So I just burned out another photon by putting the battery in backwards after charging. Can I put a diode between the bat and the photon to guard against this? if so what diode?
thanks steve
@murmsk, how exactly are you connecting the battery to the Photon (which pins)?
The VIN pin
Lots of diode types can be used for wrong polarity protection. I regularly use the B230 (https://www.digikey.com/product-detail/en/diodes-incorporated/B230-13-F/B230-FDICT-ND/815328). Aslo used in many of the particle shields
@murmsk, though @joost provides a good recommendation, the bigger issue is that powering the Photon with a LiPo through a diode to Vin will drop the voltage by 0.5 volts. If you are using a fully charged 3.7v LiPo, the voltage at Vin will be 3.65v or just 0.5v higher than the minimum recommended voltage of 3.6v. It may be better to use a boost regulator to provide 5v to Vin instead OR use an LDO regulator to provide 3.3v directly to the 3V3 pin. You can still use a reverse protection diode with the LDO without “skirting” the minimum voltage requirements.
Slightly OT: I believe that the Photon uses a 100% duty-cycle capable buck converter, meaning that the battery won't actually drop out until it gets to 3.3V, which is like 90% discharged. There's some wiggle room for conditions, but f you boost then buck, or go LDO, you're throwing away more energy in conversion efficiency.
Settle on a connector style and get the correct pin crimper tools. Don't mess around with lithiums and loose wires, it's just going to waste your time when something touches something it shouldn't.
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Another solution: https://store.particle.io/products/power-shield-with-headers
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