I very much doubt it.. Thats the same power and battery that is in an 18 hole golf battery so it would power my trolley for 18 holes... I doubt that would run 2 pumps all day.
Obviously you don't know what you're talking about-these batteries are very well made you need to do a bit of research and yes it could run to pumps 
Yep, they are very well made and very lightweight - - I use them myself, but not for window cleaning. For window cleaning there are alternatives that are a fraction of the price & work just as good!
Its also worth noting that all my lipo batteries are stored in a fireproof box and charged in another fireproof vessel,.. there have been numerous cases of spontaneous combustion of this type of cell (even with top quality, brand name ones) especially if they're handled roughly, so I really wouldn't consider them suitable for the average window cleaner...