Race AA batteries through tubes made of copper wire

Originally published at: https://boingboing.net/2019/04/29/race-aa-batteries-through-tube.html




What does it say about the battery’s quality that the varta won the drag races but lost the loop race?

What does that say about how it would perform in a toy, for example? That the toy would work “better” at first but die sooner?

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Dammit. Trying to save money but now I have to go out and buy some copper wire…


VARTA batteries are now Rayovac. Unless they’re button batteries; now they’re Spectrum.

Results in the drag race would demonstrate the ability of the cell to dump maximum current and means that the internal impedance must be low. Results in the run time test would demonstrate the ability to put out a minimum current (enough to keep moving) for the longest time; this could be actual energy capacity or merely a higher internal impedance. Neither test would really tell you how “good” the cell is. Need a hit of power – pick the drag race winner. Need to last a long time in a relatively undemanding application – pick the winner of the duration race. Me, I generally just buy a known brand that is on sale in bulk or buy lithium primary cells for demanding tasks such as operating my weather instruments outside in cold conditions.


Also their mass.


I’d like to see the same kind of video pitting different battery chemistries against each other. Carbon, alkaline, NiCd, NiMH, 1.5v lithium, 3.6 lithium, etc.


Any research on which ones, when purchased from Costco in mass quantities (ahem), will eventually leak and destroy whatever device you stick them in?


An insulin pump sucks minimum energy over a long period of time.
I was told to go with Energizer because it was designed for that purpose.


It would be nice if they spent maybe one sentence explaining how it works instead of writing “it’s cool” thirty times.


Would they last longer if they lubed the batteries? Asking for a friend.


Elon Musk, are you watching this?


The Varta battery is probably going faster because it has less stuff in it, and so it has less mass. That neatly explains both the better drag race and the worse loop results. The Energizer cell could actually be better than either electrically, but just be performing poorly in these tests because it’s heavier. If it’s heavier because the case is sturdier and it’s less likely to leak, that’s actually awesome. Maybe not – we just can’t know from these results!

If you really want to know your battery performance, either get a datasheet from a manufacturer or use a tool made for the job, like an electronic load. This a terrible way to compare performance for the purpose of actually powering things, and I love it!


A great idea except that AA cells aren’t standardized by weight, so we don’t actually know just from speed or acceleration just how much power or energy they’re putting out…

Any research on which ones will eventually leak and destroy whatever device you stick them in?

All batteries. As far as I can tell. A good percentage will always degrade. It really makes no sense to buy batteries in bulk unless you know you’re going to use them all within, say, 3 years.

What I didn’t know is that: even taking the batteries out can still wreck certain electronics, over time. I had a beautiful Sony ICF-PRO80 in storage. And, even though the inferior electrolytic capacitors would have possibly failed in any case, by failing and discharging they ruined all the other components. So, you can’t just remove the battery. You have to somehow discharge any stored charge also.

R.I.P., old friend.


If you want to unwind and save, remaindered motors and generators and whatnot are more like it (unless physical stores are obliged to have someone very high-strung explain that the State of California is so certain all that’s gonna be cancerously safe.)

So, looking forward to summer and the Katsuhiro Otomo Director’s version of hot battery/too fast. Cold SWCNT coils, batteries rehoused in glass to take polarized LWIR heat and charge, whatever it is that one does to Nd:B:FeO magnets so their ghosts keep racing after they go over the Curie temperature?


Welp… I think I just found a “explain how this works” question to add to the Physics II final exam I’m giving on Wednesday!


This would be dangerous with a 3.6 Volt lithium. With this gauge of wire you’re essentially shorting the cell. Think exploding vape.

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Yeah, I guess the circuit on protected cells might trip.

Still, for the purposes of a short drag race, an unprotected cell isn’t going to explode that quickly. I’ve also seen some 18650 cells rated at 10A continuous discharge (20A max), though I haven’t seen any high discharge 14500 batteries.

The AA alkaline batteries are seeing at least 0.75 ohms if they last 30 minutes continuous discharge (say, about 2amps. Luckily some discharge curves drain the batteries at 2A and they last about half an hour, same as with the loop test. R=V/I=1.5v/2a=.75 ohms).

So, a 14500 AA form factor lithium ion will discharge at under 5A. It’s not going to explode immediately, but it’s not going to last many charge cycles either.

A longer and larger diameter 18650 will see even more resistance, so the high current ones can easily do a continuous loop. Probably for a little over half an hour. (2800mah @5a). A 14500 will probably beat it in a drag race because it’s lighter and is running higher current, but would obviously lose in a loop marathon.

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