Questions regarding battery shield

  • Greetings. I am totally new to using batteries in projects and have a few questions I can’t find the answer to. Maybe some of the experienced Wemos users have the answers. :)

    1. Is the battery shield for lipo or li-ion (18650)? Have read that it’s important to choose the correct charger for Li batteries but can’t find if the shield is for LIPO or LI-ion on the wemos site.
    2. How to use the J2. Isn’t the J2 a direct connection to A0? I attached an 18650 with 3.9V to a shield without a Wemos attached and measured 3.9V with my multimeter. The wemos A0 is 3.2V max and Wemos are 3.3V, so how am it supposed to be used?

    And a request to @Wemos: Shouldn't the battery connection be on the opposite side to the USB? Would make it easier to put it into a enclosure since the shield and thus the usb can be placed closer to the wall that way.

    1. yes, this shield use Li-Ion / Li-Po battery (3.6v/3.7v)
    2. Wemos D1 mini module have internal voltage divider on A0 input.

    beware! use battery with protection, this battery shield is very unstable.

  • Thanks! Still confused by the a0 though. Isn't the voltage divider in the wemos from approx 1v of the 8266 to 3.2v? Or do you mean there is also a voltage divider in the shield that takes it even further so that a fully charged 3.7V won't burn the wemos?

  • i not have this version with J2, but i see it on picture. J2 connected to small resistor below inductance 4R7
    this resistor and internal divider must give correct voltage.

    alt text

  • Ok. That probably also explains why I was getting to high voltage when I tested without a wemos attached.

    Thanks a lot for the answers.

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