I'm in Cabo San Lucas, Mexico at the moment and not in an RV if that should make any difference. I do own both a DP and a TT with roof-top air conditioners that run on standard AC electricity.On this trip I've noticed a lot of new Mercedes passenger vans. I haven't looked inside of one, but they must hold twelve people. They have either dualed rear tires or a very wide single tire. Very nice looking vans.Anyway, they all have large roof-top air conditioners. What do roof-top air conditioners run on for power? It must be 12VDC? I'm thinking of these vans, school buses, heavy equipment, etc.Why don't manufacturors install this type of A/C on top of large DPs (where money doesn't really seem to be a concern) for going down the road? Often I have to run my generator and A/C while going down the road to cool off the rear bedroom over the engine before we park for the night.Bill

Trackrig wrote:Why don't manufacturers install this type of A/C on top of large DPs (where money doesn't really seem to be a concern) for going down the road? I don't know of any type that runs on 12vdc. That would require wires the size of your fist, and a lot of batteries.I run mine on a big inverter and an Li battery and solar, but not for hours.

There are 2 modes the B+ vans use.1. Standard RV roof AC with a large Inverter and Battery bank2. A system by PROAIR that they install a 2nd AC compressor on the Engine and run the Hoses to the condenser unit at the rear in front of rear bumper underneath and then a large blower fan inside for the evaporator. This system both Heats and cools. Using Engine coolant for heat. It also has a Engine RPM button up front to increase the Engine RPM's when NOT moving. Doug

Is it a possibility the portion that you are seeing is an evaporator which is running from an engine driven compressor?

2oldman wrote:Trackrig wrote:Why don't manufacturers install this type of A/C on top of large DPs (where money doesn't really seem to be a concern) for going down the road? I don't know of any type that runs on 12vdc. That would require wires the size of your fist, and a lot of batteries.I run mine on a big inverter and an Li battery and solar, but not for hours.Here you are - 12 volt powered air conditioners for boats and vehicles - other manufactuers offer them too: http://www.cruisencomfortusa.com/

pnichols wrote:Here you are - 12 volt powered air conditioners for boats and vehicles - other manufactuers offer them too: I assumed we were talking about installations similar to real air conditioning...for large DPs. If you're willing to settle for 1/2 to 1/3 the cooling capacity, then fine.I can find 12v toasters and heaters too, but they don't work very well.

Explain vehicle / equipment top air conditions not on RVs.

20 Replies

Lwiddis
Nomad
Jan 27, 2019
“Current Draw: 30-50 amps nominal” Hmmmm
2oldman
Explorer II
Jan 27, 2019
Chris Bryant wrote:
The last Prevost I worked on had 4 rooftop air conditioners, all run off 24 volt 4kw inverters.
Wow. What kind of batteries we talking about?
Chris_Bryant
Explorer II
Jan 27, 2019
The last Prevost I worked on had 4 rooftop air conditioners, all run off 24 volt 4kw inverters. The engine driven air was removed
I believe most of the Sprinter roof units are condensers for engine driven compressors.
2oldman
Explorer II
Jan 27, 2019
pnichols wrote:
The marine and truckers' 12V air conditioners, as mentioned in my link, are serious air conditioners...
The 24v 11k model just *might* work in some situations. Draws 50a, which equates to 1200w. But, that's still some serious battery with some serious charging. If you're going to go that far may as well just get a big inverter.

Again, my reply was to OP's question.. about DPs.
pnichols
Explorer II
Jan 27, 2019
Granted ... the marine world 12V (and 24V) air conditioners are lower BTU capacities than what medium to large RVs normally require ... but large enough for the passenger vans that the OP mentioned.

The marine and truckers' 12V air conditioners, as mentioned in my link, are serious air conditioners that require 4 gauge or larger wiring to the compressors - not the anemic "Mickey-Mouse 12V appliances" that plug into cigarette lighter receptacles.
2oldman
Explorer II
Jan 27, 2019
pnichols wrote:
Here you are - 12 volt powered air conditioners for boats and vehicles - other manufactuers offer them too:
I assumed we were talking about installations similar to real air conditioning...for large DPs. If you're willing to settle for 1/2 to 1/3 the cooling capacity, then fine.

I can find 12v toasters and heaters too, but they don't work very well.
pnichols
Explorer II
Jan 27, 2019
2oldman wrote:
Trackrig wrote:
Why don't manufacturers install this type of A/C on top of large DPs (where money doesn't really seem to be a concern) for going down the road?
I don't know of any type that runs on 12vdc. That would require wires the size of your fist, and a lot of batteries.

I run mine on a big inverter and an Li battery and solar, but not for hours.

Here you are - 12 volt powered air conditioners for boats and vehicles - other manufactuers offer them too:
http://www.cruisencomfortusa.com/
pinesman
Explorer
Jan 27, 2019
Is it a possibility the portion that you are seeing is an evaporator which is running from an engine driven compressor?
dougrainer
Nomad
Jan 27, 2019
There are 2 modes the B+ vans use.
1. Standard RV roof AC with a large Inverter and Battery bank
2. A system by PROAIR that they install a 2nd AC compressor on the Engine and run the Hoses to the condenser unit at the rear in front of rear bumper underneath and then a large blower fan inside for the evaporator. This system both Heats and cools. Using Engine coolant for heat. It also has a Engine RPM button up front to increase the Engine RPM's when NOT moving. Doug
2oldman
Explorer II
Jan 27, 2019
Trackrig wrote:
Why don't manufacturers install this type of A/C on top of large DPs (where money doesn't really seem to be a concern) for going down the road?
I don't know of any type that runs on 12vdc. That would require wires the size of your fist, and a lot of batteries.

I run mine on a big inverter and an Li battery and solar, but not for hours.

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Explain vehicle / equipment top air conditions not on RVs.

20 Replies

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