Sure, other UPS models exist, but I'm not sure where we'd be constrained for this much space.  This setup is 4U. As you correctly point out, several of our sites already have great power backup systems.  Haystack (3-4 weeks on battery, years on propane), SnoDEM (well maintained power system), Beacon (large battery bank), CapitolPark (another large battery bank), CampMurray (surely a good power system).  However, the sites that worry me are: Rattlesnake (Snoqualmie shack), which had no battery and a broken generator. Rattlesnake (DNR shack), which has no battery and a seemingly working generator during the last outage. Baldi (AT&T shack), which has a battery system but the brand new generator failed and we didn't load-shed quickly enough. Baldi (Middle Wiztronics shack), which has a tiny UPS, and a seemingly working generator. Baldi (North Wiztronics shack), which has no UPS, and a seemingly working generator. East Tiger (HJR shack), which has no UPS and no generator. East Tiger (Other shack), which has...unknown. Gold, which has no UPS and unknown generator status. Blyn, which has no UPS and unknown generator status. Lookout, which has no UPS and unknown generator status. BawFaw, which has no UPS and probably decent generator status. CapitolPeak, which has a tiny UPS, and probably decent generator status. Larch, which has...unknown. Triangle, which has...unknown. Buck, which has...unknown. This list may not be exhaustive, I'm working from memory. For these specific UPSes, I'd like to target Rattlesnake (both shacks). --Bart On 2/5/2021 1:43 PM, Kenny Richards wrote:

Bart,

Are there options for sites where we don't have access to that much rack / physical space? (obviously with reduced runtime)

Which set of sites would be targeted? I'm guessing SnoDEM, CapitolPark and Beacon might not need the same level of backup as Baldi, Rattlesnake, Capital Peak, etc.

Thanks Kenny

On Fri, Feb 5, 2021 at 12:41 PM Bart Kus <me@bartk.us <mailto:me@bartk.us>> wrote:

Hello,

During the recent wind storm event in January, HamWAN lost utility power to some sites.  This triggered network outages that affected users and repeaters that relied on those sites.  It was far from our finest hour.  "When all else fails", HamWAN should not be the first in line.  I'd like for 2021 to be a year we focus on reliability.  Having a reliable power system at every site seems like a good place to start that journey.  In each of the power failures in January, a generator system failed to activate.  In these cases, we need at least 24 hours to mount a response in fixing generators.  This means our battery backup systems should be sized for at least 24 hours of runtime.  I have acquired a couple UPSes that can achieve this.  They are composed of the main UPS:

https://www.apc.com/shop/us/en/products/APC-Smart-UPS-XL-Modular-3000VA-120V... <https://www.apc.com/shop/us/en/products/APC-Smart-UPS-XL-Modular-3000VA-120V-Rackmount-Tower/P-SUM3000RMXL2U>

And one external (and chainable!) battery expansion module:

https://www.apc.com/shop/us/en/products/APC-Smart-UPS-XL-Modular-48V-Extende... <https://www.apc.com/shop/us/en/products/APC-Smart-UPS-XL-Modular-48V-Extended-Run-Battery-Pack/P-SUM48RMXLBP2U>

They also feature an AP9631 network interface module in each UPS, so we can monitor and control the power system.  As you can see, each UPS costs about $3600 new, so the two I acquired would be $7,200 new.  However, I managed to find used units and purchased brand new batteries for them. *The total cost for these two systems is $963.71.*  One of them is deployed at Rattlesnake ("Snoqualmie shack") already:

https://photos.app.goo.gl/HTomAzJUnrjuJ3bw8 <https://photos.app.goo.gl/HTomAzJUnrjuJ3bw8>

If we ever want to expand the battery capacity of these, we can simply plug in more battery modules.

I'm hoping to deploy the 2nd system in the other building on Rattlesnake ("DNR shack"), but that hasn't happened yet.

