I have with these portable ACs is the inconvenience of setup and takedown, the inability to run it while driving, and the situations where it is inappropriate to run hoses out a window.

The second option is to go with a 12V rooftop AC. These are suppose to be more efficient than their 110V counterparts. Nomadic and Dometic have had units on the market for awhile but are very expensive. No name Chinese ACs sold on Amazon start at $1000 and are available with 4 year warranties. For me the biggest disadvantages of this option are the complexity of the install (I have a passenger van with an OEM rooftop AC and ductwork in the ceiling liner) and the inability to run it using my power station (12V ACs require large amperage).

The third option would be a 110V rooftop AC. These units are about $1000 for brand names. They are powerful enough to maintain a comfortable temperature in the van even in extreme conditions. There’s no setup/takedown and they use no floor space. They can be run using my existing power station and I can add battery capacity later if the need arises.

I don’t know if this post will be helpful to anyone else, but composing it has helped me sort out my thoughts.

 

[RonDean]

I just watched a youtube video review on an AC/heater that would work in an RV and off solar panels. It's called an Ecoflow wave3. It actually looks pretty good. Downside is a price on Amazon (including batteries) of $2100. That's pretty pricey, but when you consider heat AND AC and the battery, maybe it's not that bad. ???

 

[bullfrog !]

I agree with your assessment afblangley. In my camper (7’x 12’x 7’) I decided to use a cheap efficient 5,000 btu window air conditioner. During travel I simply used a foam cooler as a cover over the outside to keep it clean and prevent damage rather than dismounting it. I had two rooftop RV 110 volt air conditioners a 13,500 btu and a 15,000 btu but they would have taken up roof space I plan to use for solar panels and were just too large and heavy for the space I needed to cool. They would have taken a much larger generator as well. In a small space I tend to stay outside most of the day so a cool space to go to sleep in was my main necessity. A 2500 watt dual fuel generator will power it just fine and using a 100’ extension cord allows it to be far enough away to be silent to me inside, although I seem to not be bothered even when I run the generator mounted to the tongue. The new EcoFlow products seem great but very expensive as well as being unproven as far as durability to me so far. I spent less than a $1,000 and also have the advantage of being able to plug in at full hookup sites I often get while work camping. The components are cheaper to replace rather than buying a complete system like the EcoFlo. I have an EcoFlo Delta 2 power station and really like it but still occasionally need to charge it with the generator so powering a Wave 2 would probably require the generator anyway unless I had a lot more solar. Having the Delta 2 has decreased the amount of time I run the generator along with 100 watts of solar. Once I get 3 or 4 250 watt solar paneles on the roof it might be feasible to get an add on EcoFlo and not need to run the generator other than cloudy days. All this stuff takes up space and the more you can mount outside the better in my opinion.

 

[Overland One]

I have less than $600 in my 5,000 BTU Keystone Energy Star window AC unit (Draws 446 watts) and my Champion 2,000 watt inverter generator. (1,700 watts continuous) I looked around for a long time and I doubt I could find a cheaper/better solution. Later on down the road, I am going to install a trailer hitch and a hitch cargo carrier and bolt a vented steel box to put the generator in so I can run it while driving down the road. I can simply plug it into my shore power plug and save me from running the engine driven ac so I can squeeze a little bit better gas mileage out of my van in the summers. Some folks (YT comment section) do not like how window ac units in a van's rear window look but, I do not care what they think and, I think it is better to be cool than to look good, ha ha. PS bullfrog, I like your idea of the foam cooler for a cover. Simple, cheap functional and light. Nice.

 

[bullfrog !]

I actually coated the outside of the cooler with Poor Man’s Fiberglass to make it last and installed two eye bolts on either side to attach a bungee cord to insure it stays put but it is a tight self sealing fit anyway. It keeps the dust out when traveling over dusty dirt roads and in winter insulates and prevents outside cold air from getting in. In winter I use a small 110 volt electric ceramic heater to warm the camper up while bulk charging batteries with the generator in the mornings on cloudy days.

 

[Overland One]

I actually coated the outside of the cooler with Poor Man’s Fiberglass to make it last and installed two eye bolts on either side to attach a bungee cord to insure it stays put but it is a tight self sealing fit anyway. It keeps the dust out when traveling over dusty dirt roads and in winter insulates and prevents outside cold air from getting in. In winter I use a small 110 volt electric ceramic heater to warm the camper up while bulk charging batteries with the generator in the mornings on cloudy days.

I had to look up the formula for poor man's fiberglass and see there is one for using on wood, and the other for using on foam. Looks like a great material to be able to make so, thanks for mentioning it. I watched that Hobotech video on the "heat pump" from EcoFlow. He does excellent testing and reviews. (I bought my Bluetti AC200P after seeing his, and a few other reviews) That looks like a well designed piece of equipment but, very short battery life/run time and very high price. I could buy exactly 10 of my window ac units for that price. Yes, they only cool and do not heat, but wait. Ever walk past a window ac unit's exhaust side when it is running? Very hot air is being blown out of it right? I am now considering exploring how to design my mount so I can easily pull the ac unit out in the fall and put it in backwards. So, I will have hot air blowing into the van and cold air going outside. I was a design engineer in another life and this idea just crossed my mind when watching the HoboTech video so I have not thought it all the way through just yet. First issue I see is that my controls would be on the outside. As long as I weather proofed them I could just set the controls how I wanted them to be and turn the unit on/off via a switch on my power strip where it is plugged in. I have not seen anyone else do this so, this is either an excellent original idea or, there is a good reason no one has done this that I do not know about. Just playing around with it in my head. Maybe the unit would freeze up running it like that when the temps got below 30 degrees outside? Not sure. I have run a window unit in the winter before and it still blew very cold air so I "assume" it was still exhausting very hot air. I am going to look into this more.

 

[bullfrog !]

Another heat source I have wondered about is the bottom air space below large rigid solar panels. They get really hot and need ventilation to function well. Maybe close in the sides and circulate the air in that space into the van at floor level in winter with a couple of computer fans in a couple of PVC pipes during the sunny days? Many RVs simply put heat strips into the air conditioner housing. It is hard to beat a cheap simple ceramic heater for dry heat.