balance charging 18650's / 26650's

Batteries and Chargers Chargers
1

here is a 2s balance charge lead set up for 18650's i had to cut the springs in the battery boxes as they are for none protected cells and I'm using protected cells so to get them to fit i had to remove the spring and reverse the polarity of the battery boxes (run the batteries the other way round) i have also made some singular ones for protected cells and use red heat shrink to cover the black wires and black heat shrink to cover the red wires so there is no confusion witch way the battery goes.

here is a pic of the 2s balance charging set up

here is a pic of the single 18650 ive been using.

this is a 3s1p protected charge box i brought off fleabay its only good for unprotected cells, but has built in protection, over voltage under voltage plus a few other features.

I'm waiting on some more bits to make 3s balance charging leads and a 6s balance charging lead for the 18650 batteries, ill post up some pictures of them once the bits get here.

2

Thats awesome! I Made my 4 cell one out of fire-enhancing plywood! lol.

Which battery holders will fit the protected cells? I'm particular interested in finding a holder to take my 2600 XTAR 18700s, but if they take my trustfires ill be happy. The ones ones I've found so far only seem to be rated to 18650 unprotected.. Links would be great!

3

thanks mate unfortunaly i have not found any that fit protected cell,s i broke two trying to mod them for protected cells, i brought the battery holders off ebay 6 for 8 bucks delivered but they will break if you put a protected cell in them, i had to cut the negitive spring off and put the battery in back wards to make contact with the metal tabs in the battery holder but now i can use them for charging protected batteries.

my next lot will be using magnets but i got big mangets 8 x 8mm and to try and make it neat im going to use 2 x 3s lipo 6s balancer adaptor from hobby king, so i only have to worry about balancing wires, ill post up a picture in a couple of weeks when every thing gets here.

4

You can get 18650 holders that fit protected cells from Luminous DIY. They look like this:

I wonder why you charge in series, why not use parallel.

5

i charge in series for ballancing charging, with lipo,s for my Rc car i charge in parallel and still ballace charge becuase the packs are made up in series 2s1p x 4 or 3s1p x 2 on a parallel charging board.

Be-Seen Triker
i dont have any on them as ive never brought a charger like that i use my RC charger and power supply, but i have a few clear 18650 battery holders like the ones in your link, but they only just fit the greys and the flames are 1mm long it only just closes, but i got mine of ebay for $1 delivered so they might be shorter.
6

I can understand that it is necessary to charge battery pack in series, but not loose 18650 cells.

As long as the 18650 are close to the same voltage, it is fine to charge in parallel, you get perfectly balanced cells that way.

When series charging cells with different voltage the charger might limit the charge current to the maximum balancing current (That is 300mA for the iCharger).

7

but im not charging loose cells im ballance charging 2 x 18650 at once in series and the other single 18650 battery holders have no ballancing they plug directy to the charger and charge like normal as theres no need to ballance a singe battery.

im making 3s and 6s ballacing/charge leads to ballance charge 3 x 18650,s at once and 6 x 18650,s at once, the batteries will be used in difrent torches under diffrent conditions with diffrent end voltages and i feel its best not to parrallel for this reason and i feel its best to ballance charge them together then to charge one by one and it will save alot of time.

when charging in parrallel the cells will balance to an extent, if they are close to start with ive found, i do like charging in parrallel for lipo,s as you can use higher charge rates and charge as one big battery pack, but the batteries are not always close in voltage, the more the diffrence in voltage the more they spark ive noticed while conecting multible cells together

its very easy to make series ballancers i dont think you understand how the icharge works when balacing, the icharge does not limit the charge to 300mA while charging as it would be usless, if the cells are out of balance the balancing works totaly diffrent, the charge will maintain the same charge rate but thats when the balancing module kicks in.

the icharge 106b+ the model i have has a balance modual built in with a max draw of 300mA, so you can ballance charge mutible cells at what amp rate you chose, if one or more of the cells is higher then the rest the icharge will draw from that balance wire or wires upto 300mA to bring the voltage down on that cells or cells to the same as the others to ballance the cells while maintaining the same charge rate, thats the whole point of the balance wires, it can drain voltage between the cells to ballance them. (the max charge rate for my model is 10 amps)

so if you have 3 batteries in series the first one is 3.4v second 3.9v and the last one 3.4v and you have set the charger to charge at 1 amp, the charger will charge at 1 amp but the balance modual through the 4 balance wires for charging 3 cells will drain 300mA through the two midle wires draining the midle cell down while the other two come up, if that makes sense, the charge will give you a read out of how each cell is going and what the voltage is while ballancing you can actualy see it work with the voltage of the cells, when ballance charging in series each battery has balance wires connected at the positive and negitive side of the battery plus the main charge wires, so the voltage of each cell from 2 to 6 batteries at a time can be adjusted (ballanced)

i have used series charging for lipos for years with Rc and have been parrallel charging for a while now in Rc, there is no right or wrong with series or parrallel charging depending of what your doing, each has its good and bad points, i perfer parrallel for multible lipo packs, but for 18650,s i have chosen series with ballancing as ive noticed some diffrences in voltage between batteries with a torch that uses multible 18650,s at once in series, the icharge balances pretty fast and will get the cell,s with in 0.01 volt of each other and you can calibrate it if needed, if they are good cells (unlike the ones ive got pictures) they will all be spot on.

