Advice for transitioning solar to solar + powerwall?

Questions
#1

Hi all,

i have an SMA5000 inverter which pushes data to sunpower unencrypted, so for a few years i’ve been using my own script to snarf and upload that data to PVO.

soon i will probably become a powerwall customer and i’m wondering if anyone else has made this transition. from reading around it seems like the powerwall itself will be able to figure out what the solar generation is and i suppose PVO can now understand what the current battery capacity is and how much energy the PW is using to power the house, etc. and compute the net consumption as it does now in the absence of storage.

again from reading it looks like the powerwall will be reporting cumulative numbers, which obviously will start from 0 after it is commissioned. what i’m wondering is if i should stop running my PVO script and just let the powerwall uploader do its thing… or if i should be running both, or what. seems like i could hack the powerwall script to add in the cumulative solar generation at the time the powerwall script takes over.

has anyone gone thru this process? how would i find systems on PVO that have storage so i can get familiar with how it all looks when it’s up and running?

thanks,

rob

#2

I transitioned from Enlighten microinverterrs solar and added powerwall. You can get all data including extended data from just the powerwall, which will include both generation and consumption

#3

thanks - yeah having read a lot on the tesla forums in the last couple of days, i see that their gateway box is measuring everything. so i guess unless i want to commission a new system for the purposes of PVO, i could just hack the cumulative solar total to start wherever i happen to be at the cutoff.

did you do that or did you just start a new system on PVO when the powerwall was commissioned?

i guess part of my problem is that i was too clever and used a couple of the extended fields to report the interval energy and inverter temperature to PVO. i was worried that this might somehow conflict with what PVO expects for the various powerwall-specific data.

one thing i haven’t gotten my head around is how energy consumption is computed in the presence of storage. normally PVO looks at the difference between generation and net import/export to compute the consumption. but conceivably with a battery the net export and generation could be the same number while the battery is satisfying the consumption. does this mean PVO doesn’t compute this anymore and the uploader tells PVO what the consumption is based on what the tesla gateway says?

#4

The ‘load’ data from the Powerwall are gross consumption and is be uploaded without any calculation.

Battery data can be uploaded to extended parameter.

1 Like
#5

ok, i guess that means then that i just upload everything the gateway has to say and forget about uploading the inverter’s data. i was a little confused because i can see at least one system with a powerwall that has 15 minute interval solar generation data on the first tab, but much smoother generation data on the extended tab. that indicated to me that for some reason you need to upload both your inverter’s data to PVO and the powerwall’s data as well (as extended data)

#6

for some reason you need to upload both your inverter’s data to PVO and the powerwall’s data as well (as extended data)

You do not. The powerwall has all data.

And by the way, expect delays to get a powerwall. Not as bad as when the powerwall unit was moved to model 3 delivery but still delays. I ordered mine in August 2018 and got it installed in February 2019. Best thing I ever did. I have Enlighten microinverters, and consumption less than generation on the average. Right now, with a single powerwall, I could stay off the grid for weeks. In California, with SCE now indicating that they may follow PGE and shut down the grid when fires are in their areas, this is no longer a luxury purchase.

1 Like
#7

You can also look at mine at https://pvoutput.org/intraday.jsp?id=64310&sid=57175.
I have solar production uploaded from my Fronius inverter, and then everything else is coming from the PW2 uploader (inluding voltage on the main tab). In the ‘extended parameters’ tab the solar is the value reported from the PW2, which is slightly different (lower) than reported from the inverter.

Yes, PVO will take consumption from the PW2 uploader. What doesn’t work well is calculations of import/export. With storage attached, PVO still calculates as if the storage wasn’t there, so some of the ‘export’ is actually going into charging the battery and not the grid, while some of the ‘import’ is also coming out of the battery, not the grid.

There is a ‘feature’ to help true-up the money calculations for this effect though - see https://pvoutput.org/help.html#extendeddata-crdr - you can apply a debit or credit-rate to an extended parameter (usually the battery charge/discharge parameter) which will be incorportated in the tariff calculation, so you can ‘add back’ your consumption charge rate to correct for $ (but not kW / kWh) saved or borrowed by the battery.

1 Like
#8

sorry for the late reply, i lost track of this thread.

in theory tesla will be out to install my powerwalls in a couple of weeks… but who knows. one person on the teslamotorsclub forum says that they may have delayed all bay area installs into 2020 due to personnel problems.

in fact this is why i am buying the powerwall - at first i thought i could deeply arbitrage with it but PGE does not allow that and anyway tesla configures these things to only charge from solar so they don’t run afoul of the federal ITC rules. so the arbitrage can only happen between partial and peak hours… not super profitable.

however, in october i went thru a PSPS event and it was terrible. not knowing when they would turn the power back on was the worst part of it. so i immediately signed up for 2 powerwalls. if they really install on time then it will have been a 2 month lead time.

#9

thank you, i’ll take a look at your system.

thanks, i think this is what was puzzling me the most… now that i know it’s not supported i won’t have to rack my brain anymore trying to figure out why i couldn’t figure that out. :slight_smile:

ah ok, thanks. that was another missing piece from my understanding.

i’ll have to study it a bit since when i wrote my own uploader i uploaded interval energy and inverter heatsink temperature as v7 and v8, and i think there’s probably a conflict in there somewhere. not sure if the pre-powerall v7 and v8 are going to mess things up if i have to overload those… hopefully not since PVO seems to not recalculate anything unless you ask it to.

so it sounds like what i’m doing is decommissioning my uploader and instead uploading solar, grid and battery flow/SOC to PVO once the powerwalls are online.

#10

Good luck with it all