Hi Bill, It DOES vary significantly among different technologies. It varies less from vendor to vendor or implementation to implementation but can still be significant. However, as a general rule of thumb, Lithium rechargeable batteries are better than 80% efficient. Lead acid varies more but is about 70% efficient and gets worse over the service life of the battery. For Lithium, basically all of the inefficiency is due to charging voltage being slightly higher than discharge voltage. For lead acid, this is still true, BUT it is also true that you don't even get out as many amp-hours on discharge as you put in during charge, especially when you fully charge the battery or when it is aged. I'm not as familiar with NiCd or NiMH but my understanding is that they fall in-between Lead Acid and Lithium in terms of efficiency. Sean On Fri, Apr 29, 2011 at 2:17 PM, William "Chops" Westfield wrote: > > On Apr 29, 2011, at 9:22 AM, Dwayne Reid wrote: > >> My preferred battery technology is still Lead-Acid. > > Does charging efficiency vary a great deal between different battery > technologies? > Different implementations/vendors within a technology? > > BillW > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .