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Powerwall 2: Technical
- Thread starter Aussie
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Kant.Ing
Member
The screenshot from Google Play, I cannot know which device provides such info to the app if the grid is engaged, the gateway?
My first post here but I've been "reading the mail". I had a site survey by Solar City on April 12 and haven't heard anything yet. I have a deposit on 2 Powerwall 2's and I want a whole house backup. I guess Arizona is too far East to get an early installation.
The picture you posted seems to show the "Gateway". That's the first picture I have seen of the interior. Could you post a shot of it wired? I'm wondering if there are any auxiliary contacts that could be used to load shed an air conditioner. I know I could just use a relay tied to the switched supply but would like to keep it simple. I have a 7 Kw solar array with an SMA inverter. A description of the solar system is here.
The picture you posted seems to show the "Gateway". That's the first picture I have seen of the interior. Could you post a shot of it wired? I'm wondering if there are any auxiliary contacts that could be used to load shed an air conditioner. I know I could just use a relay tied to the switched supply but would like to keep it simple. I have a 7 Kw solar array with an SMA inverter. A description of the solar system is here.
And the smaller panel between the PW2 and the Backup Gateway is the "critical loads" panel?
I'm assuming that Tesla is just using the Neurio hardware to collect the data about how much the solar is generating and your total household usage. Their software, at least the customer facing portion, is probably not involved.
The attached datasheet should answer most of your questions.
As far as the discharge duration that would be depend on the load you applied to it.
pdxrunr
Member
Sure, here are some screen shots from the app. The only thing you see in My Tesla is the PW itself and the serial number, no other info is presented there. All info is on the mobile app. There are no "settings" for the PW in the app, it's used only to monitor the state of charge, the energy usage from the grid to the house, or from the PW to the house if you're on battery power. It also has some graphs that show the energy usage over time and a page that shows "Events", meaning when you have lost power and are running on battery.
The one thing it doesn't have, and the engineers agreed with me is that it doesn't have a notification feature that notifies you when the grid is down and you're on battery power! That is just silly given the notification that the car portion has with regards to charging, summon, and software updates, etc.
The one thing it doesn't have, and the engineers agreed with me is that it doesn't have a notification feature that notifies you when the grid is down and you're on battery power! That is just silly given the notification that the car portion has with regards to charging, summon, and software updates, etc.
Yeah, but I doubt you want to charge the car during a grid failure - power becomes precious at that point and only if you had to get ready to "evacuate in a dangerous situation" would that wall power be useful as car power. Grid outages in my area usually last a few minutes and the one outage every three years to me isn't worth the costs (would rather keep the cash growing in mutual fund, etc.) Great conversation piece and also moderate convenience if home-business is in play. The PW should talk to an HPWC and signal "I'm the power now, consider not charging the car unless owner overrides this". Otherwise, a car charging at night, then the gridfails, could drain the battery quickly if smarts aren't integrated but the HPWC is in the circuits backed up by the wall(s).
The powerwall "not" telling you that it is the source of power after a cut-over is a real lacking feature.
We bought a nat gas fed Generac for relatives who had medical conditions a year ago. Turns out the man of the couple perished a few months later but the woman still runs a business at home but moved to laptops, thus allowing a smooth fail-over should they endure the 10-second generac cutover. Costs about the same as the wall - but could run "days" should it be needed (NG amount limited to municipal feeds, so of course problems there if pumps fail).
The pricing of the wall starts to compete with the Generac solutions out there now and as such, since it doesn't require trenching and sighting outside, is more compelling for a cleaner install. Generac should consider battery solutions as another business division as well - standby power shouldn't be "required" to be fuel-based only. And batteries would not need the annual maintenance these folks charge (oil change, test runs of the engine, etc.)
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So there are no settings at all, anywhere? That's disappointing. I figured it would have settings for stuff like:
A) Charge level (keep it at 90% or 100%, owners choice)
B) Charge up to X percentage during overnight off-peak rates, let solar fill it up the next day. This is for those with smaller solar installations.
C) Blocked out "charge from grid" hours. Basically to avoid charging a powerwall during peak rate periods.
pdxrunr
Member
The battery stays at 98-99% and is fully managed for best performance/life span I was told, no need to manage this. As for the other settings you mentioned, I don't have solar but the installers were telling me there are things that can be done like that, can't remember if it was on the app, or something in the "brains" of the gateway that they can customize.
greghanssen
Member
If anyone else out there has an old 48V grid tied inverter I know a source for some decent lithium batteries (about $1500 for 10kWh). I've been using these on a 16yr old Trace SW4048 for the last year in SoCal Edison territory and have been playing around with arbitrage on the TOU-D-A plan. I'm not sure how much the new monthly NEM cap will be utilized by SCE (it seems they're still trying to figure this out). Unfortunately the inverter isn't smart enough for me to set what % charge is off-peak vs from solar.. I can charge all off peak (which is the most financially advantageous) but SCE isn't really keen on this. I can do some charging off peak and let the charge finish with solar (which is what I'm trying now) but then on overcast mornings I end up charging with mid-peak grid power... Either way it's set to export as much as possible from 2-8pm during the super-on peak. I don't know what my cap will eventually be but I'd like to think there is some leeway as: A: I could charge off peak and run all my loads on-peak, B: I could charge 100% off solar and discharge 100% on-peak, C: my old 48V inverter isn't as efficient as a PPT so maybe I can make up for that a little?? 16 years with solar and this is the first year I've had a negative balance for the 12 month cycle.
Powerwall 2 battery usage customization update out today for iOS! I believe I am at 59% or so when the solar starts to kick in to refill the battery in the morning so I set it at 50% reserved for backup power for now. Will adjust as the time of year and weather changes. Very nice to see this capability added today!
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Ulmo
Active Member
And now:
Only for those using a fine tooth comb on my setup who have this curiosity:
I should clarify the SolarEdge doesn't need nor use any battery backup capability; as far as my set up is concerned, the solar can be any type of inverter delivering solar input inverted to AC; even though I was forward-looking and got a PowerWall 1 compatible SolarEdge inverter, my inverter has no battery hooked up to it directly, and I wasted money on its extra capability. All the Tesla equipment is capable of battery backup switching, with the PowerWall 2 batteries. If I wanted to, I could scrounge up a second hand PowerWall 1 or 2 or any other type of battery the SolarEdge battery port accepts and have it installed, but I don't think it would be optimal, plus it's just plain dumb with the PowerWall 2 since it has a much better power rating. The only reason now that I'd ever hook up a battery to the SolarEdge is if someone gave me something like a PowerWall 1 for basically quarter price or so. That's how much better these PowerWall 2's are.
As I said, I want to double or triple both the solar and the PowerWall 2 batteries. That would be fantastic. For now, I have no electric car to charge, but I will again within a year or two.
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Your Powerwall is full now. Your phone on the other hand desperately needs charging...
