I'm about to move and need to pick a router that suits my new setup. I'm looking at the MikroTik L009UiGS-2HaxD-IN, which offers 8 gigabit ports, 1x SPF, and supports WiFi 6. My main reason for this choice is the ability to use a PoE backup power supply to keep my security cameras running, as they also operate on the same PoE IEEE standard. Ideally, I'd like to replace the ONT fiber box provided by my ISP with this router (with their permission) to simplify my setup and reduce the number of devices needing backup power. However, I'm not experienced with PoE and have some questions. I've seen PoE injectors that take a DC barrel jack and the voltage is customizable. Can I connect four 12V batteries to achieve 48V? Or are there additional voltage protection measures I need to be aware of?
2 Answers
Instead of overcomplicating things by replacing your ONT with a different router, why not just get a router you like, plus a PoE switch? You can use a traditional UPS for your backup power needs, giving you more flexibility with whatever devices you add later. It keeps things simpler!
Per the 802.3af PoE standard, devices usually accept between 37V and 57V DC. This is especially important since voltage can drop over long distances, like with CAT5/6 cabling. So connecting four 12V batteries to get 48V could potentially work, as long as everything is set up correctly and within the amperage limits. However, make sure your PoE injector can handle the voltage range you're working with! Also, remember that other PoE standards may have slightly different voltage requirements.
That's a good thought! But finding a UPS that can support PoE 802.3AT for more than 30 minutes, especially since I'm powering multiple cameras, has been tricky. I'm aiming for about 6 hours of backup, so I figured a single power source would work better.