When we saw [Max.K]’s automatic NiMh battery charger float past in the Hackaday tips line, it brought to mind a charger that might be automatic in the sense that any modern microcontroller based circuit would be; one which handles all the voltages and currents automatically. The reality is far cooler than that, a single-cell charger in which the automatic part comes in taking empty cells one by one from a hopper on its top surface and depositing them charged in a bin at the bottom.
Inside the case is a PCB with an RP2040 that controls the whole shop as well as the charger circuitry. A motorized cam with a battery shaped insert picks up a cell from the bin and moves it into the charger contacts, before dumping it into the bin when charged. What impresses us it how slick this device is, it feels like a product rather than a project, and really delivers on the promise of 3D printing. We’d want one on our bench, and after watching the video below the break, we think you will too.
yeah, I would absolutely buy one of those. Nice job!
Me too – this is a fantastic little device and I need to buy one now!
As someone who owns several dozen AA NiMH batteries, this could keep them topped off until needed.
Anyone remember the Supercharger?
It would recharge NiCds as well as alkaline batteries?
Its downfall was that it was too conservative in its settings and not charge the batteries enough. Something like that could be incorporated and not automatically reject alkaline cells.
I bought my Supercharger at a Salvation Amy store for 25 cents!
I’ve always heard you can’t recharge alkaline batteries and video attempts seem to suggest you can revive them a bit once or twice before they start leaking.
Yes, the Supercharger could only give alkaline batteries a “bump” up for a limited amount of times.
But, still, more useful life.
I’d like to know more about this “Supercharger”. Unfortunately that term is so common now Google is no help without (I assume) digging for hours.
There’s nothing magic about refreshing zinc-carbon and alkaline batteries. Charge an alkaline AA with 50mA and stop at 1.65V (20mA for AAAs). But there are caveats: refreshed cells like to leak and cells with already deteriorated intestines (high discharge current, depleted below 1V, stored for too long, etc.) won’t take much charge. It isn’t worth the effort anymore since small LiPo pouch cells can replace 2 AAs in many applications and are available practically for free nowadays.
I absolutely knew I needed this, but it was 20 years ago when I didn’t have the requisite skills or the 3d printing and pcb manufacturing capability to pull it off. And now when I have everything I need, I no longer need AA’s. :(
seems like it’d be easy enough to scale up to 18650s, that’d be the shizzle.
Problem I think would be finding things that could use them outside of vapes.
This being Hackaday, I would guess the 18650s would be for DIY projects.
What are you talking about. 18650’s are in so many things it’s not funny.
Usually not in ways that are easy to swap. Most thing I’ve seen them in they are spot welded in packs, and not in simple slots like AAs.
They make 18650 holders that allow you to convert those spot welded setups. My next easy project involves one to fix an old Bluetooth speaker.
It was my shower radio and the one I got to replace it just doesn’t compare.
flashlights
I have a shortwave radio powered by a 18650
I use 18650s to power many things like
Airsoft guns
RC cars
RC boats
RC planes
Drones
Mobile power banks
My houses off grid power bank (it uses hundreds of them)
They’re so universal it’s unreal
I mean yes, but generally they are in packs and spot welded together and not individually removable cells in easy to access bays. And with drones or RC vehicles, they are usually LiPo cells and not 18650s.
I think flashlights (and vapes) would be the only somewhat common instances of that. Even still most flashlight still use AA/AAAs or Cs if they are rather large (not including the flashlight enthusiasts) and an unfortunate number of vapes have integrated LiPo cells.
You’re not wrong – I have a very large box of salvaged cells that really need characterising, so I should probably consider putting something together just to work through that pile :)
olight had a kickstarter for one but I missed out. Doesn’t seem like you can buy them any other way yet.
https://www.olightstore.com/ostation-x-super-charger
Is it polarity agnostic? I could see wiring up MCU ADC lines to the terminals to determine polarity, and some kind of H-bridge circuit on/in the charging circuitry to be able to flip it’s direction to match
biggest danger would be is the cell got so discharged the polarity flipped (because you’d start charging it backwards), but then the voltage would register as too low to be safe to charge anyway and get rejected
I thought the video mentioned the batteries can be loaded either way.
Yes, you can insert batteries both ways. And you correctly guessed how it works. (H-bridge and two adc channels, although a bit more complicated than that.
Gotta say, at first glance it’s hard to see that’s 3D printed. I need to try some of that matte or wood filled filament.
Is het loading an alkaline cell?
It recognises and rejects an alkaline cell.
Watch the video.
Could it be made self contained and independent of external charger by utilising already charged batteries and when they require charging are swapped out into the conveyor to get charged in the same manner?
m_(o . o)_m
Kilroy was here!
Hooray! Free energy at last.
But seriously. Think about what you just wrote. Why would you bother losing energy just transferring it from one battery to another?
Thanks Mr Cans, i took your advice. i now realise my error, its not a Rube Goldberg machine it’s a perpetual energy machine and as a bonus i have your headache as well.
What a well-executed project. Lovely minimalist mechanism, nice features, and it all just looks so slick. I’m impressed.
With kids around though, I would want a larger hopper and bin ;-).
“With kids around though, I would want a larger hopper and bin ;-).”
The hopper would need to account for the various sizes of your kids, and their growth!
I made something similar for a solar powered robot when I was younger. It would individually charge each cell of a battery pack one at a time, because there wasn’t enough current to charge the entire battery pack as a whole, then it would bank switch between two different battery packs, using one whilst the other was charging. I think I repurposed it for a greenhouse controller in the end.
👍
The servo is struggling. The diameter of the carrier wheel should be smaller and thus the angular path longer so that the servo exercises less torque.
Its struggling because the near end of the pivot shaft is floating. I suspect the missing end cover (so we can see the insides working) includes a bearing support for the floating end of the shaft and the normal action is less fraught.
I wish all these power cells had a write on space for when bought and set number or use description. They should be kept in that order after put in service when new, only single cell uses should be handled this way mixed at random. A working stack of different aged cells will be down to the weakest cell, and then it reverses and becomes something bad.
Label or mark new cells from the start.
I want something like this to go through my used alkaline batteries and use the remaining charge (with a boost converter) to charge another battery. In fact, you could use this charger to transfer the leftover charge from your alkaline batteries to your NiMh cells
My wife was like “It only charges one at a time?” and I was like “but it can charge a whole stack while you sleep or are away from home.” She wasn’t impressed.
It’s a cool project but completely impractical if it only accepts 6 batteries at a time. 4 bay chargers are standard and 8-bay fast chargers are common. Why spend money/effort building this to charge fewer batteries more slowly? Its a neat design, but there’s not much wow factor after it’s built.
I figure its ideal for duty cells that you dump in the hopper at the end of a day/shift and load new full cells. With an appropriately sized input/output tray it handles storage and rotation. The one cell at at time at 1a max would be a plus for some applications, slap a reasonable small solar cell on the roof of the shack and youre good to go.
Seems to me that modifying the upper “hopper” part of the design to accept more batteries would be a relatively simple exercise, given that this is 3D printed. Hell, he even provided the STL, get in there and turn it into a 16 battery beast.
Soon on Aliexpress…cloned by a chinese company!
I made something similar a while back to check capacity of some A123 cells I had. Soo handy to just stack em up and leave it to run.
I want one! What I really want is one that does all sizes from AAAA – D lol or one with multiple bays