Powerwall Location Options

[BIC1]

Forgot to ask earlier. I'm having a Powerwall installed tomorrow morning. Apparently two location options.

1. An unfinished storage area in the center of the basement next to the main electrical panel. This area is conditioned space, year-round temps probably range 65-75F.

2. An unfinished storage area under the suspended garage next to the electric meter & PV switch. This area is not conditioned with temp range probably 40-75F. It's mostly a concrete bunker with a small amount of wood framing at the walkout.

Space is not a concern in either location, can easily fit multiple Powerwalls, although starting with one due to cost. I like the center basement for temperature stability. I like the concrete bunker as it would be more fire-resistant should the Powerwall ever decide to melt itself down. It would be rare, if ever, for temp in bunker to get to freezing, but 40F would not be unusual during cold spells. Claimed operating temp is down to -4F. It occasionally gets to that outside, but don't think it would ever do that inside the bunker. At some point, there will be an EV car in the garage.

Any thoughts on location? Should I be considering potential Powerwall fire in the decision? Fire damage between the two locations would be significantly different. Thanks.

 

[BIC1]

I don't see an edit button. One more thing. The center basement area does have an overhead fire sprinkler system, which the bunker does not have.

 

[schrodarkian]

Great question on the fire. Haven't heard of any catching fire, but it is a large lithium-ion battery after all. If EVs are any indication the problem would be putting the fire out! However, these days we have all kinds of these batteries all over our homes... cell phones, laptops, etc.

The NFPA actually tested what happens when you set one on fire:
Tesla set fire to a Powerpack to test its safety features - the results are impressive - Electrek

The main concern with outside / unconditioned placement is that if the Powerwalls are below 50 degrees AND you have a power outage, the Powerwalls may not charge from solar as they should. There are some threads out there on this:
Grid down, cold, and can't charge PWs?

 

[patrick40363]

Forgot to ask earlier. I'm having a Powerwall installed tomorrow morning. Apparently two location options.

1. An unfinished storage area in the center of the basement next to the main electrical panel. This area is conditioned space, year-round temps probably range 65-75F.

2. An unfinished storage area under the suspended garage next to the electric meter & PV switch. This area is not conditioned with temp range probably 40-75F. It's mostly a concrete bunker with a small amount of wood framing at the walkout.

Space is not a concern in either location, can easily fit multiple Powerwalls, although starting with one due to cost. I like the center basement for temperature stability. I like the concrete bunker as it would be more fire-resistant should the Powerwall ever decide to melt itself down. It would be rare, if ever, for temp in bunker to get to freezing, but 40F would not be unusual during cold spells. Claimed operating temp is down to -4F. It occasionally gets to that outside, but don't think it would ever do that inside the bunker. At some point, there will be an EV car in the garage.

Any thoughts on location? Should I be considering potential Powerwall fire in the decision? Fire damage between the two locations would be significantly different. Thanks.

#1

 

[charlesj]

While it may not charge by solar at 50 and below grid down, forgot if it would also not deliver power to the house at and below that temp.

 

[BIC1]

Hard time finding the original thread over at the Tesla factory forum. They have no search function and no dates on the list of posts. Google search found it. Anyway, definitely sounds like the stable, moderate temperature is critical with the Powerwall. That overrides the small fire risk. Here's the original post. Thanks for the tip about 50 degrees.

PowerWall 2 does not like cold temperatures | Tesla

 

[Dan123]

I think both of those locations are fine. I would probably chose #2. Is there a way to insulate the bunker so it doesn't get as cold?

 

[gpez]

FWIW my Powerwall is outside on a north facing wall so it's out of the sun but otherwise exposed to the outside air. Temperatures this winter got below freezing but not substantially so (mid/low 20s). The Powerwall is configured for backup only we had a substantial outage due to wind in January for about 2.5 hours. It was in the high 30s outside and the Powerwall had no issues. No problems charging the next morning when the temps were in the low 40s either.

If I were to do it over I'd probably better evaluate placing it in the garage but the convenience and lowered expense of having all of the equipment on the one outside face of the house was a compelling enough reason for me to have it done this way and so far it has not been an issue.

 

[Merrill]

Same for me, to install the Powerwalls in the garage means running conduit in the attic for 60 feet and makes the install more expensive. Having them outside 3 feet from my main panel with all the solar inverters make it an easier install, it is under the roof overhang and northwest so no direct sun. It does get into the mid 40’s in the winter, also mainly for backup in the September October months.

 

[schrodarkian]

Yeah I think the issue was that the Powerwalls need some grid energy to precondition in cold temps (e.g., < 50° F), so if the grid is down the Powerwalls wouldn't charge even if solar was available. Charging from solar below 50° F was not listed as a concern when the grid was up. So, long story short: below 50° is only an issue for when you're trying to charge when the grid is down. And... not sure if this is still the case. The threads I reviewed listed this as a concern but that was a few firmware releases back.

