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2x Powerwall on 2-phase UK supply: sensing PW SOC individually

TyneTes

New Member
Aug 23, 2021
2
0
UK
I would greatly appreciate it if anybody has the answer to a bit of knotty problem I am trying to sort.

SitRep. Had 1x Powerwall + 1x Gateway 1 + 1x solar array on a single phase UK electricity supply for about 2 years. All working fine.

Have recently upgraded to 2-phase grid supply with our DNO (Northern Powergrid). We are very rural, they do not support full three phase supply up here in rural Northumberland. Upgrade done to accommodate 2x Air Source Heat Pumps which will shortly replace our oil boiler.

Gateway 1 now upgraded to Gateway 2 Config is now split as follows.

The L1 phase has 1x 5kWp solar array + 1x PW2 + 1x zappi + core domestic loads, which are designated to be supported during power outages by the Powerwall on the L1 phase. In near future 1x ASHP will be added to this phase.

The L2 phase has 1x 5kWp solar array + 1x PW2 + non-core domestic loads, which are not designated to be supported during power outages by any Powerwall. In near future 1x ASHP will be added to this phase.

Both phases are controlled by the one, newly installed, Tesla Gateway 2 unit. The incoming grid supply and solar production are all being highly accurately recorded by the SMETS1 polyphase meter on the grid connection and the SolarEdge app recording inverter production. That is to say, the system is functioning entirely as expected. I'm generally happy with it.

The one thing I would like to be able to achieve is to individually monitor the SOC of each of the Powerwall batteries. The Tesla app simply aggregates total Power Flow and total SOC across both phases. It is doing this entirely accurately. However, I would like to know individually what energy each of the two PWs has stored at any given time, so that I (or a home automation system) can intelligently connect/disconnect loads to either the L1 or L2 phases, depending on the SOC of the specific PW on that specific phase.

Does anybody know a way of reliably doing this in the Tesla app? Or by some other means? Any advice gratefully received. Thanks in advance.
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
10,874
12,600
Riverside Co. CA
The tesla app only aggregates everything. In order see what the individual totals of each powerwall has, you have to access the tesla api to get that information out of the system.

There is a sticky thread on that topic at the top of this subforum, here:

 
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Reactions: BGbreeder

sashton

Member
Jun 14, 2018
50
25
Somerset UK
@TyneTes I would be very interested in your experience of a split phase supply and a gateway2. We currently have a number of PW2 and a GW2 on a single phase supply but have reached the DNO prescribed generation limit.
The solution being offered by WPD is a second supply 180 degrees out of phase fed off the same PMT.
It is reassuring to hear the GW2 supports two phases. Our plan is to leave the PWs and house loads on PH1 and just install an additional ~25kWp on the second phase.
A polyphase vector sum SMETS2 meter should provide a reading being the sum of the two phases.
...that's the plan anyway.
 

ACarneiro

Active Member
Jun 20, 2019
1,423
1,138
Shrewsbury, Shropshire, UK
@TyneTes I would be very interested in your experience of a split phase supply and a gateway2. We currently have a number of PW2 and a GW2 on a single phase supply but have reached the DNO prescribed generation limit.
The solution being offered by WPD is a second supply 180 degrees out of phase fed off the same PMT.
It is reassuring to hear the GW2 supports two phases. Our plan is to leave the PWs and house loads on PH1 and just install an additional ~25kWp on the second phase.
A polyphase vector sum SMETS2 meter should provide a reading being the sum of the two phases.
...that's the plan anyway.
Our of interest, why not go with a three phase supply and a three phase inverter for your total solar array?
 

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