I recently saw a product designed for DSLR
If you have a battery grip, the original battery fits inside it.it has a tray wherein you can put either an original battery or 6 AA battery
But this product removes the tray altogether and is one big battery.the whole cavity inside is replaced by one big battery.itis also designed to be charged directly with an ac charger.so i theory, you can directly plug your camera to an ac outlet
I saw that it is available for NIkon d3100 and d7000
I forgot the product name
My question is what do you call it and where can i buy it?
См. статью: What is this DSLR Battery grip product called?