Either location should be fine 99% of the time. I chose the garage for mine because it wasn't too inconvenient, and we get down to the teens sometimes, and we have lots of critters (field mice, squirrels, racoons, not to mention bugs of all sorts), and they like to get into everything and muck things up.

 

[charlesj]

FWIW my Powerwall is outside on a north facing wall so it's out of the sun but otherwise exposed to the outside air. Temperatures this winter got below freezing but not substantially so (mid/low 20s). The Powerwall is configured for backup only we had a substantial outage due to wind in January for about 2.5 hours. It was in the high 30s outside and the Powerwall had no issues. No problems charging the next morning when the temps were in the low 40s either.

If I were to do it over I'd probably better evaluate placing it in the garage but the convenience and lowered expense of having all of the equipment on the one outside face of the house was a compelling enough reason for me to have it done this way and so far it has not been an issue.

Was the grid down during those cold spells below 50?
If not, then the grid provides the power for the battery heaters to keep it at design temps, from what I have read here by others what happens when the grid is down and temps are at or below 50.

 

[charlesj]

Hard time finding the original thread over at the Tesla factory forum. They have no search function and no dates on the list of posts. Google search found it. Anyway, definitely sounds like the stable, moderate temperature is critical with the Powerwall. That overrides the small fire risk. Here's the original post. Thanks for the tip about 50 degrees.

PowerWall 2 does not like cold temperatures | Tesla

This is only an issue when the grid is down it seems. Grid power keeps heaters running as needed, or cooling.

 

[JayClark]

Either location is fine. I will say, I have seen my PWs take up to 30-45 minutes to warm up before powering the home when my garage gets below 50 (as best I can tell that was the reason one morning for the delay).... so my only comment would be warmer low end temps might be a slightly better choice - but if the other factors are important, then neither option is bad it seems in your case.

 

[bob_p]

If only installing one PowerWall, and you may consider adding another in the future, would recommend the installation be on the floor - not the wall, so that a second PowerWall can be added by stacking with the first one - and reuse the conduit already run for the original PowerWall.

We had 4 PowerWalls installed in our garage, in two stacks - and it's worked well, without taking up that much floor or wall space.

 

[jrweiss98020]

My circuit breaker panel is in a basement storage/utility room. Perfect place for the PW!

 

[gpez]

Was the grid down during those cold spells below 50?
If not, then the grid provides the power for the battery heaters to keep it at design temps, from what I have read here by others what happens when the grid is down and temps are at or below 50.

Yes - it was in the high 30s out and the grid went down. Powerwall had no problems.

 

[BIC1]

We went and installed in the climate-controlled space next to the main panel in the middle of the basement. What's a a little confusing, after reviewing the various forum threads, is that most, but not all, have the cold weather problem. The only explanation I can think of for that is different firmware versions, but that doesn't seem to be the issue.

My thinking in deciding the location is that even if the issue goes away, in a cold weather outage, you still have to drain valuable watts pre-heating PW to 50F. I'd rather not do that is I don't have to. I have a large house with only one PW being in the budget. I'll have to carefully select a few critical circuits if clouds are forecast or I have snow on panels during a power outage. With sunshine, all circuits are go.

I'll only regret this decision if the PW burns my house down. Thanks for all the inputs. My installer was unaware of this issue, but they've just become PW certified. I'm their third PW project. Their next one is 100 PV panels & 6 PW.

I appreciate all the input. This seems like a great forum.

 

[Merrill]

This thread has me wondering if I should spend the extra money and install in my garage, probable would cost around $1000 to run the conduit thru the attic to the main panel.

 

[jjrandorin]

This thread has me wondering if I should spend the extra money and install in my garage, probable would cost around $1000 to run the conduit thru the attic to the main panel.

Everyones decision making process is different, but the way I would look at it is, the powerwalls have a warranty of 70% capacity remaining at year 10 if charged by solar... meaning that your expected use time is at least 10 years, but likely more.

If it costs you 1000 to put it in a location that you think is better (and all things considered, I think a place with more temperature control / less temperature swing is a bit better), then you can consider the up charge of 1k over the expected life expectancy of the system, based on warranty, of at least 10 years / 120 months.

So, it will cost you $8.33 a month additional (not saying you are paying by the month, just looking at what it costs "additional"). How long does it take you to make $8.33 in wages? I would imagine that its much less time than 20 minutes for you to earn 8.33. Its the cost of a fast food lunch a month. If the cost was 5k, same math would apply but obviously a much higher total.

If it were me, and it were 1k additional to put it inside the garage vs outside, I would pay that. I wouldnt pay 4-5k though. The above is how I would consider it.

 

[patrick40363]

This thread has me wondering if I should spend the extra money and install in my garage, probable would cost around $1000 to run the conduit thru the attic to the main panel.

It is money well spent.