My solution was a little different. I use the "Accessory Socket" with a dual USB outlet for Phone and GoPro. For other misc charging and battery maintainer I did the following with the worthless toolbox. Got the idea for the USB and SAE from someone on the user group, but added an illuminated switch on the left so I could switch the additional USB off (Switch does not show on this picture as it was added later). Both are hooked through an Eastern Beaver unswitched circuit so that I can charge a headset or something else while stopped for lunch.
GL1800A, KLR 650, ATAS, 1972 CT2 Cessna Skylane
Fly low, fly high, but fly!