CHICAGO (CBS) — It’s a safe place to charge your cellphone while you’re out.

At a bar with friends after a Michigan State – Ohio State football game, Dave Adams noticed all their cell phones were nearly dead.

That’s when inspiration struck.

Adams and a friend sketched out on a napkin an idea for what would become SafeCharge, essentially a locker for your phone, with battery chargers to accommodate any phone made in the last 16 years.

Customers navigate a touch screen, swipe a credit card, and one of six charging station doors pops open.

It’s about the price of a beer.

SafeCharge started in a Lincoln Park bar that Adams and co-founder Doug Charron used to live above; and has spread to 50 locations in Chicago, a few suburbs, Florida, Texas and Michigan.

They’re considering expanding to malls, casinos, convention sites and stadiums.