I charged it to 100% and put it in the trunk of my car. And there it sat for 10 months (verified order date). I come out to a dead car battery yesterday. I pull out this jump starter, connect it, flip the switch to on and it shows 100%. Nice. Per instructions, I hold the button on the clamps and the LED goes to green. Ready to start. Wait... it just changed to 30% battery. Damn. Well let's see if it can start my 2013 4 cylinder Ford Focus. Nope. Not even close. And now it shows 6%. Damn it. So lesson learned to ensure this jump start battery is routinely brought inside and recharged. I get it. My fault. But at the same time, the self-discharge rate of Li-ion is 2-3% per month. I lost 70+% in 10 months. Cap that off with the normal use/storage of a device like this. To require someone to remember to pull this from the trunk and recharge every 3 months is excessive. This sits in the trunk and gets forgotten about until that one rare day when you need it. So if it has higher than normal self-discharge, that indicates poor quality Li-ion cells and is NOT conducive to a product like this. It has an on/off switch, so parasitic draw from its electronics over time should not be an issue. I'll recharge it, keep it recharged, and continue to carry it. If I successfully jump a car with it, I promise to update my review from 3 stars. EDIT: So I have since successfully jumped someone else's car with this pack, twice. I have been remembering to bring it inside and recharge it every few months. So when I needed it a 2nd time, it worked twice. It jumped a 6-cylinder Altima twice and showed about 55% battery left. I'm increasing my rating to 4-stars.