@Juergen_Bruegl Thanks and very detailed - clearly the real electrical engineer of the group 
Thanks for sharing and I’ll read through your linked wiki today!
@Leon_Yuhanov - I know it buddy - small world Say hi to a kangaroo for me
@Gibbedy_G - YES - 3.7v lipos work just fine, and I’ve started playing around using drone batteries for some smaller projects. They’re cheap and have great power density.
However, my main problem is only for really big projects - more than 1000 pixels or so. For big stuff, a single lipo cell can’t sustain the current output without running into explosion problems, or at the very least the capacities of the inexpensive ones aren’t enough to last through a night out
Just following up with everyone who was so helpful on this thread…
So I’ve had my 1500 pixel vest operational for about 2 weeks now, and I haven’t run into the problem with tripping my power supply that I had with my playa coat from last year (coat had 1300 pixels)
So my current theory is that @Leon_Yuhanov hit the nail on the head and the flash on startup probably comes from inferior manufacturing. The strips that I used on the coat last year might just be crappier than the ones I’m getting from aliexpress now.
I still get a few pixels flashing white for a split second on startup with the vest, but it must be a very small percentage of them, so it isn’t actually causing me any problems!
Thanks again everyone