Does anyone have files (schematics and gerber) for UPS for Arduino?
Something like this?
Does this shield allow you to have an uninterrupted power supply and the LiPower source only during the absence of external source?
Think of it as power always coming from the battery, but the battery is always being charged whenever external power is present.
The LiPo Rider is a bit cheaper and also has a low voltage disconnect for the battery to prevent overdischarge. It also takes a few weeks to ship from Seeedstudio, unfortunately.
Also take a look at the LM1117 datasheet from TI for a battery backup scheme.
What about 3.3 V Arduino? The LiPo shield boosts the voltage from 3.7 V to 5V, but I need 3.3 V for the Arduino Pro Mini.
As far as I understand, the 5V/3.3V is the only reason to switch them off. if that's not the point, internal + external pullups should be fine, then the activated internal ones are not doing any damage.
borutg:
Does this shield allow you to have an uninterrupted power supply and the LiPower source only during the absence of external source?
Power should never be drawn from a LiPo while it is being charged. For this reason there is (or should be - see the microchip datasheet for the charge controller) a P-Channel MOSFET that bypasses the LiPo when there is external power available.
When there is power, the power is split between running the Arduino and charging the LiPo.
When there is no power the LiPo discharges into the Arduino.
majenko:
borutg:
Does this shield allow you to have an uninterrupted power supply and the LiPower source only during the absence of external source?Power should never be drawn from a LiPo while it is being charged. For this reason there is (or should be - see the microchip datasheet for the charge controller) a P-Channel MOSFET that bypasses the LiPo when there is external power available.
When there is power, the power is split between running the Arduino and charging the LiPo.
When there is no power the LiPo discharges into the Arduino.
I agree with you lol.