Power at VBAT versus BAT_IN

When I have no USB connection, but have 4 x AAA rechargeable batteries (~4.8V, ~600 mA) connected to GND and BAT_IN, will I see full power (voltage x current) at the VBAT pin or is there any drop in voltage or current between BAT_IN and VBAT?

I had a look at the power diagram at https://www.espruino.com/Pico and that assumes BAT_IN and VBAT are equivalent. However the board view in the forum comment https://forum.espruino.com/comments/12247605/ seems to indicate that there are devices between BAT_IN and VBAT.

Thanks for any answer or tips where I can look for info!

So just to be sure, we're talking about the 2x 0.1" pins, BAT_IN and VBAT as shown on: https://www.espruino.com/Pico#pinout

For those:

• BAT_IN is the one you should connect batteries too (it's also connected to the JST connector footprint that's on the rear of the board)
  
• VBAT is what's actually marked as 5V in this schematic: https://www.espruino.com/Pico#-a-name-power-a-power-and-the-fet-b0-jumper
  
  

When I have no USB connection, but have 4 x AAA rechargeable batteries (~4.8V, ~600 mA) connected to GND and BAT_IN, will I see full power (voltage x current) at the VBAT pin

You'll see full voltage, but power goes through the FET so it's not 'full current' - but it should easily handle 1A which sounds like it's fine for you.

When USB is connected you'll see USB volts via the volt drop of a diode - and I'd avoid trying to pull any more than 500mA off that because the diode won't like it!

Hi Gordon,

Yes, I am refering to the naming on the "pinout" picture.

Thank you for the clarification!

Do you recommend the limit of 500mA for VBAT only when using USB power or also when using battery power that comes in via BAT_IN?

Do you recommend the limit of 500mA for VBAT only when using USB power or also when using battery power that comes in via BAT_IN?

If you're just using battery power then 1A should be fine, but when you plug USB in it switches over and you'd end up using the diode...

So really, if you have a project where you're planning on using batteries all the time, I'd suggest wiring your loads direct to the battery/BAT_IN pin

Ok, thanks, I will do that.