Thursday, April 07, 2005

Andre on Lipo batteries

It seems that there are no pills for stupidity, but in all fairness the dangers of Lipo cells are grossly exaggerated, and are probably newsworthy because we are now using them in our day-to-day life (cell phones, rechargeable drills, etc.)

I even saw an article in SAMAA news a few issues ago, expanding on the dangers and hazards. With all due respect, it seems that we are repeating the same message without questioning or testing the validity of the statements. I do not want to underplay the dangers of incorrect Lipo use, but that should not scare us away either.

My experience is that any battery should be viewed as potentially hazardous, and treated as such. As far as stupidity is concerned, I have also have an experience or two that I would rather forget. Some were very impressive though, like the morning that I soldered a micro Deans plug to a brand new 910mAh Kokam battery pack. The solder bridged the two pins, and first thing that I noticed was that the pack was becoming unusually warm! I snipped the wires, but it was too late. Expecting a major explosion/fire etc. I tossed them outside. Fortunately the only result was a very impressive smoke ball, and a smell that kept the dogs away for days. The batteries (or what was left of it) did not ignite, but became hot enough to ignite any flammable matter that it was in contact with. I also have a variety of "fat packs" outside my workshop (on a pile of bricks) that show the extent of abuse that these packs can suffer without dangerous consequences. The one Lipo pack is about 3 times its normal thickness (came from a customer) and the other about twice its normal thickness (charged with a Triton charger that was repaired locally, but obviously the voltage cut-off function was not working). I also have some Lipo packs that have been in crashes (squashed to half their normal length) without disastrous consequences. Bottom line is that we should not cry wolf and over-exaggerate the dangers of Lipos, but at the same time be conscious of the dangers associated with the incorrect use of batteries, and take the necessary precautions.

As a matter of interest, we have some guys at our club flying planes that have an amp draw of more than 80A, and if I remember correctly you normally weld steel at about 60A!!!


No comments:

Blog Archive

Total Pageviews


Web site terms and conditions

Copyright of material on all the pages of this site is vested in the SAMAA or the original authors. You may use the material in terms of the Creative Commons license for non-commercial purposes on the condition that you acknowledge its origin.

This work is licensed under a Creative Commons License

The views expressed on this web site, or on any directly or indirectly linked site, are not necessarily those of the SAMAA Committee, or the web editor. The information provided on this site is provided for recreational purposes only. The SAMAA and the authors of presented content assume no liability whatsoever on the use of information contained in this site. The information on this site is provided on an "as-is" basis, without warrantee of any kind. Links provided on this site will let you leave the SAMAA web site. The linked sites are not under the control of the SAMAA, and the SAMAA is not responsible for the contents of any linked site, or any link contained within a linked site, or updates to such sites.