Smart Solar Charging the CT?

[SlegMD]

What’s the size of the solar array? 49a is high and might keep your charging threshold from charging from solar. From my experience;

Turn it on and leave it alone, it does the job fairly well. My setup is only 12.5kw so if AC (summer) triggers charging the EV is null, typically lowers to 1-3kw. This is at 18a. I lower the charging amperage for demand charge and heat management.

Other option is I deactivate charge on solar (CS) and pull from the array and battery(PW3)with AC/house demands going as normal, battery (PW) remains ~80%+, then I deactivate EV charging to top off battery. This method manually prioritizes the EV where I’ll achieve the expected load whereas CS will not.

Sponsored

 

[Miznat411]

Don't think you can enable charge via solar until net metering is enabled. Waiting on the same.

Yes can only charge with Tesla solar. I was able to install my own PowerShare as we are Qmerit installers. Wired it to the existing solar grid ties and it was reading a negative feed. That’s how we found out. Lame we are unable to solar charge during an outage without Tesla gear.

 

[DJAlan2000]

Not sure why you have a separate inverter... Tesla's Powerwall 3 has a built-in solar and battery inverter already that will allow 20kW of DC solar input.

The one key thing to note though is that you will NOT be able to 'charge on solar' if the Powerwall is not fully charged up first... Solar will prioritize the battery over charging (via solar)... Also, when charging via solar, you don't get as much 'charge' power... Usually about half as much...

You CAN charge off the grid though at a faster speed and then just 'sell' the power back via your solar system... Although depending on your utility and the NEM level they may have you on, it may not be worth it to do it that way... I am on NEM 2.0 (barely got approval before they went to 3.0) here in California and believe me, if it was ONLY 3.0 I would ONLY charge on solar unless it was a dire emergency!

You can of course contact your installer to ask them about it.

 

[GnarlyDudeLive]

Not sure why you have a separate inverter... Tesla's Powerwall 3 has a built-in solar and battery inverter already that will allow 20kW of DC solar input.

As I understand it: The Powerwall 3 does allow 20kW of DC solar power in but only under circumstances of the battery not being at 100% charge. It diverts up to 5Kw of power direct DC to DC to charge the battery (bypassing the inverter as there is no need to convert it to AC). The output is the limiting factor where you don't want to use it by itself to handle this large of a system. It would clip pretty hard for 5 months out of the year. Being on Net Metering, you ideally do not want to see any clipping as you want to pull that power back at night or when your home power spikes beyond what you are producing. The inverter in the PW3.0 is rated at 11.5kW output for reference when converting DC to AC (outputting power to the home).

At this stage of the install, only the PW3 is providing power until ComEd approves me for Net Metering 2.0 in the next couple of weeks. At that point the second inverter will be brought online.

Today for example I have seen spikes of 12.6kW coming in on the system. It is close to clipping with only 2/3 of the panels attached to the PW3 and my battery fully charged. The other 1/3 of panels are balanced onto the 2nd inverter. We are also already out of the prime/top solar producing months.

To add some more perspective to this, my PW3 battery starts the day at 20% charge (fully depleted for non-backup usage) and by 11:00am is fully charged. This is with only 2/3rds of the panels online. Once the other 1/3 come online, it will be fully charged well before the system hits the best 4 hours of sunlight window where you want to be generating the most credits possible for night time usage after the battery is depleted.

 

[GnarlyDudeLive]

Not sure why you have a separate inverter... Tesla's Powerwall 3 has a built-in solar and battery inverter already that will allow 20kW of DC solar input.

The one key thing to note though is that you will NOT be able to 'charge on solar' if the Powerwall is not fully charged up first... Solar will prioritize the battery over charging (via solar)... Also, when charging via solar, you don't get as much 'charge' power... Usually about half as much...

You CAN charge off the grid though at a faster speed and then just 'sell' the power back via your solar system... Although depending on your utility and the NEM level they may have you on, it may not be worth it to do it that way... I am on NEM 2.0 (barely got approval before they went to 3.0) here in California and believe me, if it was ONLY 3.0 I would ONLY charge on solar unless it was a dire emergency!

You can of course contact your installer to ask them about it.

The reason for the second inverter is that the DC to AC inverter is only 11.5 kw. While the PW3 can handle 20kw that really is only when 5kw is being diverted to charge the battery. Most days the battery is fully charged by 10am leaving several more peak hours being limited by the inverter output (clipping). Though I do have slight change to the system now where the second inverter was replaced with second PW3. Even with both batteries charging, they go from 20% charge to 100% charge by 11am daily. Even though it is now a bit out of the peak months for solar production, I still have seen 22kw+ solar production at around 1:15pm. I would not be surprised at all if during May/June that I still see some clipping occurring once the batteries are fully charged. I do wish Tesla would allow the Powerwall3's to delay charging until peak hours to take advantage of the batteries charging during peak times specifically to prevent clipping by taking advantage of the extra 5kw per battery DC charging.

The issue with Net Metering on ComEd in my area is they only credit me for the supply portion and not the delivery/tax portion. The delivery/tax portion is roughly $.09 per kw while the delivery is hourly rated and rarely goes of $.04 per kw until around 9pm. Peak pricing might once a week or so for an hour go above $.12 per kw. In reality I have to send them 3x-4x as much power as I pull to zero out my grid usage costs, assuming I have any for the month.

Sponsored