I don’t have what you are asking for. Are you looking specifically for a battery holder which attaches to the head/helmet with a strap?
In the meantime:
- Have you seen this 2s2p holder? Hooray! New Solarstorm BC-2 4x18650 battery (2S2P) case for bike lamps
- For 1s applications you can take a 1x18650 tube light host with a contact board in place of a driver and just bring wires out the front of the light. There are also a variety of holders available for securing tube lights.