Powerwall not connected to Hot Tub and Air Conditioning

Powerwall not connected to Hot Tub and Air Conditioning

I got a powerwall 2 installed and turned on about a month ago. I also have a Tesla 3.9kW solar system turned on a few months before that. I checked my PGE bill and I'm still using a lot of energy even though the Tesla app says I am 99% self powered every day.
I found out that my hot tub and air conditioner (two of the biggest power demand things I have) are not wired to the powerwall or to the tesla gateway. These devices were wired before the powerwall was installed. So the Tesla app doesn't count these systems in my electric use, and those devices draw directly from the grid, so I am still paying for electricity. When I got the powerwall I was under the impression that everything in my house would be run through that and that the grid would supplement when the load exceeds 5 kW or the powerwall battery is depleted. Am I mistaken? I am arguing with tesla on tech support that they should come out and fix this.

mcdonalk | May 18, 2018

When designing your system with Tesla, do you ever recall discussing which loads that you wanted backed up (or "relocated") and which loads that you didn't want backed up? Perhaps the discussion entailed identifying circuits or appliances that absolutely must be available in an outage (backed up), and those which were not necessary (not backed up). That discussion should have taken place. In my case, we discussed this in detail, and we even reviewed the plans prior to any commitment. Any circuits that are not backed up would not be tracked in the Tesla app.

Kykevinlau | May 25, 2018

I only have 1 PW2 as well. AC and 240v EV charger are not connected via PW2. Reason- PW2 cannot handle the AMP for those 2 circuits. I was told that I needed 2 PW2 to be able to run (back-up) for the entire house.

You will probably be able to find your hot tub and AC breakers still in your main box which directly connects to the grid.

As far as "paying for electricity" to run the hot tub and AC, look at your net metering. If the system was designed to produce 100%+ of your usage and your usage has not changed, then you should still be close to net 0 and not paying even though those two circuits are not on the battery.

Just for an exercise, pretend you don't have a battery back-up. You overproduce from your PV system and dump into the grid during the day when the sun is out and draw from the grid when the PV is not producing. Over the course of a day/month/year. If your PV produces equal to or more than your usage, then you are even or ahead.

Add the battery back into the picture. It doesn't produce or consume, it just stores energy. So now, when your PV overproduces it will dump into the battery (then into the grid). Now, if the grid goes down (or when the sun goes down) you can draw from the battery (first) instead of the grid. The PV still does what it does and if designed correctly will produce enough to offset your usage or more.

The battery is really just like a mini grid that's only connected to your house. You're "off the grid" for the circuits the battery is managing. If you have a lot of power outages, especially during times when you need to power your hot tub or AC, then you may want to have Tesla Energy re-evaluate your needs- a second PW2 battery might be the solution.

Battery for Net Metering: Some say you can try to game the utility company by timing when you store (off-peak) and/or release into the grid (during peak times) but you'll have to check your utility contract since most of the time, the energy you release into the grid is paid out at bulk rates (low ~ 4-5 cents/kWh) versus the time of day rates (higher ~ 30-40 cents/kWh @ peak times).

SUN 2 DRV | June 14, 2018

@stephen.powelson: PG&E's NetMetering effectively give you an unlimited capacity to store your excess solar and use it at another time (based on dollar credits). And because of ToU rates this often works out to your advantage financially since you get paid the highest rate for your afternoon and early evening solar.

The primary benefit of a Powerwall is as a backup power source when the grid is down. And in that situation most homeowners want to use that backup energy to power only the essential household items like lights and refrigeration. A hot tub is considered non-essential and sometimes the AC is too.

The main factor in your utility bill is the size of the solar system and the total power it generates. The size of the powerwall is relatively less important since PG&E's net metering provides unlimited capacity to offset your excess generation against later consumption.

3.9 kW is a modest size system and probably was sized for the strongest ROI and not to fully drive your utility costs down to zero. But that's the key number you should be looking at, not how the Powerwall is wired.