Tesla Powerwall Installation & User’s Manual Posted Online
Thinking back to the initial announcement of Tesla Energy, it feels like a lifetime ago. The launch was expected with the word already out on the street that Tesla was going to build a battery for home storage, but unexpected at the same time because no details were known.
At the news conference, Tesla blew everyone away with the announcement of a new entity, Tesla Energy, with two upcoming products — Powerwall and Powerpack. With this new launch, Tesla boldly proclaimed that:
“Tesla is not just an automotive company, it’s an energy innovation company. Tesla Energy is a critical step in this mission to enable zero emission power generation.”
Tesla shared that Powerwall is the residential product, with two pack sizes: a 7kWh pack intended for daily cycling and a 10kWh offering for weekly cycling. At its core, Powerwall is designed to “store energy at a residential level for load shifting, backup power, and self-consumption of solar power generation.” Powerpack, on the other hand, was said to be the utility-scale or business-scale product, with a larger physical footprint and a correspondingly larger storage capacity.
Fast forward to today and both products are running strong with Powerpacks being installed at large businesses across the globe, such as Target and Amazon Web Services. Forward-thinking utilities like Southern California Edison and Advanced Microgrid Solutions are also testing the waters with some larger installations.
Powerpacks are already being installed in Australia and in the UK, with other regions coming online over the next few weeks.
Supporting the early installations, Tesla Energy posted the Installation and User’s Manual for Powerwall, which, in addition to the more mundane bits about the physical installation, includes technical specifications and a few interesting insights into how it operates.
To secure the full 10-year product warranty, the Powerwall must be registered. This is a common requirement but is extra critical given that it’s a brand new product with what should be a long life ahead.
Immediately after the lengthy safety section, the manual busts out with a pretty sweet description of what Powerwall is. It starts out by boldly stating that it is “THE FUTURE OF SUSTAINABLE ENERGY” — just the type of bold leadership these new solutions need to succeed — then goes on to describe the purpose of Powerwall:
“Powerwall is a lithium-ion battery system that turns solar panels into an all-day resource while offering backup power in the event of a grid outage. Powerwall enables storage of renewable energy, allowing optimized home energy control and an increasing amount of total electricity production to come from renewable sources. Reliable renewable energy improves the resiliency of the grid, reduces energy costs, and increases the impact of electric vehicle ownership.”
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Interestingly enough, while the Tesla Australian homepage continues to display the daily cycle Powerwall as having 7 kilowatt-hours of storage while other values have changed over time, I see people selling it in Australia giving its energy storage as 6.4 kilowatt-hours. Mind you, it is being sold as a system and I presume that figure includes system losses. But that’s considerably more loss than I would have expected. Mind you, it’s still early days and the storage figure might be revised upwards as data comes in.
The math is: 7×92%= 6.44 kwh. So it seems they are taking the 92% round trip efficiency loss into consideration as the total cycle energy available. Rather scrupulous of them.
Looks like the unit is cooled by a fluid and that power is required for that. I did not know that. I wonder how much power that consumes?
Perhaps the cooling is accomplished without power only by conductive loss through the fluid, that would make sense.
The spec shows there is a 12V connection from the inverter that may be for cooling. It also talks about a thermal fluid. This could all be passive cooling and just a monitor or perhaps an active motor that pumps the fluid through the battery to a heat exchanger. Also must be why they spec space around the unit and to keep snow from piling on top so that heat can be dissipated
How do they keep it warm enough in the winter? In my climate I’m not worried about cooling for an outdoor installation…
Actually, it looks like I CANNOT do an outdoor Powerwall installation. We have occasional days with -22F weather. This is just upstate NY. In Minnesota it gets colder. Indoor installation only, I suppose.
Get some bubble wrap around it and you’ll be fine 🙂
Still, the heat represents the energy loss.
I’ve been thinking about Panasonic (Tesla) versus LG (Bolt) batteries and the much discussed issue of supercharging. Could the explanation be as simple as heat (and not the politics of compliance cars)?
I mean, Tesla cells are small cylinders, easily cooled. LG, as well as the cells in my Leaf, are larger flat (pouch) cells, perhaps not so easily cooled – therefore, having a max charging rate lower than Tesla’s packs. This is pure supposition – I’d like to hear more from the experts. I mean, if there’s an inherent problem in flat pack cells with regard to max charge rate, now would be the right time to redesign.
With the cylindrical cells, its easy to intersperse cooling channels between rows. With flat packs, its harder to make them dense and flow channels in between. Picture trying to cool a stack of papers. One way is to use a heat conductive metal sheet. The whole effort is to remove the heat from the layered pack. Don’t want to get too dense and be unable to cool.
