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ToyKeeper / anduril

Anduril 2 Flashlight Firmware and FSM UI Toolkit
GNU General Public License v3.0
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Request: Add support for 3V batteries #88

Closed travisce closed 3 months ago

travisce commented 3 months ago

Flashlights such as the Sofirn SC21 Pro running Anduril could benefit from being able to run CR123A 3V batteries. An example use-case would be in a car emergency, where an (empty) SC21 left in the glovebox could be used as a signal/work light (with a pack of spare CR123As stored in the car).

CR123As are rated at 3V, but will drop to 2.5V under load, which will trip Anduril's low-voltage protection (LVP).

Would it be possible/feasible to add a toggle for LVP to support 3V batteries (CR123As, or theoretically even smaller 3V batteries) for flashlights running Anduril? The idea would be to have LVP enabled by default, but allow the user to turn it off if they want to use a 3V battery.

SammysHP commented 3 months ago

There are very few flashlights (with Anduril) that can operate on such low voltage (the SC21 Pro isn't one of them). At most they would glow a little bit due to the forward voltage of the LED.

LVP is a safety feature that should not be user defined during runtime. It is already possible to change it during compile time for these rare cases.

ToyKeeper commented 3 months ago

If a manufacturer makes an Anduril light designed to use 3V cells, I'll add support for it. However, it's tricky to support 3V and 3.6V in the same build, because their voltage ranges overlap. It's difficult for the light to know what type of battery is being used, so it might guess wrong and then break LVP and damage the battery. It's not like AA/14500 support, where the voltages have no overlap, thus making it easy to detect the cell type.

So I'm waiting until 3V Anduril lights actually exist. The SC21 isn't designed for that and won't perform well at low voltages.

In the meantime, if you have a SC21 that you only use with 3V cells, I'd recommend building your own version of the firmware with LVP disabled. Or maybe use the voltage calibration function to make it think the battery is more full than it really is. The manual shows only +/- 0.3V of correction available, but you can add more than 0.3V by clicking more times. That way, instead of activating LVP at 2.9V, you could set it to activate at 2.5V or even 2.4V or 2.3V. But the battery check function will show values higher than reality, so you'll have to convert the values in your head.