Even after 6 months of non-use, a fully charged CTECHi power station will store more than 50% of the charge. However, we recommend you charge the device every three months, even if it is not being used, to ensure the power station lasts you for an extended period. In case of a fully discharged product, you must charge it using the AC adapter. If you still haven't found a satisfactory answer, you can submit your queries directly on the product page, drop us an email at Service@ctechipower.com or directly send us a message, and we will get back to you as soon as possible, and we'll be glad to guide you further.