Tesla Power Wall as Emergency Backup Power Source for Surgery Center

Tesla Power Wall as Emergency Backup Power Source for Surgery Center

I work at a surgery center which has a diesel generator as backup source of energy. We inquired about using Tesla power wall (less maintenance and smaller footprint). Tesla stated they do not recommend the power wall in this situation but did not list a reason. Has anyone else looked into using a power wall in this situation? I wonder why it is not recommended in this situation.


ir | September 25, 2019

Pretty simple. Tesla doesn’t want to be liable if something goes wrong. There are “mission critical” backup systems that cost a lot more, not so much for raw materials but due to the higher level of testing, certification, service specialists and liability insurance policy.

Eyeballmd | September 25, 2019

I would think a Power Wall would be more reliable than a diesel generator. Our corporate owner said a lead acid battery backup system could be used...

Tesla-David | September 25, 2019

Tesla PW2’s are generally coupled with solar, and our residential installation includes 13.2 kWh solar + 2 PW2 batteries and have worked exceptionally well for us over last 15 months. The solar is required to charge the PW2’s. I would expect PW2’s would be a suitable backup system and certainly better than lead acid battery backup system or diesel generator.

Eyeballmd | September 26, 2019

I understand the liability issues. Our critical equipment has their own battery backup systems. Our generator runs lights and plugs (when it works) and I think a PW2 would be a great solution for us (and many small surgery centers). I understand it was designed to be charged by solar, but I presume it can be grid tied as well.

ir | September 26, 2019

Like Tesla, I probably heard “Surgery Center” and ran away.

Another theory is I’ve only ever heard of Powerwalls being sold to residential customers. Maybe their commercial power division that could sell you a Powerpack instead?

Are you on 2-phase or 3-phase power?

Eyeballmd | September 27, 2019

We are in 2 phase power. Our generator provides 25 KW which is overkill for the power we need as it runs a limited number of lights and outlets.

Patrick | September 27, 2019

My guess is Tesla would prefer using a PowerPack design instead of Powerwalls for a commercial use case.

Eyeballmd | September 27, 2019

I looked at the PowerPack information, looks like overkill for our needs. Thanks for all of the responses.

FossCoder | October 24, 2019

The smallest PowerPak is 50kVA which is about five times our need for a small medical office for server room battery backup, so i could see it being too much for a small surgery center as well. Most businesses are three phase 208v power, not two phase. Is it the case that there is only a single phase on the existing generator circuit?

Anyone use PowerWalls in lieu of traditional lead acid uninterruptible power supplies for about 13kVA of computer server room equipment?

gregbrew | October 24, 2019

When the internal PbA batteries die on my UPS, I replace them with much larger external PbA batteries. It's pretty easy to do if you are at all handy with a soldering iron. Because the wires to the battery are longer, I replace them with larger wires (smaller gauge number) to reduce resistance in them. I also make sure that the larger batteries are fully charged before hooking them up, otherwise it could take a very long time for the UPS to fully charge them, as it thinks it's charging a much smaller battery. Since the UPS gauges how much capacity (%) remains on backup based on battery voltage, that bit of information is still valid, but *time remaining* will need to be "adjusted" based upon the battery capacity increase. IIRC, in mine, I multiply the time by four, because the external battery has four times the capacity that the internal one had. Be sure to remove the internal battery before attempting this. Mixing different sizes or types in a parallel configuration is a definite no-no. This also assumes that the UPS uses PbA batteries. It wouldn't work for lithiums.

Seems to me that you could get a UPS with the instantaneous power capacity you need (13kVA), and put as many larger external PbA batteries (in parallel) that you want to achieve the desired backup longevity. Make sure the external PbAs are the same age, brand, size and type. I recommend AGM. (I like VMax Tanks. They're pricey, but are American made, and shipping is free through Amazon. I use eight 125Ah versions for my solar PV battery backups.)

As always, YMMV, and any modifications to electronic devices will void the warranty, and above all ...DOING ANY OF THESE MODS IS AT YOUR OWN RISK.

lilbean | October 24, 2019

Doesn’t your machine already have a backup battery to complete the treatment in progress?

DermMD | November 12, 2019

I just booked a powerwall installation for my practice with an in house surgery center. I called Tesla before I placed the order as reading on their website did not answer the question whether a powerwall could be installed at a business (not necessarily commercial as that implies Grid in energy back up setups). They told me they do install powerwalls at businesses for grid power back up (without solar installation).
As someone else pointed out, energy back up setups for outpatient medical facilities (and in many cases hospitals as well) are only required to power a few essential circuits for critical functions. For outpatient surgery centers the Medicare (and Medicare is the law of the land in these setups) requirement is for power backup to essential circuits for 90 minutes only. This would allow for the safe completion or termination of any surgeries in progress. I would certainly cancel my pending surgeries in the event of grid failure as would most centers, I believe. So, in my opinion battery backup is just as safe and probably more reliable as/than ICE generator. Indeed one would not realize there has been a grid failure if operating a tool attached to a Tesla powerwall supported outlet whereas ICE generators do lead to a loss of power albeit for a minute.
If indeed Tesla refuses to install at my site after a survey, they will just be losing business to any one of the many other battery backup vendors coming online. In fact, I have found an overseas manufacturer who's already shipping Lifepo4 batteries to the US. I'd just prefer a Tesla system at this point.

