I received my Torq w/ lithium battery on Sept 8, 2006. I have since ridden 1300 miles on almost completely flat ground, The W&OD trail in Virginia, USA. My first battery reached 50% capacity (9.2 miles @ 20m.p.h average w/ peddling) within the first 6 months. After a winter break, I tried getting the battery replaced. The second lithium battery failed within the first week (turned out to be battery terminal screws), but then after service from
Electric Bikes | Folding Bicycles | Powered motor kits | Scooters (New York), the battery reached 50% within 6 months and was out of warranty. I am now in the process of deciding between the "new and improved" lithium with fewer cut-outs, or the tried and true NiMH. I'm 90% certain that I will buy the NiMH, because research has shown that the LiMn batteries lose ~30% of their capacity every year and that they suffer when used to depletion (as I was doing every day).
The 2006 Li-ion batteries were useless, I went through three, two in six months, and one bought at the end of the year in 10 months. The current Li-ion batteries are better and have had their cut-out point altered, but they are still unlikely to last as long as a good NiMh.
However, things haven't been standing still and are still moving on, and the theoretical 30% per annum drop in capacity isn't appearing on the best quality Li-ion batteries that are supplied with the Panasonic motored bike or the BionX motor. Indeed, Panasonic are happy to give a two year warranty on their battery, and some users of the BionX are reporting little loss of capacity at two years.
Those two batteries are expensive though, at about £150 per 12 volts @ 10Ah in the UK, while the eZee ones have been about £83 per 12 volt at 10Ah, little over half the price. The moral is obvious.
Research and manufacturing is improving matters though, and there will be better performances and life from e-bike Li-ions before too long, and the progress will be continuous. I'm currently a confirmed NiMh user, one of the first to turn back to them from 2006 on, and I have three NiMh batteries for my two bikes, but I'm confident that I will be using only Li-ion before this year is out.
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