Monitor Issue

I have a 2013 MacBook Pro with Retina Display, 4GB DDR3RAM, 128GB PCIe-based flash storage, 2.4GHz Intel Core i5, and the Intel Iris 1536 MB Graphics card. I plugged in two Acer H226HQL Displays using two Mini DisplayPort to VGA adapters. If my MacBook is charging I can usually just close the lid and the display will still show up on my two monitors. Whenever I take it off of the charger, the monitors just go to a black screen and I usually end up having to open the lid slightly to use my monitors. This is very annoying and inconvenient. Any thoughts, solutions, or suggestions? Plz tell me in the comments.