Thanks for all the help - here are my off grid plans!

[Jay Gatsby]

Hi everyone.

I am very much appreciative of all the assistance here on this forum, last couple days as I plan to use Tesla to transition off grid over the next 12-18 months. Here in Inner suburban Melbourne Australia.

Kindly shoot holes in this plan - Id' welcome any comments!

Our place has two phase power. I couldn't avoid it. I didn't wire it that way.. I inherited "the problem". The place was renovated around 20 years ago, when 2 phase power was all the rage here in Aus. I get it's a PITA. It's just going to be too expensive to sort the existing wiring (and start again), so I am stuck with it..

Ok so now to the solution...

18 months ago, I put up an 8.1 KW SolarEdge controlled solar array on the back garage "dwelling" aka "outhouse", aka Man cave (and granny flat above) at our house. This phase powers all this garage/man cave area (and now the solar, and PW2) the other phase is the main house. (Where we live most of the time)

The garage also houses all my networking, internet, computer Home assistance server, etc - so it was essential to go Tesla simply for the backup function alone.

Anyway I added a Powerwall2 with Gateway2 (rather than the SolarEdge home battery onto their invertor) out back because of its better backup function, power reserve and pulled the trigger once PW3 was announced - knowing full well PW3 was coming. PW3 will suit us to a tee. We are yet to put solar on the front (main) House/phase and I have the collection roof capacity for another 8-12K Whr of Nth facing roof (remember I'm in the Southern hemisphere). The PW3 will be awesome here, as I can drop the panel wires straight into the PW3 batteries, add another gateway straight above on a balcony above the main meter and board..(run will be only a meter or so- 3 max). Put it all outside on the balcony and no messy additional invertors, gateways inside the hallway of this historic Victorian house. Keeping the Wife factor +ve. The PW3 will also be awesome as we have the higher peak load devices like heating, cooking, dryer, laundry etc in the front (main living house) ie on this other phase.

I came onto the forum a week or so back after I noticed (I can monitor my smart meter real time using a Rainforest Zigbee device) that the PW2 was obviously wired only and sensing only on the garage phase. So when the sun was blazing, it was stealing all the solar (as it should) but the net metering then detecting no solar going to the grid, delivering power from the grid to the loads in the front house (other phase) during the PW charge. Not ideal.

Worse this was happening during hi peak times (3pm till 9pm) ..say when I plugged in the car charge, the sun still shining here in Summer till quite late (around 7pm)

Obviously adding more solar/battery storage onto the main home phase (where we live) is a no brainer (to solve this problem long term) and the second gateway here will be clamped right around the in/outs on the main board. So all will be sweet..

Problem is they are saying late 2024 for the PW3 here in Aus (that means 2025) ..so I was after a temporary fix for the next 18 months, that's all...

I'm not unhappy, just learning as I go (which is the best way I feel) as capital is not spent on solutions that don't work in a complicated wiring set up I inherited at my place.

I can suck it up I guess (with a non ideal monitoring solution) the next 18 months.

Long term, its a pity I guess with 2 gateways, the app doesn't handle them "as one" etc (like solaredge does?), but what can you do?

I have Home assistant which can pull it all together anyway.

... Any other suggestions (what to do).. help (if I need to change direction and I'm going astray.)... would be welcome.

It aint necessarily easy retrofitting solar to a 150 yr old house....

Rock on Tesla

Cheers

JG

 

[GregBallantyne]

You didn't mention battery capacity, and I'm sure you may have previous posts where this may have been discussed that I either didn't see or forgot - so I'll just share a bit about my own setup. I would love to acheive off grid operation, but it's quite difficult especially in my location.

My system doesn't produce as much as we use annually - it's lining up to be about 75%. So my first effort to get close to off grid capability is to reduce useage. I can almost see a path to getting the annual numbers to fit, but seasonal considerations are something else. I am wired as whole house backup, which for my house requires a minimum of 2 PowerWalls. Got to have the startup load burst capacity for larger appliaces/systems. I went for 3 PW. 2 would have got me across the threshold of whole house backup, but 3 lets me get into the middle of that space. to claim off grid capability in the easier seasons, I would need a minimum of 4 and more preferably 6 to allow for a couple of concurrent lower production days during times of higher demand. The edge cases drive capacity requirements, and therefore the $$ of course... During the winter season, I would need to move almost completely into the realm of fossil fueled heating in addition to the additional PowerWalls. I do not want to do that, since I would rather eliminate fossil fuel use, but have to accept some level of it to satisfy my energy security goal. And, when you think about true off grid capability, fossil fuels are grid. Someone has to bring them to you, unless you have your own gas well or some such.

Not sure about the PW3 advantages since enough PW2's give you all the peak load capacity you could need. Maybe the II phase power has something to do with that, a subject not in my knowledge wheelhouse.

Good luck!