Wish to run my Room Air-Conditioner on solar during day time

[SunEagle]

Hum...
Last time I checked a AC and and a fridge is cycling regardless.

Looks like everyone is following the route that got mentioned in the previous post - As I lack in brilliance I have to go the BS route.

There are two types of cycling. The normal way when a set point like the AC or fridge thermostat is satisfied and the compressor comes to a stop. This is ok and the equipment is designed for that type of operations.

Now when the power goes out in "mid cycle" for an AC or fridge the compressor has not gone through it typical operation of shutting down by relieving the pressure. So when the power comes back the AC or fridge compressor now starts under a much higher load which puts a strain on the equipment. Especially if the cycle of power being on - off - on is very short. Better for the equipment if the power has been off for a while allowing the compressor to release some of the pressure it built up while it was running before it starts up again.

Does that clear up what I have tried to say?

[Johann]

That feature on the SMA inverter is pretty nice but still is limited to only working continuously if the sun doesn't play "peek a boo" with clouds. Without continuous sunshine even that sunnyboy feature won't help you.

I don't mind a light fixture going on an off but I would have a big issue if my refrigerator or AC unit kept cycling.

Hum...
Last time I checked a AC and and a fridge is cycling regardless.

Looks like everyone is following the route that got mentioned in the previous post - As I lack in brilliance I have to go the BS route.

[paulcheung]

Which way is cheaper? to increase the panels size by 5 X the need wattage or just buy 4 automobile 12 volt battery which cost about $80 each have 500 amps crank power?

[SunEagle]

This would be a fairly different track but if the others don't work and you do not want batteies The sunnyboy inverters have a new feature that can continue output during a grid outage without batteries. But it is a manual switchover. Not too convenient if your grid is going up and down constantly.

That feature on the SMA inverter is pretty nice but still is limited to only working continuously if the sun doesn't play "peek a boo" with clouds. Without continuous sunshine even that sunnyboy feature won't help you.

I don't mind a light fixture going on an off but I would have a big issue if my refrigerator or AC unit kept cycling.

[nomadh]

This would be a fairly different track but if the others don't work and you do not want batteies The sunnyboy inverters have a new feature that can continue output during a grid outage without batteries. But it is a manual switchover. Not too convenient if your grid is going up and down constantly.

[Mike90250]

Possible, but not likely. Maybe if you are in a cloudless area (desert) and can be assured of 99% sun during the core hours.

Maybe somewhat more likely with a "mini-split" system that can modulate it's compressor speed a bit, and has better restart capability.

The main problem is solar PV cannot supply any "surge" power. A generator has pounds of rotating mass that can "flywheel" though a compressor start. A battery & inverter can "surge" for a second. PV has no such feature, so you have to have 5x the running power, available in PV to start a compressor. 400W running, you need 2,000w on line. (about 2,500w of PV nameplate installed).

[SunEagle]

I think it is possible to power your AC without an battery if you do not mind getting service disconnects with clouds. I will find out next summer.


All you really would need is to hook up a voltage regulator to the panels so the output has the same voltage at all times. Then you incorporate a voltage sensor that you can set the 'on' and 'off' voltages to turn the inverter on and off. Hook your inverter up to your voltage regulator output.

Now when a clouds comes the inverter will turn off and when the cloud passes the inverter will resume to power up again without having to reset the inverter.

As long as your panel wattage and sun output is high enough to overcome the starting wattage of your AC you should be ok.
With AC you may have to install a 5 minute time delay after power is disconnected before power is applied again to avoid that the compressor is trying to start under pressure/load.

Mod note - Johann is also following the route I mentioned in the previous post - As I lack in brilliance I have to go the BS route!

Even with all those low voltage and time delay "safeties" you still run the risk of cycling your AC system too many times in one day and probably cause the compressor to fail. You need a constant power source for an AC system. Batteries can do it (although will be expensive). A generator will be a better solution if you lose grid power.

[Johann]

I think it is possible to power your AC without an battery if you do not mind getting service disconnects with clouds. I will find out next summer.


All you really would need is to hook up a voltage regulator to the panels so the output has the same voltage at all times. Then you incorporate a voltage sensor that you can set the 'on' and 'off' voltages to turn the inverter on and off. Hook your inverter up to your voltage regulator output.

Now when a clouds comes the inverter will turn off and when the cloud passes the inverter will resume to power up again without having to reset the inverter.

As long as your panel wattage and sun output is high enough to overcome the starting wattage of your AC you should be ok.
With AC you may have to install a 5 minute time delay after power is disconnected before power is applied again to avoid that the compressor is trying to start under pressure/load.

Mod note - Johann is also following the route I mentioned in the previous post - As I lack in brilliance I have to go the BS route!

[russ]

If you cannot baffle them with your Brilliance, then dazzle them with BS.

As I lack in brilliance I have to go the BS route!

[Sunking]

Your plan is good but amperes can never be same air condition or air purification units. It is about to 25 to 30 in the start but in the running it came to 8 9 10 11. It never be constant at 8.

If you cannot baffle them with your Brilliance, then dazzle them with BS.

[russ]

Your plan is good but amperes can never be same air condition or air purification units. It is about to 25 to 30 in the start but in the running it came to 8 9 10 11. It never be constant at 8.

Meaning?

[David35]

Your plan is good but amperes can never be same air condition or air purification units. It is about to 25 to 30 in the start but in the running it came to 8 9 10 11. It never be constant at 8.

[paulcheung]

Just get 4 cheap 12 volt batteries, you are not use them to power the AC, just use them to turn on the inverter and keep it on.

Cheers.

[Sunking]

Real simple, you need batteries. Not going to happen without them.

[digimart]

Thanks for your inputs.
So it seems that, all I can do for time being is that if I install a VFD, I be able to cancel the starting torque of the air-conditioner, and then I could get hold of a usual Inverter + battery bank + controller, and connect my Air-Con with the same.
As there be a VFD , so i be needing inverter with lesser power, and battery bank size would be less too.