I want to power my Photon via batteries via the Photon’s vin pin. Is this a good way to power the Photon or should I buy a battery shield?
You can do this as long as you supply the correct voltage. I personally prefer using a portable usb power pack, so that I can power my Photons over usb.
@rpiswag, take a look at the documentation here:
https://docs.particle.io/datasheets/photon-datasheet/#power
Its a bit problematic to use batteries directly, 3.6V-5.5V means neither 3 or 4 standard batteries are optimal.
3 will be 4.7-3V so you wont get the last 0.6V of useable power.
4 will be 6.25V-4V so too high on fresh batteries.
So it seems you need a regulator to use the full range of standard batteries, if you use 3 you can use a boost type to 5V or a buck/boost to 3.3V(more expensive and more complex circuit), if you use 4 you can use a buck converter to 3.3V instead if you dont need 5V support.
@MORA, not sure how you got 6.25v from four regular batteries producing 1.5V each!
@rpiswag, @MORA’s recommendation of using a buck/boost is good, getting the most from the batteries. For example, THIS unit from Pololu will produce 3.3v from an input voltage of 2.7v to 11.8v. In their description:
- A 3-cell battery holder, which might have a 4.5 V output with fresh alkalines or a 3.0 V output with partially discharged NiMH cells, can be used with this regulator to power a 3.3 V circuit.
- A single lithium-polymer cell can run a 3.3 V device through its whole discharge cycle.
This is just an example and there are variety of great products to chose from.
They are 1.5V nominal, fresh batteries can be slightly above this by 0.1-0.3V, 6.25/4=1.5625V
@MORA, that represents an “unloaded” voltage. Once loaded, the voltage will drop
Hmm maybe, I cant test how much current you can put on it before it dropping atm, but heres a 100mA test.
That shows 0.05hours before dropping, with the photon drawing 80mA when running for a few seconds and <100uA during sleep that could be several hours running with a vin slightly over max, it will likely still work and not take damage since the voltage regulator has 6.5V absolute max though…
@MORA, the more reason then to step-up/step-down the battery pack!