Dual Alternators for A/C Removal, newbie

[joexsmoot]

Good morning everyone! I'm joe, new to the forum. To give a super quick backstory, I bought a 87 Minnie Winnie for $500 about a year ago, it was stripped and a leaky mess. 1 year later, me and my girlfriend updated the whole thing. Took it on one or two trips, engine smoked a lot.

Fast forward, i'm pulling the 460 8 cyl 7.5l EFI out, and replacing with one with lower mileage. The A/C did not work, and it is the old style refrigerant which is hard to come by and expensive, especially if I don't even know why it didn't work. However our 110v roof top unit works amazingly, and i'd like to capitalize on that.

Is it possible and realistic to remove the A/C compressor and install an additional alternator in it's place? I would run the 2nd alternator's lead (with external voltage regulator) directly to a fuse block which connects to my house battery bank and the DC to AC inverter

Ideally, it'd go something like this:


This would be something that would benefit me by: saving me to upgrade the A/C system to the current refrigerant, be a lot more cost effective (alternator is $100 autozone, wiring and fuse roughly $80, no frills regulator $30-50) VS starting off with a $350 compressor (autozone) let alone whatever else needs to be replaced (sensors, tubing, condenser, cooler, blower assembly are all 35+ years old, plus refrigerant etc). When the DC to AC inverter isn't drawing more then what the 2nd alternator is supplying it acts as a charging unit for my batteries, which saves me $100-300 just for that unit alone.

I don't use the unit dry very often, it's usually hooked up to some form of campsite power. I figure this method would be best for my short and sporadic uses. It benefits me cost wise, I don't ever plan on selling, and I don't foresee a power issue seeing the house batteries / appliances are a completely isolated charging system.

What do you all think?? Let me know, feel free to give me any ideas or issues you forsee in the future!




THANKS EVERYONE!!!

[Bird_Freak]

Some one is ripping you off! R134 conversion kits are cheap and there are r12 compatible refrigerants available. Been doing this for years.

[joexsmoot]

thanks gordon and bordercollie for the replys

Gordon - That's true I didn't think about that. I have a automatic transfer switch going to a 110v fuse panel currently powered by either the inverter or hook up power. I can just as easily take the 30A plug for docking and plug into a generator. for while I'm on the road / camping somewhere without power.

Bordercollie - From the bit of research ive done, if I do it myself it'll be in the ballpark of $800 and roughly 18 hours of labor, assuming Murphy is feeling nice. (Murphy's Law). You have to replace pretty much everything except the tubing and the fan/heater core assembly, although its recommended to disassemble and clean out because of the oils in r12 vs r134a, but at that point id pick up the tubing anyways.

If I have a place do the full retrofit kit, I found one that offered a flat rate $2000.

I guess I could find all used parts from a 96+ e350 that with some modifications, I could make work. That would bring the cost down to 300-400 if I found some good deals.

[Bordercollie]

What would the total cost be to replace dash AC with current type and refrigerant and retain normal and convenient dash AC function? How about a used AC components. The dash AC is quite effective for driver and passenger comfort while underway. Some run the RV generator to run the roof AC while underway. If you ever do want to sell the rig, an operating dash AC plus roof AC will help sell it. Don't expect an old refurbished rig to sell for much more than 4500-6000 dollars though. Good luck with whatever you do.

[GordonThree]

Welcome to the forums!

I'm with Sam - get a used generator installed, let that run your rooftop unit. Benefits are many, but most importantly, you don't have to idle the main engine to run your A/C while you're overnighting at a rest area or camped out at a rustic campsite.

Running the rooftop unit via inverter and high output alternator is going to cost more than buying a used generator. You need an expensive beefy inverter to start the compressor, something with at least 3000 watts surge capacity. That means running heavy wires from under the hood to a battery (or several batteries), like 4/0 gauge from the alternator to a battery and from the battery to the inverter.

I've run my rooftop off my inverter before, it draws about 150 amps - an alternator rated for 150 amps continuous output will be expensive, most are rated to operate well below their advertised peak output number.

[joexsmoot]

Thanks for the quick reply Sam and Tyler.

Sam - I thought about running a generator, what are the benefits of a generator VS the electrical route? I believe the gas line from the tank to the generator is still there, just capped off at the moment.

I have considered talking to a mechanic, any quotes I've received "because of the old style refrigerant / system" have been upwards of $350 to diagnose, and an estimated $300 to refill the system plus labor charges, assuming everything works properly.


Tyler - Thats a good question. I could replace it but i'm trying to avoid that because of the high costs the refrigerant. Is there anyway to bench test a compressor that you know of? I tried to jump the pressure sensor momentarily to see if it would kick on, I got nothing.

[Tyler0215]

Are you sure ypu need a new compressor? You may just have a leaking seal. Recharge with new refrigerant may be all you need.

[Sam_Spade]

joexsmoot wrote:

Is it possible and realistic to remove the A/C compressor and install an additional alternator in it's place?

What do you all think?? Let me know, feel free to give me any ideas or issues you forsee in the future!

Possible, probably.
Realistic, certainly NOT.

Running a generator to power the A/C would be a better option.

Second better option would be to pay a vehicle A/C mechanic to make the original configuration work again after your engine swap.

Some have tried to run the A/C off the batteries through an inverter and it almost NEVER works out really good.