[PLUG] UPS shopping

[Russell Senior]

Hi folks,

This isn't strictly a Linux question, but since it is to power a Linux
machine (or several) I think it is probably close enough.

I have several Uninterruptible Power Supplies scattered around the
house. A week or so ago, one of them started beeping at me a few times a
day to let me know it thought its batteries needed replacing. Since it
tended to beep at me (at least when I heard it) at night, after
battery-supplier-store hours, I'd mentally note it and then the next day
I'd have forgotten about it. However, last night around 1am, things went
sideways. I'm not sure what the trigger was, but the UPS decided that if
I wasn't going to take it seriously, it was just going to to lights-out
completely dead. As I bypassed the UPS with a plain-old power strip, I
also found that one of my devices, a 16-port dumb network switch was not
entirely happy either. Its 12V ac adapter had apparently given up
(unloaded, I was seeing about 9V out the end). I replaced the wall wart
and switch function returned to normal.

The long-and-short of the matter is that I'm now in the market for a
replacement UPS. The old one was a pretty old APC Smart-UPS 1000,
probably 20-ish years old and had seen numerous battery replacements.

Does anyone have recent experience, either positive or negative, and/or
any advice on replacements. I'd consider a used older model. I actually
have two 12V 17A-hr SLA batteries on the shelf from a previous
misadventure (I managed to kill another UPS while removing the old
batteries, ripping a custom transformer off the UPS circuit board), so
bonus points if the UPS takes that size batteries. I am pretty sure I
got a replacement for it off ebay.

I recall Keith lamenting that Li-FeO4 backed UPSs were not on the market
not so long ago.

Anyway, I am soliciting advice to help broaden my long-but-narrow
personal experience.

Thanks!

-- 
Russell Senior
russ...@pdxlinux.org

Re: [PLUG] UPS shopping

[Russell Senior]

Out of my price range, but:

https://www.amazon.com/Tripp-Lite-SMART1000RM2UL-UPS/dp/B07VDQ7TZV

On 12/29/23 02:36, Russell Senior wrote:

Hi folks,

This isn't strictly a Linux question, but since it is to power a Linux
machine (or several) I think it is probably close enough.

I have several Uninterruptible Power Supplies scattered around the
house. A week or so ago, one of them started beeping at me a few times a
day to let me know it thought its batteries needed replacing. Since it
tended to beep at me (at least when I heard it) at night, after
battery-supplier-store hours, I'd mentally note it and then the next day
I'd have forgotten about it. However, last night around 1am, things went
sideways. I'm not sure what the trigger was, but the UPS decided that if
I wasn't going to take it seriously, it was just going to to lights-out
completely dead. As I bypassed the UPS with a plain-old power strip, I
also found that one of my devices, a 16-port dumb network switch was not
entirely happy either. Its 12V ac adapter had apparently given up
(unloaded, I was seeing about 9V out the end). I replaced the wall wart
and switch function returned to normal.

The long-and-short of the matter is that I'm now in the market for a
replacement UPS. The old one was a pretty old APC Smart-UPS 1000,
probably 20-ish years old and had seen numerous battery replacements.

Does anyone have recent experience, either positive or negative, and/or
any advice on replacements. I'd consider a used older model. I actually
have two 12V 17A-hr SLA batteries on the shelf from a previous
misadventure (I managed to kill another UPS while removing the old
batteries, ripping a custom transformer off the UPS circuit board), so
bonus points if the UPS takes that size batteries. I am pretty sure I
got a replacement for it off ebay.

I recall Keith lamenting that Li-FeO4 backed UPSs were not on the market


Li-FePO4, not what I said before.


not so long ago.

Anyway, I am soliciting advice to help broaden my long-but-narrow
personal experience.

Thanks!

Re: [PLUG] UPS shopping

[Rich Shepard]

On Fri, 29 Dec 2023, Russell Senior wrote:


The long-and-short of the matter is that I'm now in the market for a
replacement UPS. The old one was a pretty old APC Smart-UPS 1000,
probably 20-ish years old and had seen numerous battery replacements.

Does anyone have recent experience, either positive or negative, and/or
any advice on replacements.


Russell,

I've had positive experiences with RefurbUPS .
They can advise you about reliability as they have the expertise and
experience.

Regards,

Rich

Re: [PLUG] UPS shopping

[Michael Ewan]

A related question for rolling your own UPS, I have two 12V sealed lead
acid batteries that I recently replaced ($200) in my mother-in-laws scooter
which she is no longer able to use.  The battery unit for the scooter is
removable and is 24V (the two batteries in series) with a trickle charger,
the output lugs are accessible.  I can easily get a 12V full wave inverter
and put the batteries in parallel, but then I lose the nice case and
charger.  Does anyone know of a 24V full wave inverter that might work DIY,
or maybe I should just pull the batteries and go with the easy to get 12V
charger and inverter.

