I have a single family home with Tesla's small (believe 3.8kW) solar panel package along with a single Powerwall 2. We rarely have power outages, but when we do I've noticed that our Vizio TV cuts out in the brief instant that the Powerwall takes over from the grid. I've read that this is to be expected for some sensitive electronic equipment. I know that I could get a small UPS, but that seems way overkill for the application. Is there not something like a regular power strip with a small capacitor built-in that could handle covering an outage in the millisecond range? I did some searching myself, but everything seemed to be geared toward lightning strike protection, which isn't what I'm looking for.
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Power strip with capacitor?
- Thread starter UCIBtheG
- Start date
jhn_
Member
I got a CyberPower ST425 compact UPS for the same reason with our WiFi router and cable modem. They were super sensitive to the cut-over if the house was not already running off the Powerwalls when grid went down.
It’s not a power strip, but it isn’t much bigger and gets the job done. Can be found at most online stores named after large rivers and probably other places too. Looks like it’s running about twice the price I bought it for a few years ago though.
It’s not a power strip, but it isn’t much bigger and gets the job done. Can be found at most online stores named after large rivers and probably other places too. Looks like it’s running about twice the price I bought it for a few years ago though.
I have something similar from Eaton, for a similar reason. similar size device as well, I believe.
Am I wrong in thinking that a regular power strip with a built-in capacitor wouldn't be cheaper and better suited for this purpose? If not, what is holding back a company that already makes power strips from making such a model? Is it just too small a market at this point (no economy of scale)? Or am I way off in thinking that a small capacitor could supply maybe 500W for 100ms or so?
100ms is 16 cycles of the AC. A passive capacitor can only work for 1/4 of a cycle, so it needs active electronics of some kind, which makes it into a line-interactive UPS. A big enough capacitor to hold enough power would be huge, so you still need a battery, lead acid or lithium
So a UPS that only runs for a few seconds - not very attractive. All the cost of the product is the same, only the battery size changes to give you tens of minutes.
So a UPS that only runs for a few seconds - not very attractive. All the cost of the product is the same, only the battery size changes to give you tens of minutes.
I can't find one. You can find UPS all over the place. I even thought about taken a car audio capacitor and use it in place of a battery but those things are expensive too.
Does your TV work on DC power? If not, just adding capacitors alone won't help.
Yeah, my line of thinking about the "power strip with a capacitor" came from a car audio cap mindset. Thanks tomuo and cali8484 for clearing things up as to why that wouldn't work. I'm far from an EE, and figured there was something I was missing, so glad to learn something new.
Don't forget to check to see if you need to have Tesla reduce the max frequency rise used to shutoff off the inverter when the battery is full, and you are off the grid. You don't want to trash your new UPS by raising it too high. If you have an all Tesla system they might have a different inverter control. But it would not hurt to call Tesla and ask. I had mine reduced to 62 Hz which is enough to cutoff my inverters but not so high that it effects the UPS.
EVRider-FL
Active Member
I was searching for a solution like the OP asked about and came across this thread. I already have a CyberPower UPS, but when there's an outage and the Powerwalls kick in, the 65 Hz frequency causes the UPS to go into backup mode. I've asked my solar installer to check with Tesla about reducing the frequency to 62 Hz, but that didn't go anywhere. I'll either keep pursuing that option or ditch the UPS, since the transition to Powerwalls is pretty much immediate.
The frequency kicks up when the grid drops to control the solar output. If your powerwalls are fully charged there is no where for the power to go from your solar in a grid down condition. The powerwall increased the frequency until the solar inverters get out of range and turn off. When the powerwall gets down to 90% or so the frequency drops and the inverters turn back on. I plug in my car to pull the powerwalls down in a grid down sun up situation. No benefit for me with a net agreement with the utility to run in a self powered mode. Typically the grid goes down at least twice a month for me so back up is important.
Reach out to Tesla support directly. Worked for me even though I hard a 3rd-party installer.
most of us asked tesla directly ourselves (for them to lower the frequency). They can absolutely do it remotely. Tesla has not been hesitant to do this, other than to lower it lower than 62hz since this sort of became a thing.
Cyberpower UPS work at 62Hz (mine do anyway). Call tesla energy support tier one, tell them you have issues with your UPS, led lights etc when you are off grid, and be prepared to give them the model number of your cyberpower UPS if they ask.
They have to escalate it to their tier 2, and it takes 5-10 days normally, but they should do it for you. No idea about why your installer had issues doing it, other than sometimes tesla asks for specific model numbers of devices having issues and your installer probably didnt have that and didnt follow up with you.
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