I installed the strato pi ups with a 12v lead acid battery. I decided on this because it had a built in RTC, heartbeat reset, and serial ports so I could talk to my alarm panel at some later date.
I put them both on an expansion hat so I could fan cool the pi 4 while having the strato, pin expansion, and adc boards as well. .
Looks great, but €91?
I have tried this on three different powerbanks and none of them are suitable. On two of them, the output glitches when the supply is cut from them and this is enough to cause the pi to power-off. On the other, it turns off the output when it is being powered (charged). I suspect that a suitably large capacitor on the output of the ones that glitch may be a solution, though I haven’t tried this.
100% DIY using a Battery Tender brand floating charger, 14.8VDC monitor supply brick, big burly overkill 5V regulator, a couple of diodes, 12V pbAcid battery, and an arduino nano to measure mains on/off, UPS on/off, battery level, and doorbell on/off (first 3 via dividers, doorbell via 5vac hall sensor):
The circuit for a DIY UPS like this is insanely simple. The main ingredients are 2 diodes, and a power supply that will output at least 1V more than your battery can output. When the supply is on, the diodes only allow current out of the supply. When the supply dies, the diodes allow current to flow from the battery. This is all powered by a big UPS as well, so there’s some power down time before that battery even kicks in.
I couldn’t use a smaller system, because this battery also runs the alarm sirens (hence the relays). This way, if a thief cuts power to the house, the alarm remains fully functional for the better part of a day, sirens and all. A day is plenty, because I get a telegram tex immediately when power goes down (lots of time to check camera feeds and call neighbors… yes dvr and router also on UPS).
I could have just bought a commercially available unit, but this was way more fun to do.
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That’s pretty damn cool, I like the way it’s integrated to the alarm.
I’ve been thinking around doing something similar but keeping my Router on the UPS, that way an e-mail / signal messenger message can be sent whenever the power is cut.
I agree, I also keep my router, poe switch, and dvr (blue iris pc) powered by a big UPS. The DVR is set to power off after 30min to preserve some power for the router, pi, and sirens (this lasts the better part of a day… cameras still live recording to sd cards, and ha still shows live feeds). After that big ups dies, the DIY setup in that pic kicks in with a full battery… at this time the router and cameras are dead, but at least the sirens and sensors still operate.
Does every cyberpower UPS have an ethernet access ? Which models support the NUT ? How do I find it out in spec ?
oh I asked too early. The official NUT website has models listed: Network UPS Tools - Cyber Power Systems
Please I am very interested in your schematics. Are you still using this device?