[Gen3piglet]

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?

That vest is the incorrect voltage to plug directly into a 12v system. If you want to plug into the bikes electrical supply, you need to get a 12v rated vest, or any other heated gear. You can charge the battery from the bike with the appropriate adapter, but that's it. I use an Iurek zd920 vest by supplied battery pack. Lasts almost 9hrs on a full charge on low. That's plenty of heat under a lined windproof shell(leather). I run my heated gloves via a temp troller hard wired to the battery with an in line fuse. No fear of overwhelming the electrical system like that. But you CAN get a dual zone controller (2 heated gear items at once) provided you do your research of amp/watts draw vs available amp/watts. output.

 

[Gen3piglet]

thanks for the responses. since this is a relatively low powered vest i was hoping you all had a trick to run it off the dashboard power. i'll abandon this project and just use the battery for now and get a more powerful vest next winter!

That vest you now have should work fine as intended by the included battery supply. There is a "hybrid" type of heated gear available that allows the option to either work off of a 12v battery pack (not 5v !) or attach to a wiring harness that draws from the bikes 12v system. Unfortunately, when an attempt is made to power a 5v, 7v, etc..product off of a 12v system, it won't work. Even if you have a device to make the physical wire connections. Independent battery pack powered devices work well, but with limitations.