absolutly 
I am currently thinking about it but I have not found an easy solution yet but to have a button inside to visualize current voltage each time I go & get my mails, with a physical switch on second battery & recharge it for next time
absolutly I am currently thinking about it but I have not found an easy solution yet but to have a button inside to visualize current voltage each time I go & get my mails, with a physical switch on second battery & recharge it for next time