energy storage is becoming more and more interesting to smart home owners and we recently spotted this write up of a Tesla Powerwall 2 installation on Michael Vorstermans Blog. A great account of the practicalities of installing the domestic battery, how it functions and the finances behind it. Lire la suite pour tous les détails….
Late last year, Elon Musk surprised everyone by announcing a new version of Tesla’s less-than-a-year-old Powerwall home battery system, with double the capacity for the same dough.
The other players in this industry must have been gnashing their teeth, but bravely soldiered on with the expectation that “it’ll take them forever to deliver”.
Not so – my Powerwall2 was installed yesterday, one of the first in new South Wales, Australia – read on for the blow-by-blow and decide if you also want to be free from power blackouts and 3-figure power bills.
What is a Powerwall Anyway?
If you don’t yet know what a Powerwall2 is, read this section – if you do, skip to the next heading.
Simply put, it’s a slim, no-maintenance, weatherproof and near-silent rechargeable Lithium battery system with the front profile of a bar-fridge, located near your power board, paired with a Gateway box that manages power flows from and to your home and the battery system.
Inside it, there’s heaps of cylindrical battery cells, assembled into packs, which will also be used to power the upcoming model 3 electric car.
They are made in Tesla’s Nevada Gigafactory, and packaged inside a shiny white-painted steel enclosure, along with a charger, inverter, and water-cooling system.
The system has an installed cost of just over $10,700 in Sydney [Ed: currently £5,900 + installation in the UK] and you can get one with around a 2 month lead time today.
It’s designed to save the output of your solar power system during the day, so when the sun sets (when your solar generation falls away), it will power your entire house until it’s nearly discharged. And, if there’s a power blackout, the PW2 switches to powering your house from the battery instantly, so you still have power for your entire home until power gets restored, or the battery runs down.
It’s capable of supplying 13 kWhr, or so, of stored energy when fully charged, which for most homes will carry them through the night, and therefore saving you the cost of the power you would otherwise have to buy. The power level it can handle is 5kW Steady, 7kW Peak, enough to run most kitchen appliances, a split-system airconditioner, or even charge a short-range electric car (such as a Mitsubishi Outlander PHEV, which only draws 2KW to charge, taking 5 hours).
For me, with 4.8KW of paid-off solar on my roof, a rough calculation says the PW2 could pay for itself in 6 to 9 years, and it’s warranted for 10. If you don’t have solar power, it’s not for you, but given prices for power are only going to rise, you should consider getting solar cells anyway, if you own your home and have roof space available. I’ll go through the financial aspects in detail towards the end.
The install Process
I reserved a Powerwall2 via Tesla’s site in October last year – it’s a quick and painless process, pricing is entirely available online, it’s transparent and up front, so you have no need to chase around for quotes.
This is a significant advantage Tesla has, as there’s more than a few cowboys in this industry in Australia. Tesla’s checkout took a $500 deposit by credit card at order time, they followed up with several phone calls over the intervening months, a contractor (Downer EDI) did a site visit a few weeks before install, and then Tesla requested payment by bank transfer for the balance of the $10k this week.
7.00am: two tradie vans arrived promptly as promised, from a local solar outfit called Flash point Solar in Punchbowl. another guy from Downer also arrived to supervise. As it turns out, this was the first install for all of them.
The gear came in two large cardboard boxes – the Gateway, and the Powerwall2 itself. The PW2 weighs over 125kg (290 pounds says the sticker, but another one next to it says 67Kg, so clearly the whole “metric system adoption” in the us still has some bugs in it), with the result that a trolley is needed to shift it around. It is just wide enough to fit through a standard door.
8.00: Hardest part so far is figuring out where the wall studs are for the mounting bracket. My house has plastic cladding, so they can’t easily find the studs. .
The PW2 is expected to rest on the ground on feet, and the bracket is meant to prevent it from tipping over.
8.30: looks like they are working it out as they go – 5 guys here now – 3 from Downer, of which 2 were here just to learn, and they said they had done some training with a prototype.
9.00: Mounted, and then had to remove it.
