<div dir="ltr"><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">I forgot to mention...</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">> Actually, given that the output is a DC-DC converter, you really will</div><div class="gmail_default" style="font-size:small">>want to have some way to measure battery voltage so you can get</div><div class="gmail_default" style="font-size:small">>SOC/runtime. I would suggest writing to their support and tell them</div><div class="gmail_default" style="font-size:small">>what you want. From the site, they have higher than usual odds of</div><div class="gmail_default" style="font-size:small">>being cooperative.<br></div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">The output of this thing is NOT a DC/DC converter. It is just the raw battery voltage (3 cells in series). Thus, the output will start at about 12.6 and drop as low as 9.0 if fully discharged. I do not intend for it to ever go that low since I don't need a long run time, and I doubt the NAS could operate there anyway, so I will be very conservative when arriving at LB or similar status announcements. I think I will be OK because the discharge curves are pretty flat for a long stretch before falling precipitously. I will just shorten the run time / alarm settings accordingly until I am comfortable that the NAS still will be OK.</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">I did contact Qnap to ask about acceptable input voltage range, and I got absolutely nowhere. They kept quoting that I needed to use a 12V power adapter which was useless to my cause !</div><div class="gmail_default" style="font-size:small"><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Feb 20, 2023 at 1:55 PM Greg Troxel <<a href="mailto:gdt@lexort.com" target="_blank">gdt@lexort.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Tom via Nut-upsuser <<a href="mailto:nut-upsuser@alioth-lists.debian.net" target="_blank">nut-upsuser@alioth-lists.debian.net</a>> writes:<br>
<br>
>>That makes sense. So you'll have input voltage, output voltage, and<br>
>>output current I would guess. You might consider a nodemcu (ESP8266)<br>
>>publishing via MQTT to reduce power and use of unobtainium.<br>
><br>
> Yes, that is exactly what I was planning to instrument. Maybe battery<br>
> voltage too if I can access it. I thought it might be useful to be able to<br>
> see the open circuit battery voltage while charging, I dunno.<br>
<br>
Actually, given that the output is a DC-DC converter, you really will<br>
want to have some way to measure battery voltage so you can get<br>
SOC/runtime. I would suggest writing to their support and tell them<br>
what you want. From the site, they have higher than usual odds of being<br>
cooperative.<br>
<br>
> I'll look into this. I have no experience with nodemcu's, and never heard<br>
> of MQTT until your message, but I am always willing to learn<br>
> something new. Has NUT been deployed on a nodemcu? It looks like these do<br>
> not run traditional operating systems?<br>
<br>
This would not run NUT or unix -- it's an arduino-class CPU. I was<br>
assuming you have another computer on that will and the RPI was just to<br>
drive the i2c.<br>
<br>
Basically:<br>
<br>
ESP8266: very small/low-power/cheap ($7?) arduino-ish dev board with<br>
wifi and GPIO/i2c/etc.<br>
<br>
nodemcu: software that lets you write in lua for the esp8266/esp32.<br>
Or you can write raw arduino code.<br>
<br>
MQTT: message bus for IOT where you have a broker and then some device<br>
writes values to a topic. This lets you decouple the IO and the<br>
processing.<br>
<br>
I have a python program that watches nut on a system and publishes a<br>
json dictionary to an MQTT topic. I have a remote Home Assistant that<br>
ingests this and does display/logging/alerting.<br>
<br>
<br>
So basically I am suggesting making a UPS that interfaces via MQTT and<br>
an MQTT driver. A lot more work that what you are proposing; I am<br>
thinking the long game, which is not necessarily what you want to or<br>
should do -- but it's what I do....<br>
<br>
<br>
If you don't have a machine that can run nut as part of the always on,<br>
then your RPI0W approach makes a lot of sense.<br>
<br>
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</blockquote></div>