--Bart

_______________________________________________ PSDR mailing list PSDR@hamwan.org <mailto:PSDR@hamwan.org> http://mail.hamwan.net/mailman/listinfo/psdr <http://mail.hamwan.net/mailman/listinfo/psdr>

_______________________________________________ PSDR mailing list PSDR@hamwan.org http://mail.hamwan.net/mailman/listinfo/psdr

Lookout has a pretty substantial generator system, although I don’t know how often Wiztronics tests/exercises it. A UPS during change-overs at least would seem like a good idea, but I’m not sure we need a “full size” unit, although extra never hurts. Rob S From: PSDR [mailto:psdr-bounces@hamwan.org] On Behalf Of Bart Kus Sent: Friday, February 5, 2021 2:25 PM To: Puget Sound Data Ring; Kenny Richards Subject: Re: [HamWAN PSDR] VOTE: Power backup expansion project Sure, other UPS models exist, but I'm not sure where we'd be constrained for this much space. This setup is 4U. As you correctly point out, several of our sites already have great power backup systems. Haystack (3-4 weeks on battery, years on propane), SnoDEM (well maintained power system), Beacon (large battery bank), CapitolPark (another large battery bank), CampMurray (surely a good power system). However, the sites that worry me are: Rattlesnake (Snoqualmie shack), which had no battery and a broken generator. Rattlesnake (DNR shack), which has no battery and a seemingly working generator during the last outage. Baldi (AT&T shack), which has a battery system but the brand new generator failed and we didn't load-shed quickly enough. Baldi (Middle Wiztronics shack), which has a tiny UPS, and a seemingly working generator. Baldi (North Wiztronics shack), which has no UPS, and a seemingly working generator. East Tiger (HJR shack), which has no UPS and no generator. East Tiger (Other shack), which has...unknown. Gold, which has no UPS and unknown generator status. Blyn, which has no UPS and unknown generator status. Lookout, which has no UPS and unknown generator status. BawFaw, which has no UPS and probably decent generator status. CapitolPeak, which has a tiny UPS, and probably decent generator status. Larch, which has...unknown. Triangle, which has...unknown. Buck, which has...unknown. This list may not be exhaustive, I'm working from memory. For these specific UPSes, I'd like to target Rattlesnake (both shacks). --Bart On 2/5/2021 1:43 PM, Kenny Richards wrote: Bart, Are there options for sites where we don't have access to that much rack / physical space? (obviously with reduced runtime) Which set of sites would be targeted? I'm guessing SnoDEM, CapitolPark and Beacon might not need the same level of backup as Baldi, Rattlesnake, Capital Peak, etc. Thanks Kenny On Fri, Feb 5, 2021 at 12:41 PM Bart Kus <me@bartk.us> wrote: Hello, During the recent wind storm event in January, HamWAN lost utility power to some sites. This triggered network outages that affected users and repeaters that relied on those sites. It was far from our finest hour. "When all else fails", HamWAN should not be the first in line. I'd like for 2021 to be a year we focus on reliability. Having a reliable power system at every site seems like a good place to start that journey. In each of the power failures in January, a generator system failed to activate. In these cases, we need at least 24 hours to mount a response in fixing generators. This means our battery backup systems should be sized for at least 24 hours of runtime. I have acquired a couple UPSes that can achieve this. They are composed of the main UPS: https://www.apc.com/shop/us/en/products/APC-Smart-UPS-XL-Modular-3000VA-120V... And one external (and chainable!) battery expansion module: https://www.apc.com/shop/us/en/products/APC-Smart-UPS-XL-Modular-48V-Extende... They also feature an AP9631 network interface module in each UPS, so we can monitor and control the power system. As you can see, each UPS costs about $3600 new, so the two I acquired would be $7,200 new. However, I managed to find used units and purchased brand new batteries for them. The total cost for these two systems is $963.71. One of them is deployed at Rattlesnake ("Snoqualmie shack") already: https://photos.app.goo.gl/HTomAzJUnrjuJ3bw8 If we ever want to expand the battery capacity of these, we can simply plug in more battery modules. I'm hoping to deploy the 2nd system in the other building on Rattlesnake ("DNR shack"), but that hasn't happened yet. --Bart _______________________________________________ PSDR mailing list PSDR@hamwan.org http://mail.hamwan.net/mailman/listinfo/psdr _______________________________________________ PSDR mailing list PSDR@hamwan.org http://mail.hamwan.net/mailman/listinfo/psdr

