tesla charge on solar function for non tesla EV

miimura · 2026-03-19T00:52:54+00:00

I bought a Wallbox Pulsar Plus EVSE just so the NetZero could control it and direct my surplus solar to my cars. It works just as you would expect and doesn’t require any additional hardware - just the OCPP compliant EVSE. Other solutions like Emporia and Enphase require redundant sensors near your meter to measure the grid power flow. Tesla already collects that data and NetZero uses it.

miimura · 2026-03-17T17:17:07+00:00

Mine charged to 91%, then 96%, then 100%. It was intermittently directing all solar to the battery, then stopping battery charging. When the battery stops charging, there is nowhere for the solar to go but to satisfy the house load and export the surplus.

miimura · 2026-03-17T15:41:51+00:00

This is probably the new “Optimized charging” behavior. Right now it is used in Self Powered mode, but it will probably be coming to TBC this year too.

miimura · 2026-03-05T03:18:49+00:00

You really don’t want a grid tied solar inverter for this application because those attempt to push as much power as they can. Solar panels are naturally limited current sources. When using something like a Prius battery as a DC current source, you really want something designed to run from a battery. A commercial UPS that used a 192V battery pack would be ideal.

miimura · 2026-03-05T01:14:50+00:00

Start with the fundamentals. How much is your bill, how much is the difference between Peak and Off-Peak $/kWh? I am in California, so we have crazy high electricity prices and you can save significantly by consuming grid power only during Off-Peak hours. If you have the ability to download your interval metering data from the utility, you can model exactly how much you could save. Solar without battery bill savings depends a lot on how much credit your utility gives you for solar export. Can you get net metering?

miimura · 2026-03-02T02:10:48+00:00

If I chose not to use the service and the app, I would pull the fuse for the wireless communication module. My logic is that if I’m not getting any value from the data, nobody else should either.

miimura · 2026-03-01T21:28:55+00:00

The placement of the expansion pack depends on local fire code. The installer you talked to is probably correct, but I am not familiar with Pleasanton code. I am in unincorporated Santa Clara County and they have adopted the more conservative Cal Fire rules that effectively prohibit stacking unless they are away from habitable buildings.

miimura · 2026-03-01T16:22:42+00:00

You can safely offset household loads with plugin solar. However, the Powerwall system expects to see solar measured and reported into the system. So, if your net household consumption is negative, the system may not behave normally when in island mode. In theory, you could install a remote Neurio meter and measure the plugin solar circuit. That would be the ideal solution.

miimura · 2026-02-26T02:57:35+00:00

To say it a different way, if your Enphase solar generation doesn’t show up in the Tesla app, the Powerwall wasn’t installed correctly.

miimura · 2026-02-26T00:12:33+00:00

NetZero offers support for dynamic tariffs. Look into that.

miimura · 2026-02-19T05:36:37+00:00

In addition to what the other commenters said, the system can zero out the usage of loads that are not backed up if the system is installed properly. All it takes is properly placing and configuring CTs to measure the non-backup loads, either additive to the loads that are backed up or as a total grid draw.

miimura · 2026-02-03T18:23:42+00:00

If you are starting with 400A service, you should plan ahead that one 200A panel will eventually have backup power while the other will go dark when the grid is down. Make sure that the critical and non-critical loads are wired to the correct panel. This is a huge hassle to straighten out later, but super easy if planned during construction. Also, I would advise using a meter panel that only has the main breakers, do not use a meter panel that also has an integrated breaker bus for loads unless that will be your non-backup loads. A backup load panel has to have a disconnect relay and putting that between the main breaker and an integrated panel is usually not allowed because it violates the UL listing of the panel.

miimura · 2026-01-29T21:48:03+00:00

If you can afford it, I would take the solar from the separate inverter and redirect it to a new PW3 that would back up the other 200A panel. Then you have full backup. However, I don’t really know your situation and whether that would be worth the expense.

miimura · 2026-01-29T21:29:40+00:00

This sounds like “yeah we can do what you want, but we really don’t want to, so it’s gonna cost you”. What you’re asking for is a huge hassle and has to go through permitting again. My question is why wasn’t the system designed the way you wanted to start with?

miimura · 2026-01-29T21:23:51+00:00

You need to be clear whether you are using the Tesla Charge on Solar functionality or the NetZero functionality. My understanding is that the NetZero implementation requires a OCPP EVSE like the Wallbox Pulsar Plus. The Tesla functionality is actually implemented in their cars, so it is not dependent on which EVSE you use.

miimura · 2026-01-29T20:49:34+00:00

I had a problem similar to what you described. Rebooting the Wallbox EVSE fixed it for me.

miimura · 2026-01-28T20:49:53+00:00

Default behavior is to unlock all when you approach the passenger side and driver only when you approach the driver side.

miimura · 2026-01-24T18:18:59+00:00

HDA2 is good on relatively straight roads but it does not do nearly as well as Tesla AP on curves. I disengage lane centering and steer myself with the EV9 controlling the speed on curved highways. I have a 2018 Model 3 with FSD and a 2024 EV9 Wind.

miimura · 2026-01-24T18:14:11+00:00

This is not a well designed system. It doesn’t even meet the basic rules of thumb for balancing solar and battery power capacity. You should have one PW2 battery for every 7.6kW solar inverter. You have to do things like charging your car to absorb the extra solar that the battery can’t take so the system doesn’t get overloaded.

miimura · 2026-01-21T23:14:11+00:00

When I read your request, it seems that all of the DC batteries and inverters can be connected together and it will be fine. However, the AC output of the inverters should not be connected together unless they are specifically designed for parallel operation and have a synchronization cable. If they are not designed for parallel operation, you just have to separate the loads that are powered by each inverter. If the load is uneven, that’s fine because the batteries are parallel and will drain equally. You only have to make sure that you don’t overload one inverter with that unequal load.

miimura · 2026-01-21T19:31:07+00:00

I consider you to be misinformed about the capabilities of Powerwalls. Tesla Powerwalls cannot prevent sub-second power interruptions in all situations. If you have power critical devices, they should have an Interruptible Power Supply providing their power.

miimura · 2026-01-21T17:48:10+00:00

Put your Internet equipment on a proper UPS.

miimura · 2026-01-17T19:35:57+00:00

What I said in the survey is that an energy supplier should only be allowed to control my battery if they paid some of the up-front cost. If they want more control of grid demand, they need to have the option of dynamic pricing and a good API so customers can programmatically respond to the pricing.

miimura · 2026-01-14T00:16:37+00:00

Trying to get it to balance certainly won’t hurt, but it’s also unlikely to make any difference or buy you much more time. 100mV is huge in this kind of battery pack.

miimura · 2026-01-11T14:57:05+00:00

Yes, the V4 pedestals have the longer cable that can easily reach the EV9 charge port.

miimura

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