Only kind of. Zcell costs about 4x a Powerwall of the same capacity ($13k USD vs. $3500 USD) and has the same warranty duration (10 years), which to me means t

Only kind of. Zcell costs about 4x a Powerwall of the same capacity ($13k USD vs. $3500 USD) and has the same warranty duration (10 years), which to me means they're expecting it to last about the same amount of time in normal use. It's a decent alternative if you don't want Li-ion for some reason, but definitely not a good solution cost-wise in the home storage space. As others have pointed out, the benefit of flow batteries is that you can scale the tanks very large to add capacity without raising the cost too much, whereas Li-ion type batteries scale cost with capacity fairly linearly.