The lithium battery could be dangerous. Here you have an example for it.
The battery of a cargobike in Hamburg, Germany have been exploded. Here you have a short video of it.
The bike was equipped with a refurbishing electric bike kit with a battery of 25Ah. We don’t know yet, why this battery got fire.
The rider was not harmed.
Yeah, we all know that the Li-battery could be dangerous, and this is probably one fall from 10-millions… Be very careful when you build your own ebike pack.