They ended up putting a big piece of ply against the cladding to help spread the load (and give them more opportunities to bolt into the elusive frame studs). since they didn’t allow for the height of the PW2 bracket placement before bolting the ply to the wall, the ply ended up sticking out beyond the top of the PW2. The mounting bracket has a silver spring clip in the middle of the “T” that locks the frame to the PW2, and the clip can only be accessed with something very long and thin, like a spring-steel ruler. I made them a feeler to dismount it, (Tesla didn’t provide any tools with the PW2), and they pulled it off, and cut the ply down so it wasn’t visible.
9.15: apparently all the cables go in the side, to a junction box under the cooling radiator – this is a decent size one, like an inter-cooler from a car. They don’t need access to the back of the unit, although there is a wiring gland just visible there, for use with installations that require the cabling to pass through a wall. The black sides are plastic, and clip into place.
9.30: Gateway mounted, now they are discussing how to wire all the cables between the 3 boxes. There is an installer manual on an iPad, and a set of paper manuals, which are mostly safety advisories.
1.30: All cabling done. There is a clamp on the solar active input to measure it’s generation, and the gateway measures the house load from the power cable directly. The PW2 charges only from solar at the moment.
Tim from Tesla arrives to help the installer commission the unit. The Gateway has a built-in Neuros Wifi access point (TEGxxxx, username is installer’s email, password is SN#) and a Telstra 3G telco SIM, but the SIM has yet to be activated by Telstra, so Tim connects it to my home Wifi and uses a webpage to update the firmware. He says that the preferred connection method in future is via 3G so they do not need to rely on Wifi availability.
The installer used an iPad to connect to the PW2 Gateway’s AP, and defined the size of the solar inputs, identified my inverter model from a list, selected which measuring inputs in the Gateway are monitoring the load and generation, and entered my Tesla account login (you make this when you order, and there’s no ongoing costs involved).
At the end of this, the Gateway’s webpage showed the current state of the home current draw, solar generation, and charging status of the PW2. However, the power consumption figure for the home seemed too high for the few lights that were on, and closer examination of the metering setup in my powerboard showed that the solar net meter is summing the solar generation into the input to the home, so they end up running another clamp into the powerboard to measure the consumption load separately.
2.30: Done – I reckon they could shave off a couple of hours, now that they have the install experience, and if they had a brick wall to mount it on, instead of the foam pillows my house has.
To test the system, I turned on a TV that was visible from the powerboard, and then switched off the mains-input circuit breaker to simulate a power blackout – there was a slight clunking of relays in the Gateway, and the TV didn’t even flicker.
Tim said the switch-over takes only 30milliseconds, which should be fine for running PCs, and you do get a notification from the Tesla app on your phone that the house is now running on backup power. switched on the main circuit breaker again, and with some more clicks, the gateway changed over to the mains about 10 seconds later.
For solar installs here, local rules require any grid-connected solar system to shut down when the grid-power fails, to protect pole-and-wire workers. I expected this to apply with the PW2 as well, but, it doesn’t, and the solar system stays up when the grid goes down.
Tidbits
Other than the Tesla app, the only visible sign of the PW2’s operation is a LED light strip down the side of the unit that blinks when there’s a problem, is steady when nothing is happening, and pulses slowly when charging or discharging.
Monitoring: I’ve been monitoring the house load and solar generation via PVOutput for the last 6 years – this service provides a free portal to your house power flows via a webpage and phone app, once you install a small monitor in the powerbox.
There is no provision for PVOutput data from the PW2 yet – apparently it generates a huge amount of info, and Tesla are going to expose this at some time in the future, but, Tim said, they are focused on the app experience for now.
As only my dog is at home during workdays, my home’s generation was mostly exported up to now, and the majority of consumption occurred at night, so my home represents an ideal use case for the PW2. In the graph above, the green line is instant solar output, and the red one is instant consumption, with the shaded areas representing totals for each.
How long before you can get it: Apparently, there are installs booked here in the “thousands” range. Backlog for hardware is 2 months if you order now. Each team of installers could only do 1-2 installs per day, I reckon.
Dans une certaine mesure, le distributeur que vous êtes enchaîné à des contrôles à quelle vitesse l’installation aura lieu, en raison des processus de chronologie des règles et d’équipement variables dont ils disposent, qui sont au-delà Ayez les approbations prêtes maintenant.