i feel there is no harm in ballance charing multible 18650,s like the picture ive posted on a 2 x 18650,s series ballance charing set up, its more acturate then cheap auto cut off chargers and safer and much safer then not balance charging, there is no harm in parrallel charging either, if the cells voltage is close as they will ballance each other out to an extent, you cant realy ballance charge parrallel cells unless the cells are packs made into series, but when running torches that use mulible 18650,s in series and single cell 18650 torches if you want to charge multible cells all at once to save time and trips to the charger, series ballance charging is the go for me but each to there own.

8

When the first cell hits 4.2 volt, the current is limited to the balancing current. One of the advantages with parallel charging is that you can use the same tray for one or more cells, the one in my photo (see above) charges two cells in parallel and I can connect more than one of these trays to the same charger.

9

Not 100% correct, it also depends on what charge mode your using and what balance mode, just about all chargers will ramp down when nearing maxium voltage, even with nimh in delta peak or manual, li-ions, lipo’s it does not matter if its in series or parallel charging the voltage will ramp down when almost at full charge, the rc chargers I’ve used over the years all do this even if your parallel charging.
I make this thread for cheap ballance charging leads and like I’ve been saying I like parallel charging for lipos, but this is not what the thread is about its about ballance charging and in this case I prefer balancing, one of the good points with balancing and ramping down voltage when nearing maxium voltage is it’s adds a bit more MAH to the batteries, but balancing takes a little longer but when ballance charging 6 at a time with different start voltage it still works out atlest 4 times quicker.
I can speed up the balancing on the charge but you loose a few MAH you can slow it down for better results but I leave it in the midle as its still very quick for balancing, you can also you lipo charge and fast charge modes that charge full throttle till the maximum set voltage is reached, but I think normal balance charge is best for me.
I will post up some pictures of the other BALANCE charging set ups I’m going to make over the the next week in case people are interested.

10

Both are right...

The iCharger (as with many hobby lipo chargers that follow a true CC/CV profile with an inbuilt 300mA discharger) works as follows.

Series charging -

All cells receive full current. Once one of the cells hit 4.2V, the iCharger will start to apply a discharge current to the individual cell via the balance leads. This discharging current will reduce the floating voltage of the individual cell and allow the main current flow to stay at its maximum (so the other cells keep charging at full rate)

As this individual cell charges up, the discharger will eventually reach the max 300mA discharge rate, and after this will no longer be able to hold the cell below 4.2V. So the total charge current must decrease. This decrease will reduce the charging rate of the other cells if their not already at 4.2v. Therefore the less charged cells will take longer to charge than they other wise would have individually.

However, in the whole scheme of things, you can have many cells of very different charge levels charged in the same "run", so even if the run takes up to twice as long, its still noticeably more convenient and likely to be overall faster than having 2 separate charging runs.

Im a fan of series charging for this reason, because of the increased convenience, and no need to worry about differences in charge levels. Even the slightest voltage difference means large charge capacity differences, and connecting these cells together is effectively shorting the cells until the capacity differential is conducted, limited by the internal resistance of the battery.

As a Theoretical example, this gives an idea of the kind of current involved. If there is a voltage difference of about 0.5v, given a total internal resistance of 0.05 ohms, then the instantaneous current flow will be (V/R) = 0.5/0.1 = 5 Amps. So the instant you connect cells in parallel with a voltage difference of 0.5V, you will be discharging one cell at 5A, and charging the other at 5A for a short period.

A difference in voltage between a fully charged cell and an empty cell (3.0v - 4.2V) = 1.2V. Divide this by 0.1 Ohms and you could get an instantaneous current of 12A.

Better cells (like my 2000mA capacity RC lipo packs) with a measured internal resistance of 0.005 - 0.01 Ohms would share a current of 20A for a difference of 0.1V! (240A for a difference of 1.2V)

11

revision 3 for charging

single


2 cell balance charge

3 cell balance charge

just waiting on some more parts to make a 6 cell balance charging lead.

