Dynamote was a company that Vanner inc purchased around 2000 i would pretend.
They were building industrial power inverter intended to be used in service trucks. I had found one in an old fire truck of the 80’s.
Here is the user and service manual for those old power inverters that i would pretend could still be great these days.
This manual is copyrighted 1994 from Dynamote so yes, inverters last from long time ago.
Hope this helped out.