Passion2Fly | November 12, 2019

I'm not sure that the PowerWall is suitable for Mission Critical applications.
Not only the transfer switch but also the power monitoring must be designed to much higher standards.
It's very common to lose communication between your Phone app and the PW2 in case of a power outage, since the WiFi network might be affected by the outage. This is not acceptable for a Mission Critical application. This is just one example...

DermMD | November 20, 2019

So, on the phone the Tesla Power customer service told me to go ahead and make a reservation for a powerwall installation at my office as they did indeed install them at businesses.
A week later the Tesla energy advisor sent me the site survey link for their planing which seemed to imply install at a home. I completed the survey but sent him a note that I was installing this at my office. He called me a few hours later advising that TESLA DOES NOT INSTALL WHERE THERE IS A BUSINESS UTILITY METER. He seemed to imply in his explanation that the Powerwall software is not compatible with a business meter setup. So there you have it.

gregbrew | November 20, 2019

I don't understand how the meter can possibly effect how a Powerwall functions, as the PW is entirely inside the utility meter. I've seen *many* businesses with solar on the roof, so Net Metering can't be the issue. I think the Tesla Energy Advisor was blowing smoke up your posterior.

Patrick | November 20, 2019

Agree with gregbrew.

I believe Powerwalls would function quite well in this use case as long as the connected loads stayed within the published 200A gateway limitation. The type of utility meter is irrelevant for a Powerwall-only application, although some utility companies may have rules limiting their use...

A while back I managed to get a Tesla-direct Solar/Powerwall quote for a development project with multiple small office condos, another good small commercial use case. The project ultimately did not move forward, so we never found out if they would actually follow through with the installation in a commercial building.

Like others, I’m a bit puzzled as to why Tesla avoids these applications. I suspect the policy might be be related to regulatory electrical code differences, limited energy staff/resources, strong residential demand, limited supply (at least until recently), etc. wouldn’t surprise me if they change their policy over time....

DermMD | November 22, 2019

As a matter of fact I now have abdominal pain from that smoke he brew up my rear. I'll sue Tesla.

Windsurfer | December 15, 2019

Interesting thread. Like EyeballMD, I have a medical office building that incorporates a surgery center for eye surgery. We have a 50kWh generator for back up, but I would rather have a solar/powerwall backup solution. I'm also interested in solar/Powerwall for my home, and have made an inquiry off of the Tesla solar page. After a year, a Tesla rep finally emailed me back and directed me to a regional installer. After an exchange of a few emails, I've had no response and no answers to my questions. Most of us who embark on these ventures are of course early adopters, but it is frustrating that we cannot answers to simple questions from Tesla.

Patrick | December 15, 2019

For whatever reason it appears Tesla has chosen to severely limit the investments required to put well-trained presale customer support resources in place for both lines of business. Saw it when going research before acquiring our Model 3 and again while considering energy projects.

IMHO this strategy is not a huge issue on the vehicle side as the cars sell themselves and validation is readily available from happy friends and family owners, but it seems really shortsighted on the energy side. I believe their energy business could grow MUCH faster with a competent, responsive and readily available field sales staff.

One has to believe their execs are smart enough to know this, which may explain their more recent moves to authorize new dealers and re-train older ones now that Powerwalls are (finally) readily available. A Tesla-direct strategy simply cannot scale to meet current market demand in a timely manner.

Regardless - the Powerwall/TEG technology is clearly best in class and their post-sale customer support is generally good. For these reasons and others we chose a reputable local dealer to help create our design, address all my questions and concerns and ultimately install our system.

Wind - unless you live in a very rural location I’ll bet there are solar integrators that would jump at the chance to help you design a microgrid for your medical building. And maybe even clear whatever internal hurdles are holding Tesla back from supporting Powerwalls in light commercial use cases!

Forgive me for being the eternal optimist here - these use case restrictions just don’t make any sense. Especially for applications that fit well within current Tesla product/capacity restrictions.

Another possible angle - if you really need a 50 kW generator then a maxed-out PW array might not be your best choice. I expect/hope Tesla will eventually lower the high-bar qualifiers for Powerpack installations. A small Powerpack would likely be perfect for your building - maybe a well-established Tesla dealer in you area could take your case forward and seek an exception....

Windsurfer | December 16, 2019

Thanks, Patrick, for your observations. Like you, I continue to be optimistic that these types of solutions will prevail in the long run. As I write this, I'm listening to my (very noisy) 50kWh generator run its weekly exercise cycle. There's really no reason for it when there are now better technologies available. I agree with you that the Tesla cars sell themselves, but Tesla needs to up its game with marketing and servicing its energy division.

