--> FS: Cottonpickers Chargers incl. Worlds smallest Li-ion charger with display

[jollyrogr]

cotton: got my world's smallest charger today. I really like that I can watch the voltage.

[infinus]

I'd like 2 of these: the dual with upgraded IC (which you need to get higher current, and also is better charging algorithm) is $40 with the 480/700 current.

Can you make them with some small usb extensions on them (6 inch's would be great). I'll pay pal you the 80 now and if you want a little extra for the extensions I can send you more.

[cottonpickers]

Infinus: Yes, its $40 for the dual 480/700 with upraded IC. I can include a couple of extensions 6inch extensions once I can find them) at no charge. Give me a couple days to make the chargers up though please :-)

Toker: Its in the post

[Emu124]

Another WSLCWD touched down in Switzerland
Thanks Cottonpickers !

[cottonpickers]

Infinus: They are in the post. I only had one 6inch extension, so included a 50cm also - hope its ok.
Emu: Great stuff!

[jollyrogr]

got my griffin powerblock usb charger today. Charging an 18650 on high right now with it. Seems to be working great. Should be about done - charger is flashing 4.20 right now

[dsche]

dsche: They're in the post to both addresses.

Both recieved! Thanks-thanks!

[infinus]

Cottonpickers,

If I plug in a protected cell and the protection had been tripped will your charger handle this?

[hotlight]

Hi CP,

received my stuff... and THANKS again for the LF2XT lanyard ring.


thanks!

[cottonpickers]

infinus: I've never tripped one yet, but unless someone can confirm/deny before I get to test it, I'll trip an AW RCR750 tonight and post back here how it handles it. Obviously other cell manufacturers may behave differently but hopefully should give you a good indication.

hotlight: NP :-)

[infinus]

Let me know what you find!

[jollyrogr]

Cotton: I assume this charger will do fine with 32600 cells, it will just take longer?

[cottonpickers]

Jolly: Yes it will charge it, taking longer. Because of the capacity (5000mah?)of that cell its getting a little borderline (either borderline that that charger is operating on max 700ma current for over 8 hours, or risk that the cell will take so long to charge at say 500ma that you may get tempted to leave in on overnight/unattended) If I had that cell and this charger I'd be inclined to try to not let go flat and top it up regularly so that perhaps its getting a 2-3hr charge at a time.

infinus: OK, Well I ran the AW rcr750 down til it tripped. I started using my 4sevens mini 123 but it 'flashed' repeatedly then stopped , but the cell still read 3v. I never knew the mini's had low voltage protection but suspect they may. So then I moved the cell to my ra clicky and after some perserverence got it to trip :-) Both my std and upgraded IC chargers reset and charged them when connected (quickly showing 3v on the voltmeter) Other manufacturers protection circuits may behave differently but the chargers work fine on the AW tested cell.

[infinus]

Awesome!

[jollyrogr]

Thanks for the info cotton. I don't have any cells that large at the moment, but if I get some for a Mag or something I'll use my RC li-po charger that can charge at up to 2.0A rate

[LightOnAHill]

prices will range from $25 for single current with display on old ICs up to $55 for the quad charger with display. I'm building up a pilot 90/320/480/700.

$55 for a 4way 90/300/500/750 w/ upgraded IC

I'm ultra excited about this charger!!!

[infinus]

Got mine today! That was quick!

Trying them out now.

Thanks.

[radellaf]

Would it be easy to build one of these with a higher cutoff voltage, like 4.3-4.35 for the LG and Samsung "special" 18650s?

I'm having fun with my 420mA w/display. Only wish the display was USB powered (when plugged in), and worry about 420mA being over 0.5C for my RCR123s. It's around 1C for the Ultrafire "880mAh".

It is just -so- cool watching that display, though. Even cooler than the 64x128 dot display on the Bantam BC6HP.