Ha. You spotted the blue tubes in the picture? Thats for a PowerPack the 100kwhr utility model. The tech is the same as the car, IMO. It could work like a thermostat. It wouldn’t need to circulate at all if the temp was in range.
http://cdn.powermag.com/wp-content/uploads/2015/05/tesla-2.jpg
The PowerWall looks like it could be cooled passively, but I have never seen any pics under the cover.
The other matter of note is the 7 kwh powerwall has continuous discharge at 3.3 kw (as well as charging, and peak), the 10 kwh powerwall has 5 kw continuous power, 7 kw peak (10 seconds). This is the upgrade from the original 2 kw continuous power for the 7 kwh unit. Note also that the 10 kwh powerwall operates at higher efficiency in off grid mode…with 9.8 kwh available per cycle.
What is still not known is the actual total battery capacity of either of these units. Are they actually 9 and 12 kwh batteries discharging 80% which results in 7 and 10 kwh? That is my guess, but some intrepid explorer geek will need to take the thing apart to find out. I know you are out there, oh geek. We shall hear from you soon, yes? (Possibly some Einstein can deduce this from the weight of the battery alone.)
Ha, will let you know if we find out about any such explorer geek doing this. 😀
Its all about the current draw and depth of discharge vs cycle life. If the current is high, the efficiency is lower and charge stored then recovered is less. IMO, this is not a big deal unless the batteries are charged and discharged at their rated max all the time, an unlikely proposition. Thats why some of the ratings are higher for the same battery pack.
I will say this, however. IMO The 3.3kw rating for the daily pack is limited by the battery, not the electronics.
Well, they should really only need to worry about discharge losses when stating the battery’s capacity. But if they used a figure of 5.7% loss for discharge, and 3% for going from DC to AC it gives close to 6.4 kilowatt-hours. Now 5.7% might be considerably more than actual discharge losses, but it is far better to estimate too low than too high. Go too low and you get happy customers who get more storage than they were led to believe. Go too high and you have all kinds of problems including legal ones. I guess its scrupulous, but it’s also common sense.
I think somebody needs to take a ‘kill-a-watt’ to this battery and cut through the fog, once and for all. Measure complete output from 100% full. We await the final report.
And by the way, Australian news has done a few interviews with powerwall recipients that are quite good. Check out youtube https://www.youtube.com/watch?v=B2sNKa8D4bQ
Well done Catalyst. Great to see our tax funded ABC continuing to produce great science content. I wonder how many science teachers screen Catalyst at school. I lot, I’d imagine – especially when they have exams to mark.
I see I’ve written something stupid. While discharge efficiency is important, no matter what it is, a 7 kilowatt-hour battery has to be able to put out 7 kilowatt-hours of electrical energy, no matter what its discharge efficiency, otherwise it is not a 7 kilowatt-hour battery. It would be what we call a lie. So, maybe they do not expect the Tesla Powerwall to be able to output 7 kilowatt-hours a day for the 10 year warranty period or maybe there is something else going on here. I would guess it is the former.
Update: This comment is a bit thick.
One has been installed in the UK 🙂
http://www.solarpowerportal.co.uk/news/cardiff_installer_claims_to_install_uks_first_tesla_powerwall_5363
Nice. Popping up all over. Now that one has been installed we need to rush on to Powerwall 2.0! Due this summer, and completely shrouded in mystery.
Seriously. Can’t believe 2.0 is already announced (slightly). And curious what will be different.
If they’ve been watching Sonnenbatterie, maybe the new model has market watching software to make buy/sell decisions.
The website still posts the previous continuous power rating now uprated to 5kw.
Oops. My bad. Vensonata says thats an update of the 7kwr version from 2kw to 3.3kw.
I thought, when you posted 3 kW, that seemed too low. Imagine it’s a case of the web designer not updating what should have been updated by now. But who knows?
Vensonata says its a case of the 7kwhr version updated from 2kw to 3.3kw. I never heard that one before. I updated my post when I saw his comment. Might need a verification from Tesla on this one. Then we could say who knows, yes? LOL.
Hmm, maybe that’s what it was. I could probably dig up the answer in our archives… but will have to wait on that.
Verified what vensonata said. Its in the installation manual.
Daily 6.4 kwhr 3.3kw peak or continuous
Weekly 9.1 kwhr
Discharge 5kw continuous
Discharge 7kw peak,
Charge 3.3kw continuous
I have to say. This is a peek inside. It means the charge rate is limited for both types to 3.3kw continuous.
