The only failing, so far, with these redox electrolyte batteries seems to be the cost of replacement membranes and, historically, requiring membrane changes far too frequently. Perhaps this development has improved this aspect of the technology?
That's what I'm wondering, and basically what the developers are claiming as they suggest less maintenance costs. I think $500 is a bit rich for me as a donation to help something that might of course fail. It's an OK investment amount, but I think it's better to look at this as a donation to help push tech advantages, and I'm not feeling nor capable of $500 of generosity.
But ..... if they do get the cost down to 2c/kWh cycle, then that would be interesting, but with flow batts costing a lot initially, and this one having 25kWh (domestic) it might be a bit too big and expensive for me, but certainly something to watch.