Any CPUs or harddrives you don't want to risk losing power on during grid outages - and in case of 66 Hz rise - should be behind a UPS that works at 70 Hz. I suggest an Eaton UPS myself.
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Powerwall 2 + UPS Connundrum - and solution
- Thread starter NinjaVece
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- ups 65 hertz
Any CPUs or harddrives you don't want to risk losing power on during grid outages - and in case of 66 Hz rise - should be behind a UPS that works at 70 Hz. I suggest an Eaton UPS myself.
I have the same issue on my recently installed system. I thought I was going crazy before I found this thread. I have since replaced 3 of my 4 UPSs with the Eaton 5S700LCD. Haven't tested yet but feel confident those will work based on feedback here.
HankLloydRight
No Roads
wbhokie
Member
This actually depends on the total load of your powerwall panel at the time of outage, so YMMV. Think of it like how much load a single appliance uses like a fridge might use when it is starting up vs how much it uses when it is humming along. You size your breakers for that maximum load, not for the typical load. As mentioned a few posts ago, the switch over may only take milliseconds, but it might also take up to a couple of seconds, and it will not always be the same for you unless you always have very little power usage. If your device is sensitive enough that you thought it needed a UPS in the first place, it probably still does now.
The difference between a Powerwall and a UPS is that a UPS is specifically made to be "Uninterrupted" and a Powerwall is not, and Tesla will tell you that. There are several devices you might have used a UPS on before for convenience that you might not need it for now, but I'd still put them in front of sensitive electronics that you wouldn't want to shut off abruptly. (Like a NAS, Server, or even a commonly used Desktop)
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wbhokie
Member
I wish this was my power usage!
I'd have to go back to gas cars to flat-line my power-usage like that haha. Under 1 KW? I would think my system was broken.
hodad66
Member
I'm using an APC so it will be interesting to see what happens when / if I
finally get installed.
finally get installed.
wbhokie
Member
Unless it is a high-end commercial APC (Rack Mount) then it won't detect the powerwall power when the battery is near a full charge unless Tesla changes their firmware again. Almost no standard UPS units support Frequencies > 63Hz as good power. That's why a lot of people are using Eaton or Minuteman units.
hodad66
Member
wbhokie
Member
Me too! This thread helped me out a lot!!! Tesla support can also be helpful but you have to be patient and have the right information to get somewhere with them.
If you are shopping for new UPS units, I recently found out that the TrippLite SmartOnline series will accept up to 70Hz. Not only that, but since it's double conversion it will regulate the frequency to 60+/-0.05Hz if it goes outside +/-5Hz of nominal. It does not go to battery unless the frequency is below 40Hz or above 70Hz.
Example: SmartOnline 120V 1kVA 900W Double Conversion UPS Tower Extended Run SNMPWEBCARD Option LCD display USB DB9 Serial (SU1000XLCD) | Tripp Lite
The TrippLite are significantly cheaper than the APC SmartUPS RT which are also double conversion and wide frequency input.
Example: SmartOnline 120V 1kVA 900W Double Conversion UPS Tower Extended Run SNMPWEBCARD Option LCD display USB DB9 Serial (SU1000XLCD) | Tripp Lite
The TrippLite are significantly cheaper than the APC SmartUPS RT which are also double conversion and wide frequency input.
SSonnentag
埃隆•馬斯克
OK, you guys have convinced me I can't count on my computer not crashing, now about the 66 Hz frequency. Is this something I need to be concerned with as far as electronics go? I'd much rather pay $156 for an Eaton 5S1000LCD than have to fork out over $500 for the aforementioned SmartOnline double conversion unit.
Personally I'd rather spend the extra money on longer runtimes and "ride out" the Powerwall frequency issue. I'm assuming (perhaps wrong) that Tesla will eventually fix the problem and, worst case, the frequency will be out of spec only for a few moments as the Powerwall turns off the PV inverters. For me having a larger VA rated line interactive UPS for half the price would work better than a smaller VA rated double conversion at twice the price.
SSonnentag
埃隆•馬斯克
But with UPS units that are "fine" with seeing up to 70 Hz line power, the UPS battery will only need to be used for a few milliseconds to a few seconds. So as long as the UPS can handle the load, it's big enough, as run time isn't an issue. These UPS units will simply pass the >60Hz <70Hz power provided by the Powerwalls on to the devices plugged into them once the tiny power drop-out is over.
The point of the Double Conversion UPS systems is that they are ALWAYS running off of battery power and their own inverter, so they will never send out anything other than 60Hz power. They simply are able to keep their battery charged up using strange input AC frequencies.
So I think like you I'm not convinced (yet!) that my PC's power supply will be perfectly happy with 66hz. I haven't had luck finding from PSU manufactures in terms of what they physically support. My solution for now is to split the difference by working to ensure my line interactive UPS can handle the out of spec frequency until the Powerwall switches back to 60hz.
Option 1: Spend the extra money to get a double conversion UPS that will fix the frequency. This fixes every problem but is very expensive.
