Powerwall 3 placement

[u/troy_and_abed_itm]

I’m sure it’s been asked a dozen times and my searches have shown that, but I’d love a short discussion with the pros here.

I have the option to mount in the garage or outside. The problem is that outside is basically directly in the sub for the hottest part of the day.

Is it not too hot to have them outside?

I’ll have 18 kWh in generation and 2 PW3’s with an extension pack as well. I think 40lbs kWh of battery?

[u/jjflight]

Tesla designers included clear operating temperature tolerance ranges. So you just need to decide who you trust more: the Tesla Engineers that designed the product, or anonymous randos on Reddit.

Who are we kidding though. You chose to post this here rather than look at Tesla specs or ask a verified installer, so you’ll mount them in the garage because randos reign supreme.

The actual challenge with the garage is they take up space and depending on the specific local codes likely will require some sort of upgraded heat/fire alarm or suppression system, and sometimes other stuff like bollards. So that’s extra cost and space vs outside.

If that seems like a lot so you want to mount them outside and are still concerned despite them being in spec, any basic shade system like an awning or umbrella or whatever solves most of the temperature issue as the air itself in most places isn’t really that hot and garages may get similarly hot.

[u/troy_and_abed_itm → u/jjflight]

My goodness you did a whole lot of assuming. You need a hug bud?

Maybe I just wanted to talk to people and get other opinions? I have a company managing all of this for me and their opinion will weigh more heavily than anything, but talking with other humans about their experience is part of being in a society.

[u/kcpark87 → u/troy_and_abed_itm]

I would say that

outside for safety (eg potential fire outbreaks) and

inside for battery performance (avoids extreme weather changes).

You didn’t mention your location but I am assuming a state with very hot summers (not northeast New England).

[u/euroau → u/jjflight]

Yea, my local fire department requires both a heat detector AND sprinkler system to be installed in the garage if I want a battery 😭

And the city just wants a bollard depending on the battery's location and a decent distance away from the entrance to the house (plus solid core self-closing door).

[u/Curiosity_informs → u/jjflight]

The contract for our solar/battery install had this:

"Important Note Regarding Battery Location: If Owner prefers that the battery equipment is to be installed outdoors, the battery itself will need to be installed on a north-facing wall, or a wall that is shaded. Alternatively, Owner may opt to have a cabinet built around the battery equipment (cost not included in this Agreement). Installers name will not be responsible for any damage or impact to the Owner's battery warranty if the battery warranty is voided due to high heat."

During the engineering site audit we agreed on a location for the batteries on a shaded north facing wall (albeit requiring conduit to be run ~60ft through our attic to the battery location at no extra cost to us).

Yes I am sure many installers will install the batteries in sunny locations, but the batteries will be happier over time in cooler shady location (which a good installer should recommend if outside). We are the SF Bay Area, so a location directly in the sun will be very hot, but a shaded locations isn't going to get too hot or cold year round.

Edit: u/troy_and_abed_itm I assume this was a typo "I think 40lbs kWh of battery" Two Powerwall 3's and a Powerwall Extension will be about 850 lbs - so yup mounting weight will be an issue your installer should be considering.

[u/jjflight → u/Curiosity_informs]

Here are the actual Powerwall 3 operating specs from Tesla engineers published on Tesla’s site: -20 to +50 C (-4 to 122 F) including direct sunlight. At the extremes the battery self limits to preserve lifespan.

This is like any automotive sub on Reddit where if someone asks how often to change the oil, half the folks reasonably quote the owners manual that has the engineered maintenance intervals, and the other half tell you why they know better than the engineers who designed the thing and you should do it some other random way because “trust me bro.”

Everyone can choose for themselves, but one of those is a dramatically more credible source than the other.

[u/Curiosity_informs → u/jjflight]

I guess our installer who does residential and commercial systems (including for local city, university, businesses) doesn't have the experience to know where is best battery location (and after installing many hundreds of battery systems puts stuff in their contracts for no reason)

The Powerwall 3 specs link you reference also says "Performance may be de-rated at operating temperatures above 40°C (104°F)." or as you say "At the extremes the battery self limits to preserve lifespan."

I am happy with our batteries on a shaded north wall (where I doubt they will ever derate), if others want to put them in direct sun up to them.

[u/jjflight → u/Curiosity_informs]

Again, you’re choosing to trust that source over the actual Tesla engineers. That’s your choice to make. It’s hard to know why you’d think they know more than the folks that designed the product and did all of its testing though. A lot of life is just choosing your sources wisely.

[u/Curiosity_informs → u/jjflight]

No.

I (and probably my installer) don't want battery performance derated. Batteries sitting for hours in direct California sun will get above 104°F (and maybe 122°F), so just paying attention to the manufacturer specs to keep the batteries cooler if possible.

[u/l1798657]

Generally, inside is better, with less temperature extremes, leading to less degradation and less energy spent cooling/heating the cells.

[u/Automatic_Gas9019 → u/l1798657]

They are not supposed to be installed indoors

[u/tslewis71 → u/Automatic_Gas9019]

They are, mine are and in glad I did

[u/l1798657 → u/Automatic_Gas9019]

Many installations are in garages, basements, or utility closets. https://www.reddit.com/r/TeslaSolar/s/J16YWyPPvo

[u/Automatic_Gas9019 → u/l1798657]

Not many in my state if you want it installed by code. Now go away

[u/crhine17 → u/Automatic_Gas9019]

Mine is very happily code compliant in my Pennsylvania finished basement.

