I've taken a photo and will put it up, but I think the one I am concerned about is the multiple bars, like a cellphone signal strength next to a battery. I suspect it is battery charge level.
Would be handy to know what model the unit is though as the GG manual is very basic with the functions of the unit.
Also, on the manual, is anything other than add fuel "refer to qualified service personnel"? Seems like a lot of information not available officially.