It is a yellow lamp, that looks like a battery with a ripple of liquid in it. Couldn't find the same icon on the internet, looking at the owner's manual, and has all the lights listed, but skips the location of where this lamp appears just to the right of the glow plug lamp. Also, the shop manual has no mention of this lamp either.
Here is a picture, look just below the 6 of the tach.

It's a Delica GLX 1997 pre-facelift
Does anyone know what this is for?