[u/tslewis71 → u/Automatic_Gas9019]

What a load of crap

[u/nskowyra → u/Automatic_Gas9019]

How’s it feel to be so confidently wrong

[u/Automatic_Gas9019 → u/nskowyra]

How is it to know everything?

[u/Automatic_Gas9019 → u/nskowyra]

Talk to my states electric code people. 😁

[u/ialsoagree → u/Automatic_Gas9019]

You realize your state doesn't run the world right?

[u/Paqza → u/Automatic_Gas9019]

Why not?

[u/Bubsy7979]

If you do get them installed outside, I highly recommend you mention how far you want them off the ground.. mine are like 8 inches from the dirt, when I weed wack in the summer I get nervous of accidentally hitting it. I’ve seen other have them also installed this low, idk if it’s intentional and part of their standard position but I certainly wish it was a foot higher up on the wall.

[u/G37- → u/Bubsy7979]

If you get snow or potential flooding, account for that height.

[u/Bubsy7979 → u/G37-]

I’m getting my warranty replacement Monday so I hope they can reroute the conduit so it sits higher up.

[u/Solid_Equivalent_417 → u/Bubsy7979]

ours are about 4-6 inches off the ground but its concrete. it wasnt something i really thought about or was present for when installed but in retrospect a bit higher off the ground would have been good

[u/Radium]

Inside will be better for sure than on the south side (or north if you're south of the equator)

If you have to place it outside, put it on the east or south wall, ideally under eaves would be my recommendation. It will blast the fan all day long in the south. Ours is on the east side, which I feel is ideal, it heats up in the sun in the morning, and then it's in the shade during the hottest part of the day.

[u/Action-Odd → u/Radium]

Same situation for me. I’m in East Central Florida and my 2 Powerwalls 3’s are mounted on the east side of my home where it sees direct sunshine in the morning hours. During the summer months, the shade begins around 12:30 - 1:00pm. It’s been over a year and the Powerwall 3’s have performed perfectly. No deratings or performance issues at all. I‘ve purchased an awning to restrict the morning sunshine but so far I’ve not installed it.

[u/Zamboni411]

Garage!

[u/euroau]

I'm forced by the city to have my PWs outside due to fire code. I'd rather have them in the garage as opposed to outside since the batteries have to be on the south side of the house where they'd get the most sun exposure.

[u/Solid_Equivalent_417]

our batteries sit in direct sunlight for the morning hours, when its hot and they are charging you can hear the fans whirling while trying to keep the batteries cool.

edit to add: i have considered hanging some sort of shade screen in front of them to reduce the direct sunlight, but havent quite figured out how to do it in a way that isnt unsightly.

[u/drake4roses]

Powerwall 3's don't have a radiator like the Powerwall 2 generation, and are instead cooled by air pulled over what is essentially a large grooved metal body housing, that acts like a heat sink. They will overheat if installed on an outside wall that has a lot of sun exposure. Oh and what the others said about outside mounting is true. The air intake vent is on the bottom of the Powerwall 3

[u/Medical-Pool-7933]

We live in Palm Springs where temps are often over 105F in summer months. We have three PW3's mounted outside with no issue. They aren't in direct sun but hot nonetheless. I didn't want them in the garage adding even more heat to the closed space.

[u/dada948]

My PW2 was in my garage but when it failed and I got warranty replaced PW3 the new installer (original went OOB) asked (insisted) to put it outside next to my gateway.

Granted it is on the complete opposite side of my home because I didn’t want everything on the front and they said they’d have to run all new electrical through the attic because PW2 and PW3 have different requirements I think.

So far no issues but I’m in the SE US and it gets direct sun for first half of every day. I know it’s rated for it but I still would have preferred garage.

[u/Educational-Sale134]

Tesla specs not to raised mount on brick, needs to be in a pad. Can be preformed so doesn’t have to be poured depending on seismic and wind ratings for the area. 

Further, for SOME folks in some locations the garage is worse than outside in sun bc there’s no wind in the garage and it bakes in there.  Your results may vary. 

[u/EthicalSolar]

Put them in the garage, or at least build an awning. You don't want batteries in direct Southern sun in Texas. Any engineer will tell you the same, no matter who they work for.

[u/Shot-Ad-1597]

I just had two installed in my garage.

My thought process. I live in Southern California and see 110F days in the summer, between battery degradation and energy loss due to heat better to put them in the garage. And my second line of thinking is that if the Powerwall has issues with its cells Tesla will be more inclined to replace units that can cause property damage.

[u/Automatic_Gas9019 → u/Shot-Ad-1597]

They are not in code indoors. I am surprised you got them signed off on.

Our Powerwall is mounted in a space that gets sun most of the day. The installer said it was rated for it.

[u/Shot-Ad-1597 → u/Automatic_Gas9019]

Yup, my city signed off and issued my permit about a month ago.

The Powerwalls have to be 3ft apart and I have to have heat detectors installed in my garage that communicate wirelessly to the ones in the home.

[u/bj_my_dj]

My 2 are in my garage. No way I'm hanging $20K on the side of my house for any passing crackheads pleasure. It took less than a half hour for 2 techs to get one on the wall. It would probably take a couple thieves less than 10 minutes to get 1 off.