Edison Alkaline Batteries

I have a set of Edison Alkaline batteries that need the electrolyte replaced. I have an old electrical engineers reference book that states the electrolyte is a 20% solution of Potassium Hydroxide (KOH) with a little Lithium Hydroxide (LiOH). Does anyone know if the 20% solution is by weight or some other measurement? It has been a while since I took a chemistry class.

It took a bit of digging, but according to International Textbook's 1939 book on batterys, the Edison Nickel Iron battery was supposed to be filled only with solution available from the Edison Factory. You have the chemicals correct, but nothing I have indicated the percentages, either by weight or volume. The best I can do is suggest you experiment with a hydrometer. According to the book, specific gravity of the solution in discharge condition should be 1.160 at 60 degrees farenheight. A fully charged cell should have a specific gravity of 1.230. The information is somewhat confusing as it also says the solution should be renewed if it drops to 1.160.