I plan on mounting a Amazon Fire 7 on the wall as my HA dashboard. It will replace an old DSC house alarm keypad.
The DSC keypad was powered via 12v coming from the old alarm control board in a closet on the other side of the house. The alarm board was powered via 120v outlet.
I plan on using the existing wires to power the tablet. I figure I can use this to convert it from 12v to 5v to charge the tablet.
Now, just doing some forward thinking, what would be a good way to prevent the tablet from constantly being charged and the battery dangerously ballooning? I’ve read these devices are not designed to be plugged in all the time.
Here is what I was thinking:
Can I use this [Sonoff wifi switch] (https://www.amazon.com/Sonoff-Wireless-Automation-Modules-Compatible/dp/B07F6YZXST) and program it into HA (after TASMOTA flash) to turn on/off either on an interval (every 2 hours) or automate into HA to check battery level of the fire 7 and then tell the Sonoff switch to power the device?
I dont know if I’m overthinking it or going in the wrong direction. I’m only 7 or 8 days into the entire home automation world and would love some feedback, suggestion.
When you say “these devices” are you referring to all tablets or specifically the Amazon Fire 7?
I used to have a Blackberry Playbook docked in its charging cradle all day long. It worked that way for about 4 years and was eventually retired. It never experienced any so-called ‘battery ballooning’ and the only reason the device was retired was its browser had become obsolete.
You intend to re-use the wiring that originally powered the DSC’s keypad. That keypad consumed very little current (a small, low-resolution, LCD display and no battery to charge). Check the wire’s gauge and ensure it is sufficient to handle the additional current required to charge the Fire 7’s battery.
I’ve experienced an old iPhone’s battery ballooning because I had it plugged into a radio all the time. I’d be super happy if the Fire 7 would last that long.
I think the amount of current the fire 7 will need should be fine, at least I’m going based on the recommendations made in this video. I’m basically trying to do the same thing but trying to see if I can control when the tablet gets charged.
i have my android phone with tasker and a mqtt plugin send a mqtt message with the battery percentage every time it changes to mosquitto where home assistant picks it up, you could probably make an automation to turn off the charger when the battery is at 100% and on when its at 4% or something.
