All this talk of solid state inverters sometimes not being quite right for some battery chargers, got me thinking about a device I saw 20-30 years ago.
At a construction equippment shop, they had a little motor-generator unit that had a 12VDC motor and a 120VAC generator combined in the same case. I seem to remember it being about 5 inch diameter and 2 ft long, DC stud terminals at one end and a 120V duplex at the other end. A yellow tube laying on it's side on 4 little legs.
The thing being a generator, should have produced "real" sine wave power ? I don't know if the thing had any sort of speed contro; on the DC motor to try to maintain correct 60 cycle speed.
A quick Google search does not show anything like that avalible now. Anyone know if they are still being made ??