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is a 12V electric AC compressor available to replace engine driven compressor?


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My AC for "dashboard" is not working. I have leaking hose fittings/crimps at the compressor. That's the only leak I can find, but the fix (replacing hoses) is difficult. Trying to replace two 45+ ft AC hoses running along the frame is not easy. A recharge doesn't last more than a couple of weeks. On my coach the condenser is at the front, so all the components are in the front except the engine mounted ac compressor.

I'm thinking it would be great if I could get an electric (12V) AC compressor and mount that in the front and abandon the hoses running front to back. A lot of cars are coming with electric AC compressors now (similar to the electric power steering coming on all the new cars).

What do you think? Has anyone done this?

I see several company's (ProAir, Reconair, ClassicAir, etc) make 12V AC kits - which include everything for installing on a "restored muscle car", etc., but in my case I would want to use all the factory stuff - the evaporator, duct work, controls, and condenser/fan setup - and just install the electric compressor with some new hoses.

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A 12 volt AC compressor consumes about 100Amp of continuous battery power.

You would need to wire in an electrical controller.

Replace the leaking hose and you will be far ahead.

If you "know" where the leak is, then the fix is straightforward.  There are hose ends that don't require crimping.  And there are also portable crimp tools available too.

This is a job for a standard automotive AC repair place to resolve.

If you got into changing the system to electric, you will be far more complicated than just fixing what was engineered to work in your existing coach.

If pulling a hose is considered challenging, then redesigning the system and retrofitting, and rewiring, etc will be over the top.

Edited by DavidL
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100A @ 12V?  😮

Neat idea, but consider the condenser / fan is in the back, so you'll need to re-engineer that too. 

Maybe replace the RH fuel door with condenser / fan?  Don't forget a bigger alternator!

- bob

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7 minutes ago, cbr046 said:

100A @ 12V?  😮

Neat idea, but consider the condenser / fan is in the back, so you'll need to re-engineer that too. 

Maybe replace the RH fuel door with condenser / fan?  Don't forget a bigger alternator!

- bob

At least on all RVs I have owned / worked on, the condenser / fan is in the front where it gets cool air flow.

The "only" AC parts on a pusher RV is the compressor / clutch / belt, the rear of the two hoses, and possibly the low pressure switch.

Edited by DavidL
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1 hour ago, DavidL said:

At least on all RVs I have owned / worked on, the condenser / fan is in the front where it gets cool air flow.

The "only" AC parts on a pusher RV is the compressor / clutch / belt, the rear of the two hoses, and possibly the low pressure switch.

On *many* Monaco diesel pusher coaches, the condenser fan and receiver/dryer are close to the rear of the coach.  On mine it’s just behind the driver’s side rear wheel. 

Just a reminder that “your mileage may vary” based on what coach you have.  
 

——-

That said, it seems running 45’ of #2 AWG (minimum), devising a controls circuit, and increasing your alternator size to accommodate the coach battery charging and other electrical usage (est 160-200 amp) and AC (100A) would be a substantial task. Offhand I’m thinking a 300A alternator would be required  

If those items fit in your skill set and budget, I bet a *lot* of folks would be very interested in the end result. 

(PS - I’ve spent more than the cost of those items trying to find and fix the problem with my dash AC)

——-

On a somewhat related note…

I *finally* resolved my dash AC issues by replacing the compressor. The replacement compressor installed about two years ago had a bad shaft seal and would lose a charge in just 4-5 days. A bad compressor shaft seal is virtually impossible to detect, so based on advice of this group I purchased a new OEM compressor and had it professionally installed, which solved my refrigerant loss problem. I now have nice, cold dash AC, and with it working after sitting over a month, am confident it is fixed. 

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I would recommend to fix what you have.   If the hoses are in good shape, except at the fittings, you can by fittings to splice to your current hose.  My previous bus had damage fittings which are replaceable.  A lot of the shops don't want to repair the hose, but as long as the hose is in good condition, it can be repaired.  I found a shop that would repair it, but didn't have the tools.  So I went on Amazon and bought a crimping tool kit. https://www.amazon.com/gp/product/B09V4CY19C/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1 

Then went NAPA's website and bought the fittings.   It is not a big deal, you just need to find a shop that will work with you doing this.   So to repeat myself, as long as the hose itself is in good condition, you can repair the hose.   With the tools and fittings it was under $200, plus what the shop will charge you.   While doing this, I would recommend to have the dryer replace, which is less that $75.00.

 

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Lots of good ideas. Thanks. 

Replacing the hose ends was my first inclination but there is not much room to work with. But the cheapest repair I think. I guess this should be my first attempt.

On the amperage draw - I see in the specs that max output is 1200W (so 100A at 12V), but that should not be an issue my alternator and batteries can keep up with that load (which won't be a max output all the time). My Generator is mounted about 2 feet away from where this compressor would go, and has the cabling (wire size) to support adding a new feed  for this AC compressor.

