Second follow-up to HC battery storage test. My railroad has been untouched for almost a year. Sad I know. Today, while doing some testing for Tim (G8B4Life) I turned on the HC for the first time since Nov 11, 2017 - six months and three days since the last charging. The red charge bar was flashing but it still turned on. The layout room is 65F - 70F degrees. Safe to say a fully charged HC can be stored for 6 months but not very much longer.