I use many battery-operated zigbee and BLE sensors around home and I’m tired of replacing batteries every 6-18 months.
I did some math and figured out these sensors consume an average of 20uA.
My idea is to replace CR2032 battery with rechargeable one (ML2032, used in motherboards) and connect a small external amorphous PV cell, like ones used in calculators. These cells are really good in dim light, indoors, and few cm2 should be enough to recharge the battery.
Anyone tried this?
All you need to make sure of is the Voltage matches (multiply by the number of batteries to replace) to what the battery type had for the device that you want to swap it out from. i.e you can get battery eliminator cables with a usb connector then match it with the correct wallwart for power (multi battery devices will use dummy batteries for the extra slots).
I use a cable with one of my switchbot bots to eliminate the need to replace the cr2 battery it would normally use.
In your case you could use a battery bank or connect directly to the solar cell via a battery eliminator cable setup for example.
Hi elektrinis,
What Robert Koganov said. My suggestion is to get some of those sidewalk solar lights from the dollar store and grab see if that works, or at least grab the little joule thief circuit out of it to keep your voltage correct. These lights have single or parallel LED’s and use in the 3 volt range so they I think would work well.I would be tempted to use a super capacitor instead of a battery, though…
Super caps have energy density roughly 10x lower than lithium batteries, so no good.
I know my way around voltages etc, I’m just asking if anyone did this already.
You need complicated charge circuit and diode to prevent backflow.
At this point, put a reasonable size 3.2V lifepo4 cell there and you are good for the rest of your life.