diy solar

diy solar

Skip the 120vac and run an inverter air-conditioner from solar DC current ?

32 volt boater

Solar Enthusiast
Joined
Aug 7, 2022
Messages
427
And yes its kind of annoying that the abbreviation for air condition and alternating current are both "AC".
 
Last edited:

Anyway my idea is I would like the inverter airconditioners BLDC motor to run directly from the solar panels and adjust its speed/load to match the solar output MPPT style.

No nonsense, just sunny = air-conditioner on. Solar noon = peak air conditioning cooling.

Nonsence is to buy a standard 120v inverter air-conditioner bump up my solar DC to 120ac then the machine bumps it back to DC again. Seems wasteful.
 
I think as more of us in the world get solar systems installed, the companies will manufacturer more dc powered appliances so that we are not wasting so much energy.
 
There are 12 vdc air conditioner units designed for RV's and big rig trucks. They're not cheap but it goes to show that direct dc air conditioning is being done.
My son installed one in a sprinter conversion recently. He showed me how it worked. When first turned it slowly ramped up to speed but then seemed to blow nice and cold.
 
Last edited:
There are 12 vdc air conditioner units designed for RV's and big rog trucks. They're not cheap but it goes to show that direct dc air conditioning is being done.
My son installed one in a sprinter conversion recently. He showed me how it worked. When first turned it slowly ramped up to speed but then seemed to blow nice and cold.


Regular air conditioners maintain set temperature by turning on and cooling when room temperature rises above the set temperature and heating when the room temperature falls below the set temperature. In inverter type air conditioners, temperature is adjusted by changing the BLDC motor speed without turning the motor ON and OFF.

I would like to instead change the motor speed to match the maximum output of the solar and get the most cooling the solar can provide without using any batteries or cycling them.
 
A youtuber connected PVs to an e-bike without a battery and it worked.

I guess an e-bike style BLDC motor controller can deal with it. Maybe swap one into a inverter-air-conditioner.
 
I'd been pondering this myself, however it's important to remember that just because there's AC to DC conversion happening, it doesn't mean that low voltage DC is the result.
For example, the Panasonic inverter air conditioner I have (which is a 240v AC model) references voltages all the way up to 280v and 340v DC for the fans and compressor in its service manual. So there's really no possibility to do any kind of direct supply of low voltage to run it.

Of course this makes sense, because air conditioners are very high current devices and would require very thick conductors if the fans and compressor were running at low voltage DC. There's just no reason for manufacturers to add this expense when they can save money on materials and produce more efficient designs with high voltage DC.
 
Popped up on Youtube searching high voltage BLDC motor controller

Getting a motor to turn at lower voltage is very different to running it with the required speed and torque to fulfil its purpose. Running an air conditioner compressor at a tenth of the normal voltage probably wouldn't be enough to overcome the initial physical resistance to start it. If it did run, you wouldn't achieve enough suction and pressure to move a meaningful amount of heat.
 
Mr cool and pansonic sell split units that have both DC input and AC input. From what I can understand you can tell the unit to prioritize so when enough DC is incoming it will use that and then switch to AC when need.
 
Back
Top