Powercut, sun shining, PV not generating

[vivienz]

I have 6 x 2.4 kWh batteries.

[scottishjohn]

so if they were half charged you used over 7kw with minimum things turned on 

how many hours --how much usage per hour?

 and no heating you say

Edited March 12, 2020 by scottishjohn

[vivienz]

As I said, the power went off at 5.30pm yesterday and The batteries ran out at 8am this morning. Use per hour varies as we made hot drinks at different times, had showers and had lights on last night but not during the night. Feel free to do the maths, if you wish!

[vivienz]

Minimum things turned on included sewage treatment and MVHR.

[joth]

1 hour ago, scottishjohn said:

thats a question for your electrican

Yeahbut my electrician's first question is "what is the Tesla MIs and their technical recommendations"....

 

 

[scottishjohn]

2 hours ago, joth said:

Yeahbut my electrician's first question is "what is the Tesla MIs and their technical recommendations"....

 

 

they will say get an elctrican who is fit for the job to start with 

 

[joth]

1 hour ago, scottishjohn said:

they will say get an elctrican who is fit for the job to start with 

 

It would be impractical and perhaps impossible to get a Tesla-battery qualified electrician to rewire my home if I'm not actually planning to install a Tesla battery at this point.

 

I was hoping they'd say something more like "it depends whether you want to plan for a partial or a whole-house backup?  Take a look at the UK version of this guide, and here's some additional information to help you figure what sort of backup you might eventually need".

 

Edited March 12, 2020 by joth

[joth]

On 12/03/2020 at 19:45, joth said:

On 12/03/2020 at 18:17, scottishjohn said:

they will say get an elctrican who is fit for the job to start with 

 

It would be impractical and perhaps impossible to get a Tesla-battery qualified electrician to rewire my home if I'm not actually planning to install a Tesla battery at this point.

 

I was hoping they'd say something more like "it depends whether you want to plan for a partial or a whole-house backup?  Take a look at the UK version of this guide, and here's some additional information to help you figure what sort of backup you might eventually need".

 

Answering my own question, I found the comprehensive Installation manual (generic, not UK targeted) here: https://www.tesla.com/sites/default/files/pdfs/powerwall/Powerwall_2_AC_BU_NA-EN_Installation_Manual.pdf

Pages 40-48 have detailed diagrams of how it should be wired. Key thing (obvious really) is in a partial-backup scenario you need the powerwall and any solar PV inverter connected into the sub-main board that is feeding the backed up loads (downstream of the backup Gateway). Important to think about the relative locations of these things. As our supply meter, PV inverter and (eventual) battery will all be in the garage I need the sub-main there and have 2 feeds into the house (for grid and battery-backed resp.)

 

Thinking out loud - it'd be nice if I could send both those feeds from garage to house down a single run of 5-core SWA, but it maybe a bit dodgy as they're coming from different boards. ... Unless one can use in effect a split load consumer unit, inserting the Tesla backup Gateway (cutout switch) between the 2 sides such that one half is direct grid supply and the other side is the battery backed circuits, and then send the feed to house from that single CU with a L/N pair coming from both sides. Hmmmm.