Hi guys,
Another problem on the farm needs a solution!
Background:
I have 24V solar pannels & 2x12V batteries connected to a Ubiquiti MQTT charger with built in 24V Passive POE switch. For the past couple of years its been working great and shuts devices off 24V POE power to switch ports if / when the battery voltage drops below a set threshold.
My problem is that I wanted to attach a couple of 802.3af POE cameras, so I cant use the 24V passive POE. The solution is to use a POE intector that is powered from 24V and injects the 80.23af power and then connect the non POE side of the injector into the unifi switch - This works perfectly but has created another problem (that I was half expecting).
As the injector is powered directly from the battery there is no power management on the injector and downstream, so on poor solar days the batteries cant charge sufficiently to meet the exta power demand and the batteries discharge to flat.
I have half a solution figured out, but I need help with it - I have enabled SNMP on the Ubiquiti SunMax and can now query the battery voltage directly from within HomeAssistant. Knowing the battery voltage I can then create an automation to trigger a GPIO on an ESP32 device which would turn on/off a relay to shut off the intector.
Question is what device to use that can handle the power, as its too much to drive it directly from a GPIO.
This is the injector I have:
https://streakwave.com.au/shop/tp-dcdc-2448gd-hp-tycon-power-tp-dcdc-2448gd-hp-gigabit-18-36vdc-in-56vdc-out-35w-hi-power-802-3af-at-1239#attr=
This is the Ubiquiti SunMax:
https://solar.ui.com/
Simplistically I suppose I could use any automotive 12V relay (I know I have some 40A ones in the shed) and connect a GPIO to drive that high and turn on the power to the injector. But, is there something a bit more elegant? Perhaps something solid state, maybe even a hat for a PICO (running ESPHOME)??? Thoughts please.
I hope Ive eplained the problem enough, if not, shout out and Iāll try to better explain.
Thanks
Jon