Power Walls & Scheduled Maintenance Outages

[MXDogCrate]

Apologies in advance if this question has been asked/answered. I scoured the forum with no results.

In speaking to a friend with solar panels and a Siemen's battery attached to the SCE grid in SoCal, he mentioned the battery does not assist in cases of planned maintenance outages to stop feedback into the grid which is why he still has a generator.

Is this also the experience with Power Wall owners? Does the utility disable your ability to utilize the battery in times of scheduled outages?

TIA

 

[miimura]

Apologies in advance if this question has been asked/answered. I scoured the forum with no results.

In speaking to a friend with solar panels and a Siemen's battery attached to the SCE grid in SoCal, he mentioned the battery does not assist in cases of planned maintenance outages to stop feedback into the grid which is why he still has a generator.

Is this also the experience with Power Wall owners? Does the utility disable your ability to utilize the battery in times of scheduled outages?

TIA

Absolutely not. There is no difference between an accidental outage and a planned outage. The Powerwall system isolates your home from the grid and continues powering the backed up loads.

We have no idea why your friend still needs a generator with his system.

 

[cwied]

I would assume that your friend's system doesn't have a transfer switch and so cannot be used for any outages at all. I think that some battery systems that hook directly to the solar inverter work this way.

The Powerwall Gateway (also known as Tesla Energy Gateway) contains a switch that isolates your house from the grid when there's a power outage to prevent backfeeding to the grid. This allows Powerwalls to continue functioning when the grid is down.

Since your friend has a transfer switch for his generator, he could in theory get his solar running during an outage too if he could get his inverter running. It wouldn't be simple to duplicate the smarts that the Powerwall system has to balance net solar production against the house load, though. The Powerwalls absorb extra solar energy that's not being used by the house and shut the solar down when they are full enough that they can no longer do so.

 

[Ampster]

It wouldn't be simple to duplicate the smarts that the Powerwall system has to balance net solar production against the house load, though. The Powerwalls absorb extra solar energy that's not being used by the house and shut the solar down when they are full enough that they can no longer do so.

Not only would it be difficult but it would be dangerous and probably ruin the generator because it would not like to be back fed.

 

[MXDogCrate]

Thanks to all.

Anyone know pros/cons of installing battery walls inside or outside the garage?

 

[jjrandorin]

Thanks to all.

Anyone know pros/cons of installing battery walls inside or outside the garage?

The powerwalls have liquid cooling, and can heat themselves, but both of those cost power. They can be placed outside the garage, but the less temperature variance in them the less internal heating and cooling they have to do on themselves to operate efficiently, so inside is "better" if you can manage it. If not, however, its not the end of the world by any means.

 

[jboy210]

Thanks to all.

Anyone know pros/cons of installing battery walls inside or outside the garage?

I asked this same question a couple of weeks ago. There are a wide range of opinions, but a lot of people sided with inside for the termp reason @jjrandorin suggested. We are going to install them inside for that reason, plus I think they will look cool on the garage wall (thanks @MorrisonHiker ). But we are putting all of the solar boxes outside because my wife does not want them cluttering up the wall.

 

[schrodarkian]

As mentioned above, Powerwalls will kick in during *any* type of outage as they form a closed loop when the grid goes down. In fact the day after installation I had a 7 hour outage while SCE replaced a pole on our property. This I believe is Tesla's standard installation, but you may wish to double-check if you're using a certified installer, but I suspect they all use the same equipment which would isolate your home during outages.

As for inside/outside - that for a fact has been covered extensively in the forums. I was concerned about the same thing as our temps get into the teens where we are. If your temps don't go too far below 50F you'll be fine with an outside install. Some have reported that they experience problems charging from solar *when the grid is down* if it's below 50 degrees outside. If the grid is up and it's below 50, apparently the batteries uses a bit of grid power to pre-heat. I haven't personally experienced this nor seen resolution, but I suspect it can be corrected via software (if it hasn't been already).

We put ours in our garage. They are quiet and don't take up a lot of room, even when installed together. Your jurisdiction may require a bollard if it's the path of the cars, fortunately ours are mounted off to the right enough that this wasn't necessary.

FWIW we love our Powerwalls and highly recommend them. They let us totally dodge the peak rates (and actually allow you to export all solar generated during peak). And, we don't have to have a repeat of Oct 2019 where we had 3 SCE PSPS outages along with several additional maintenance outages between Sep and Nov last year.

 

[Dukeybootie]

Why are there all those small Powerwall discharge spikes before 4am? What mode/setting are you using?