Option 2: Get a line interactive UPS that has a higher frequency tolerance. Much cheaper than #1, only uses battery for the very brief moment as the Powerwall switches over, but unclear to me if the frequency pass through is "healthy" for sensitive electronics.
Option 3: Increase the capacity of line interactive UPS that has normal frequency tolerance. More expensive than #1 and will use the battery for the entirety of the out the duration the Powerwall provides out of spec power. Perfectly safe for electronics but will run out of battery and shut things down if the Powerwall provides out of spec power for too long.
Now if Tesla fixes the problem then #3 is the cheapest and easiest, so I'm sticking with that for now.
SSonnentag
埃隆•馬斯克
I decided to try the Eaton UPS method and see how my computer, modem, router and NAS systems do on 66 Hz power. I really think everything will be fine since they're all DC system anyway, and the frequency shouldn't change the DC voltage. If anything blows I'd expect it to be a power supply, but I honestly think they'll be fine.
When we built our house 10 years ago in the mountains where power can be intermittent, I built my own double conversion battery backup system for the critical networking and phone systems using a couple of deep cycle gel batteries, a battery charger and an inverter. The advantage of such a system is that it is alway running off the battery, no switching and always at 60 Hz. It is inefficient with the double conversion, but with the small loads associated with the networking system, that is not a problem.
At first I was using a very expensive Xantrex 1800 watt pure sinewave inverter that I had bought on sale for the boat, but never installed, and a Xantrex battery charger. More recently, I swapped out the Xantrex inverter for a $50 Wagen 200 watt pure sine inverter and it seems to work just fine. One can also now get smart battery chargers for a similar price and put together a double conversion backup system for not too much money. You can size the battery and the various components for the load and the backup time needed. Ideally the battery charger would be able to work at > 63 Hz, but I haven't found one that is small and affordable enough for this purpose. Plus the system just needs to operate off of the battery, sans charging, for the few minutes that the PW2 is in a bad mood and putting out 66 Hz. My current system will keep the network/cordless phones going for 48 hours without power, but that is now obviously overkill given the PW2.
I thought I could disassemble the backup system when I got my PW2, but still seem to need it given the 66 Hz problem and the fact that PW2 switchover during a failure can be long enough to knock the modem off the air for a few minutes and put my AT&T microcell back into search mode and that can take up to 45 minutes to recover. Live and learn.
At first I was using a very expensive Xantrex 1800 watt pure sinewave inverter that I had bought on sale for the boat, but never installed, and a Xantrex battery charger. More recently, I swapped out the Xantrex inverter for a $50 Wagen 200 watt pure sine inverter and it seems to work just fine. One can also now get smart battery chargers for a similar price and put together a double conversion backup system for not too much money. You can size the battery and the various components for the load and the backup time needed. Ideally the battery charger would be able to work at > 63 Hz, but I haven't found one that is small and affordable enough for this purpose. Plus the system just needs to operate off of the battery, sans charging, for the few minutes that the PW2 is in a bad mood and putting out 66 Hz. My current system will keep the network/cordless phones going for 48 hours without power, but that is now obviously overkill given the PW2.
I thought I could disassemble the backup system when I got my PW2, but still seem to need it given the 66 Hz problem and the fact that PW2 switchover during a failure can be long enough to knock the modem off the air for a few minutes and put my AT&T microcell back into search mode and that can take up to 45 minutes to recover. Live and learn.
SSonnetag, the only issue is you have 3 PW2s and the combined watt hours held in them when starting at 100% SoC will cause the Hertz level to rise to 66 for a good long time - unless your house is voracious for energy at that time. On one PW2, I see about a 20 minute hold-off by the PW2 to the solar inverters for my house's usage at 2 kWh usage. With three PW2s, you would need about 5-6 kWh usage to drop your PW2s to a point where the inverters come live again at 60 Hertz within 20 minutes.
While I think your units will weather 66 Hz, given your great storage capability, you may want to consider a double conversion unit. Of course, you can always simply check with the electronics mfrs of the items you're putting behind the UPS to see if they are cool with 66 Hz...
SSonnentag
埃隆•馬斯克
Yep, we set it up to be able to go completely off-grid. Our power outages are seldom longer than 5 hours. When I tested the system, I turned on every light in the house and started a load of laundry washing in order to create a power load. I only managed to get it up to just under 2kW, and it took over 90 minutes for the battery levels to drop to 92%, which is when the PW2s switched back to 60Hz and allowed the solar inverters to come back online.
I'm due for a new computer anyway, so I'm going to just roll with the 66Hz during power outages for now. If we ever do go off-grid, I'll revisit the issue and perhaps opt for the double conversion UPS. Until then, I'll just make sure my important files are backed up off-site.
So I did a test tonight after the sun was certainly down and turned off the grid power to the house. UPS did not like the power and my LED lights were flickering like crazy. I don't have a way to measure the power frequency but all signs point to the Powerwall providing 66hz even with no input from the PV system.
I have an open ticket with Tesla but has anyone else tested this?
I have an open ticket with Tesla but has anyone else tested this?
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