This kit provides a mobile power solution for devices that need or can handle over 5V. It's great for robots or small remote-controlled vehicles, and can serve as a battery backup system for embedded electronics. It is a complete power output and charging system. The kit includes two 18650 "protected" type lithium-ion cells (3.7V, 2400mAh each), rubber feet, a two-pin power adapter and a spare 2A fuse. Use this board to provide your device with 7.4V DC at up to 2A. The batteries can be recharged with a 5V to 12V power supply (charging circuit requires 1A minimum current) via a 2.1mm center-positive jack.
The board measures 3 × 4 inches and is 1 inch high. It provides battery power output via either a polarized two-pin connector (a barrel jack adapter is included for 2.1mm center-positive jacks) or screw terminals. A third power output allows you to power your device from your attached power supply during charging.
The battery holders are especially tight, so once the batteries are in they are very difficult to remove, thus providing excellent shock resistance.
Overview of LEDs and Connectors The diagram on the right shows the connections and LEDs on the edge of the board. Their usage is explained below:
Green LED — Indicates when power is applied to the Charge Power Input barrel jack.
Charging Power Input — 2.1mm barrel jack, center positive, +5 to +12 VDC input. Do not reverse the input voltage as this may damage the charging circuitry. Charging time is dependent on the amperage available from the power supply you choose (1A minimum), as well as the capacity of the cells.
Auxiliary Raw Power Output — Polarized, right angle, female, bottom pin positive. This connection can be used to power another device. For example, you can charge the Li-ion cells and operate another device from the same power supply. When you plug power to the Charging Power Input (to charge the Li-ion cells), you can use the included Molex-to-Barrel adapter cable to provide power to another device. This is not power from the cells; this is the same power that is charging the cells. Of course, your power supply input will need enough current to run the charging system and your external device.
Cell B Red Status — This LED indicates a fault condition in Cell B. If it's solid, there is/was a fault in the cell or there was a glitch during the charging process (remove and re-apply power to try again). If it's blinking, the temperature of the cell is outside the safe charging zone (typically between 32 and 113 °F).
Cell B Blue Status — This LED indicates the charging status of Cell B. If it's solid, the cell is charging. When the cell becomes fully charged, the LED will blink. (If the cell already was fully charged thus no charging operation began, the LED will remain off.)
Cell Power Output — Polarized, right angle, female, bottom pin positive. This power output jack provides the output from the cells. When there is no Charge Power Input, the two 3.7V cells are connected together in a series configuration, and the resulting power 7.4V DC is available at this jack. Upon application of Charge Power Input, Cell Power Output is disconnected from the on-board cells, and this jack is disabled.
Cell A Red Status — This LED indicates a fault condition in Cell A. If it's solid, there is/was a fault in the cell or there was a glitch during the charging process (remove and re-apply power to try again). If it's blinking, the temperature of the cell is outside the safe charging zone (typically between 32 and 113 °F).
Cell A Blue Status — This LED indicates the charging status of Cell A. If it's solid, the cell is charging. When the cell becomes fully charged, the LED will blink. (If the cell already was fully charged thus no charging operation began, the LED will remain off.)
Auxiliary Cell Power Output — Two-pin Screw Terminal Block, Square Pad Negative. This connection simply provides an alternative way to connect your application to the Cell Power Output. Be careful to check the polarity of your circuit, as this is not a polarized connector.
Usage Diagrams The following diagrams demonstrate how the various connectors are used and when.
Powering external device during battery charging. In this example, a power supply is plugged into this board's barrel jack, and an external board is connected to the Auxiliary Raw Power Output via the included Molex-to-Barrel adapter. The external board is receiving power from the power supply input — not from the batteries.
Powering external device via batteries (two options). In these examples, an external board is connected either to the Cell Power Output via the included Molex-to-Barrel adapter, or to the Auxiliary Cell Power Output via bare wires. The external board is receiving power from the batteries. (Notice there is no external power supply connected; battery output is available only when there is no external power input.)
Uninterruptable power supply. To create uninterruptible power, your external device will need a couple of diodes and a sufficient capacitor. The external device is connected to this board via both the Auxiliary Raw Power Output and the Auxiliary Cell Power Output. When the external power input is connected, your device will be powered from the Raw connection; when external power input is removed (or there's a power outage), your device will be powered from the Cell connection. This setup works as a battery backup. For example, you can use high-quality solar panels (need decent amperage for this!) permanently connected to the power input. Whenever the panels stop producing enough power, this board will switch to Cell power output automatically.
Download the Li-Ion Charger Board User Manual and be sure to read the warnings and the instructions about the placement of the rubber feet. You must apply the rubber feet to the correct locations to avoid risk of a dangerous electrical short. Download Li-Ion Battery Charger Board Schematic
If you use either of the optional universal power supplies listed below, set it to the 6V setting. A lower setting won't provide enough voltage; a higher setting won't provide enough current.
Optional Recommended Products for this Item