PhysOrg.com reprints a press-release from Texas Instruments about their new "Impedance Track" technology, which they claim provides a 99% accurate measurement of battery capacity. It's not widely known that the battery gauge on electronic devices is actually a crude estimate based on use, not a real measurement of remaining charge. This is why laptops and cameras and such will occasionally go from "half-full" to empty -- the estimate didn't match the reality. This can also happen with bigger batteries, such as those in hybrids (a hybrid mailing list I'm on is currently discussing this rare but not-unknown problem). It can also result in devices shutting down because the gauge has calculated the battery is near-empty, even when it's not.
The TI technology, which works with LI, NiCD, and NiMH battery systems, is able to measure precise charge levels, and can even take battery degradation into account when making charge-remaining estimates. Given the increased reliance on rechargeable battery packs, a technology to make these devices more reliable is welcome indeed.