Would need to figure out what size compressor I need to fit with my OEM condenser and evaporator/drier. The one listed below is 20cc (not sure what the OEM compressor size is).

PS. My Condenser is located in the front behind fiberglass cap on drivers side. (Not at rear sandwiched against radiator like many coaches).

https://www.guchen-eac.com/what/low-voltage-electric-compressor/ld20a12ab-12v-dc-mini-refrigeration-compressor.html 

 

Edited by CountryB
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1 hour ago, CountryB said:

Lots of good ideas. Thanks. 

Replacing the hose ends was my first inclination but there is not much room to work with. But the cheapest repair I think. I guess this should be my first attempt.

On the amperage draw - I see in the specs that max output is 1200W (so 100A at 12V), but that should not be an issue my alternator and batteries can keep up with that load (which won't be a max output all the time). My Generator is mounted about 2 feet away from where this compressor would go, and has the cabling (wire size) to support adding a new feed  for this AC compressor.

Would need to figure out what size compressor I need to fit with my OEM condenser and evaporator/drier. The one listed below is 20cc (not sure what the OEM compressor size is).

PS. My Condenser is located in the front behind fiberglass cap on drivers side. (Not at rear sandwiched against radiator like many coaches).

https://www.guchen-eac.com/what/low-voltage-electric-compressor/ld20a12ab-12v-dc-mini-refrigeration-compressor.html 

 

Isn't your generator 110volt?

The AC compressor is 12volt DC.  So the generator location isn't important.  Or is the idea to use the 12 volt wires that start the generator for the potential AC 12volt compressor?  Note, if the AC was on, and you tried to start the generator, you likely will be attempting to consume more amperage than the old 12volt wires were originally scaled for.

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The higher voltage with the engine running will take care of an extra 100 amps starting. Like Counyry B, my condenser is up front, but behind the front axle. 
I recently added a starting battery beside the generator so definitely wouldn’t be an issue for me. IF something major goes bad at the back, I’d seriously consider this.

IMG_5949.jpeg

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On 5/12/2023 at 10:43 AM, CountryB said:

Would need to figure out what size compressor I need to fit with my OEM condenser and evaporator/drier. The one listed below is 20cc (not sure what the OEM compressor size is).

20 cc is a very small compressor. It does run at higher rpm however still  not fast enough to do big boy work. The law of diminishing returns as to higher rpm applies here. Our compressors are probably 100 cc or so. 

Edited by Gary Cole
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A typical automotive A/C compressor is between 3-5 tons of cooling. Motor home application may be even higher. The compressor would need a40-60A AC circuit and the generator would need to be capable of double to triple that capacity for the in rush starting capacity. Using an inverter type condensing unit would be a conversion but would also require the indoor fan coil as well. No always the nicest look. I would guess the replacement of the refrigerant hoses would be a much simpler and cheaper option 

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Tim, I'm talking about the dash AC, not the roof AC units. I only need to cool the driver/co-pilot area (while driving) not the entire coach.

My home AC unit is 3 tons. Not sure your numbers are correct for an automotive use. I don't know, but there are many 12V AC compressor systems being used on classic car restorations, etc. and on those applications they are cooling the entire interior (I just want cool air blowing on me when driving) so I don't need to run my generator/roof AC).

Check out Custom Cooler IV. Universal Air Conditioning Kit (classicautoair.com) for example... If a car can use an electric AC compressor, then my motorhome should be more than capable (as I have a much sturdier electrical system - 160A alternator, dual chassis batteries, etc.)

However, I decided that I am going to cut off the hose ends and replace them first. If that doesn't work - then I'll go back and rethink the electric compressor idea.

Thanks

Edited by CountryB
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It is all dependent on what you are willing to live with. If you look through a Sanden compressor catalog you will see compressors with even higher capacities. I would imagine automotive systems are designed for very quick recovery which requires more BTU capacity. No one wants to wait an hour for their vehicle to cool down on a short drive. I was matching the most likely capacity of the existing compressor. You can find many 12vdc compressors with reduced capacity. Try Rigid Hvac and condensing units. Not a big issue to build just not the most cost effective. https://www.rigidhvac.com

Edited by TimSpencer
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On 5/18/2023 at 8:20 PM, TimSpencer said:

A typical automotive A/C compressor is between 3-5 tons of cooling. Motor home application may be even higher. The compressor would need a40-60A AC circuit and the generator would need to be capable of double to triple that capacity for the in rush starting capacity. Using an inverter type condensing unit would be a conversion but would also require the indoor fan coil as well. No always the nicest look. I would guess the replacement of the refrigerant hoses would be a much simpler and cheaper option 

Tim - Thanks for that info - Makes sense - the auto AC units need to output lots of cooling tons just to make up for the automotive heat loads especially with the large amount of single pane glass and basically zero insulation.