Responses in-line. On 2/5/2021 2:07 PM, Dale Skyllingstad wrote:

I agree, this is a great idea.  Bart and I discussed it a little the other day.  I think our priorities should be the non-commercial/ham sites that have less reliable generators and therefore a greater likelihood of extended downtime.  Sites like Bawfaw that have public safety repeaters have great generator track records and should be at the bottom of our list, in my opinion. Agreed!   We may even be able to get away with smaller capacity units at these sites.

I think we should still strive for 24 hours as a minimum in case a well maintained generator fails.  Possibly extend beyond 24 hours for known-flaky sites.

Since we're using an on-line/double conversion UPS, dirty generator power shouldn't cause a failure. These units I bought are line-interactive, not double-conversion. Double-conversion usually carries a price and availability premium.   Earlier this year, my gear at Baldi failed to come back on generator when my [standard] UPS didn't like the slow 50-something hertz the Wiztronics generator was producing.  An on-line unit shouldn't care, within reason. Yes, specifically for the Baldi Wiztronics shack(s) where we've had a switch get wiped due to generator failover, we should consider a double-conversion unit(s).

With the deployment of multiple UPS battery banks now, we should think about implementing a battery replacement schedule and budget.

Absolutely.  For each of the UPSes in this email, the battery replacement cost is $262 (after shipping + taxes), and rated battery lifetime is 3-5 years.  I have saved the battery replacement date in the firmware.  I'd also like to see automation of calibration tests (runtime estimation), to alert us if the pack has degraded or if the load has increased. --Bart

Dale AH6ET

On 2/5/2021 12:41 PM, Bart Kus wrote:

...

Hello,

During the recent wind storm event in January, HamWAN lost utility power to some sites.  This triggered network outages that affected users and repeaters that relied on those sites. It was far from our finest hour.  "When all else fails", HamWAN should not be the first in line.  I'd like for 2021 to be a year we focus on reliability.  Having a reliable power system at every site seems like a good place to start that journey.  In each of the power failures in January, a generator system failed to activate.  In these cases, we need at least 24 hours to mount a response in fixing generators.  This means our battery backup systems should be sized for at least 24 hours of runtime.  I have acquired a couple UPSes that can achieve this.  They are composed of the main UPS:

https://www.apc.com/shop/us/en/products/APC-Smart-UPS-XL-Modular-3000VA-120V...

And one external (and chainable!) battery expansion module:

https://www.apc.com/shop/us/en/products/APC-Smart-UPS-XL-Modular-48V-Extende...

They also feature an AP9631 network interface module in each UPS, so we can monitor and control the power system.  As you can see, each UPS costs about $3600 new, so the two I acquired would be $7,200 new.  However, I managed to find used units and purchased brand new batteries for them. *The total cost for these two systems is $963.71.*  One of them is deployed at Rattlesnake ("Snoqualmie shack") already:

https://photos.app.goo.gl/HTomAzJUnrjuJ3bw8

If we ever want to expand the battery capacity of these, we can simply plug in more battery modules.

I'm hoping to deploy the 2nd system in the other building on Rattlesnake ("DNR shack"), but that hasn't happened yet.

--Bart

_______________________________________________ PSDR mailing list PSDR@hamwan.org http://mail.hamwan.net/mailman/listinfo/psdr

_______________________________________________ PSDR mailing list PSDR@hamwan.org http://mail.hamwan.net/mailman/listinfo/psdr

Answers in-line. On 2/5/2021 4:46 PM, Tom Hayward wrote:

The cost seems reasonable for an experiment at two sites, so my vote is Aye, but I have some questions...

