Ryobi 40V battery to 12 volt Transformer
I have a Ryobi Electric Lawnmower that uses 40V batteries. I have three of these batteries and I have found a way to extract 12VDC from them.
A web search turned up a dock for the battery.
https://www.amazon.com/gp/product/B07J17Z42R/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
A Buck Converter solved the problem of reducing the voltage. I opted for the 20 amp version. https://www.amazon.com/gp/product/B0953ZQQ5Q/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1
I wanted both USB output and 12V output and this handled the USB end of it. I used a 3D printed receptacle for the PowerPole output.
https://www.amazon.com/gp/product/B091CZ25TR/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1
I purchased a toolbox at Lowes Hardware and put the system together.
The battery dock on the bottom board is placed so that the board can be tipped up to install the battery. When the dock is lowered into position the back side of the battery bears against the inside end of the toolbox which secures it nicely. Please note the notch on the end of the board - it allows access to the battery release latch.