four batteries in parallel (with average voltage of 14.8V and 1020 mah)
I guess what I'm basically trying to find out is whether there is a difference in efficiency in the Uno's step-down regulator, going from 14.8V down to 5V or from 7.4V to 5V.
Thanks a lot for the advice. I have put two li-ion's in series, will also look for a better battery pack.Lefty, I had another question specifically for you - because I'm using lithium I want to be very careful with over-discharging, so I want to have an auto-shutdown mechanism when the battery level gets too low. I think a relay would work well for that. I noticed that you wrote about this in an older thread: http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1232478475. Unfortunately the ebay-link does not exist anymore. Would you know of any other seller that sells a simple and small (single coil) latching relay? I can only seem to find relays that are meant for switching main ac currents, which are quite bulky. Thanks!