A123's are better packs than Ping and YESA. Lots of folks swear by the Ping packs, but they are not hauling the heavy loads I do. A recent trip to the lumber yard came in at a total (trike w/motor, batts, me, trailer, solar and 120# of Sacrete) weight of 520#. Sure, I coulda geared down and crawled home at 8 mph or so, or I could pedal hard and use 40wh/mile to achieve a safe speed in traffic, on a cold day with the sla sagging from the cold. Throttles are fine things, in my book!

I wish I had the knowhow to make my own battery packs, but my background is special education, with minors in sportscar racing, martial arts and recumbent trike riding, not EE! Maybe some day soon I'll start to experiment and try to teach this 60 y/o dog a new trick. Until then, it's gotta be storebought for me.