Comme d’habitude, Elon marche sur les orteils dans cette industrie, en permettant aux parieurs américains de réduire notre dépendance à l’égard des monopoles énergétiques – ils feront naturellement tout ce qu’ils peuvent pour limiter l’absorption du stockage résidentiel de la batterie.
AC vs DC: Alors que Tesla a initialement parlé des murs de puissance chargés de DC et de l’AC étant disponibles, ils se sont installés uniquement sur les personnes chargées par AC – Tim dit que cela a éliminé tous les problèmes qui pourraient résulter de diverses capacités DC des nombreux tableaux solaires différents Utilisé dans le monde entier, car la sortie CA d’un onduleur solaire existant est assez standard en comparaison. Oui, il y a des pertes dans la conversion de l’alimentation CA en DC dans la batterie, et vice-versa, mais cela signifiait un temps plus court pour commercialiser, une certification simplifiée, un meilleur contrôle du processus de charge, des prix inférieurs en raison de la mise à l’échelle d’un seul type, et Aucune exigence pour les installateurs de PW2 de devoir se moquer de recâbler les configurations de câblage solaire existantes.
Commission: l’activer le jour de l’installation dépend du règlement du distributeur d’énergie du client. Il y a un interrupteur sur la batterie et un autre à l’intérieur de la passerelle pour contourner le système.
Je suis avec Endeavour NSW, qui est heureux de faire signer les Sparkys, tandis que certains autres distributeurs insistent sur les inspecteurs certifiés L2, etc. pour le commander. Apparemment, les efforts sont également d’accord avec jusqu’à 10 kW de solaire sur une maison monophasée.
Surcharges: J’ai demandé ce qui se passerait si le tirage au courant de la maison dépassait la puissance de la puissance du PW2 – Tim a déclaré que la tension de sortie commencera à baisser, puis l’unité se réinitialiserait, pour perdre les charges et vous donner la possibilité de désactiver tout ce qui Dessine trop – ce serait le même scénario que lorsque j’ai fait sauter un disjoncteur la semaine dernière, car il y avait une voiture à chargement + lave-vaisselle + micro-ondes + chauffage de colonne en même temps, et la charge dépassait 8 kW.
Acoustique: cela fait du «tic» légèrement légèrement faible et un son de vhirgage à faible puissance lorsque le ventilateur fonctionne. Vous ne les entendrez que si vous vous asseyez juste à côté. Le ventilateur souffle dans le coin supérieur droit, en face du radiateur. Il est plus calme que l’onduleur solaire, qui fait toujours un bruit de butée.
Vol: Certaines personnes ont mentionné s’inquiéter de l’entrée de l’unité, car elle n’est pas derrière une porte verrouillée. Je n’ai aucun moyen de le mettre derrière un chez moi (pas de garage), mais comme il pèse 130 kg, les drogués aléatoires ne seront pas assez forts pour le soulever, et ils auraient besoin d’un camion-remorque pour le tirer hors du mur, à cause du clip délicat.
Compte tenu de la politique de non-publication de Tesla, j’imagine que la grande majorité des gens ici n’auraient aucune idée de ce que fait cette boîte blanche mystère sur mon mur, ni ce qu’elle vaut. Et, j’ai un système de sécurité de sauvegarde au cas où…
L’application Tesla Phone
Vous pouvez télécharger l’application Android ou iPhone gratuite de Tesla pour gérer vos voitures Tesla et vos promenades. Mon application Tesla n’avait pas de dispositifs enregistrés le lendemain de l’installation, et Tim a dit, à l’époque, que quelqu’un à Tesla USA aurait besoin de cocher une boîte. J’ai chassé le contact e-mail Tesla que j’avais pour le processus de paiement, et il a rappelé une heure plus tard pour dire que cela a été fait (un samedi matin également).
Fondamentalement, il vous permet de savoir si tout va bien avec le système, en surveillant l’état des flux d’alimentation et l’état de charge de la batterie. Ci-dessous quelques captures d’écran:
C’est la page d’accueil que vous obtenez après avoir signé. Il faut environ 5 secondes pour aller chercher l’état actuel lorsque vous ouvrez l’application, et jette un coup d’œil rapide pour voir ce que fait la batterie et à quel point il est plein. Dans cette photo, le mien est presque libéré, et très peu de puissance a été utilisée à partir de mon solaire