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Guest Ray Davis

Most auto air cond work very well and that's essentially what our coaches have.  However, we are asking the AC to do too much,  it's overwhelmed by the area and heat. My first thought about a 12v elect compressor was that'll never work and I still can't imagine an improvement in cooling.  So why reinvent the wheel,  but then I'm reminded of Ted over on IRV2 who took his engine coolant fan off and converted it to elect.  Truthfully, I thought that'll never work, but apparently, it's working very well.  https://www.irv2.com/forums/f115/electric-cooling-fan-conversion-2000-endeavor-dp-557437.html         Ted also has a youtube channel  https://youtube.com/channel/UCaQHHoLTPa5QGklGwqXCoYw   he is a real getter done engineer guy, get him interested and he'll probably at least let us know if he thinks it's feasible.  He may even take on the task.

Edited by Ray Davis
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An electric compressor could be used. Without matching it to the metering device and coil it would not work properly. Matching the btu output of the belt driven compressor would be the best option.  An inverter driven compressor or better yet condensing unit(compressor and condenser coil) would be even better. Controlling all this would take a few minutes to get working correctly. The engine driven compressor is not perfect but it is well designed and already controlled. Replacing refrigerant hoses is not fun or particularly easy but it is a far cry easier than redesigning the coach hvac system. Maybe trying to package a system like this in the dash area would be a better option. This would eliminate/replace the current system.  https://www.supplyhouse.com/Sanyo-26UHW72R-24000-BTU-Single-Zone-Mini-Split-Concealed-Duct-Heat-Pump-Air-Conditioner

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23 hours ago, Ray Davis said:

Most auto air cond work very well and that's essentially what our coaches have.  However, we are asking the AC to do too much,  it's overwhelmed by the area and heat. My first thought about a 12v elect compressor was that'll never work and I still can't imagine an improvement in cooling.  So why reinvent the wheel,  but then I'm reminded of Ted over on IRV2 who took his engine coolant fan off and converted it to elect.  Truthfully, I thought that'll never work, but apparently, it's working very well.  https://www.irv2.com/forums/f115/electric-cooling-fan-conversion-2000-endeavor-dp-557437.html         Ted also has a youtube channel  https://youtube.com/channel/UCaQHHoLTPa5QGklGwqXCoYw   he is a real getter done engineer guy, get him interested and he'll probably at least let us know if he thinks it's feasible.  He may even take on the task.

Yeah, Ted was my first thought when I started reading this. At one point he was planning to replace his compressor with a 120v compressor up front driven by the inverter and replaced his engine compressor with a 2nd alternator to help supply the extra power needed. I don’t think he got around to installing the compressor, but he spent a lot of time planning the project and was thoroughly convinced that the solution was practical. I think a120v compressor would probably be a lot more cost effective than 12v

That being said… I’m with y’all that are thinking that repairing the hose is by far the path of least resistance.  

Edited by wamcneil
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Guest Ray Davis
52 minutes ago, wamcneil said:

Yeah, Ted was my first thought when I started reading this. At one point he was planning to replace his compressor with a 120v compressor up front driven by the inverter and replaced his engine compressor with a 2nd alternator to help supply the extra power needed. I don’t think he got around to installing the compressor, but he spent a lot of time planning the project and was thoroughly convinced that the solution was practical. I think a120v compressor would probably be a lot more cost effective than 12v

That being said… I’m with y’all that are thinking that repairing the hose is by far the path of least resistance.  

I originally had the idea we bought the coach to enjoy not work on.  We do enjoy it but upkeep has proven to be significant.  It's mysterious to me but some folks seem to actually enjoy working on their coach to the extent of reengineering things.  I applaud you guys,  you're the guys that defy conventional wisdom and sometimes bring us new improved products.  You are probably smarter than most coupled with a great deal of curiosity.  In this new age of batteries,  inverters, and elect motors many of the old conventional ideas are being thrown out of the window.  I would like to see someone come up with improved air conditioners for both the dash and the house,  ya know it's coming.

 

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I followed the link to the classic ac site and I belive that by saying all electric they mean no vacuum lines needed to operate vents etc..

I think they still use and engine driven compressor.

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5 hours ago, Ray Davis said:

It's mysterious to me but some folks seem to actually enjoy working on their coach to the extent of reengineering things. 

It could be that RV's provide a "vehicle"  for many different hobbies and interests short of plowing the north 40 with a team of mules. There might even be an Amish version of that RV. Engines, electronics, woodworking, interior decorating. For the thrill seekers air leaks, fading brakes, the smell of smoke from under the dash, my transmission never did that before , predatory mechanics and tow trucks.  I have even seen people carrying what appears to be a flower and vegetable garden and set it up and repack it as they go.  

 

Edited by Gary Cole
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