Battery Bot Makes Sure Cordless Tool Packs Are Always Topped Up

There was a time not that long ago when every tool was cordless. But now, cordless power tools have proliferated to the point where the mere thought of using a plain old wrist-twisting screwdriver is enough to trigger a bout of sympathetic repetitive injury. And the only thing worse than that is to discover that the batteries for your tools are all dead.

As [Lance] from the “Sparks and Code” channel freely admits, the fact that his impressive collection of batteries is always dead is entirely his fault, and that’s what inspired his automatic battery charging robot. The design is pretty clever; depleted batteries go into a hopper, under which is a 3D-printed sled. Batteries drop down into the sled, which runs the battery out from under the hopper to the charging station, which is just the guts of an old manual charger attached to a lead screw to adjust the height of the charging terminals for different size batteries. When the battery is charged, the sled pushes it a little further into an outfeed hopper before going back to get another battery from the infeed side.

Of course, that all vastly understates the amount of work [Lance] had to put into this. He suffered through a lot of “integration hell” problems, like getting the charger properly connected to the Arduino running the automation. But with a lot of tweaking, he can now just dump in a bunch of depleted packs and let the battery bot handle everything. The video after the break shows all the gory details.

Of course, there’s another completely different and much simpler solution to the dead battery problem.

19 thoughts on “Battery Bot Makes Sure Cordless Tool Packs Are Always Topped Up

    1. The next step is a mobile bot that hunts down dead batteries and loads them.

      Then it mutates into a bot that seeks out charged batteries for “food”.

      1. That reminds me of some guy who was selling some laptop and saying it’s “wireless”. But this is not because it has WiFi connectivity, but because he lost all wires and a charger for it.

        1. Could just use a good old hand drill. Should be able to find one at your local swap meet for less than $1. Less parts to fail, and you don’t have to worry about electricity or charging batteries in the first place.

  1. I still think I’d have gone with printing multiple charging connectors and having a chain of relays swap which was connected to the charger every time the charged led comes on.

  2. Thank you for sticking with it and seeing this through to a successful end. After seeing the issues you encountered, if I were to build something similar, I think I would let the batteries remain stationary and move the charger. Above each battery have a tricolor LED (red is dead, yellow is charging, green is charged).

  3. Interesting idea, but I can’t help thinking it’s upside down. Why go to all the effort of adjusting the height of the charger to match the position of the connector relative to the base which keeps changing depending on the capacity when there’s a very fixed relationship to the other side. Drop them in connector side down then any capacity battery could be slid onto the charger without issue, just leave a little wiggle room and the design of the battery will guide itself into place.

    1. His ejection path would be blocked as designed. If the connector does not move, then the battery would either require lifting or pulling to continue the ejection.

      That being said, I do not like dropping the batteries after charging.

  4. Placing the batteries into the hopper ‘upside down’ would mean the contacts would all be at the same height and the second axis (and method to measure contact height) could be eliminated entirely.

  5. Or, y’know, a CORD!

    I dislike all the battery operated items for power tools. Every one I have gets a memory, and then I can’t source replacements….so I no longer purchase power tools unless it has a cord.

    1. I haven’t had that problem with the lithium-ion packs I use; the Ni-cad packs were the *worst* in that regard.

      Back on the main topic, This is neat, but I would have gone the easy route and bought a multi-charger if there’s one for that specific system. I’ll state that ryobi’s 18 volt multi pack charger has a carry handle, although the instructions that came with it state to not keep the packs plugged in for long periods of time. :shrugs:

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