DermMD | February 12, 2020

There is hope as lots other companies are entering the energy storage market. LG energy comes to mind. Most of their dealers will want to integrate the energy storage with a solar system which is not what I want for my surgery Center. I did find a local installer who's willing to install an LG backup battery system for us. Meeting with them next week. If I'm successful, I will update this thread in case it helps others.

SteveWin1 | February 12, 2020

Thanks DermMD. I'd be interested in hearing what you find out also.

Haggy | February 12, 2020

You could also check with a Tesla certified installer. Many of them work with batteries from multiple companies, and they would be able to tell you which one might be suitable. Or they might be willing to install something that Tesla might not, depending on whether the limitation is physical, legal, or policy based.

DermMD | February 13, 2020

Good point. I'd really like the Tesla system. 2 Powerwalls would give me 26 KwH which is all I need. No other system comes close to the capacity of 13 Kwh for a single unit at the price point offered by Tesla. I know the limitation is not legal as Generac, probably the world leader in backup power systems albeit not necessarily battery, told me they will install their battery on a commercial system. it does have more stringent code requirements they said. Generac is coming out for a site visit next week so I will update this thread then with both Generac and LG estimates. From what I have read online my $20K budget may be insufficient which would be more than sufficient for 2 Powerwalls installed by Tesla.

Jones | February 14, 2020

FWIW - There is one small nuance to consider if you have anything already on a UPS that will be served by the Powerwall. When the grid power is lost, the powerwall generates a synthetic 60 HZ power signal. At the time of grid restore, the 60 HZ has to be synched before the actual re-connection is executed by the controller. In order to make sure the two signals will re-synch, the synthetic 60 HZ is actually a bit high (my pair of PW is 60.4). Resynching takes just a minute or two. The consequence is that if you have equipment that senses or needs EXACTLY 60 HZ, it will have problems. Case in point - most UPS units sense not just voltage but also frequency in order to determine a grid failure. Every single one of my UPS interpreted 60.4 HZ as a grid failure and activated when I did my own after-install investigation and documentation. Computers and such were not affected, but my ethernet and wireless network were on dedicated UPS and were this limited to the battery capacity of each individual UPS. My solution was to install very high end surge suppressors and remove the dedicated UPS - which has worked very well over the course of 17 grid disconnect events and 52 hours of off-grid operation.

gregbrew | February 15, 2020

I noted the same, about six months ago. My UPS refused to reconnect to house power when the PWs were powering the house during a grid falure, because the PWs put out a frequency that was too high for them. The PWs do this during outside grid failures, to shut off the string inverter when the PWs are full, because the PV power has nowhere to go with the grid down. The result was that the house was running just fine, but the equipment on the UPS shut off when the recalcitrant UPS depleted its own internal battery.

It appears that when Tesla released PW firmware 1.43, they tightened up the 60Hz enough to "please" some UPS devices, yet still be enough out of the 60Hz frequency spec to shut down inverters.

My UPS works fine now, on the PWs. YMMV.

I also installed a whole-house surge arrestor in my main electrical panel. It replaces two breaker slots, but provides two breakers (in addition to the surge arrestor function) to replace them. Nifty gadget, and easy to install in a live panel... if you're careful. I'm careful.

Note that breakers are specific to a type of electrical panel, and if you're at all uncomfortable with working in a live electrical panel, hire a skilled and licensed electrician. Mucking about in a live electrical panel can kill you.

Patrick | February 15, 2020

Gregbrew - just curious - what brand/model of combo surge/breaker did you install?

gregbrew | February 15, 2020

Siemens QSA2020SPD Whole House Surge Protection with Two 20-Amp Circuit Breakers for Use Only on Siemens Panels

On Amazon.

DermMD | February 21, 2020

A Tesla installer came by today to look at my setup. Apparently my 3 phase main panel is not compatible with Powerwall. He will provide a proposal with a different storage system. I know that not all commercial setups are 3 phase so it is possible that others may still be able to install Powerwall.
The point being that a Tesla installer is a viable option for those whose electrical wiring is compatible with the Powerwall.

DermMD | February 21, 2020

I meant third party Tesla Installer in the above submission

Passion2Fly | February 21, 2020

that is correct. I don't' understand why they wasted their time to come see you if you have a commercial tri-phase feed. The US TEG only supports single and split phase feeds. The European, Australian, UK support both single and tri-phase feeds...

Passion2Fly | February 21, 2020

Do you need tri-phase? Do you use heavy machinery in your business? You might want to consider downgrading to a regular 200A split phase...

luckysai917 | February 21, 2020

emergency backup Power app to know the emergency backup Status.

primepowersolut... | May 4, 2020

This is Tesla exonerating itself from any future issue with the system.
I think the industrial power pack is more suitable in this case
The power wall might not be too reliable for such work.

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