I'm working on my first robot project. I previously used a 12V 6Ah sealed lead acid battery, but recently I aquired some 15 ASUS Li-Ion battery packs, each of them 14.8V and either 2200 mAh or 4400 mAh. The laptops have been discarded, and some of the battery packs seem to be dead.

The battery packs have an 8 pin connector. Inside, I assume there's a bunch of 18650-cells and some electronics.

My robot can handle 14.8 V directly.

How can I use these batteries? How can I charge them without the laptops? I'm a little put off by the idea of taking the 18650-cells out of the packs and rebuilding my own battery pack and charging system, but if that's what's needed I have to do it.

The packs are marked ASUS A41-A3 for the 2200 mAh ones, and ASUS A42-A3 for the 4400 mAh ones.


1 Answer 1


None of what I will say in this answer is safe, and you should not even attempt it without proper supervision, safety equipment and a class D fire extinguisher around. Lithium ion batteries need to be handled carefully, in both the mechanical and electrical sense. Physical stress can cause fires, as can improperly charging or discharging.

Given the danger of reverse engineering the cell management circuitry in your batteries, it would be better to disassemble them and treat them as individual cells. Any of the cells that haven't gone flat need to be grouped to minimize any mismatches in their charge levels or lifetimes. Then you can look at constructing a battery management system that can safely deal with the cells you have.

  • $\begingroup$ I've looked up the datasheet for these batteries. They're Samsung ICR18650-22E batteries. According to the datasheet, they should handle 12V at 2.2A for 2.5 hours in room temperature (they will be ruined, but no explosion or fire). However, I've decided to take them out, build a battery pack and buy an Imax B6AC-charger with voltage monitoring. I only wish I could find a more powerful charger; 15-20 amps. I accept your answer for now, and if a more thorough answer comes, I'll change. $\endgroup$
    – frodeborli
    Commented May 13, 2014 at 18:47

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