In the Options menu there is a setting 36/48V
You can test by making a "shortcut" from the 48volt battery take 18cells.
Then go to the options menu and set it to 36, see what happens.
Maybe you have to adjust the setting for the battery charge indicator, but thats in the Options menu too.
This is ONLY to be used to report flooding, spam, advertising and problematic (harassing, abusive or crude) posts.