LiPo batteries that run RC hobby are potentially dangerous devices. When not handled properly they can ignite or even explode. And they do not live forever. Even the best battery, no matter how taken care off, loses capacity, swells and has to be disposed. When we combine both facts we face a problem: how to dispose old LiPo batteries if they can catch fire? It's extremely hard to find a place that accepts them for utilization. Throwing out with garbage is not a good idea. Disposing with popular alkaline batteries might sound as a good idea, but it is not either. So, how to utilize old LiPos? This is quite easy...

  1. Build a LiPo discharge device using 24V halogen light bulb. No high-tech here, just a way to connect light bulb to a battery. 12W halogen is generally a good option for both 3S and 4S LiPos
  2. Put a battery inside ceramic pot with some sand (not flammable if thing go very very wrong for any reason), connect "discharge device" and let it do its job. Light bulb limits discharge current, so LiPo should discharge nicely without extra swelling or overheating Magical LiPo tree
  3. Let it there for at least few hours. The longer, the better. When cell voltage is below 0.5V, it's time to shorten the wires. There almost no charge inside and we do it only to be 100% sure that battery will be fully dead before we proceed
    shortened wires
  4. At this point, battery is almost "safe". It will not ignite or explode. But it still contains reactive lithium
  5. Leave LiPo with shortened wires for a few days. I've left those for more than 3 months wrap removed from LiPo
  6. Now, let's kill it completely
  7. Prepare saline. Just pour salt into water and stir until salt stops dissolving saline
  8. Remove wrap and separate battery cells nano tech discharged LiPo cells separated LiPo disassembled
  9. Put cells into saline cells in saline
  10. Now comes the fun part. Remember everyone saying "Never, ever puncture LiPos!". Now you can. Take a knife and rip those cells open! LiPo cells punctured
  11. Salt water will neutralize lithium and every trace of charge that might have been left there
  12. Leave them in saline for few hours LiPo utilized
  13. Since there is no technology to recycle lithium, just throw them out. From environment point of view, you did all you could!