Adafruit Pro Trinket LiIon/LiPoly Backpack Add-On

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SKU: ADA2124 Brand: Adafruit

If you have a 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...

$10.20 AUD, inc GST

$9.27 AUD, exc GST

In stock, ships same business day if ordered before 2PM
Delivered by Tue, 24th of Dec

Quantity Discounts:

10-25 $8.99 (exc GST)
25+ $8.81 (exc GST)

If you have a 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 Pro Trinket and allows a LiPoly/LiIon battery to plug in. When the Pro Trinket USB port is powered, the battery is recharged automatically. Unplug the USB port and the Pro Trinket will switch over to the rechargeable battery.

Ideally, this backpack is for use with the 3.3V Pro Trinket, so that the battery voltage (3.7V-4.2V) will get regulated down to 3.3V on the Pro Trinket board. However, many times, you can run a 5V Pro Trinket + accessories off of the ~4V from the LiPoly battery with no problem. (Technically its overclocking but Adafruit have never seen that affect the Pro Trinket itself, AVRs are happy to overclock without complaint).

Solder 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.

If you want to add an On/Off switch, They 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 with two wires from a switch like this slide switch, or this pushbutton one, for example.

Charging 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.

For use with Adafruit LiPoly/LiIon batteries only! Other batteries may have different voltage, chemistry, polarity or pinout.

Comes assembled and tested
Uses the 5V input via Micro-B USB connector on the Pro Trinket
For charging single Lithium Ion/Lithium Polymer 3.7/4.2v batteries (not for older 3.6/4.1v cells)
100mA charge current, adjustable to 500mA by soldering a jumper closed

Batteries and Pro Trinket not included.

Note: You may get an off-white or a black JST connector. It's normal for the the red and green LED's 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 backpowers the charger chip.

Technical Details

Details:

Dimensions: 15mm x 17mm x 2mm / 0.6" x 0.7" x 0.08"
Height w/ JST: 7mm / 0.3"
Weight: 1.3g
Datasheets, PCB files and Fritzing available in tutorial page

This product is listed in:

Development Boards

Product Comments

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Products that weigh more than 0.5 KG may cost more than what's shown (for example, test equipment, machines, >500mL liquids, etc).

We deliver Australia-wide with these options (depends on the final destination - you can get a quote on the view cart page):

$3+ for Stamped Mail (typically 10+ business days, not tracked, only available on selected small items)
$7+ for Standard Post (typically 6+ business days, tracked)
$11+ for Express Post (typically 2+ business days, tracked)
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Some batteries (such as LiPo) can't be shipped by Air. During checkout, Express Post and International Methods will not be an option if you have that type of battery in your shopping cart.

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Unit 18, 132 Garden Grove Parade
Adamstown
NSW, 2289
Australia

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