EBJ wrote: liveforphysics wrote:
mvly wrote: Lipo are unstable when exposed to heavy shock
I love guys who can watch a video of LiPo enduring an absurd amount of shock, beating, smashing, pulverizing into ripped shreds of cell between asphault and a 24" wrench, not do as much as get warm or make a puff of smoke, and then make a blanket statement like "LiPo are unstable when exposed to heavy shock."
There are all different types of LiPo. BMS battery has the most dangerous cells I have ever tested from anywhere. Other types of LiPo can be stabbed and crushed and shot and pounded and grinded against a grinder shooting sparks, overcharged, over discharged, shorted, and not do as much as make a puff of smoke or even get warm.
It's like playing with gunpowder, having it burn, and then declaring powders are dangerous, when some are as dull as beach sand, though they my outwardly look identical.
How do Turnigy and Zippy cells compare in your opinion?
All their modern stuff is 3rd generation formulas. This is why you see the ~3.85v nominal voltage rather than 3.7 of the early generations. We have had folks here who dropped a LiPo pack, and had it get hit by a car at speed, picked it up, and it still worked fine despite being flattened out. lol In one of my recent LiPo test videos, I take an over-charged 6S 40C Turnigy LiPo pack and stab it with the sharpened tip of a 30lbs 4ft chunk of steel multiple times as hard as I can. It made a cloud of white smoke, but I was very disappointed to have it never flame up or even get hot enough to do anything impressive.
Everytime I test the more modern packs, they blow me away with the amount of overcharge they safely take, how they handle shorting by just instantly and harmlessly popping the cell tabs, and the absurd amount of physical abuse they can take without doing anything dangerous to the user.
However, you can still always make them blow with extreme overcharge.
Some of these modern RC cells take like 6.5v before they go though! A tip for folks doing it, you will watch voltage rise very slowly while it's actually still storing the charge, then around 4.8v you see voltage start to climb quickly to about 6-6.5v, then it starts to pull down voltage, and when voltage starts dropping down again, this is when it's about to blow up, generally around 5.4-5.7v for most cells before they erupt into flames.