Supercap drill

[darryl]

It wouldn't be for everybody, but it might be an interesting way to do it. Cordless drill with a base unit, a holster kind of. When you put the drill down it charges. Pick it up and use it, put it back down it charges. No battery to go bad. Extremely fast charge. Should be cheaper than replacing batteries- but the charger will cost as well. Might be an option for drills that are fine, but that you'll never find batteries for.

Where are we at now with super caps? I read somewhere that we're up to about 1/5 the energy density of batteries, so that doesn't seem too anemic for this application.

This is probably not very good for portable applications, but in a home shop it might be ok. I probably have at least a dozen drills that are great tools, but too old to replace batteries for. Granted- it would be a lot of work to build a super cap array onto every drill, and to provide a pair of high current connectors for charging. And then the charger-

Ah, it's probably a stupid idea- but I'll leave it here.

[MattiJ]

Supercaps have about 50 to 100 times worse energy density than lithium.

https://www.maxwell.com/images/docum..._datasheet.pdf

you could put 8 of those supercaps to something like large makita 18v battery case.
resulting ”battery” would be 0.8 watt-hours max and maybe about 0.6 watt-hours of usable energy. Or 2160 watt-seconds.
small cordless drill might draw 20 watts no-load and 200 watts fully loaded.
so you would get 100 seconds of operation without any load and about 10 second with heavy load.

also note that supercapacitors have limited lifetime. 4 years self-life and 10 years projected lifetime under voltage for the example I used. Other brands/models are the same.

[epicfail48]

You know, going off the math Matti posted a cordless drill like that would be next to useless, but a cordless screwdriver with that mechanism would be pretty nifty to have on an electronics workbench. Something like one of these little gizmos:https://www.banggood.com/SEQURE-SQ-E...r_warehouse=CN

What would be really awesome is finding a way to make the charging wireless, maybe using something like the Qi chargers cellphones already use. Pick up the driver, work with the few screws on your project, drop the driver back onto the charging pad while you do whatever else with your project. Find a way to add in torque controls and im willing to bet gunsmiths would beat down your door to get one

[dian]

is that by weight or space?

[darryl]

50 to 100 times less energy dense- forget it.

[Lew Hartswick]

MattiJ would you please explain what <50 to 100 times worse> means in some form of mathematics or simple arithmetic ??
...lew...

[boslab]

Much like the clockwork vibrator I invented, stops just when you need it most, just like me
mark

[MattiJ]

MattiJ would you please explain what <50 to 100 times worse> means in some form of mathematics or simple arithmetic ??
...lew...

Supercapacitors have abt 4 wh/kg
lithium ion is something like 200wh/kg

I won’t get into semantics...