What is the grand design for our power architecture going forward? There isn't a unified design.  We have different sites with different requirements and restrictions, so I would expect we'll use a variety of approaches. So far, we have a mix of AC and DC powered sites. UPSs are an obvious choice at sites that have full-size servers, but where we only have networking gear, a 24V battery bank is an option. We have done this at some sites. Are you advocating for standardizing on UPSs at all sites? Or just those with servers? Is this efficient? (Does efficiency even matter?) For the sites in downtown Seattle, atop apartment buildings, we deployed giant battery banks and use DC feed.  This is a good match for these locations, since we can't be running generators at residential facilities, so batteries are the way to go.

For these mountain-top locations where we have limited 2-post rack space and no server load (yet), I think the 2 UPSes I purchased are a good fit.  If we add servers, we may want to expand those banks, which these units let us do. Running on 120VAC gives us maximal equipment flexibility at the cost of some efficiency loss.  Answering this question actually made me do the efficiency science just now in the lab!  I connected the UPS to my "battery simulator" power supply, and removed 120VAC input. The no-load overhead draw is 77W-100W, depending on battery voltage (44V-56V).  Adding a 450W load (small vacuum cleaner) to the UPS showed nearly 100% efficient conversion (10A draw @ 56V, including the 1.7A overhead from idle).  So it seems the only inefficiency is that static no-load overhead.  It's surprisingly high.

Would it behoove us to use a redundant array of inexpensive, low-power, DC-powered (likely ARM-based) servers to extend runtime of our higher-layer networking services? Maybe?  Although we can load-shed the servers if a site falls onto battery power.  Choosing servers is a more complex discussion. Do we plan to support non-HamWAN loads on these battery systems (e.g., a DMR repeater in addition to the networking stack)? I'm not sure if we should support non-HamWAN loads on these.  We did plug the VHF DMR @ Rattlesnake into the new UPS, however it is on its own outlet group.  If we get an alert about power, we can load-shed as appropriate.  Perhaps repeaters that want to share in the power backup can supply additional battery storage?

--Bart

Tom

On Fri, Feb 5, 2021 at 2:36 PM Bart Kus <me@bartk.us> wrote:

...

Responses in-line.

On 2/5/2021 2:07 PM, Dale Skyllingstad wrote:

I agree, this is a great idea. Bart and I discussed it a little the other day. I think our priorities should be the non-commercial/ham sites that have less reliable generators and therefore a greater likelihood of extended downtime. Sites like Bawfaw that have public safety repeaters have great generator track records and should be at the bottom of our list, in my opinion.

Agreed!

We may even be able to get away with smaller capacity units at these sites.

I think we should still strive for 24 hours as a minimum in case a well maintained generator fails. Possibly extend beyond 24 hours for known-flaky sites.

Since we're using an on-line/double conversion UPS, dirty generator power shouldn't cause a failure.

These units I bought are line-interactive, not double-conversion. Double-conversion usually carries a price and availability premium.

Earlier this year, my gear at Baldi failed to come back on generator when my [standard] UPS didn't like the slow 50-something hertz the Wiztronics generator was producing. An on-line unit shouldn't care, within reason.

Yes, specifically for the Baldi Wiztronics shack(s) where we've had a switch get wiped due to generator failover, we should consider a double-conversion unit(s).

With the deployment of multiple UPS battery banks now, we should think about implementing a battery replacement schedule and budget.

Absolutely. For each of the UPSes in this email, the battery replacement cost is $262 (after shipping + taxes), and rated battery lifetime is 3-5 years. I have saved the battery replacement date in the firmware. I'd also like to see automation of calibration tests (runtime estimation), to alert us if the pack has degraded or if the load has increased.

