Hi,
I am running from battery and would like to know how much power I can draw from the vsys pin on the lipo expansion board.
Use case is to drive a relay and pump load. Draws 300ma. I have 3 sets - so potentially 900ma, although plan to run sequentially rather than in parallel.
TIA
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Hi @murray117914 - welcome to the forums!
I designed this board (schematic) 
I’m glad you’re using it in your project! The on-board mosfet Q1 which acts as a diode is good for 2.3A continuous, but that would make it pretty hot.
Note this value is only valid when running from battery power. When plugged into USB, all VSYS current passes through the Pico’s schottky diode (Figure 18, D1) which is only rated for 1A
So to play it safe, i would always say the max current you can draw from VSYS under all cases is a bit less than 1A (since the pico needs to power itself too).
If your project is only ever powered by battery, that value can be higher.
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ok thanks. From that info I should be good even if I ran everything together, however plan is to run them one at a time.
regards
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