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Are UPS's needed when one has batteries?
- Thread starter h2ofun
- Start date
It depends upon your needs. Are you running a server farm or a laptop.If you have a medical device that has its own backup you may not need one. Search for UPS on this forum. It has been discussed thoroughly. Some work better than others and some require adjustments to cohabit with Powerwalls.
I do not use one and can deal with the occasional blinking zeros on my Microwave.
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I think for sensitive electronics like servers, NAS, etc. it is a good idea to have one. They can crash in a few msecs. TVs, DVR, etc. seem to fine without them.
I have UPS units on my NAS, cable modem, routers, switches, etc. And for belt and suspenders, also on our desktop computers. All of our UPSes are from CyberPower.
I have UPS units on my NAS, cable modem, routers, switches, etc. And for belt and suspenders, also on our desktop computers. All of our UPSes are from CyberPower.
Sorry, just a little off main topic...
I have several CyberPower UPS units around the house on the servers, NAS, internet cabinet, and important workstations. They are small 900 units just to protect against surge or the PowerWall switch over.
My 2x PWs run in self-powered mode. Every night my PWs serve my house loads completely with about 25-35% remaining at sunrise and recharge time. I feel ok with that level because we rarely have grid outages in Las Vegas.
At this time, the UPS units have not triggered yet. I’ve read a little about the frequency thing for like 62.5 or something, but I’m not sure if it’s something I should be concerned about yet.
Is the frequency thing something that happens when the PWs take over or just when the grid goes out and the PWs reach full capacity?
I have several CyberPower UPS units around the house on the servers, NAS, internet cabinet, and important workstations. They are small 900 units just to protect against surge or the PowerWall switch over.
My 2x PWs run in self-powered mode. Every night my PWs serve my house loads completely with about 25-35% remaining at sunrise and recharge time. I feel ok with that level because we rarely have grid outages in Las Vegas.
At this time, the UPS units have not triggered yet. I’ve read a little about the frequency thing for like 62.5 or something, but I’m not sure if it’s something I should be concerned about yet.
Is the frequency thing something that happens when the PWs take over or just when the grid goes out and the PWs reach full capacity?
Have you found this supplier works best with powerwalls?
I want to protect my computers. I have one that I use for video encoding. Is the pits when it has been running for many hours and I lose power and have to start over again
Man, they have tons of models. Which one(s) model are you using? They have no issues with the frequency shifts?
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I have done a search and the threads I read do not jump out. That is why having one that is just about UPS might make things easier to find. So which one(s) work best with powerwalls?
that was one of the comments I remember hearing about is some units do not work with the frequency shift. So, if I boy some, want to make sure I get something that will work
aesculus
Still Trying to Figure This All Out
Just when grid power disappears. If the batteries take over while the grid is still up you won't see a disruption.
Search isnt working very well for me on the site right now. Search this section "eaton UPS". There are a few different threads with a lot of discussion around this topic.
The high level overview is
1. Because "sometimes" the swap from grid to powerwall power can be as long enough to notice (flickering lights, reset clocks etc) depending on where your power is coming from during a grid power outage event, many people put small battery backup units on "important" devices.
2. Whats "important" is up to you, and in general, you only need enough battery backup power to cover a few seconds while it swaps over.
3. Some battery backup devices do not handle the frequency being raised higher than 62 Hz, so when on backup power, when there is no grid AND the powerwalls are full, when the powerwalls raise the frequency to turn off the PV, it gets set to 65 Hz, which can cause these devices to not recognize the power flow (and beep, continuing to provide backup power until drained or the frequency is lowered.
4. UPS Devices from Eaton tolerate up to 70Hz so work fine with the raised frequency.
5. Most of us feel its better to get tesla to lower the frequency, since the higher frequency can cause issues with more than just UPS devices.
And to answer the engineer in you,
no, I can not definitively tell you exactly when you will notice the swap and when you wont. I have some suspicions but no proof
No i cant tell you what frequency tesla will lower your system to, when its installed. This is system dependent.
Yes, I can verify that I have an eaton UPS device (currently connected to my modem / router), and have tested it when the frequency was raised to 65hz. It worked fine.
No, I dont have a number for "most of us" here at TMC.
The high level overview is
1. Because "sometimes" the swap from grid to powerwall power can be as long enough to notice (flickering lights, reset clocks etc) depending on where your power is coming from during a grid power outage event, many people put small battery backup units on "important" devices.
2. Whats "important" is up to you, and in general, you only need enough battery backup power to cover a few seconds while it swaps over.
