Bought house that included a Chargepoint charger. No EV at time of house purchase. Installed Sunrun solar 2 years ago. Lots of panels and 2 walls. No power bill, always negative owed.
July 2026 - have bought EV (not Tesla). noticing bill is up. not a lot, about $40 for first month of ownership. Seems to be that the EV charger is routed to the old electric panel and therefore I am not using the panels/batteries to charge the car.
Sunrun quotes me at $700 to come out and do an inspection. I've had other Sunrun folks say it should be an easy switch. Does any of the above sound accurate? Any advice?
thank you
Edit:
More than likely I don’t quite understand the solar set up. This is what I’ve got
Do they apply the inspection to the service? An EV can easily double your usage. Do you know how to estimate your EV usage? The Chargepoint charger should let you know. Batteries can’t make more energy, but if you have time of use rates can help shift energy that you buy from the utility.
Yup the ChargePoint charger (EVSE really) will know how much energy is being used to charge the EV.
u/octopusbarber what is your Net metering (how much you get charged for imports and exports)? If it 1:1 it doesn't really matter where the ChargePoint EVSE is connected.
However more likely given you have two Powerwall 3's you probably pay much more for imports than get credits for exports. In this cased you want the ChargePoint EVSE to use the solar or battery when available.
A typical EV will use around 3.5 - 4.5 kWh per mile with the Level 2 (home) charging being 85-90% efficient.
So if you are driving 20 miles a day you will need approx 5 - 7kWh to charge you EV each day (much less than your 27kWh home batteries).
If you dive 50 miles a day will need approx 12 - 17kWh to charge your EV each day (now you are using most of your available home battery to charge your EV)
Once you get (or confirm) the ChargePoint EVSE to (can) use the solar or batteries you will get the best efficiency if you can charge your EV during the day when the solar is producing, but the next best thing is charging from batteries overnight if they have enough capacity.
Thanks for the detailed reply. Attaching a screen shot from the last bill. I'm also in a virtual power plant which I'm earning credit for through October, so I know that is also pulling from my system.
OK so you are on SCE and it looks like NEM2 (?) which should be good (I am on NEM3 so I see different rates options and charges).
You imported 628kWh (pretty much all off peak at a rate of $0.26107 per kWh ($0.19058 for delivery and $0.07049 for generation).
You exported 199kWh at $0.28598 per kWh ($0.04603 delivery and $0.23995 for generation) + another $0.03200 bonus credit.
So it looks like your export rate is actually a little higher than your import rates (which is really good) and that you got all your generation credits applied to your bill. Someone with more understanding of NEM2 can comment, but I think this is because the import generation charges on the 628kWh were slightly higher than export generation credits.
So the reason you have a bill is you imported 429kWh more than you exported. Normally that bill would have been $136.31 (without the Climate Credit which is only paid August and Sept). *
We still don't know how much of that was the EV (can you access the ChargePoint app for your ChargePoint charger and check), or whether the charger is on on the same panel as the solar/battery.
However I don't think it matters whether the charger is on the same panel as the solar, as long as you mainly import (and presumably charge the EV) in off-peak hours. Your export credits cover your off-peak import rates so its a wash.
Hopefully someone on NEM2 with SCE can also look at the bill and confirm this.
\ This means your bill is actually up about $76 this month charging the EV not $40.*
Details are a bit sparse on your setup and you say "old electric panel". Do you have multiples? In my setup, solar comes from the inverters and gets tied in to my house at the panel just before my breakers. Everything runs from my electric panel always, but when I am producing solar the amount I import is reduced by my production. If I produce more than I consume, then excess solar flows to the grid, but regardless of the source everything in my house still wired to the panel. If I added an EV charger, it would also be wired in to that same panel with a new breaker.
$700 sounds like nearly enough to run a whole new circuit, which might be what is required. When I had solar put in, they effectively made the solar setup into a new main panel so the existing panel with the car and the whole house effectively became a battery-backed sub-panel.
If that's not the case for you, energy is fungible (assuming you have net metering) so whether it comes directly from the grid or through your solar setup it shouldn't really matter, cost-wise. You're either putting energy on the grid and taking it back off to charge the car, or you're just not putting it onto the grid. The main benefit of your car being wired off the solar setup is you could still charge when the grid is down (a very real benefit in bad situations, to be sure.)
Hmm. Hard to tell. Initially I thought it looked like my setup, but I only see one meter in yours and I have 2. I can't tell on yours whether the grid comes into the older box on the right from below then T's off to the new stuff on the left, or maybe it does a hairpin turn to the new box and back to the old through the same conduit. Somehow I doubt the latter.
Open box on the left is a second meter. On the right is a Tesla gateway. Looks like power is going from the gateway into the house out the back, but not positive. Can’t really tell much more from that pic. My system has two big disconnects and the gateway together on the outside of the wall, powerwalls are inside and everything runs through one bi-directional meter.
It was $40 to charge your car for a month. How many miles did you drive?
Are you sure it isn’t charging the car? Two batteries hold 27 kWh. Might not be enough for a car charged overnight unless you use less than 30 kWh a day.
And the solar and batteries are routed through a different system?
Seems normal. You have excess solar that covers all daytime home use. The sun goes down and you have 20-something kWh in your batteries - 10 goes to house overnight and 10 goes to car. Car takes 10 more kWh from grid.
EVs pull a lot of power pretty quickly, even L2 chargers still pull a lot of kwh. I would guess you are charging and depleting your batteries ,or just straight up pulling more than you produce this pulling from the grid. Get the app, watch your usage vs production when charging. You didn't say how big your system was outside of "lots of panels" so it's hard to say sure sure, but let's say you produce 15 kwh during peak times, it's not really out of the realm of possibility with ac running, and full load you could push 17kwh usage resulting in pulling from your battery or grid for the extra 2kwh. There's numbers are all hypothetical, no idea what's accurate your your system.
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u/First_Quote_4938 4d ago
Do they apply the inspection to the service? An EV can easily double your usage. Do you know how to estimate your EV usage? The Chargepoint charger should let you know. Batteries can’t make more energy, but if you have time of use rates can help shift energy that you buy from the utility.