At this year’s MobileCon, a mobile commerce panel wondered what was holding back widespread adoption of the mobile wallet.

The minds of Verizon CEO Dan Mead, Isis CEO Michael Abbott, Jamba Juice CEO James White and American Express Group President for Enterprise Growth Dan Schulman set to the task. In search of the answer, the group noted that the smartphone had effectively taken over for many other aspects of personal life (i.e. calendar, address book). Why not the wallet?

The simple answer is that if the phone takes over for the wallet, there’ll be almost no jobs left for our back pockets. But the real answer is that a wallet—or more generally, access to money—is too vital to be tethered to the ticking time bomb of a smartphone battery.

Even without adding the stress of keeping your phone alive so as to not cut off access to your bank account, smartphone battery management is still harrowing. Just when you think you’ve got a handle on the correlation between your normal usage and its drain on your device, you’re at 15 percent without a charger in sight.

If your phone runs out of juice, you can live without your address book. But if the same fate befell your pocket book, the consequences could range from seriously inconvenient to catastrophic.

As CNET concluded, even a phablet like the Galaxy Note 3 with a healthy battery might still only get you 15 hours of charge, leaving lots of opportunity to run out of life through the course of day.

The threat of battery death doesn’t just hang over the NFC-enabled ISIS mobile wallet the MobileCon panel was discussing. It affects Bluetooth Low Energy, geo-fencing, QR, biometrics or any other potential mobile payment technology.

Mobile payments will inevitably gain more traction with consumers, merchants and retailers as the technology becomes more widely distributed. If one technology eventually prevails in the market, that would be even better for adoption. But the likelihood of a connected device fully replacing our wallets is about zero until battery life turns into afterthought for smartphone users.