5700mAH Petzl Nao+ battery pack for $20


New member
May 9, 2021
Recently I had a long running event where I needed all-night capacity in my headlamps. My trusty old Ay-Ups are packing it in, I only had one battery for my Petzl Nao+, and Petzl replacement battery packs are stupidly overpriced.

After reading the excellent work by Szemhazai and the threads about modding Nao packs, I was going buy some 18650s, a charger, and molex connectors etc. But there's an easier way - just use a USB power bank.

The fancy Petzl socket takes power from the battery pack on the two black connectors. Looking at it with the white connectors on top, the bottom right is positive.


I wanted to be able to still use the original battery pack, so I fashioned a plug using four breadboard pins (2 male, 2 female). The two female plugs face the white terminals and ensure I don't hook it up in reverse.

An outer sleeve of PVC tape and some hot glue make for a weather resistant connection.

The wires from the fabricated plug are soldered to the +5V and ground wires of a USB cable, and covered in heatshrink (for now).

I plug the USB into a small powerbank in my running pack and I have a very cheap 5700mAH battery pack that has a built in power meter and can be charged without a lipo charger. All night on high brightness for $20 and a couple of bits and pieces.

* A note on power banks. If you want to run the headlamp on low power, you need a powerbank with an "always on" setting. Most will turn off if after 15minutes if they don' have a sufficient drain on them.