Tech Tricks: Homemade Balance Charging Cradles.
- Thread starter Conte
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Hack On Wheels
Enlightened
I'm in more or less that same boat, as I'm looking into putting together a hobby charger setup for probably up to 6 cells... I don't believe you can readily purchase magnetic leads. You can do it yourself if you are skilled with a soldering iron; I've read that you can ruin the magnetic ability of the magnets if you aren't fairly quick with your soldering.
That's another reason why some go for the cradles; I know I can manage to make one like Conte's even with my rough soldering. The magnetic leads are still an attractive option though, it really doesn't get more flexible or compact!
Thanks for keeping this thread updated, it's a really great guide and has given me a bunch of ideas for my own eventual setup. lovecpf
Black Rose
Flashlight Enthusiast
Another magnet option for Canadians is Lee Valley tools (if you have one nearby).
They have a good selection of rare earth magnets.
They have a good selection of rare earth magnets.
GarageBoy
Flashlight Enthusiast
Magnets dont mess up the batteries?
benckie
Newly Enlightened
here is revision 2 on the 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, got to practice soldering magnets.
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, got to practice soldering magnets.
benckie
Newly Enlightened
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.
single
2 cell balance charge
3 cell balance charge
just waiting on some more parts to make a 6 cell balance charging lead.
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benckie
Newly Enlightened
this would have to be a great one
http://www.hobbyking.com/hobbyking/store/__14856__Parallel_charging_Board_for_6_packs_2_6S.html
if you made your own balancing leads, you could charge from 12 to 36 li-ions at one time, or 6 x 2s up to 6 x 6s lipo,s you would need a charger with a 6s balance port and atlest 10 amp charge rate, or 20 amp charge like the icharger 208,s
i use that parrallel charging board for my lipo,s for my rc truck, with a icharger 106b+ and a p350 power supply
http://www.hobbyking.com/hobbyking/store/__14856__Parallel_charging_Board_for_6_packs_2_6S.html
if you made your own balancing leads, you could charge from 12 to 36 li-ions at one time, or 6 x 2s up to 6 x 6s lipo,s you would need a charger with a 6s balance port and atlest 10 amp charge rate, or 20 amp charge like the icharger 208,s
i use that parrallel charging board for my lipo,s for my rc truck, with a icharger 106b+ and a p350 power supply
jhn.holgate
Newly Enlightened
Great thread, thanks guys. A couple of home made cradles in parallel for my 18650's....
Im glad i found this thread as ive had my Hyperion 720i charger about 2 months now and mainly just do test cycles for capacity and rely on my Pila to charge cells since i have nothing set up for mass cell charging.
But i do have a question, How well do these cradles setup with the balancing leads handle discharging?
Does it just do a basic discharge, Or is it just as reliable as a single cell discharge cycle when using the balancing leads?
My main goal is to cycle many of my Li-Ion cells which tend to increase in capacity when new after a few cycles.
Im not sure which way i want to go on building a way of using my balancing leads as i do prefer cradles over magnets, But each has its good and bad points. I do know im not to fond of just hooking them in series or parallel and charging multi cells in that manner as you loose control of everything since the charger just sees one large battery.
Thanks for all the work in doing up this thread and pics as it should make my build easy, Especially i was just never gonna build a setup for multi cell balancing. Now i can get the full use of my charger and can see up to 6 cells graphs all running on my laptop as the charger does its job.
But i do have a question, How well do these cradles setup with the balancing leads handle discharging?
Does it just do a basic discharge, Or is it just as reliable as a single cell discharge cycle when using the balancing leads?
My main goal is to cycle many of my Li-Ion cells which tend to increase in capacity when new after a few cycles.
Im not sure which way i want to go on building a way of using my balancing leads as i do prefer cradles over magnets, But each has its good and bad points. I do know im not to fond of just hooking them in series or parallel and charging multi cells in that manner as you loose control of everything since the charger just sees one large battery.
Thanks for all the work in doing up this thread and pics as it should make my build easy, Especially i was just never gonna build a setup for multi cell balancing. Now i can get the full use of my charger and can see up to 6 cells graphs all running on my laptop as the charger does its job.
KiwiMark
Flashlight Enthusiast
Looks pretty similar to http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=15237 which I have ordered with my 208B and should arrive Monday or Tuesday. I don't normally parallel charge, but I figure there will be times that I want to get more batteries charged in a hurry and being able to charge 2 or 3 or 4 at once couldn't hurt. I have plenty of those T connectors and alligator clips to make more charging leads as required.
I think either cradle or magnets with serial balance leads or as one big parallel capacity will all work fine with discharges, as long as you are using the thicker main wire leads. The coating on the magnets of course has some resistance if you are using them to join cells in series or parallel, but if contact surfaces are clean, I have discharged cells connected with neodymium magnets at 10 Amps without noticing any resistance related heat with them.
