Which engine should I use to see what the charge level is on the battery?

A tutorial on techbase said soliddevice, however when I open it in plasmaengineexplorer, there are no data sources.

I'm trying to write a javascript plasmoid that uses the information.

BTW. is there actually something thats called api.kde.org? I've been trying to go into it for a week, but it's always down.

api.kde.org is hosted on the same machine as the EBN which is currently undergoing maintenance.

The "powermanagement" data engine should be able to provide the desired information.