If your using A123 cells then here is some useful info from Hangtimes<font size="3"><font face="Arial"><span style="color: black"><span style="color: black">http://hangtimes.com/a123_batteries_for_giants_faq.html


Here's an area where A123's are radically different than Nicad or NiMH packs...L</span>oad TestingA123's in the traditional way is ineffective for determining state of charge...the beasties just don&rsquo;t 'react' like we expect.. a 1 amp load for 10 seconds will convince somebody not familiar with them that there&rsquo;s something wrong with the load tester or the pack.. the needle starts to sag after a few seconds with some meters, (resistor impedance valuesjump up rapidly under the continuousload) anddecreasing voltage displayed on the meter usually indicates approaching doom for the resistors, switch &amp; connectors rather than reflecting any useful info on the state of charge for the pack. Continued loading can melt out connectors, meter resistors, switches, etc. ESV 'loading' just doesn't work with A123's in thetried and true sense as the cells are quite happy delivering enough amperage to melt out your gear, even when nearly discharged.Because of the incredibly flat discharge curve and the ability of the cell to deliver massive amounts of current, using a standing voltage level under load to decide when to recharge can lead to a disaster via damage to switches &amp; connectors... Further, when A123's DO go flat, they do so remarkably fast. So, we go to the next question..</span></font></font>