On 6 Nov 2016 at 22:31, Chris McSweeny wrote: > It's not that that's the issue. This is for an external battery fo= r > something which also has an internal battery. When the external battery i= s > unplugged it will switch to the internal battery, but apparently that's n= ot > happening when the external battery is left plugged in but runs flat. Typically (but I appreciate this could be inappropriate for any number of r= easons)=20 one might include diodes so the battery with the highest voltage supplies p= ower.=20 Seamless switch-over when either battery goes flat. --=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 .