I created a mod but it is slightly too big for the attachment system, so just put this into a mod to restore the rechargeable battery mod:
[{
"type" : "recipe",
"result": "rechargeable_battery",
"category": "CC_ELECTRONIC",
"subcategory": "CSC_ELECTRONIC_PARTS",
"skill_used": "fabrication",
"skills_required": [ "electronics", 3 ],
"difficulty": 5,
"time": 15000,
"reversible": true,
"decomp_learn": 4,
"autolearn": false,
"book_learn": [[ "manual_electronics", 3 ], [ "textbook_electronics", 3 ]],
"qualities" : [ {"id":"SCREW","level":1,"amount":1} ],
"tools": [
[
[ "soldering_iron", 5 ],
[ "toolset", 5 ]
]
],
"components": [
[ [ "scrap", 4 ] ],
[ [ "cable", 5 ] ],
[
[ "small_storage_battery", 1 ],
[ "UPS_off", 1 ]
]
]
},
{
"id": "rechargeable_battery",
"type": "TOOL",
"symbol": ";",
"color": "light_green",
"name": "rechargeable battery mod",
"description": "A homemade, rechargeable power cell built from salvaged electronics. With enough electronics skill, you could attach it to an electric-powered device to provide it with energy. The power cell is not compatible with standard batteries; it must be re-energized via a special recharging station.",
"price": 2000,
"material": ["plastic", "aluminum"],
"weight": 142,
"volume": 1,
"bashing": 0,
"cutting": 0,
"to_hit": -2,
"max_charges": 0,
"initial_charges": 0,
"charges_per_use": 0,
"turns_per_charge": 0,
"ammo": "NULL",
"revert_to": "null",
"category" : "spare_parts",
"use_action": "RECHARGEABLE_BATTERY"
}]
Wait, what now? You don't need to have a charged UPS in your inventory! I have several UPS-modded tools, happily recharging in the station, and I can take them out and use them, no problem. No UPS needed!
UPS modded items are still subject to all their old restrictions, except now recharging stations will also recharge them.
edit:looking at the new fix, it removes the rechargeable flag, so this won’t work once that goes in.