you can wire them for 24volt .
i have never done it . the regulator i use can take 24v . but as i have never needed to try it i really cant help you on the 24v side
mine is pos&neg off 24v to the 24v side of the split charger then a 12v pos & neg off it to a 12v
battery on my truck . i then take a pos lead to a connector on the trailer . the 12v neg goes to earth (vehicle).i pick it up again through the fifth wheel hitch.
for yours the 12v side could go to your leisure batteries wired 12v .
i used to use a 2kw
inverter but now use two 1kw inverters as and when .
1 works my 240v fridge on board . plus other items .
if i want to use washing machine i use the second
inverter.
i stopped using a three way fridge years ago . never used ehu. found they use a fair bit of gas . and once i had
solar 240v fridges are cheap. been using
solar on the trailer 13yrs now . works for me . but i do go away for 5-6months a time in winter.
in summer i power fridge and freezer in the house off one
inverter in the trailer . saves a shilling . only changed the batteries once . so its not expensive .