--Bart

Dale AH6ET

On 2/5/2021 12:41 PM, Bart Kus wrote:

Hello,

During the recent wind storm event in January, HamWAN lost utility power to some sites. This triggered network outages that affected users and repeaters that relied on those sites. It was far from our finest hour. "When all else fails", HamWAN should not be the first in line. I'd like for 2021 to be a year we focus on reliability. Having a reliable power system at every site seems like a good place to start that journey. In each of the power failures in January, a generator system failed to activate. In these cases, we need at least 24 hours to mount a response in fixing generators. This means our battery backup systems should be sized for at least 24 hours of runtime. I have acquired a couple UPSes that can achieve this. They are composed of the main UPS:

https://www.apc.com/shop/us/en/products/APC-Smart-UPS-XL-Modular-3000VA-120V...

And one external (and chainable!) battery expansion module:

https://www.apc.com/shop/us/en/products/APC-Smart-UPS-XL-Modular-48V-Extende...

They also feature an AP9631 network interface module in each UPS, so we can monitor and control the power system. As you can see, each UPS costs about $3600 new, so the two I acquired would be $7,200 new. However, I managed to find used units and purchased brand new batteries for them. The total cost for these two systems is $963.71. One of them is deployed at Rattlesnake ("Snoqualmie shack") already:

https://photos.app.goo.gl/HTomAzJUnrjuJ3bw8

If we ever want to expand the battery capacity of these, we can simply plug in more battery modules.

I'm hoping to deploy the 2nd system in the other building on Rattlesnake ("DNR shack"), but that hasn't happened yet.

--Bart

_______________________________________________ PSDR mailing list PSDR@hamwan.org http://mail.hamwan.net/mailman/listinfo/psdr

_______________________________________________ PSDR mailing list PSDR@hamwan.org http://mail.hamwan.net/mailman/listinfo/psdr

_______________________________________________ PSDR mailing list PSDR@hamwan.org http://mail.hamwan.net/mailman/listinfo/psdr

---

PSDR mailing list PSDR@hamwan.org http://mail.hamwan.net/mailman/listinfo/psdr

Correct, Buck is on generator year round. -----Original Message----- From: PSDR <psdr-bounces@hamwan.org> On Behalf Of David C. Jenner via PSDR Sent: Friday, February 5, 2021 4:42 PM To: Puget Sound Data Ring <psdr@hamwan.org>; Bart Kus <me@bartk.us> Subject: Re: [HamWAN PSDR] VOTE: Power backup expansion project Doesn't Buck Mtn run on generators all the time? With maybe 6 months or more fuel? 73, Dave K7DCJ On 2/5/21 12:41 PM, Bart Kus wrote:

Hello,

During the recent wind storm event in January, HamWAN lost utility power to some sites. This triggered network outages that affected users and repeaters that relied on those sites. It was far from our finest hour. "When all else fails", HamWAN should not be the first in line. I'd like for 2021 to be a year we focus on reliability. Having a reliable power system at every site seems like a good place to start that journey. In each of the power failures in January, a generator system failed to activate. In these cases, we need at least 24 hours to mount a response in fixing generators. This means our battery backup systems should be sized for at least 24 hours of runtime. I have acquired a couple UPSes that can achieve this. They are composed of the main UPS:

https://www.apc.com/shop/us/en/products/APC-Smart-UPS-XL-Modular-3000V A-120V-Rackmount-Tower/P-SUM3000RMXL2U

And one external (and chainable!) battery expansion module:

https://www.apc.com/shop/us/en/products/APC-Smart-UPS-XL-Modular-48V-E xtended-Run-Battery-Pack/P-SUM48RMXLBP2U

They also feature an AP9631 network interface module in each UPS, so we can monitor and control the power system. As you can see, each UPS costs about $3600 new, so the two I acquired would be $7,200 new. However, I managed to find used units and purchased brand new batteries for them. *The total cost for these two systems is $963.71.* One of them is deployed at Rattlesnake ("Snoqualmie shack") already:

https://photos.app.goo.gl/HTomAzJUnrjuJ3bw8

If we ever want to expand the battery capacity of these, we can simply plug in more battery modules.

