The Thunderbolt electric heated socks is the culmination
of over 20 years refining a practical method for keeping your feet
warm on cold days.
Thunderbolt Battery Pack
The present Thunderbolt sock heating system represents the culmination
of over 20 years refining a practical method for staying warm outdoors
on cold days. Heated sock designer, Bob Williams, says he saw his
first electric socks when he received a pair for Christmas in 1958.
They were powered by two six-volt lantern batteries and produced
good heat - for a short time. A major problem soon surfaced; buying
replacement batteries became very expensive for a high school student!
Fast forward to 1975:
Realizing that a rechargeable battery was a must, Bob snipped the
cord to the lantern batteries and devised an over-the-shoulder sling
to hold a motorcycle battery. At last there was substantial rechargeable
electric power for the socks. However, climbing into a tree stand
carrying this battery with liquid sulfuric acid sloshing around
wasn't yet the perfect solution.
The 1980's, enter the NiCad rechargeable battery:
At last on the market appeared a powerful, sealed, reasonably lightweight
battery. Bob quickly bought a video camera battery and modified
it to work with his sock heating system. Unfortunately, a problem
with the nickel-cadmium battery proved to be its "memory"
effect. Unless great care was taken during the recharge cycle the
battery soon lost a significant portion of its electrical capacity.
All in all however, the heated socks were becoming practical and
easy to use.
1990, time to improve the key element - the sock itself:
Believe it or not, the original 1958 socks (with occasional washings)
had lasted until the 90's, when Bob retired them in favor of a redesign,
with a larger full-foot heating element (most electric socks just
heat your toes). This proved to be more comfortable and passed more
heat to the body through the circulatory system, so the idea was
2000, battery technology makes another leap:
When the nickel-metal hydride battery became available, it offered
a major advantage over NiCads: it greatly reduced the memory effect
from recharging and allowed much more flexibility in using the electric
socks. No longer was it necessary to completely discharge the batteries
before recharging; they could be "topped off" before heading
for the woods.
2002 brings significant increases in NiMH capacity:
Even though retaining the same physical size and weight, the electrical
capacity of the new Thunderbolt battery pack has doubled, allowing
twice the productive time outdoors for the user.
Since the Thunderbolt heated sock system is modular, improvements
in technology can be incorporated as they become available. You
won't have to scrap your complete sock system to upgrade.