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-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-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
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
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