I got a hobby charger to recharge my 18650s, but I need help making a cradle/holder to charge them with.
I plan on buying one of the premade ones, but while I wait for those to arrive I need a temp charging holder.
My 18650s are Samsung ICR18650-30B.
I am new to charging and want to make sure I don't blow something up.
Can anyone give me suggestions on how to make a charging holder for my 18650s?
Ideally you’d use those little tiny neodynium pucks. A magnet that big and strong, I tend to think it would have an effect on the particles of the anode and cathode reforming.
Ok, I won't use those ones then.
Any suggestions on an easy to make charging holder without a lot of assembly?
Going to edit my title to something more relevant.
I don't know if anyone makes a balancing cradle for 18650's, but they should.
As for charging right now, you could take metal strips like the kind used in laptop battery pulls, and affix those to the ends of your battery with the magnets, and then attached your croc clips to the strips.
Should I use the big magnets? I have 2 little, less powerful ones I could try.
Is that safe? (I'm worried about blowing something up or starting a fire.)
The batteries are from a laptop pack and I saved those metal strips.
My 18650s are Samsung ICR18650-30B.
http://www.alibaba.com/countrysearch/CN/icr18650--30b-samsung
html http://www.orbtronic.com/batteries-chargers/3000mah-samsung-icr-18650-30a-high-capacity-li-ion-rechargeable-18650-battery-cell
It just needs to hold the strips on. It has a safety factor in that if they slip off, the chance of shorting is much lower since the clips aren't magnetically attracted together.
Good for you for saving the strips. I save them too, thinking that they might be good for something...someday.
So, use my little magnets and attach them to the positive and negative ends then put the metal strips on top of those?
Metal strips under the magnets.
Got my 18650 charging doing it that way. Thank you leaftye!
Next question is what should I charge and discharge at for my specific battery?
Should I start a new thread for that?
I'm not a battery pro, but recently others said 1C. Take your mAh, divide by half, and that's your mA to charge at. 1.5A in your case.
http://www.fasttech.com/product/1286603
Charging rate? 1 amp per 18650 battery is what I use as so many batteries have less capacity than what they claim, and higher amps in the CC phase means more time spent in the CV phase and lower battery capacity as the cutoff is 1/10 of the charge rate, so lower resting voltage for the higher charge rate.
Parallel charging is faster than balance charging as you don't have to wait for balancing.
The other forum has a good thread on this, complete with measured currents etc/.
Basicly, less than .5 volt difference between cells is recommended for Parallel charging
http://www.candlepowerforums.com/vb/showthread.php?161299-Li-Ion-Paralle...
Wow! Didn't know fasttech had those, and for $4.07. I've been wanting one.... the low capacity spare 18650s I have could be put to use.
Anyways, I am only doing single cells for now.
BatteryUniversity says "Manufacturers recommend charging the 18650 cell at 0.8C or less. Charge efficiency is 97 to 99 percent and the cell remains cool during charge"
The 18650s were pulled from an unused new dell laptop pack, so should be genuine samsung ICR18650-30B, which are 2900mAh min.
My charger will let me charge up to 2C, so 6amps and I can change the voltage to anything from 3.6v up to I think 11.1v (On my 12v power supply).
So, I can charge my 3000mAh at 2.4a(0.8c) safely?
And as for voltage, should I be charging the ICR18650-30B's at 4.2v or 3.7v for the best charge?
That USB pack has no electronics for charging etc and so it makes a good cheap charging cradle.
I recommend that you use the Lipo setting for a 3.7V(1S) on your hobby charger which will charge the 18650's to 4.2 volts during charge, with a resting voltage determined by the cutoff charging rate which is automatically set to 1/10 of the charging current, so I recommend a 1 amp charge rate, which should give you a resting voltage (after 30 minutes) of approx 4.18 volts. A higher charge rate will give you a lower resting voltage due to the higher cutoff, i.e., at 1 amp the CV stage will cutoff charging at .1 amps, and at 2.4 amps the CV stage will cutoff at .24 amps.
Try charging at both currents, and look ate the total charging time there isn't as much difference in time as one might expect, and there is a noticeable difference in resting voltage.
One of the things I like about hobby chargers is that they never exceed 4.2 volts, which means longer battery life and slightly lower resting voltages than most stand-alone chargers.
The only way to get 4.2 volts resting voltage on a LiIon is for the charger to use more than 4.2 volts during charging.
Thanks for the info, I actually got a battery to charge and not blow up. :D
My charger kept showing me the 0.10amp and when I moved over it, it would switch to the 1amp I selected. Now I understand why, that's the CC and the CV stage thing.
My samsung batteries say their max is 4.35v, can I charge it up to that?
And how should I discharge. Stop when the battery hits 3.1v? What rate should I use to check a cells max capacity?
I've some 4.3 volt laptop pulls but no 4.35 ones, and I've just been using them at 4.2 volts.
The only good CC/CV 4.35 charger currently available is the one from cottonpickers
HKJ review here: http://www.lygte-info.dk/review/Review%20Charger%20CottonPickers%204.35V%20DM%20UK.html
There is a dual battery one and here is HKJ's review of that one: http://lygte-info.dk/review/Review%20Charger%20Heseny%20HXY-18650-2A%20UK.html
Harbor Freight has these small adjustable vice grips for $2. It’s what I use.
The copper terminal lugs come from Home Depot. In the electrical area. I think they were $1.49. My photo shows banana clips fitting into the terminal lug holes, and alligator clips work just as well.
I just receive a hobby charger, I am using magnets right know, I was thinking in buy a cheap charger that old 14500 and 18650, take the electronic out and use it…
That will work.
I found this http://www.fasttech.com/products/0/10003990/1286603-diy-234-x-18650-batteries-holder-case-box-mobile-p and it makes a great holder for unprotected 18650's.
I was thinking in something like this
http://www.fasttech.com/products/1421/10000969/1037800-aaaaa6f2218650-universal-battery-charger-2013