Inverter for 18V Lithium Power Tool Batteries

Im looking to get an inverter that I can hook up my Lithium power tool batteries too. I currently have a bunch of 4ah 18V batteries and a 4ah 56V battery pack.

Having looked at the 48VDC inverters, most of these say the maximum supply voltage is actually 60VDC.

So my question is, what happens when you hook up 60V’s Will it overheat if that’s what is constantly supplied? Will it just waste the extra voltage meaning it will operate in effect the same as if I connected 4ah 48V cells? Or is it just that it will take the 60VDC and convert all of it to 240v AC (im in NZ)?

So say this inverter " KRXNY 1000W Pure Sine Wave Power Inverter 48V DC" from amazon (just one I found on Amazon, gives max input voltage of 58Vdc, but some are up to 60Vdc and I realise I would need a 240v output version)