Let's assume that we have grid tied powerwall connected to a solar system. The powerwall is fully charged, but it is turned off at the power switch, and also shut down at the circuit breaker. Now, in the middle of the night, there is a power outage. The owner turns on the circuit breaker, and also turns on the powerwall at the switch. Will the powerwall come on to power the house? Thanks for any replies to this question.
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Power outage question
- Thread starter Instaurare
- Start date
woferry
Member
Pretty sure the simple answer would be no, as I don't think the Gateway would have any way to receive power. Another thread here recently mentioned that there's a pair of terminals on the Gateway that is designed to input ~12V DC, to allow for a 'jump-start' of the Gateway electronics. My guess is you'd need to provide that power to get things up and running, which would presumably then get the house islanded from the grid and command the Powerwall to start its inverter (assuming it had enough battery to do so, remember that the Powerwall's cells will continue to drain the whole time the breaker/unit switch is off, mine sat that way for a few months between install and PTO, and the charge dropped roughly 1% a day while waiting).
Shutting it down would minimize potential damage to equipment from a power surge coming from the grid. If Powerwall is used for outages only, it seems unnecessary to have it continuously connected.
I'd be curious to know the answer to the question as well. I actually suspect the answer is that it would work, since the Powerwalls would probably go into island mode in the absence of any grid power. I believe the jump start connector is only needed if the Powerwalls have no charge left.
Note that the restart procedure when the grid is down but the Powerwalls still have reserve power left is to wait until the sun is up and then cycle the power switches. This seems analogous to what @Instaurare is proposing.
Note that the restart procedure when the grid is down but the Powerwalls still have reserve power left is to wait until the sun is up and then cycle the power switches. This seems analogous to what @Instaurare is proposing.
Have you considered putting a whole house surge protector in front of the gateway? That would (presumably) stop any surges from the grid.
Have that in place already. That will handle ordinary utility surges, but not the more exotic variety, such as emp.
A sufficient emp would fry any unshielded electronics, even those not connected to a grid or turned off. Same reason it disables car electronics. If an emp is really your concern a faraday cage plus surge protector would suffice.
No doubt a sufficient emp would have that effect, just as a sufficient lightning strike would overcome other protections. But a lesser degree of solar CME strike might be resisted by simply having the unit deactivated and reducing the quantity of wire feeding into it. And it would not be an easy task to construct an effective faraday cage around inverters plus battery. Not to mention what a sealed cage would do to the cooling system.
For sensitive electronics airgapping from other components would offer protection from external surges, having them deactivated will not prevent any damage from the currents induced inside of the components during an EMP/CME. Remember that the Powerwall is a battery plus computer and is designed to be hooked up to the grid in a way that meets safety standards for external surges (including lightning). Even if you physically unplug it from the grid and turn it off the physical components inside the Powerwall are still very susceptible to an EMP/CME. Nothing short of a faraday cage will prevent that damage which is far and away the most likely source of damage during one of those events.
Of course as it is unfeasible to protect your entire home (unless of course it was built as a faraday cage) meaning even if you were to protect the Powerwall it wouldn't have anything to provide for as every other electronic item would be toast...
Again, to use the lightning analogy, there is quite a substantial range of effects, ranging from massive to nil, depending upon distance and stregnth of source. It is by no means an all or nothing proposition, and it is a given that some electronics will be far more susceptible to damage than others. Some are small enough to store in a small metal container. In any situation, a deactivated unit, with a minimum of wire feeding in as antenna, will be more resistant than one that is fully operational. One also must consider modifications that could impact the functionality and the warranty of the system.
I think you may be misunderstanding the physics of how sensitive electronics are damaged in an EMP/CME vs lightning because what I quoted above is simply not the case if you're talking about only EMP/CME here. The amount of protection you get by deactivating and unplugging it is negligible.
Unless the device is physically struck by lightning the only source of damage is an external surge travelling in to the device from where it is plugged in. Similar to a lightning strike an EMP/CME can induce large amounts of power in utility wires, causing a surge. However unlike a lightning strike an EMP/CMP will induce relatively large current inside of even the smallest wires, solder, solid state chips, resistors, capacitors, etc causing those to melt, short, arc, etc. And while those components are much smaller than large utility wires meaning they'll experience a smaller current they're orders of magnitude more sensitive to even the smallest variances. It is this current that causes the most damage by far and an EMP/CME that is sufficient enough to worry about a surge from the utility lines bypassing existing protections is more than enough to damage those small components. This source of damage cannot be stopped with a surge protector, the only way to prevent it is to shield the entire device from the EMP/CME itself with a faraday cage.
IMO you're worrying about the smaller of the two risks by focusing on the external surge if you're truly concerned about the effects of an EMP/CME on your setup.
I fully grasp the scope of your argument, but when considering the broad range of events, including lightning as well as everything else mentioned, it surely affords greater protection to disconnect and deactivate than it does to maintain continuous service when unnecessary. And I sincerely doubt that anyone on this forum has a faraday cage installed over their Powerwall.
Your exact statement earlier was "That will handle ordinary utility surges, but not the more exotic variety, such as emp.". My point is that if an EMP is sufficient to cause a lightning surge protector to fail you have bigger problems from the EMP than the surge alone. A highly rated surge protector will provide exactly the same amount of protection from an EMP that disconnecting and turning it off will: either way your Powerwall will fry if the EMP is substantial enough.
mikemillar
Member
To get back to the original question, it should be a perfectly simple question to answer, but my Powerwall is still on order so I can't carry out this test. Turn off the Powerwall and Gateway master switches (at night so no solar input). Then trip your main RCD or otherwise disconnect the grid. Now turn on the Powerwall and Gateway master switches. Does it work? I look forward to the definitive answer!!
mikemillar
Member
It is not that the cme would cause the surge protector to fail, but rather that the cme pulse would travel faster than the ability of the surge protector to react. And that an added layer of protection would be to disconnect and shut down the electronic device. Not to say that this would avoid damage to the product in all cases, but rather it would lessen the susceptibility to damage in the event of a glancing blow. You would be avoiding the additional harmful surge introduced by a great deal of external wire. Honestly, do you see a faraday as a realistic post install addition to a Powerwall?
I have no idea where you're getting the idea that the surge induced in utility lines from a CME would propagate faster than the speed of light. A surge protector that would defend against a lightning strike will offer the exact same protection against a surge created by a CME.
And yes, faraday cages are incredibly simple to construct. All you need is a sufficient metal mesh or solid covering. Building one around your Powerwall would be a straightforward undertaking. As I mentioned in an earlier post building one around your house to protect the things that your Powerwall would provide power for, not so much.
I don't see the step to apply 12v to the JUMP contacts as described in other posts.
The Powerwall is designed to respond to the power surge. If the system detected any anormal behavior from the grid it will disconnect. Also, If you turn off the Powerwall and gateway, you lost the communication with Tesla servers and that will reduce you warranty to 4 years.
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