> This growth forced the creator to build a separate warehouse, located about 50 meters from his home, to store the batteries and the new charge controllers and inverters.
The hazard appears to be accounted for.
Yeah wind has never been known to blow fires 50 meters.
How do you know the prevailing wind direction in his location?
How do you know that a favorable wind direction will eliminate the risk of a fire hazard?
How do you know it won't?
How do you guys know if the batteries will catch fire at all? Maybe the guy is lucky and for the next 50 years they won't?
Random lithium battery fires are extremely rare. It's like people freaking out about serial killers. It's something that definitely happens, definitely catches the news, and definitely is unlikely to happen to you even in 10,000 lifetimes.
The infamous Samsung note 7 exploding battery catastrophe was 90 incidents out of 2.5 million phones, or 0.003% exploding.
My home was burned to the ground by a fire started by a charging electric skateboard. Well engineered battery systems, like an EV or a name-brand phone, are very safe, but these NMC cells are extremely volatile, and large packs cannot be extinguished once in runaway. I'm very glad the OP has this setup in a separate shed.
I think it's a stretch to compare the battery in a phone to the hand-wired collection of lithium batteries from various laptops. Even if the odds are still low, the calculus works out to be concerning when it's your home and livelihood.