THE CHEMISTRY PART
“I was busy, so I couldn’t attend to
eBee for a couple of more months. She
was sitting out at my frame-building
school. I took out the battery charger
because I knew her batteries were low. I
knew not to leave the batteries unattended
when charging, and Justin had showed me
some lithium-polymer batteries that had
bulged from overcharging. The batteries
on the eBee are rated at 52 volts and
charge to 58 volts. They started
charging at 13 volts.
“As I was teaching a class of four
students one day, I’d made sure to
check the batteries every so often:
25, 31, 52 volts. Before I could
attend to it one more time, I decided
to go and get a quick lunch. You
guessed it! Just as I was coming to the
shop I was greeted by a big commotion
inside. Not sure what was going on, the
only thing I took notice of was all the
aerospace students running around with
fire extinguishers in their hands. Uh-oh.
Sure enough, when I finally took sight
of the eBee, it was engulfed in a bright
orange flame that was literally 3 feet wide
and 3 feet high. She was on fire! It took
three fire extinguishers to put out the fire,
and eBee was a total mess. I was stunned.
I knew lithium-polymer batteries were
risky, but I had no idea my bike could
catch fire and burn.
“I thought the battery charger was to
blame at first, but I found out later that
when lithium-polymer batteries get too
low in voltage, they should never be used
or charged because the chemistry inside
the battery changes. I had never left eBee
switched on, so it’s a mystery why and
how the battery voltage went so low.
“The universe is full of mysteries, and
this was just one more. I’ve taken eBee
apart and intend to restore her to her
former glory when time permits.” ■
This is how I often work—make a crude sketch
and grab a chunk of 6061 aluminum.