I'm not saying law enforcement never does it, but that sounds like a very bad idea. Your power bank will be out of phase with the grid, and both will be feeding

I'm not saying law enforcement never does it, but that sounds like a very bad idea. Your power bank will be out of phase with the grid, and both will be feeding into eachother, which can cause all sorts of problems if I recall my classes properly. There's a device for doing that properly that automatically detects the appropriate moment for changeover and does it near instantly. It's still quite dangerous. https://wiebetech.com/products/hotplug-field-kit/ https://wiebetech.com/products/hotplug-field-kit/