[infinus]

Finished charging up some batteries and have a little feedback. On the AW cells this charger really works well. On some of my other cells however I have some minor issues. I have 2 EagleTac cells and a couple other brands as well. The AW cells seem to have particularly strong magnetism at the two poles and this works very very well with the system you've devised using magnets. This doesn't work as well on the EagleTac cells and a few of the others I have. The magnet on the positive pole is always firmly attached. On the negative end however where the PCB protection is I find that the magnet wants to jump off the pole and down just a tad on the battery. I've had difficulty maintaining a firm connection. I might look into making myself a battery holder unless you have any other recommendations.

[radellaf]

I bought some larger diameter (3/8"x1/16") gold plated magnets for the negative pole, and some 1/4"x1/16" for the positive. Stick the magnets to the battery and then stick the charger lead magnets to them.


I made my own leads for a hobby charger with the high-temperature N42SH material, 1/4"x1/4" size D44SH. They stick well on their own to the hard-to-stick negative ends. Not sure if that's because they're bigger magnets, or because they hold their magnetism better when being soldered. IDK if the included leads use hi temp or normal magnets. But, I'm happy with this solution.
Also, with magnets that size they are powerful enough you can put them on the outside of the charger leads' magnets and they help them stick to the battery without adding the resistance of another magnet to the circuit.

[cottonpickers]

Redelaf: Unfortunately the cut off voltage is fixed at 4.2v +/- 1%. I reckon I can make one that takes its voltage from the usb, but the displays I have that could do this are are pretty huge :-o

Infinus: Thanks for the feedback on some cells not having magnetic poles. I'm sorry about that - I don't really have a workaround other than to make up a cradle. I've updated the FAQs (should have done this earlier) to hopefully warn future purchasers that not all cells are iron based and should be checked before purchasing.

Lightonahill: Its in the post

[LightOnAHill]

Awwwweeeesssoooommmeeee!

[infinus]

I ordered a cradle from http://www.luminousdiy.com. I figure I'll just use the alligator clips to clip onto the metal tabs. Should work for all battery types. I think this solid connection will give me more peace of mind while charging.

I love these chargers by the way! With my other one I hated having to always bust out the volt meter to double check cell status. It's freaking brilliant that I can see voltage while charging with these!

[davec611]

Paypal sent for
Triple current setting Smallest Charger in World with Display and upgraded IC; choice of 3 current settings and 2 sets of leads (crocs and mags) $50 Default is 90/320/620

[cottonpickers]

davec611: Its winging its way to you

[tokerblue]

Received my charger today! It's a lot smaller than I expected. Quick first timer questions.

1. Does switch labeled M=480 and H=700 for charging?
2. I'm currently charging an AW RCR123a 750mAH. It started at 4.17 and it's currently flashing at 4.20. Do I wait for the red LED on the back to go off to signify a full charge?

[biker1]

[QUOTE=tokerblue;2611929]Received my charger today! It's a lot smaller than I expected. Quick first timer questions.

1. Does switch labeled M=480 and H=700 for charging?
As per your order in post #178, Yes

2. I'm currently charging an AW RCR123a 750mAH. It started at 4.17 and it's currently flashing at 4.20. Do I wait for the red LED on the back to go off to signify a full charge?
Yes

[tokerblue]

Thanks. I just topped off two RCR123a and love this charger so far. Next up is a 18650.

[biker1]

These chargers are really nice. I am extremely pleased with the chargers cottonpickers makes. A lot of effort has gone into making these, and there has been much R&D regarding the IC's with the very helpful input from wapkil, and the end result is one of the best cc/cv chargers available imho. The charger works as advertised and the on-board voltmeter is Fantastic!!
And of course, this charger is the Smallest Li-Ion Charger w/Display that I have ever seen

[cottonpickers]

Toker: like what Biker said :-)

The reason you wait for the red light to go out is that the charger 'holds' the voltage constant at 4.20/4.21 while the cell voltage rises to meet this. You can stop the charge as soon as the display shows 4.2v but the cell voltage will immediately drop a lot. If you wait longer the cell will continue to charge during this constant voltage stage. It seems odd to watch the voltmeter constantly show 4.2v but things *are* really happening underneath during this phase :-)