I'm hoping to deploy the 2nd system in the other building on Rattlesnake ("DNR shack"), but that hasn't happened yet.

--Bart

_______________________________________________ PSDR mailing list PSDR@hamwan.org http://mail.hamwan.net/mailman/listinfo/psdr

_______________________________________________ PSDR mailing list PSDR@hamwan.org http://mail.hamwan.net/mailman/listinfo/psdr

I vote yes. Good points raised by Tom and others, and I welcome us spending time and resources on power infrastructure in the future. I don't believe 1 size fits all needs but some level of standardization is good. -Doug- On Fri, Feb 5, 2021 at 4:52 PM Tom Hayward <tom@tomh.us> wrote:

On Fri, Feb 5, 2021 at 4:42 PM David C. Jenner via PSDR <psdr@hamwan.org> wrote:

...

Doesn't Buck Mtn run on generators all the time? With maybe 6 months or more fuel?

I don't think this impacts the need for batteries. The goal of battery backup is to stay online when the normal power system goes out. This can happen with utility power or local generator. The batteries should last longer than the typical time to restore power after an outage. If we think it might take a few days to get a generator mechanic on site, that should be our target for battery runtime.

Tom _______________________________________________ PSDR mailing list PSDR@hamwan.org http://mail.hamwan.net/mailman/listinfo/psdr

The UPS was not installed at the time of the outage.  The outage triggered me buying said UPSes and deploying the first one the day after the storm. Your experience was likely due to the DNR shack @ Rattlesnake having a working generator, and even though we did lose power, the generator did kick on to bring us back up.  I've since observed many more power outages at the DNR building (all equipment logging reboots at the same time).  This is where a UPS would help things out. --Bart On 2/5/2021 5:46 PM, Stephen Kangas wrote:

Bart,

That’s interesting that one of the UPS units is installed currently at the Rattlesnake site.  I can attest to the valued performance of that, as when that widespread power outage occurred, the Rattlesnake DMR repeater down during the outage, yet HamWan continued to be operational at that same site.  I can guess that the UPS and emergency generator system at that SECAST shack did not work, and yet your UPS did.  I was able to use HamWan for Winlink email communications with members of our North Bend ARES Team, demonstrating the value and resiliency of that HamWan site. It’s good that you’re aiming to replicate that reliability to other HamWan sites.

73 de Stephen W9SK (North Bend)

*From:* PSDR <psdr-bounces@hamwan.org> *On Behalf Of *Bart Kus *Sent:* Friday, February 05, 2021 12:42 PM *To:* Puget Sound Data Ring <psdr@hamwan.org> *Subject:* [HamWAN PSDR] VOTE: Power backup expansion project

Hello,

During the recent wind storm event in January, HamWAN lost utility power to some sites.  This triggered network outages that affected users and repeaters that relied on those sites. It was far from our finest hour.  "When all else fails", HamWAN should not be the first in line.  I'd like for 2021 to be a year we focus on reliability.  Having a reliable power system at every site seems like a good place to start that journey.  In each of the power failures in January, a generator system failed to activate.  In these cases, we need at least 24 hours to mount a response in fixing generators. This means our battery backup systems should be sized for at least 24 hours of runtime.  I have acquired a couple UPSes that can achieve this.  They are composed of the main UPS:

https://www.apc.com/shop/us/en/products/APC-Smart-UPS-XL-Modular-3000VA-120V... <https://www.apc.com/shop/us/en/products/APC-Smart-UPS-XL-Modular-3000VA-120V-Rackmount-Tower/P-SUM3000RMXL2U>

And one external (and chainable!) battery expansion module:

https://www.apc.com/shop/us/en/products/APC-Smart-UPS-XL-Modular-48V-Extende... <https://www.apc.com/shop/us/en/products/APC-Smart-UPS-XL-Modular-48V-Extended-Run-Battery-Pack/P-SUM48RMXLBP2U>

