I noticed it was kind of discharging too fast, I have a device that runs on 350 - 370W and it was showing me that it could power it only for 5.5 hours at that load but 5.5 x 370W = 2035 Wh, which is only 56.53% of the total capacity 3600 Wh. But to my calculation 350 - 370 W / 3600 Wh should be around 9 - 10 hours. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.