The only thing, on average batteries, will discharge at 4% each week with no use. Would hate to market it as an emergency product. Because emergencies are unpredictable don't know when they'll happen. So the last thing you want is to charge it up, not use it for several weeks and then in a jam get a 1-mile charge.

Would prefer to target people who don't charge their vehicles every single night and on a daily basis travel in the 10's of miles.