They also feature an AP9631 network interface module in each UPS, so we can monitor and control the power system.  As you can see, each UPS costs about $3600 new, so the two I acquired would be $7,200 new.  However, I managed to find used units and purchased brand new batteries for them. *The total cost for these two systems is $963.71.*  One of them is deployed at Rattlesnake ("Snoqualmie shack") already:

https://photos.app.goo.gl/HTomAzJUnrjuJ3bw8 <https://photos.app.goo.gl/HTomAzJUnrjuJ3bw8>

If we ever want to expand the battery capacity of these, we can simply plug in more battery modules.

I'm hoping to deploy the 2nd system in the other building on Rattlesnake ("DNR shack"), but that hasn't happened yet.

--Bart

_______________________________________________ PSDR mailing list PSDR@hamwan.org http://mail.hamwan.net/mailman/listinfo/psdr

The only thing for this vote is in bold, below.  It's just for the 2 UPSes already purchased.  If HamWAN doesn't want to fund it, I'll eat it out of pocket or sell the equipment. --Bart On 2/5/2021 6:00 PM, Rob Salsgiver wrote:

So the subject line calls for a vote, but I don’t see any specific thing we’re voting for….

Are we reimbursing you for the 2 UPS units, committing to the same flavor at an undetermined number of sites, or just the idea to implement backup power at much needed sites?

I’m not against any of it, just want to know what specifically we’re to vote on!

Cheers,

Rob

*From:*PSDR [mailto:psdr-bounces@hamwan.org] *On Behalf Of *Bart Kus *Sent:* Friday, February 5, 2021 12:42 PM *To:* Puget Sound Data Ring *Subject:* [HamWAN PSDR] VOTE: Power backup expansion project

Hello,

During the recent wind storm event in January, HamWAN lost utility power to some sites.  This triggered network outages that affected users and repeaters that relied on those sites. It was far from our finest hour.  "When all else fails", HamWAN should not be the first in line.  I'd like for 2021 to be a year we focus on reliability.  Having a reliable power system at every site seems like a good place to start that journey.  In each of the power failures in January, a generator system failed to activate.  In these cases, we need at least 24 hours to mount a response in fixing generators. This means our battery backup systems should be sized for at least 24 hours of runtime.  I have acquired a couple UPSes that can achieve this.  They are composed of the main UPS:

https://www.apc.com/shop/us/en/products/APC-Smart-UPS-XL-Modular-3000VA-120V... <https://www.apc.com/shop/us/en/products/APC-Smart-UPS-XL-Modular-3000VA-120V-Rackmount-Tower/P-SUM3000RMXL2U>

And one external (and chainable!) battery expansion module:

https://www.apc.com/shop/us/en/products/APC-Smart-UPS-XL-Modular-48V-Extende... <https://www.apc.com/shop/us/en/products/APC-Smart-UPS-XL-Modular-48V-Extended-Run-Battery-Pack/P-SUM48RMXLBP2U>

They also feature an AP9631 network interface module in each UPS, so we can monitor and control the power system.  As you can see, each UPS costs about $3600 new, so the two I acquired would be $7,200 new.  However, I managed to find used units and purchased brand new batteries for them. *The total cost for these two systems is $963.71.*  One of them is deployed at Rattlesnake ("Snoqualmie shack") already:

https://photos.app.goo.gl/HTomAzJUnrjuJ3bw8 <https://photos.app.goo.gl/HTomAzJUnrjuJ3bw8>

If we ever want to expand the battery capacity of these, we can simply plug in more battery modules.

I'm hoping to deploy the 2nd system in the other building on Rattlesnake ("DNR shack"), but that hasn't happened yet.

--Bart

_______________________________________________ PSDR mailing list PSDR@hamwan.org http://mail.hamwan.net/mailman/listinfo/psdr