I went the same route, but with a 200w ISDT discharger. My laziness too got the best of me, and I'm a sucker for bluetooth features. This is where I like it, being able to set the voltage cutoff- so I discharge to a hair below storage. Then let it settle and, finally a storage charge.I was originally going to build something myself. But then I noticed that, in terms of material cost, I couldn't beat a 30€ ISDT Discharger. So my laziness won and I just bought that
Plus it's handy that it stops roughly at storage voltage.
Can't nearly do 300W of course! But it's sufficient for me.
@fpvmiller do you have a photo of the discharger? it must be pretty cool looking.