Nothing to see here. Move along please.

Commenting on a Google Buzz post about boiled potato batteries for emerging nations, a friend related how impressed he was with his electrical drill battery pack. Being the type I am, I replied enthusiastically with the following …

That will be the ‘A123′ branded (inside the pack) Lithium Iron Phosphate (LiFePO4) tech, heavily used by Dewalt. I have two 4-packs of those. Each cell have a nominal voltage of 3.3V and capacity of 2300mAh.

Far as I know, A123 were the first to use nano-laser techniques to make the substrate for the chemicals to rest in. They still hold tight to their patent, so I don’t think anyone else is doing it exactly that way yet. (A123′s primary target market is electrical vehicles.)

But there’s a whole new generation beyond that now, back into the lighter weight, more power for size/weight Lithium Polymer stuff. These are known as the ‘Generation-3 Li-Polys’ or simply ‘G3 packs’.

Lithium polymer cells typically do not have a (heavy) hard outer casing like the A123 cells. They are also rectangular so as not to ‘waste’ so much space, and have a nominal cell voltage of 3.7V vs. 3.3V. In the past, the G2′s and prior could not handle the type of charge current the A123′s could (by far) and had a much shorter cycle life. But that gap has really been narrowed won now with the G3 tech. The new G3 packs are very, very cool — especially when combined with 3-phase electric motors with total efficiency (including controller electronics) approaching 90% in some cases!

My Align(tm) T-Rex 500 Helicopter runs on a G3 2600mAh 22.2V pack (6-cell or ’6S’ as they’re known). It puts out about 300 Watts of mechanical power during average aerobatic flying manoeuvres, peaking almost a 500 Watts when pushed hard (at about 75% electrical efficiency if I recall correctly). Flight times are about 5 minutes — and that’s more than enough for my nervous system I can can assure you!

A similar version to what I have. It’s a very fun machine. But I’d just *love*
to have a T-Rex 700E! I’ve seen the 600′s fly and they’re so amazingly
stable and ‘floaty’. The 700 must be awesome.