LIPO battery explosion

[koeze]

I've seen a number of questions here regarding the use op LiPoly batteries in subs. I've always advised against them but now I can show you guys why.
Movie is 9mb and takes quite a while to reach the climax but worth the wait. You would not want this to happen in your expensive boats.

http://ludwigdanninger.de/Videos/Sonstige/LiPoExplosion2.mpg

EJK

[tsenecal]

EJK,

were you charging or discharging

EJK,

were you charging or discharging the battery when you got it to do this?

Tim

[koeze]

Actually this movie wasn't made

Actually this movie wasn't made by me. It was made by a German guy.
Place where I found it]http://ludwigdanninger.de/0822_LiPoVideo.HTM[/url]
It states that the explosion was intentional and took place after deliberately overcharging the cell. The author wanted to see what happened when a lipo cell failed.
While probably not the best way to research such a thing there are stories of models exploding after the batteries were drained.

EJK

[Guest]

I've been using Li-po batteries

I've been using Li-po batteries for over a year now in my flying models.

I'm not concerned by this- all batteries are potentially dangerous if abused.

Li-po's tend to die if discharged too fully, also if you are discharging them at rates well above recommended guidelines there is a risk that you can overheat the cell.

Li-po's are being installed in all manner of domestic equipment, from cameras to mobile's.

If they were as dangerous as some of the doom mongers are saying, they wouldn't be used in that application.

The only downside to li-po's is their price.

Andy

[tsenecal]

I asked, because i too

I asked, because i too have some experience now with lipos, and in my experience, the condition video taped is now relatively rare.

I have destroyed two battery packs by discharging them too far, and they are "dead". They will no longer accept a new charge. they did not, however, overheat.

overheating is caused by discharging the battering at too high an amperage, or overcharging them. Today's lipo chargers make it almost impossible to overcharge them. that leaves discharging at too high a rate... which cannot be removed as long as someone refuses to use the right "size" battery for a given situation.

This used to be a much greater problem than it is now. first generation lipos were as little as 6c (discharge at less than 6 times stated battery amperage) meaning that a 10 amp draw would melt anything smaller than a 1700 mah battery. today's lipos can be found with discharge rates as high as 20c, (a 500mah battery can take a 10 amp hit) making it much easier to remove the issue of discharging at too high a rate.

Tim

[tang]

I remember when nickel metal

I remember when nickel metal hydride batteries were coming into use for r/c car/truck racing applications. Many were being overheated during charging because the chargers of that time period had a peak detection setup that was based on NiCad values. (nicads peak & fall over a much broader range of voltage than does a NiMH)

Without any experience with LiPo cells, I would imagine the low current draw of sub motors would allow their use without much danger. But gosh, if they did blow up .......