Authors: Michel and Gernot
The following DIY manual describes an easy-to-implement battery backup module for the BeagleBone Black. This can be useful in certain applications, such as out-door usage where constant power is not present and it is not desirable to just drop power on the BBB board. It was built for a RasPBX setup with the motivation to have a safely powered BBB in all situations. The BBB is unfortunately suceptible to slowly rising supply voltage when powered on. It sometimes does not boot at all, which can be a serious problem after a power glitch. On top, voltage irregularities can cause the device to crash as well.
The battery backup can be applied to any BBB installation, running RasPBX, the original Anstrom Linux or any other distribution. However, USB devices cannot be used while running on battery, as the UPS does not power the USB host port.
The 1950 mAh Li-Ion battery used in this example keeps the board powered for more then 6 hours when running idle most of the time. It is currently in stock for around 36 Euros at Farnell.
The instructions are based on Shabaz’ work documented on Element 14, and have been slightly modified with a different circuitry and used battery type.
WARNING: The modifications presented here can destroy your BBB when not done carefully! The authors of this article are not responsible for any hardware defects that might occur when implementing these modifications. BeagleBone Black power supply MUST be removed before working on it
Another BeagleBone UPS with more simple components is described further down in this topic. In this other small projet 2 leads battery is used instead of 3 leads battery. A Bill of Material is also available. After checking this main tutorial, it is perhaps interesting to have a look at this other small tutorial
- Solder wire
- Side cutter
- Soldering iron
- Wire stripper
- Metal file
- Nail file
Bill of Material
- 1200 mAh (Panasonic CGA-633450)
- 1950 mAh (Panasonic CGA-103450)
The small prototyping board has been built with a saw and a metal file. All the used components are generally available in local electronic stores. The multi-stranded wires were taken from an old defective PC power supply.
This is a part of the Texas Instruments TPS65217C block diagram. A bridge between BAT and BAT_SENSE must be soldered on the BBB board.
The used Adafruit enclosure needs to be modified as shown. Cut off acrylic sheets of
this particular enclosure at the sides. To protect the acrylic sheets during the job, leave the brown adhesive paper on. The red hatched parts need to be removed.
If the enclosure and the BBB are already mounted, it is safe to disassemble them and prepare the enclosure sides as described (see red marks).
This shows the modified enclosure and the BBB reassembled without the top cover.
Before soldering components, verify that no tiny copper parts may fall from the small board onto the BBB when installed (possible damage!!). If necessary, use the metal file to carefully remove copper parts that the saw didn’t correctly cut. Clean the board when done.
The components (connector, capacitor, resistor and coloured leads) must be placed along the copper strips parallel to the coloured lines as shown. Also have a look at the solder side further down.
CAUTION: Set the shrouded header in the same position as the picture displays it. When battery connector is plugged into the JST shrouded header, the coloured leads must match the coloured strips as shown. Incorrect header positioning will damage your BBB! The electrolytic capacitor is polarised. Its negative pole needs to be connected to the “GND” copper strip. The shortest lead connected to the capacitor body is the negative pole. Take a look at one of the previous pictures to avoid wrong insertion. Watch the small minus sign on the capacitor side to clearly identify it’s negative pole. Magnify the picture if necessary.
If a header is going to be used, remove one header pin as displayed before soldering. This is done to ensure a safe connection in the correct orientation. A polarising key must be inserted into the matching connector.
IMPORTANT: DO NOT TRY TO DRILL LARGER HOLES. This will damage the BBB because it is probably built with a multi layer PCB. Existing metal coating, within the holes, builds electrically conductive connections between different layers and may not be removed by drilling larger holes.
Although this is not recommended, It is easier and cheaper to directly solder the three leads onto the BBB. In this case the small Harwin crimp housing doesn’t need to be mounted on the three leads (check previous pictures). Before soldering the leads, have a look at the following picture and description.
When soldering the coloured leads, a bridge must be made on the BBB between TP5 and TP6 as shown.
Tip: strip off a longer wire part from the red lead before soldering it and use it to make the bridge. Insert the red lead into the TP5 board hole, fold it on the solder side so that the TP5 and TP6 connection can be soldered at the same time.
Red lead from the small board connects on both TP5 and TP6 on solder side, yellow lead on TP7, black lead on TP8.
Connect the battery to the shrouded header and place the small board between the enclosure sides and available notches. Place the battery cables into the cable notch.
Place the battery along the enclosure side, where temperature is lower than on top. The Lithium-ion battery fastened on that side will probably last longer.
Don’t place it inside the enclosure! Eventual battery leaks may damage the BBB.