Here's my suggestion: https://www.paulcbuff.com/Portable-P...i-Lithium.html

I'm not sure about the minimum requirements needed to run your strobe, but I'm 95% sure the one linked above will do it. I have 3 of the older Vagabond II's that I use with studio lights up to a White Lightning x3200, which to my understanding, has a similar power requirement as your Godox300SDI.