I like the KJ Magnets which are durable, and triple coated with Nickel-Copper-Nickel but you can see there are comparative limits when using various metals.
Im kind of lost on this wire and plug wise.
These are the boards and adapter wire that came with my Hyperion 720i.
Do i need to use the board, Or can i cut the wires going into it and build my leads from that?
Or do i need a 7S plug that goes into the board from a battery pack?
And i included pics of both boards i have in case one is more useful than the other.
My goal is to build something from a 7S balancer set of wires and just use what i need. But im not sure what set of wires should be used to start from.
If i need a certain plug can you point me to one that is exactly what i need so i have no confusion.
These are the boards and adapter wire that came with my Hyperion 720i.
Do i need to use the board, Or can i cut the wires going into it and build my leads from that?
Or do i need a 7S plug that goes into the board from a battery pack?
And i included pics of both boards i have in case one is more useful than the other.
My goal is to build something from a 7S balancer set of wires and just use what i need. But im not sure what set of wires should be used to start from.
If i need a certain plug can you point me to one that is exactly what i need so i have no confusion.
benckie
Newly Enlightened
same thing, just with deans plugs (t connectors) just makes sure the batteries voltages are close
i like mine, but you must only plug batteries into it that have the same voltage and the same cell count, i only use mine when i use my rc car and ive run down say 4 batteries and they have all come off the same low voltage cut off and are pretty much the same voltage.
becuase this parrallel board is great but only for charging match cells with the same voltage after being discharged and the same cell count meaning you can either parallel ballance charge all 2s or all 3s to 6s but you can not mix a 2s and a 3s together, for this reason and for safety i balance charge in series.
jhn.holgate
Newly Enlightened
Mine is the same sort of thing - I'm going to keep my board intact because I have various LiPoly battery packs with the balancing leads already attached. But I've ordered some JST-XH extension leads - I figure I'll just cut the end off that I don't need and solder some ring terminals to suit my battery setup. You can get extension leads in 2-7s in packs of 10 for a few dollars from here: http://www.hobbyking.com/hobbyking/store/__9735__JST-XH_2S_Wire_Extension_20cm_10pcsbag.html
It can probably be wired up straight to the balancing plug in the charger, bypassing the board altogether.....but I'm not that smart!
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KiwiMark
Flashlight Enthusiast
Yes, if the voltages aren't around the same then I treat them as separate batteries and charge them separately. I only charge matching sets as a group (either balance charging in series or parallel charging) everything else gets charged one cell or one battery at a time.
I do have a couple of 4 cell battery boxes that use 4 x 18650 in parallel as a power source to charge a cellphone - because these are 4 cells in parallel they will always have the same voltage, so they should be fine for charging in parallel too. I'm using 4 x 2500mAh cells which I'd probably charge at 1.2A, so if I charged the 4 cells in parallel at 4.8A then they should get ~1.2A each.
I now have my 208B charger (capable of charging at 20A) and my parallel charging board as mentioned. I can use my 106B+ and my 208B at the same time (powered from the same ATX PSU) and charge 2 different cells (or sets of cells) at the same time - this makes it easy to charge my 4 x 2500mAh cells for my cellphone charger while also charging the 14500 from my EDC light. A hobby charger may be good, but 2 hobby chargers is better!
Maybe someone does know how to make a simple schematic from my plug so i can use it as a 7S set of leads all on its own. But if not the extension put me on the lead and idea of what i need. They show a 6S extension thats back-ordered so ill just find one somewhere else. The thing is i only need one plug as ill do it with magnets so its configurable as i need it to be.
I may pull the soft rubber backing off this board i have and look at the pin-outs and match them up to directions and pictures in the thread.
Thanks for the help.
I may pull the soft rubber backing off this board i have and look at the pin-outs and match them up to directions and pictures in the thread.
Thanks for the help.
KiwiMark
Flashlight Enthusiast
If any of this is wrong Lux will correct me (he knows his stuff)
There is no reason why you couldn't run off the that lead that plugs into your charger. Counting pin1 from the OPPOSITE end to the red wire I think it may works something like:
Pin 1 connects to the negative of cell 1 (same as main black wire), pin 2 to the +ve end of cell 1 (same as -ve of cell 2) pin 3 to the +ve of cell 2 (-ve of cell 3), etc.
I think you start from the pin furtherest from the red wire and stop once you are connected to the same place as the main red wire.
i.e.
3 cells:
pin 1 -ve of cell 1 (main black wire also connected here)
pin 2 -ve of cell 2
pin 3 -ve of cell 3
pin 4 +ve of cell 3 (main red wire also connected here)
other pins - not connected to anything (may need to insulate to ensure no contact)
Possibly something like a dab of paint on each wire (different colour for each wire) near the plug and another dab of the same colour near the end would help in keeping the wires in the right order.
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