On Fri, Dec 29, 2023 at 5:45 AM Rich Shepard 
wrote:

> On Fri, 29 Dec 2023, Russell Senior wrote:
>
> > The long-and-short of the matter is that I'm now in the market for a
> > replacement UPS. The old one was a pretty old APC Smart-UPS 1000,
> > probably 20-ish years old and had seen numerous battery replacements.
> >
> > Does anyone have recent experience, either positive or negative, and/or
> > any advice on replacements.
>
> Russell,
>
> I've had positive experiences with RefurbUPS .
> They can advise you about reliability as they have the expertise and
> experience.
>
> Regards,
>
> Rich
>

Re: [PLUG] UPS shopping

[Bill Barry]

On Fri, Dec 29, 2023, 11:00 AM Michael Ewan  wrote:

> A related question for rolling your own UPS, I have two 12V sealed lead
> acid batteries that I recently replaced ($200) in my mother-in-laws scooter
> which she is no longer able to use.  The battery unit for the scooter is
> removable and is 24V (the two batteries in series) with a trickle charger,
> the output lugs are accessible.  I can easily get a 12V full wave inverter
> and put the batteries in parallel, but then I lose the nice case and
> charger.  Does anyone know of a 24V full wave inverter that might work DIY,
> or maybe I should just pull the batteries and go with the easy to get 12V
> charger and inverter.
>
>

Can you rewire the inside of the case to put them in parallel?

Bill

Re: [PLUG] UPS shopping

[Tomas Kuchta]

On Fri, Dec 29, 2023, 12:00 Michael Ewan  wrote:

> A related question for rolling your own UPS, I have two 12V sealed lead
> acid batteries that I recently replaced ($200) in my mother-in-laws scooter
> which she is no longer able to use.  The battery unit for the scooter is
> removable and is 24V (the two batteries in series) with a trickle charger,
> the output lugs are accessible.  I can easily get a 12V full wave inverter
> and put the batteries in parallel, but then I lose the nice case and
> charger.
>

UPS needs deep cycle batteries. Scooter and/or car batteries are not deep
discharge. They will die after handful of deep discharges, typically 3-5
times.

Additionally, simple battery + invertor will not seamlessly  transition
between grid and battery. For that, you would need to keep the inverter
synchronized to grid and make fast transition switch when grid drops +
resynchronize the inverter to grid before transitioning back to grid.

Perhaps, whole house UPS, such as Tesla would make better use of persons
time and $$$.

Just my 2¢, T

>

Re: [PLUG] UPS shopping

[Neal]

There are plenty of 24 volt input inverters available, typically for
commercial trucks.

NealS

Re: [PLUG] Looking for some WiFi AP Security Advice

[MC_Sequoia]

> > "I want to set up some sort of secure connection between the cell phone
> > and the web site running on the Pi."
> > 
> > This should be doable via a vpn client/server. A quick google search on
> > "raspberry pi cell phone vpn" returned this:
> 
> 
> Are you saying a VPN is needed along with the SSL, or as a replacement? Why
> both, or why as a replacement?

An SSL certificate enables a web site to use HTTPS and it also verifies the 
website's domain authenticity through a certificate authority. This is all more 
for end-user security and privacy. Self-signed certs are for non-production 
enviros. 

This does provide end to end security for any and every connected device, but 
with a VPN, you can restrict which ip addr(s) can connect only via the vpn. But 
since, "It is not accessible to the Internet, as the AP is not connected to the 
Internet this is all happening on a private ip network", all of this is secure 
connection concern is irrelevant as no one outside of the private ip net can 
access the launch web site. 

Yes, it's possible to spoof a mac address, forge ip packets, etc. And curious 
tech savvy kids will be curious tech savvy kids, but you're talking about a 
fairly serious amount of time, effort, knowledge, skill and tools to pull this 
off. 

I'd suggest there are far more interesting internet things for those curious 
tech savvy kids to hack & crack on and/or into. 

I walked away from a lucrative cybersecurity career a few decades ago because 
my experience was that the whole industry was built on the idea of scaring 
people to buy security products and services. Yes, there are very real 
vulnerabilities, exploits, security concerns and bad actor hacker/crackers but 
people fail to correctly asses the real risks, threats and targets. 

If you setup a reasonably secure launch situation and some black hat genius kid 
cracks it and launches the rocket on you, they gotta be close enough to get 
onto the WiFi and not in mom's basement over the internet. 

You should also be able to monitor the devices in real time that are connecting 
to the WiFi AP. If you're not familiar with this, either poke around on the AP 
mmgmt. web site or look through the instruction manual for mac table, ip table, 
arp table, connected devices, or the like. If you see a new device that you 
don't know connect to the AP before the launch, don't launch until you figure 
out what's going on and/or disconnect/block that device. 

I hope that gives you a better understanding of this whole secure launch 
concern and gives you some peace of mind. Cheers!