Otherwise, a beautiful looking energy graph!

 

[gpez]

Why are there all those small Powerwall discharge spikes before 4am? What mode/setting are you using?

Otherwise, a beautiful looking energy graph!

Not my graph but I could guess that it is the furnace blower kicking on periodically over the night hours. Mine has similar blips!

 

[schrodarkian]

Alas, it's an electric oil-filled radiator heater we use during the winter for our bedroom. We try not to run the NG furnace at night as it's pretty loud by our bedroom.

I'm using Advanced > Balanced. I've set my peak from 4-9 pm (actual peak, 36 cents in winter), and shoulder from 9p - 4a. I actually don't have a shoulder rate, I just want to encourage the Powerwalls to do their thing all night. I set my backup reserve at 40%, and usually these days I get down to about 45-50% before 4am, which I've set to be off peak (4a - 4p). Of course you all probably recognize the spike at 4:15 am... my wife's MS kicks in. I try to charge my M3 off pure solar (part tree-hugger and part masochist) as I'm semi-retired and what work I do is from home. This February has been kind after a fairly foggy Dec / Jan period. I can show you some pretty ugly graphs too. My lowest production thus far was 10 inches of snow on the panels and they still managed to eke out 0.1 kWh.

Ideally I would prefer the Powerwalls to not charge the cars, but that isn't possible at this time. I've heard they may be working on that. The concern is that if the power goes off at 3am the MS will suck the batteries dry right-quick, and then we have no actual backup reserve left.

I would also prefer to be able to set the car charging amps from within the app, or somehow have a setting of "only charge the car off solar". Yes, persnickety for sure, but I'd prefer to stay as off-grid as possible.

 

[getakey]

Does your utility have an EV rate? I charge my EV at the off peak EV rate. More valuable to send solar to the grid than charge my EV

 

[woferry]

My lowest production thus far was 10 inches of snow on the panels and they still managed to eke out 0.1 kWh.

I'd wonder if your inverter agreed with that, or if it was just Gateway measurement error. Every morning shortly before the sun comes up my Tesla app already shows 0.1 kWh of solar production that day.

 

[bob_p]

We installed our 4 PowerWalls in two "stacks" inside our garage.

The installers were able to run the conduit through the outer wall, so we don't have any conduit running the garage. And even though the PowerWalls are stacked two deep, it hasn't posed any problems with parking our S and X in the garage.

If you can get them inside, would highly recommend it - and keep them where the temperature is better controlled and they aren't exposed to the elements.

 

[Mokuzai]

Anyone know pros/cons of installing battery walls inside or outside the garage?

We had ours installed in the garage. It was a more complicated install to run the conduit to the garage bit well worth it IMO if only for the aesthetics (but also get the benefits of a more controlled climate). Don't even mind seeing the conduit exposed...in fact the drywall was sorta messed up at the base and now it's covered.

 

[schrodarkian]

Well I wish I had 4, and they were red!

2 are working well for me, and the garage install is clean. Now, the outside of my house has some conduit.

 

[jboy210]

We installed our 4 PowerWalls in two "stacks" inside our garage.

View attachment 509540

The installers were able to run the conduit through the outer wall, so we don't have any conduit running the garage. And even though the PowerWalls are stacked two deep, it hasn't posed any problems with parking our S and X in the garage.

If you can get them inside, would highly recommend it - and keep them where the temperature is better controlled and they aren't exposed to the elements.

Looks nice. Are these on the ground or them mounted side by side to the wall?

 

[jjrandorin]

Looks nice. Are these on the ground or them mounted side by side to the wall?

If they are stacked, they have to be on the ground (or on something thats on the ground). If you want to wall mount them suspended on the wall, they have to be individual.

 

[bob_p]

When stacking, the PowerWalls must be sitting on the floor, because the weight of two PowerWalls is too much for wall mounting.

In the stack, the PW closest to the wall is mounted to the wall (so that stack is not free standing), but the weight is on the floor, not held up by the wall.

We have space at the other end of the wall nearest to the garage door to add another stack of 2 PW in the future, if we decide to expand the system.

 

[jboy210]

When stacking, the PowerWalls must be sitting on the floor, because the weight of two PowerWalls is too much for wall mounting.

In the stack, the PW closest to the wall is mounted to the wall (so that stack is not free standing), but the weight is on the floor, not held up by the wall.

We have space at the other end of the wall nearest to the garage door to add another stack of 2 PW in the future, if we decide to expand the system.

I thought floor mounting was a requirement because of the weight, but wanted to see if there was a way around that.