Hello, I have a project using the 32u4 datalogger and I'm using a small LiIon cell as a backup battery so using the on-board charging circuitry is fine.
I also want to use a separate charging circuit and battery system (on a different version of the same project) (still 1S, so 3.7V) that has its own charge circuitry. Can I still plug in the cell voltage to VBAT so I can get a reading of the battery level with the controller, even though I don't want to use the charge circuitry on the board? Is there a way to disable the boards charging circuitry? The problem I foresee is the two charge circuits trying to charge the batteries at once. Would this be solved with a diode allowing voltage TO the feather board and not FROM the feather board via VBAT? Seems like a brute force solution but if it works, it works.
I would use a different board type but I'm trying to make the motherboards I'm designing as modular as possible, and not needing to use a different board for the two versions (integrated and separate charging/battery circuits) would be nice.
Turn off Charge Function on 32u4 Datalogger?
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- jacobfister
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- Franklin97355
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Re: Turn off Charge Function on 32u4 Datalogger?
Do you need the USB connection on both processors? If not there may be a way. If you do then I'll have to ask other techs about it.
- jacobfister
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Re: Turn off Charge Function on 32u4 Datalogger?
Not necessarily. It would be a "nice to have" but the idea is that one would be a mobile version (the one with the larger battery cells and separate charging circuit) and one would be a bench version (the one with just a small backup battery connected to the JST port on the feather board). I COULD sacrifice connectivity/serial output on the mobile version if I needed to. I was also thinking since I made the first post that it could possible hook a transistor up to the VBUS pin through a NOT gate to disable the charging from the standalone charger when the feather is hooked up to USB? (sketch attached) It seems like it would work, but I might need some sort of cap in there to prevent any sudden voltage changes on the VBAT line.
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- adafruit_support_bill
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Re: Turn off Charge Function on 32u4 Datalogger?
One solution would be to simply cut the +5v VBUS wire on a USB cable to use when you need USB communication. That will give you the USB data connectivity while avoiding any battles between the voltage regulators.
Please be positive and constructive with your questions and comments.