SmartThings presence sensor V2/V4 battery upgrade

Hi guys,

I've done the battery upgrade for my presence sensor that most people have done with 2 AA or AAA batteries, but the problem is that it's very bulky.

The original size is ok and I still have one on my keychain connected to ST.

On the HE side it seems that the battery lasts only a month, whereas on ST I still have it working after a few months of usage. (I'll have to dig into that once my sniffing tools arrive so I can see if I spot any difference between the reporting between the ST and HE connected sensor, but more on that at a later date)

I've done a little bit of research and I see that the presense sensor uses an EM357 MCU which has an absolute max voltage rating of 3.6V, so the idea of using a 16430 battery with a custom designed 3d printed case goes out the window as typically rechargeable batteries go up to 4.2V which would damage the MCU.

I've kept on doing more research and I found a rechargeable CR123A battery that has a max voltage of 3.6V is a bit on the expensive side but I'm sure I'll find something cheaper.

The other alternative would be to find a relatively small Lithium Iron Phosphate Rechargeable Lithium Ion Battery and design a custom case for that. I've never designed anything with CAD so I'd have to enlist the help of one of my friends for that.

Long story short I'm wondering has anyone gone down the root of trying to minimize the size of the smartthings presence sensor but using a slightly larger battery than the original one?



Here is a thread from years ago on the ST forum that discusses using AA batteries, among other things:

Thanks, I actually found that one first and read the full thread and no one there seems to have made up a 3d printed case.

I posted here in case someone this side did something themselves or perhaps they're aware of some 3d printed designs

The hack may be a bit bulky but I just toss them into a vehicle glove box and compliment (as a virtual presence) with Life360 for the phone.
That gives a combination that is a bit redundant and covers most of your coming and goings.