Was watching a video on YouTube about making super capacitors and they guys pulls out a 18650 and starts pulling it to pieces, so for those of you curious about what goes into a 18650 here it is:
Have a bunch of dead cells sitting in the draw… so I’m almost tempted to drain them as far as possible and get out the Dremel. 
>>>>>>so I’m almost tempted to drain them as far as possible and get out the Dremel.
Lot of NASTY chemicals in those things. Better put on the head-to-toe hazmat suit with full air supply.
Not to mention the toxic fumes produced when the innards ignite, and ignite they might no matter how careful you are.
http://environmentalchemistry.com/yogi/hazmat/erg/gn/147.html
HF acid is one heck of a dangerous chemical. It dissolves GLASS.
http://pennstatehershey.adam.com/content.aspx?productId=117&pid=1&gid=002499
Not something I’d want to play with.
http://web.utk.edu/~ehss/training/has.pdf
It’s a byproduct of a li-ion cell burn. I don’t know if it is present without heat, but I sure wouldn’t take the chance.
“HF acid burns result in an extremely slow and painful death.”
Oh great, thanks to the 'related videos' I have discovered the world of using a bank of capacitors as replacement for stupid lead acid car batteries. Just great! I'm going to be dead broke forever, aren't I? xD
link?
And another, using six D-cell size(!): http://www.youtube.com/watch?v=z3x_kYq3mHM & http://www.youtube.com/watch?v=8miq6sDy0wA
I really am not so sure about the validity of that video.
Sure, capacitors can deliver tremendous amounts of current, but it has very little capacity compared to a lead-acid battery.
What that cap bank, I would be afraid to leave the lights on even for a minute without the engine running.
True, but, even at low voltage where a SLA would be truly dead, the capacitor bank still has enough amperage available to start the car. Once it's running the alternator takes care of the rest. SLA at 8 volts can only deliver approximately zero amps, but 8 volts with enough amperage is easily enough to run the starter motor.
A small solar array can easily keep them fully topped up to overcome any parasitic drain, apparently.
Or one or two 18650s hooked up to a boost circuit should do it.