3. Some battery backup devices do not handle the frequency being raised higher than 62 Hz, so when on backup power, when there is no grid AND the powerwalls are full, when the powerwalls raise the frequency to turn off the PV, it gets set to 65 Hz, which can cause these devices to not recognize the power flow (and beep, continuing to provide backup power until drained or the frequency is lowered.
4. UPS Devices from Eaton tolerate up to 70Hz so work fine with the raised frequency.
5. Most of us feel its better to get tesla to lower the frequency, since the higher frequency can cause issues with more than just UPS devices.
And to answer the engineer in you,
no, I can not definitively tell you exactly when you will notice the swap and when you wont. I have some suspicions but no proof
No i cant tell you what frequency tesla will lower your system to, when its installed. This is system dependent.
Yes, I can verify that I have an eaton UPS device (currently connected to my modem / router), and have tested it when the frequency was raised to 65hz. It worked fine.
No, I dont have a number for "most of us" here at TMC.
Thanks. I have read some have gotten the frequency changed to like 62? what is as low as you would want to go? Can only tesla make the change or can the installers do? Thanks
jrweiss98020
Tessa's Tesla
Dunno 'bout "best", but I use the Cyberpower 1500PFCLCD. The PFC designation means they have true sine wave output and work with newer computer PSUs that have Active Power Factor Correction. I have 4 of them for my computers and stereo, plus 6 older units that I cycled out of main service when I bought the new ones. The old ones cover non-critical loads.
I have found that, depending on what causes the power outage, the UPSs will trigger briefly - anywhere from a fraction of a second to a couple seconds - before the Powerwalls cut in. So, I have decided to keep maintaining them, replacing their batteries when necessary (every few years). The UPSs are rated for +/- 3Hz, so they are compatible with the Powerwall frequency triggers.
And to further clarify, not always exactly when the grid disappears. If there is no AC coupled solar running, there us no need for frequency changes. When there is AC coupled solar producing, if the loads are large enough and the battery has to support the loads there should be no need for frequency shift. However because of the unpredictability, some people with critical prefer to use UPSs.
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I believe that only tesla can make the change, even if its a third party installer. How low they will lower the frequency depends on what equipment you have installed, so is dependent on your specific equipment.
So many people have talked to tesla about this, it is no longer "unknown" to tesla. By the time I called (january 2020), tesla seemed to have a support flow in place for this. It also means that, while they used to customize it for each user and would sometimes go below 62hz if someones equipment shut off earlier, they now set it to 62 / 62.5 no matter what (no lower).
FWIW, I have 1 eaton, then called tesla to get the frequency lowered. Once it was lowered to 62 Hz, I bought a couple cyberpower UPS (the exact same one that @jrweiss98020 has), as with the frequency lowered, you can use whatever UPS you want.
the big thread is called:
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Powerwall 2 + UPS Connundrum - and solution
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Probably 50 pages on this topic (of frequency shifts, UPSs etc)
jrweiss98020
Tessa's Tesla
I wonder, though, if the power supplies in your equipment are rated to operate normally with those frequencies. The ATX12V Power Supply Design Guide for PC PSUs specifies a 47-63 Hz range, accommodating 50 and 60 Hz systems. Wouldn't it be better to have tighter tolerances in the UPS and have them trigger with the high freqs? You can set alarms to be silent, and you can shut down the equipment during the times the freqs are too high...
Oh man, video encoding is such a slow process I can see why you don't want to do it twice.
Regarding models for our deskside systems, we are using the CyberPower 850PFCLCDs. I sent this model to number to Tesla when I asked them to adjust down the inverter shutdown frequency on my TEG. I believe they set the frequency to 62 Hz. And when I tested it by taking the system off the grid and letting the TEG shutdown the solar, the CyberPower unit did not have any issues.
That depends on how you look at it. My UPSs disconnect from AC at anything above 61Hz and switch over to their own battery which is a good thing because the $3K in Unifi networking I have does NOT not do well with much variance above or below 60Hz. And with recent changes by Tesla, PWs are outputting 62Hz+ at anything over 80% disconnected from the grid and below 80%, frequency drops to 59.6Hz.
Basically you'll never see 60Hz except transiently with the latest powerwall firmware when running off grid. This also makes it impossible to charge up to anything resembling full from solar when running off grid.
We have UPSs to backup home servers even with the Powerwalls. Had them before and didn't see a reason to get rid of them, especially as Powerwall cutover with power loss, full batteries, and PV generating hasn't been seamless. We had Tesla lower the frequency to 63Hz, unfortunately the APC BackUPSs that we have still cutover to battery even though it shouldn't. Trying to figure out why...
