Upvote:2
The heaviest example I could find was this outfit, which according to the photographer was on display at the Zwinger museum in Dresden back in 2005. He said it was displayed as "16th or 17th century". The museum in question probably has some info on its weight.
However, from everything I could gather, this level of barding was uncommon by the 16th Century. Protective barding seems to have primarily been a reaction to the longbow, as bowmen at battles like Crecy and Agincourt found they were able to defeat heavy cavalry by targeting their horses.
The Longbow was on the way out as an army's principle weapon by the beginning of the 16th Century, replaced by firearms. For whatever reason (I suspect lack of effectiveness against firearms) I cease to be able to find a lot of images of heavily barded horses after this point.
This nifty page on the various types of barding is a good illustration of the point. All of the examples shown of full coverage barding are from the 14th century.