When not in use this Duracell rechargeable size D battery will withhold its energy for up to one year went in use after recharge. This will allow you to recharge your battery when it is convenient and store it away, knowing it is ready to use when you need it. Powering any energy draining devices that are used on a daily basis his Duracell rechargeable size D battery is a useful item to have in the household or the workplace. Rather than replacing the cell when the power runs out, you can take the environmentally friendly option of simply recharging it. You will be able to do that up to 300 times before having to replace it.