u/John_of_heart

So I had a legacy Solar City/Tesla system installed a long time ago and this was great (net neutral on power use) until we got an EV and our annual true up started climbing (~$2k Last year)

Since we're PG&E - this also means that blackouts are always a possibility, so this led to a modest Enphase solar add-on, a controller and a 10C battery.

Worth mentioning we're not allowed to export any of the new power and still keep NEM 1.0 (for the next 9 years)

The problem is that Enphase insists on charging the battery from both the new and the old solar. Which means at this time of year the battery hits 100% by 11AM, and then all that new solar goes to waste.

Literally to waste as the new solar won't even contribute to the house load during these times, it just cuts its output to zero.

I've mitigated this by building a smart EV charging system using Home Assistant - Basically get the house battery to drain so that the new solar kicks in again, with various bits of logic to keep the house battery above 60% (because blackouts) and try to get as close to 100% by nightfall.

But I'd rather the Enphase system would just let me choose the power sources it charges from myself. This way I could prioritize charging from the new solar, export from the old, and just top off the house battery from other sources if needed.

Anyone know a way to do this?

I'm about a month in with a new Enphase system, that includes a 10C and a modest 5 panel setup.

I also have an old Solarcity/Tesla system they were able to integrate into the new 6C combiner.

The whole reason for the additional solar was to offset as much as possible charging our EV. Pre-EV we'd see a net annual usage of roughly 0.

Post E-V our annual true-up was running just under $2K

However I'm one of those lucky bastards who is on NEM 1.0 with PG&E, so I'm not allowed to export any of the new solar, hence the battery.

Here's the issue - The battery is charging off both the new panels *and* the old panels - This means solar production has basically charged the battery to 100% by 11 AM. Leaving the next 7-8 hours of production from the new panels to go to waste.

The old panels still export. Thank goodness.

I've done some fancy playing around with Home Assistant and my OpenEVSE charger, so that as much as possible it tries to shunt any extra to the EV, but even then I'm seeing production on the new panels drop to zero for much of the day.

Ideally I'd love to only charge from the new panels, and have the option to also charge the battery from the new panels, but only when it makes sense to do so (heck, I'll even charge from the grid)

In a perfect world, the new solar would charge the battery around 25% a day.

I could use that to power the house during peak hours (not that I have to, but it seems the "nicest to the rest of the grid time to do it) and I could optionally use my old solar (and even the grid) to make sure I have enough reserve for one of PG&E's inevitable blackouts.

Seems to me that as long as I'm never exporting from the battery, I should be able to decide how the battery gets charged.

And just to add to the mystery, in the Enphase app my battery says "export only" (bug?) - This seems contradictory given that I should only be able to self-consume, not export, this power.

Anyone have any experience with this sort of setup?

Thanks in advance!