Getting creative with the Electron Fuel Gauge (and avoiding smoke)

Hey Friends,

I have an interesting inquiry. I’d like to integrate an Electron with a 7.4v (2s) 90C Lipo battery and monitor the voltage for one cell. Here’s my setup: A switching regular is knocking the 7.4 down to 5v (3 amp) , and I plan on feeding this 5v directly to VIN.

Being a 2S battery, and having a balancing port, I can see the voltage for each cell (so roughly ~3.7v). I don’t want to charge the cell, but I am curious about connecting one of the cells to Li+ and leveraging the onboard Fuel Gauge.

Is this a silly idea? Is it possible to disable charging ? I have a number of concerns, but curious what the community take is on this and what safeguards might be recommended.

Thanks!

You won’t need an extra regulator, the Electron can take up to 12V on the Vin pin

https://docs.particle.io/datasheets/electron-datasheet/#power

And yes you can disable charging via the fuel gauge class.
Electron : fast red blink when Vin connected without LIPo

Hey @ScruffR,

Thanks for this clarification on VIN. I should have mentioned that I’ll be needing the 5v elsewhere on the project, which is why i’m including the reg.

Also thanks for calling out the disable class – very helpful.

Curious if any EE’s have thoughts on what implications this setup may have on passive cell drain?

Curious if any EE’s have thoughts on what implications this setup may have on passive cell drain?

This is an old thread, but I’m trying to do something similar and searching the community for references. The charger’s quiescent current draw from VIN pin isn’t great. It’s at least 1.5mA typical compared to the 110uA typical Deep Sleep Current of the entire Electron, and the charger is going to make your battery drain faster (assuming your battery device is in deep sleep most of the time).

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