[Timlang60]

In theory it should work. Your plug adapter has a max output of 36 watts, the battery pack maxes out at 22.5. The wildcard is not knowing what the vest input requirements are. If it requires 9v, you're adapter may be a little shy - it provides a max of 2 amps, the battery pack provides 2.22 amps. Is there a tag anywhere on the vest that lists technical details?

 

[Timlang60]

That vest is the incorrect voltage to plug directly into a 12v system.

Based on his picture of a USB lighter outlet converter and the question asking why it wouldnt run off that, I assumed that was what he was trying to do.

 

[Timlang60]

There you go - I knew if it was running off a USB port on a Li battery pack, it was running on USB power, and should be able to run off an adapter. Now I know why it wouldn't run off that particular adapter.