This 21 page pdf paper written from an R/C flight powering perspective discusses the derivation of formulae for calculating the Internal Resistance, Max Current Draw and true C Rating of LiPo batteries. The maximum discharge ratings are based on claims that LiPo thermal damage during discharge can be kept to an acceptable level if internal battery power dissipation is kept below 6 Watts per Ampere-hour of capacity. While the assumptions behind that blanket figure would need to be examined on a case by case basis when high discharge and long [tm] life of LiPo cells is required the figure, and this paper do provide a useful starting point and possibly as good a one as any available. (That justifies the "utterly superb" rating, I think :-) ). http://www.maac.ca/docs/2013/lipo_batteriesinternal_resistance_max_current_= draw_true_crating__rev3_toc.pdf Russell Basis of system - page 5. Does it work? / Is it any good? TBD --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .