I bought this power bank (Speedy 3000 mAh) for about PHP35 or $0.67, the plastic casing is dented and dirty. It appears to charge (the Red LED inside the casing lights up) but there is no 5V output from the connector.

To disassemble it, there are four + screws hidden under the sticker near the ports.

Inside, you will find a board (charger) with another board (step-up boost) and a battery that is rated for 2600 mAh, so it is not 3000 mAh!

The battery label says “sinowatt ICR 18650E 2014.12.22” and the positive side has a spot weld but the negative side does not, because there is a spring contact soldered to the board. The battery’s voltage is at 3.82 V and that is good for long term storage, but still the powerbank does not output 5V. Could the step-up boost circuit is destroyed? Upon visual inspection, I could not see any damaged SMD components.

Spring Contact

There are two boards soldered together, the charging board has the USB ports and the chip “5056”, a quick Searx reveals that the chip (based on the datasheet) is a AP5056 1A Linear Li-Ion Battery Charger, it is a complete CC-CV linear charger for single cell lithum ion batteries available in SOP/MSOP package and low external component count to be ideal for portable applications. You can download the datasheet for youself and I will just mention the important parts, the IC has eight pins two for the battery and another for a temperature (NTC) for the cell. But in this case there are only two connection for the battery and the temp sensing is disabled. There are two LED to indicate the charging and full charge status. I have reverse engineered the schematics of this powerbank and you can download it below.


I have salvaged the charging board and it works well, I am now using it to charge some laptop batteries.

Testing the charging module

Charging a Sanyo battery

For the boost (step-up) module, it does not work. If I apply a li-ion battery to it’s input pins the voltage output will go to 5V for about a second and will drop to the battery voltage. I cannot find any datasheet for the two IC in it, they are the TS02A 3J (8 pin) and 6008b (6 pin) IC.

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