What mobile PC battery had the longest-term production?

[automobus]

What mobile PC, past or present, has the longest-term support for the battery (replacement, availability)?
Or, What mobile PC batteries were produced for the longest time?

Nowadays, most batteries are of a proprietary, closed design. Even when one owns the battery (the material thing), the battery might not fully belong to em. Physical detail is not the problem. One can crack-cut a battery open without technical drawings. The cells usually are a standard variety; the wires are short, but they can be worked with. The secrets are in the electronics. More troubling than one-shot fuses, are authentication chips. Like a ThinkPad, its companion battery has "COPYRIGHTED CODE AND PARTS CONTAINED HEREIN.". This is the problem.

I love Nokia, if only because they still produce batteries for many (if not most?) of their old cellular telephones.
I love that the good camera companies still produce batteries for cameras more than ten years old.

I love how older laptops used "dumb" NiMH batteries: today, they can be replaced with L.S.D. (low self discharge) AA-cells. The dumb LiONs can also be recelled, not with off-the-shelf consumer cells.



Battery availability is naturally higher for the big three brands' business laptops than consumer lines. That is true for most all parts. Bonus points to those big brands, for providing maintenance manuals. But their batteries are not available forever. I think ThinkPad RTZ60 battery is a candidate for "longest available laptop battery", since it was reused in the 400/500 line. Also considerable, T20 in 2000 through T30 in 2003: that is four years as "the current model".



Not all mobile PCs are laptops. What I currently hold as the winner, is Motion Computing's 5-series slate tablet PC. Motion's C5 arrived in 2007. Motion's 2012 C5t and F5t were introduced four days ago. That makes five (and counting) whole years during which the batteries are produced, and forecasts at least two more years of full production. C5's warranty duration is up to four years—even if the series is discontinued, new batteries might be produced in smaller batches to provide for those with support agreements.



In this discussion, "personal computer" means something featureful or expandable. A budget PDA which has no I/O, but does use plain AAA cells, does not count. I would like this discussion to be very inclusive. Some graphing calculators are very programmable, have a serial port, and use plain AAA cells. Therefore, you may mention them. Anything from palmtop to nineteen-inch desktop replacement is welcome. Please do mention lovely machines like ThinkPad 701C, which can be upgraded with modern AA cells.