{"product_id":"adafruit-liionlipoly-backpack-add-on-for-pro-trinketitsybitsy","title":"Adafruit LiIon\/LiPoly Backpack Add-On for Pro Trinket\/ItsyBitsy","description":"\u003cp\u003eIf you have an ItsyBitsy or Pro Trinket you probably know it's the perfect little size for a portable project. This LiPoly backpack makes it really easy to do! Instead of wiring 2 or 3 boards together to make a charging system, this little PCB sits on top of the PCB and allows a LiPoly\/LiIon battery to plug in. When the Pro Trinket or ItsyBitsy USB port is powered, the battery is recharged automatically. Unplug the USB port and the microcontroller will switch over to the rechargeable battery.\u003c\/p\u003e\n\u003cp\u003eIdeally, this backpack is for use with the 3.3V Pro Trinkets \u0026amp; ItsyBitsy, so that the battery voltage (3.7V-4.2V) will get regulated down to 3.3V on the board. However, many times, you can run a 5V microcontroller + accessories off of the ~4V from the LiPoly battery with no problem. (Technically it's overclocking but we've never seen that affect the microcontroller itself, AVRs are happy to overclock without complaint).\u003c\/p\u003e\n\u003cp\u003eSolder the backpack on with the extra long header so that it can still plug into a breadboard, or clip the long header leads short afterwards for a slim package. There are two LEDs - one red and one green. While charging, the red LED is lit. When the battery is fully charged and ready for use, the green LED turns on. Seriously, it could not get more easy.\u003c\/p\u003e\n\u003cp\u003eIf you want to add an On\/Off switch, we also made that really easy. The two 0.1\" holes with a box around them are the battery output line. Carefully cut the trace between them with a hobby knife and replace it with two wires from a switch like this slide switch, or this pushbutton one, for example.\u003cbr\u003e\u003cbr\u003eCharging is performed in three stages: first, a preconditioning charge, then a constant-current fast charge and finally a constant-voltage trickle charge to keep the battery topped up. The charge current is 100mA by default, so it will work with any size battery and USB port. If you want you can easily change it over to 500mA mode by soldering closed the jumper on the bottom, for when you'll only be charging batteries with 500mAh size or larger.\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eFor use with Adafruit LiPoly\/LiIon batteries only! Other batteries may have different voltage, chemistry, polarity or pinout.\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eComes assembled and tested\u003c\/li\u003e\n\u003cli\u003eUses the 5V input via Micro-B USB connector on the Pro Trinket or ItsyBitsy\u003c\/li\u003e\n\u003cli\u003eFor charging single Lithium Ion\/Lithium Polymer 3.7\/4.2v batteries (not for older 3.6\/4.1v cells)\u003c\/li\u003e\n\u003cli\u003e100mA charge current, adjustable to 500mA by soldering a jumper closed\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eBatteries and Pro Trinket or ItsyBitsy are \u003cstrong\u003enot\u003c\/strong\u003e included. You may also want to have some Kapton tape or other tape on hand to protect the backpack from shorting against the USB connector.\u003c\/p\u003e\n\u003ch3\u003eNotes\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eFor the Itsy nRF52840, this backpack covers the reset\/user buttons (you could use 3 wires instead of having it sit on top.\u003c\/li\u003e\n\u003cli\u003eYou may get an off-white or a black JST connector. It's normal for the red and green LEDs to be very faintly glowing when the battery is attached but not charging, there is 500uA reverse-leakage current from the Schottkey diode from the battery that back powers the charger chip.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003ciframe title=\"YouTube video player\" src=\"https:\/\/www.youtube.com\/embed\/6wSZWXRm830?si=Ku0Vv0FDTb4i9BIj\u0026amp;start=1802\" height=\"315\" width=\"560\"\u003e\u003c\/iframe\u003e\u003c\/p\u003e\n\u003ch2\u003eSpecifications\u003c\/h2\u003e\n\u003cdiv class=\"panel-collapse collapse in\" id=\"tab-technical-details-content\"\u003e\n\u003cdiv class=\"row\"\u003e\n\u003cdiv class=\"col-lg-12 col-md-12 col-sm-12 col-xs-12\"\u003e\n\u003cul\u003e\n\u003cli\u003eDimensions: 15mm x 17mm x 2mm\u003c\/li\u003e\n\u003cli\u003eHeight with JST: 7mm\u003c\/li\u003e\n\u003cli\u003eWeight: 1.3g\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eResources\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eTutorial and Downloads\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cul id=\"product-files\"\u003e\u003c\/ul\u003e\n\u003c\/div\u003e","brand":"Adafruit","offers":[{"title":"Default Title","offer_id":43493222023245,"sku":"nkw1787257390053","price":3.84,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0644\/1182\/8301\/files\/adafruit-liionlipoly-backpack-add-on-for-pro-trinketitsybitsy_1.jpg?v=1787257394","url":"https:\/\/www.grandorchard.shop\/products\/adafruit-liionlipoly-backpack-add-on-for-pro-trinketitsybitsy","provider":"My Store","version":"1.0","type":"link"}