Hi. I'm curious if the power walls can start and power a central AC. I have spoken to 2 non-Tesla installers that say they can't.
By definition they can, if you have enough batteries to do that. IME, from multiple solar installations, people assume any high usage device cannot be done. It is just a matter of scaling. Whether the economics work is up to the buyer.
FWIW, I have listened to ‘experts’ tell me my solar project were ‘impossible’ or ‘impractical’ for nearly 30 years. The solution is to carefully calculate your expected usage by season and peak periods, then size your system to see what your probable economics will be. Since you are grid-connected the reserves can be pretty low, just enough to allow coping with power outages or minimize use of peak pricing periods.
Whatever you do don’t accept the sellers assumptions without checking them very carefully yourself.
In my opinion these decisions are analogous to BEV vs ICE. Pure economics is one metric, desire is another. Desire includes contributing to survival of the human species.
Tesla does make the entire process very easy with Powerwalls. One major factor is almost never discussed. That is that Powerwall output is “Pure Sine Wave”. That means the power output is cleaner and more stable than any grid power. If you set up your system to use only Powerwall output while recharging from both Solar/wind/hydro and grid, you’ll end out with electrical supply that will have everything run more quietly and last longer. That benefit is largely ignored, but does have both economic and environmental benefits.
Many, probably most, commercial inverters have square wave output because that makes the equipment cheaper and they assume clients will not know the difference. Tesla, as usual, does theirs in what I consider to be the ‘right’ way.
As investors we tend not to see such apparently minor points. In fact, a core value evident in all Tesla products is to do everything electrical and electronic in the best way they can. In the long run that is the least costly way.
Thus, size you system correctly, feed all power from a Powerwall directly and your A/C will run more quietly and efficiently, so last longer. To do this efficiently you can have 220 output Powerwall(s) for heavy loads and 120 output for those loads. Few domestic users tend to do that but that will provide an excellent result in a house. Were I doing such a job today I would do it that way.
Capital cost will be higher than other options, but you’ll end out with quiet, long lived energy consuming devices. As others have mentioned the A/C should have ‘soft start’ which nearly all the highly efficient ones do. If yours does not have that feature you’ll might save money by upgrading anyway.
