These aux charging posts are very common.
We had them on the back of our race cars so opening up panels or hoods was not necessary. We also had them in the truck of our patrol cars, to allow jumping a person's car without pointing the car the wrong way, or turning around on a highway.
Like DJ has pictured. If you live in an area where there are Race Shops or Truck Upfitters, you will find them locally. Or ordering them off line is another option.
After doing so, this is a great way of supplementing your converter charger with an aux smart charger. Twice the power for less time running a generator or truck engine.
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