Hey there. I was wondering how the Piicodev LiPo Expansion Board for the Raspberry Pi Pico worked, and what type of LiPo I would need for it, if you could give me a few recommendations that would be great. Thanks for your help, this forum is amazing!
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Hi Ezra,
In regards to the workings all of the schematics can be found on the product page! What part in particular were you wondering about?
Any of Core’s 2 pin LiPo’s should work perfectly, the 1100mAh is recommended.
Glad you are liking it 
Thanks, I had assumed that the 1100 mAh was correct, I just wanted to be safe.
I was wondering if I needed to charge the LiPo beforehand, or if the Pico plugged into the Piicodev expansion board will supply it with charge.
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Hi Ezra,
Certainly, the Recommended Essentials are hand-picked so you know they ought to work!
It’s best practice to charge the LiPo beforehand as it ships at a reduced charge (about 30% usually).
Once charged try to keep tabs on it to make sure the battery doesn’t over-discharge (To setup a monitoring circuit you could make a voltage divider with the Vsys, analog and GND pins; or check with your multimeter every so often).
If you’re looking for longevity with a sensor, I’d check out the Nano power timer HAT or using a micro-USB plug.
I would like to be able to monitor external power supplied to my Pico W… which I have connected on a dev board with LiPo attached
I need to detect loss of external power so I can do some cleanup before things go dark (flushing data to the drive etc), whilst running off LiPo, So far, I’m doing all my testing using power from the USB, but in production, that wont be possible, I will have an external 5V PS connecteing to VSYS (or VBUS).
My hope is to connect said external power to a GPIO pin also (possibly via a voltage divider), if it goes low, I can do my housekeeping etc.
Am I on the right track?
Any cautionary comments?
Thanks,
T.
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Hi @Trevor277988,
Sounds like you are on the right track to me.
A voltage divider circuit or a 3.3V voltage regulator would be needed as the GPIO pins won’t handle 5V input without complications. You will need to make sure this signal does not go outside of the 0-3.3V range.
Otherwise, this seems like a sound idea to me!
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You can choose Adafruit 3.7V LiPo Battery with JST-PH Connector (500mAh, 1200mAh, or 2000mAh).
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Some good suggestions for potential LiPo batteries from @lia262073!
You can see our category page for Lithium Ion and Lithium Polymer batteries here:
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Hi Trevor,
It’s worth mentioning quickly that PiicoDev and a lot of the items Core stock are hobby grade, and depending on the application likely not fit for commercial products.
As Sam mentioned a voltage divider is probably the way to go, depending on the scale of production there might be a dedicated IC to handle both inputs, regulate and provide the data you need out with low power consumption.
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Yep… noted. My project is for home use, albeit a serious one.
Turns out I don;t need a voltage divider at all… if I read the Pico datasheet thoroughly earlier, I would have seen that you can monitor VBUS on WL_GPIO2. Have implented this and it works just dandy 
Can’t create an ISR on it, but for my purposes, polling every 15 seconds is just fine.
Cheers,
T.
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Hi @Trevor277988,
Glad to see you found a way to get it working for your project.
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Hi Trevor,
Noted - just saw the word ‘production’ and automatically assumed commercial.
Nice find!! For closure, WL denotes a pin from the wireless interface - Infineon CYW43439.
So no ISR available on the W variant 
R1 and R10 are next to some pins if you do want to pop a bodge wire there though:
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