wa8yxm wrote:
There is no reason an electric motor . be it a blower motor or a compressor motor can not be made to run on 12 volts.. but since the compressor pulls over 1000 watts.. that's a whole lot of 12 volts.
Let get down to "brass tacks" ! An air conditioning compressor is almost identical to a refrigerator compressor. They are simply an electric motor drive a pump.
The most efficient electric motors use 3 phase power. So everyone is now saying, "Yeah, where do I get 3 phase power on an RV ?". Through the "magic" of modern electronics, you simply "make it" from what ever power source you have
(actually works best if you have DC).
Danfoss is a long time manufacturer of HVAC compressors. The sell small compressors that take 12VDC (or 24VDC or 48VDC), convert it to 3 phase and send it to their motor. Don't get me wrong, these things STILL TAKE A FAIR AMOUNT OF POWER (500W+). Danfoss only sells the compressor so it is up to some one else to incorporate it into a product. They are most commonly used in small 12VDC refrigerators so they clearly do not have the capacity to cool and RV. AT least not one unit. Scaling up only requires better/most cost effective DC-to-3 phase AC inverters.
Danfoss was a Danish company, but was sold to a German company, Secop, in 2010. They then sold it to a Japanese company, Nidec, in 2017. Nidec has also acquired Embraco, a Brazilian compressor company. Nidec is probably not going to sit around and do nothing with these acquisition. With hybrid/electric cars coming there is a big demand for electric A/C. If they could get the power consumption down, auto makers would love to have a 12VDC air conditioner for non/mild hybrid vehicles !
