steve writes:

http://www.shyding.blogspot.com

Interesting. Nice quacky responses, all the way from vague to incredible.
Read that "25 year" claim carefully, and see if you can spot the
backhandedness that makes it meaningless, the antithesis of a direct,
engineering type of answer.

You should ask Henderson how many BTUs (or the metric equivalent) you get
pumped for your amp-hours of "current".