12

Looking good, is that one set of wires for every setup?
Oh and just noticed your in wa, well what kind of rc are you into, ive got my rc foamy planes, 1/10 on-road tamiya, are you northnor south, im south.

13

each set up has its own balancing wires, i was into large scale off road but ive been playing with a traxxas mini e revo Merv for short great little car one of the best rc,s ive had for a while.

ive thought about using this 2s to 6s charging board, i use it to parallel ballance charge my lipo,s for my Merv i could make 6 x 2s balance leads so i could balance charge 12 x 18650,s at once but thats a bit much

14

Just bringing up an old picture of my charging setup. The balance connector is connected to the 4 cell socket, and I just move the single alligator clip to suit the number of cells connected. The wire on the left is the temp sensor, just sitting between the cells.

15

These cheap Ultrafire battery holder fit my biggest protected cells and they are around $1dollar each a couple sheetmetal screws and some small springs and you are good to go.

16

Thats the true budget way to do it from parts shipped from your local HK dealer... haha love it!

And those are nice wheels! your not using hard pack lipos?

17

you got to love hobby king, cheap parts and batteries, im not using hard case lipo,s to hard to fit into the two side battery trays, the batteries are well protected inside the sealed side trays on the Merv and these batteries are like 8 bucks each lols, the parrallel board you could use it for balance charging torch li-ions also from 12 to 36 batteries at once witch ive thought about.

6 x 18650,s is about all i need balance charged at once, two torches run 3 x 18650,s each and one runs 1 x 18650, one torch runs on 2 x 18650,s but ive given that one to my old man with a single 18650 battery holder for charging, what ive made sofar and the 6s im waiting for some more magnets for should be ok till i buy more torches.

18

Wow, Odd seeing benckie here after all his help at CPF in doing my setup. First ill say he inspired me to get off my duff and get my balance charging station built so i could use my Hyperion for more than capacity testing cells and charging single cells which takes forever. Many times id just pull out my Pila charger so i could do it faster.

My charger is the Hyperion EOS 720i NET3 AD and will do 7s on Li-Ion cells while balancing them and its 100% software controlled threw my laptop. With benckies help all i had to do was figure out my pin-out on my balancing lead and i had perfect sized copper single wire to make extensions with and solder magnets too. I can pull out leads i dont need or add them as needed depending on how many cells im working with.

My setup is built around my cell rail, Its made from two ratchet socket holders that i pulled the snap-on clips off and insulated all the steel with first masking tape and them electrical tape so no shorts happen. I used 4 clips that i pulled off the rails to hold the rails back too back and also to stabilize the whole rail by making it wider like feet. Then added silicone adhesive on the ends and in the middle. I also placed 6 20mm O-rings on it to help keep the cells in place just as a precaution and one helps keep the temperature probe tightly on a cell also.

I did run into an issue in how my charger uses its leads in a different order than others ive seen done, So that took a bit of experimentation to get that right and i use NiMH cells so i didn't explode any Li-Ion cells.

First is a screen shot of the software as it runs, This is 5s 18350's doing a discharge and all were close in voltage but not the best so you can see how the charger is affecting the loads to each cell. When its done with this discharge cycle they all will be 3.0v and ready to charge as a group, But im cycling these a few times to breaking them in as they are new from BIO.

In the first set of pics with the 18650 IMR's i have the red wire inline with the chargers red wire, But ive found thet since my chargers balance wires are different it was easier to put it at the other end as its the first wire that gets hooked up every time now.

19

i like it over here better

20

You and me too brotha....

But CPF does have helpful members many times, What was odd was this time i got help there it was from a member here! lol

I just act more kool and snooty to blend in when im there.

While im here i better ask this. We had a power outage at my house tonight and of course my lights were used by the family to light up the rooms and carried when moving about the house. So i have MANY cells to charge tomorrow. But i have no clue on the do's and donts of different charging characteristics a hobby charger can handle.

I have 2 types of 18650's that will need charged 2600mAH and 2900mAH of different brands, Can both be done with the balancer? Also what should be the max voltage cell gap if it matters or not?

Im pretty sure i cant charge 18650's and 18350's together?

Maybe another question, Ive read that cycling Li-Ion cells a few times will help them reach their peak capacity as it goes up the first 5 or so cycles it goes threw even when used in a light. Does it really help?

I was told that it for sure do anything for IMR cells, True?

Lastly a comment, Maybe it is bragging tho i dont know. But i just love this charger. If it has a weakness i haven't found it. It has 4 buttons on it that ive never touched due to the easy to use software that does 100% of everything. I know i wont be talking anyone into getting one due to the price, But this was one time i felt i needed to treat myself as i knew pushing buttons for hundreds of options would be a nightmare for me. But if you get a chance, Check one out. You wont be dissapointed, Even with the high price tag.