External battery for Aquatica housing Sony a7r II

Has anybody used an external battery inside an Aquatica housing for Sony a7R II. I've never had an issue with battery life while using wide angle lens but recently I started using a Macro lens (90mm) and all the focusing seems to drain the battery quicker. I now that Nauticam sells an external battery, but I'm using a flash trigger therefore I'm unable to use it. The housing seems to have some available spaces. I was looking into this battery BigBlue Power Bank With Built-in Lightning Cable (https://smile.amazon.com/dp/B01NAQQTA9/ref=psdc_7073960011_t3_B01KUVLMPK).

Any experiences or suggestions?

Hello, in the next few weeks engineering will be working on adapting an external battery that can be installed on the inside of our A7rII housing.

Hello, in the next few weeks engineering will be working on adapting an external battery that can be installed on the inside of our A7rII housing.

So I bought an "ultra-thin" external battery with the following dimensions 3.7”x2.4”x0.2”in). Unfortunately it didn't fit. I'll be waiting for Aquatica's battery now or some other ideas.

Hello, in the next few weeks engineering will be working on adapting an external battery that can be installed on the inside of our A7rII housing.

Very interested in this! Thanks, John

Have you looked at this battery pack, http://reefphoto.com/shop/index.php?main_page=advanced_search_result&search_in_description=0&keyword=a6500+battery+pack

I can't find the dimensions anywhere.

Hello, in the next few weeks engineering will be working on adapting an external battery that can be installed on the inside of our A7rII housing.

Is the project still ongoing?