I've been using the Sony Li-ion batteries for a couple of weeks, and have been disappointed with their capacity. Generally, its been 60% - 70% of what I expected. But I think I've found a potential problem with Lithium Ion batteries. I went out browsing for more info and found a page that compares battery capacity to discharge rate: http://www.pcim.com/arc/art0006/freeman1.htm My wearable now uses 5-6 watts per hour and at that rate I am drawing 1-1.5amps from a single Li-ion battery (I've been only using one so far). Based on the graph in the above page, @1.5A the Li-ions have only about 85% of the capacity they are rated at. Compounded with the fact that I found out the DC-DC isolator I have been using from Datel is only 75% efficient gives me roughly 13.5 watts from a 21watt battery. :-\ I think the way to fix this is to switch to a DC-DC converter with 14v (2 Li-ion in series) battery side and get a more efficent converter. This will reduce the current from 1.5A to 0.75A which raises the capacity of the batteries from 85% to 95%, and Datel has a new DC-DC converter that is >90% efficient (although I'm still waiting for someone to call me back about availability and pricing). Also, I have been surpised by the wide range of voltages these Li-ions run at. They start fully charged around 8.5V and slowly drop to 6V, which makes managing power a little crazy. -Paul -- R. Paul McCarty / DARS Coordinator // x52059 317 Lattimore Hall, University of Rochester, Rochester, NY 14627 Computers don't make mistakes;what they do,they do on purpose.-Dale/KOTH
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