Looking for Power station (technically a charger) recommendation that can easily swap out core

I am looking for a power station that can easily take a replacement battery. I have a spare 12v lifepo4 battery that I planned to use for a trolling motor, and instead of keeping it idle, I figure I can have a power station that can easily have double the power when I can semi-easily swap out the core with a charged spare.

Most power stations are built to prevent swapping so I am looking to see if anyone had come across one that’s easier than others. I don’t mind some customization, as long as it can be opened easily w/o damage then I can tinker the innards with some rewiring and soldering if necessary. My dimension requirement is roughly 3x7x7 as the battery size.

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