For long term storage, which is any duration of time greater than three months, the battery should be:   Stored at a temperature above -20C/-4F but below 20C/68F. Stored in a dry location with a relative humidity below 70%. Stored with a 30-40% charge. PowerAway P8: the charging time to get to 30% when the battery is depleted is 2 hours.  PowerAway P10: Charge until two LED indicators are lit Micro PowerAway: Charge until shortly after one LED indicator is lit