I needed a “flashy” marketing technique to get as many folks as possible to complete a 2-3 min survey for a school project. I started with this clever lil guy but realized it wouldn’t last nearly as long as I needed it to - probably 8-10 hours at best. So I nerded out a bit on all-things-batteries and crunched some numbers and found that size D batteries should power my 3 individual 3V LED’s for nearly two weeks - Fun Fact: battery capacity is directly related to the volume of a battery, …who knew?!). Turns out I didn’t even need to add the salvaged on/off switch I stole from my kiddo’s old forgotten toy
Here’s a shameful plug to the 100% anonymous survey for my group project for if you happen to have 2-3 minutes to spare. My team would super duper appreciate it!
If you’re just dying to know the punch line, you can click the link and not go on with the survey
That is a properly bad pun! Congratulations. I used tons of tiny coin-cell batteries with LEDs, never tried to get 8hrs of continuous life out of it - nice work (and a good shtick to get folks to your survey!)
HAHA, great pun! Filled out the survey but I am not your target market for the survey. My dog is not the adventurer type. LOL He’s a Great Dane and this is basically how he gets out.
He just sits and waits for his servants (me) to wait on him. LOL
Oh my goodness, I’m dying over here Is his name “Blue”, by chance?
Thanks so much for doing my survey - totally ok that you’re now in the target market, all data is helpful!
His name is Luke. LOL And he is 13 and loves people. Just an amazing dog
Look into 18650 batteries, massive capacity and rechargeable.
They’re the kinds of batteries that power cordless tools and Teslas.
I just did your survey, thank you for sharing
I did your survey because I am a CU alum.
Funny you suggest that because it’s what I did before this solution. I had an old weedwhacker battery that no longer charged. Took the sucker apart only to find out that not even one of them was holding any charge, and I believe that means they’re all bad, yes? Or is there still any hope that I could try and charge them? I do hear good things about 18650’s though, especially since you can rig them up to recharge them. I’m a few recommendations away from taking apart a fully functioning ryobi battery for its innards…
I had a Ryobi pack that was being difficult and yoinked a ton of 18650’s out.
Almost every flashlight I have uses that size battery so now I have backups. (A couple use 14500s, which are evil things because they’re exactly the size of AA but way more voltage. Would be easy to kill something by putting hem in instead of AAs)
They make other sizes too, the 18 is mm diameter and 650 is .1 mm’s. So this is a 1.8 cm diameter battery, 6.5cm long They make 24650 and 32650 sizes too, which would be cool for me because my charger can’t go any longer.
Anyway, like you said volume of the battery matters so the 24 and 32 size would be a lot more capacity, they’re just harder to find.
Nice project! It almost makes up for your CU connection…almost. CSU alum here if you hadn’t guessed yet:joy:
Very resourceful making the holder from scratch.
The highest capacity 18650 is 3,600mAh, most common are <2,500mAh, The average D-cell is 10,000mAh.
Of course, you could run multiple in parallel. Then you need a charge circuit. You can buy cheap power banks with everything included, but then you need to drop the voltage - or switch to 5V LED modules. Then it needs to be the kind that doesn’t power off unless above a certain load…
Your solution is simple and elegant. I built a pantry lighting system that used a 9-pack of D-cells to power a 12V LED strip around the inside of the door frame. The batteries last around 2 years, as long as the kids fully close the door after grabbing snacks!