That means the charge rate is either limited by DC-DC converter or battery. Limiting charge rate could help lifetime, but we don’t know if that is an intentional design choice.
For the daily discharge battery, the 3.3kwhr peak or continuous rating means the battery is the limiting factor, hands down. This is likely because C rate is one of the trade offs for increasing lifetime and cycle number.
One more thing. Early announcements rated the batteries at 10kwhr and 7kwhr. These slightly lower ratings probably reflect efficiencies.
You always get more out it your discharge/charge current is low.
https://www.teslamotors.com/sites/default/files/pdfs/powerwall/Powerwall%20Installation%20and%20User's%20Manual-online.pdf
Verification from Tesla is in the Manual. 3.3 kw continuous, peak and charge rate. All three are the same. Download the manual.
Boy, they sure kept that quiet. 🙂 Thanks. will do. Nice detective work.
I checked, thanks. See my comment below.
why only 9 amps?
The voltage is high. 350-450 volts acccording to the graphic above. So it should have no problem outputting the 3.3 kilowatts of power it says it can.
how does that translate? For example. i have 200 amp service to my house. Assuming that is 240 volts?
If you are in Australia, yes. 200 amperes by 240 volts equals 48,000 watts. So your house could draw a maximum of 48 kilowatts, which is a lot.
In the US they have half the voltage so that would be 200 amperes by 120 volts for 24,000 watts, which is still more than enough for most households.
So if the Powerwall has 350 volts at 9.5 amps that comes to 3,325 watts or very close to 3.3 kilowatts, which is the figure given. If it usually operates at around 400 volts that’s 3.8 kilowatts.
cant even run my water heater with this…
If you are attempting to run an electric hot water system off a Powerwall you are not doing it right. An electric hot water system is an energy storage system, so it makes sense to charge it either with electricity from rooftop solar, or if that’s not available electricity from the grid.
if a power backup solution does not allow me to do the things i need in my house, it does not serve its purpose. A gas generator can do what this does for a tiny fraction of the cost.
No, it’s definitely not going to pay for itself as a power back up system. Under the right circumstances it can pay for itself in Australia by storing rooftop solar generated electricity during the day for use in the evening.
i am not familiar with rates in Australia. I am in the US. For me, the price would need to drop be a factor of 10 to be sensible.
Came across this chart today
Why is the 10KWH only for weekly discharge? Don’t they use the same batteries? What in the circuitry makes it unable to be used daily and why not? Could the 10KWH be set up in a way to feed the 7KWH batteries? Say 2 10s feeding 3 7s when and if they get low or to the discharge point you don’t want to go pass? I am trying to figure out why a 10 could not be used for both daily or weekly discharge and what difference it make to the manufacture?
They actually don’t use the same battery chemistry, according to what Elon said. They have two different chemistries.
The 10 kwh battery is similar to the model s battery in chemistry. About 1200-1500 cycles. The 7 kwh is Nickel manganese aluminum. 5000 cycles.
The 10 kwh battery is about $350 kwh so anywhere from 23cents to 29 cents kwh. The 7 kwh is $428 kwh so including 8% efficiency loss plus decline to 80% capacity is roughly 5000x.92×90= 4120 cycles x 7= 10.5 cents kwh.
Which do you want? By the way you can cycle the 10 kwh battery daily, it just is not as economical as the 7kwh.
These prices are only for the battery, they do not include installation or other parts of the system. But on the bright side they also do not include the possible 30% tax rebate or state incentives which could cut the price in half. In the end, the numbers are head spinning, with multiple variables possible.
Can somebody please confirm the following:
7 kWh Model – NMC chemistry, 5000 cycles at 80% DOD, 0.5C/0.5C nominal charge/discharge rate
10 kWh Model – NCA chemistry,1500 cycles at 80% DOD, 0.5C/0.5C nominal charge/discharge rate.
Much appreciated !!
Musk said “this is a 5000 cycle battery” referring to the 7 kwh powerwall. He also said “this is a 15 year battery”. That is as precise as you can hope for. The 1200-1500 cycle life for the 10 kwh powerwall is similar to the Tesla Model S batteries as well as the Powerpack battery. That has been endlessly discussed and debated. Pessimists say 500 cycles based on a German study. That study, unfortunately rapidly charged and discharged the Tesla battery to 100% 500 times. But that is not possible in actual use since there are electronics that prevent that kind of abuse. I could design a study where we drop a Tesla battery from 100 meters and it would only get 1 cycle! But that would be foolish wouldn’t it?