Tech Tricks: Homemade Balance Charging Cradles.

[benckie]

I have got my battery holders from www.luminousdiy.com its a pity Chris is no longer going to be selling them

2 x 18650 and a compact 6 x 18650 (3 top 3 bottom)

I'm going to make these into balance charging box,s

 

[benckie]

2S balance revision 0

ill neaten it up a bit but so far i like it better then the magnets.

 

[jenskh]

Here is my setup:

I have placed both the charger and the charging cradles in a metal toolbox as an extra precaution.
The charging cradles are made from cheap chargers bought on e-bay, where I have ripped out all electronics, and soldered wires to the positive and negative terminals. This way, I can set up this as I want parallell or in series. Normally I use it in series with balance leads connected. All actual battery sizes fits. I can charge any number of batteries (at current up to four) by just moving the positive wire from the charger. This looks a little messy, but is very easy to use. I have earlier used magnets, but found it very cumbersome to get all the balancing leads in correct position.

 

[benckie]

Looks good, the magnets can be painful when they keep clanging together when your trying to set up some batteries for charging, the rare earths are prity dam strong, I believe my 6 x 18650 compact holder is going to be messy with all the balance wires going from side to side

 

[DFiorentino]

Technically, this probably doesn't belong here, but since I do have it hooked up to my iCharger's balance port (1S) here you go:

1S6P charging clamp station...

Built to take the pain out of the few hundred battery tests I've done and am doing recently.

-DF

 

[Battery Guy]

Also, since you are charging loose cells, there is no need (or advantage) to balance charge them in series - just charge them in parallel. Here's how I charge 1-8 cells at the same time.

rmteo

Where did you find that awesome cell holder? I have been looking for a multi-cell, parallel holder like that for charging 26500 and 26650s in parallel, but I have not been able to find one.

 

[Battery Guy]

Not necessarily. Some lithium ion cells show improved internal resistance after a few cycles from new. There can therefore be an advantage to "breaking in" lithium ion cells to get the best performance out of them.

Hi Mr H. I've seen this suggested from time to time, however I've never seen where any manufacturer recommends a "break-in" for Li-Ion cells. Maybe this applies to the newer high cap cells with the nickel safety layer?

If the cell manufacturer knows what they are doing and the cells going out the door are fully formed and aged properly, then there is no need or advantage of running a break-in cycle. Unfortunately, many cell manufacturers either don't know how to properly perform formation on their cells, and/or they shortcut the aging process to get product out the door. If you get cells from these manufacturers, then a couple low rate charge/discharge cycles may indeed help improve internal resistance and stabilize capacity.

Cheers,
BG

 

[Justin Case]

rmteo

Where did you find that awesome cell holder? I have been looking for a multi-cell, parallel holder like that for charging 26500 and 26650s in parallel, but I have not been able to find one.

That rig looks like a row of Bulgin BX0123 holders.

 

[45/70]

Unfortunately, many cell manufacturers either don't know how to properly perform formation on their cells, and/or they shortcut the aging process to get product out the door.

Well, that's not exactly reassuring to hear LOL!

I have to say though, that even with cells of unknown origin (think CrapiFire, BangiFire etc.), I have never witnessed a Li-Ion cell that improved with cycling. There have been minor variations in tested capacity from time to time, but this goes both ways, higher and lower. I have attributed this to difference in room temperature, difference in time since the cell was last charged/discharged etc. And, as I've said before, other than hearsay, I've never read, or heard anything from a reputable source, that any Li-Ion cells require, or benefit from cycling.

Dave

 

[eatkabab]

I'm trying to simplify and shrink the connector for a battery pack I'm making out of 2 RCR123's to be run in parallel and was wondering if the following setup would be a safe charging method.

I'd rather use a TRS connector rather than a TRRS for simplicity and the increased difficulty of four wires rather than three. I would also like to avoid having to use a hobby charger (trying to make this thing idiot proof). I figure the dangerous aspect of using lithium batteries is charging them, so I want to make sure I have that down. I figured this would be the best place to ask this given that you guys are thinking outside the box(es).

Thank you!

 

[MikeAusC]

TRS connectors will short out the battery when you insert or remove the plug!!!

Also you may not be able to connect together two terminals of the charger.

 

[eatkabab]

TRS connectors will short out the battery when you insert or remove the plug!!!

Also you may not be able to connect together two terminals of the charger.

With the orientation that I've drawn above, the batteries shouldn't short when inserted/removed because the (-) terminal won't make contact until it's all the way in. That being said, I know there are points when one contact will touch 2 'bands' on the connector. Again, with the ground being the last thing to make contact, this shouldn't be a problem.

Just a question; each cell has it's own protection circuitry so if they were shorted upon insertion/removal, would it shorten the life of the battery or it's PCB at all?

As for your other point, that's what I'm worried about. Will the charger be able to read the two voltages independently from a single ground contact and separate (+) contacts?

 

[Mr Happy]

Just a question; each cell has it's own protection circuitry so if they were shorted upon insertion/removal, would it shorten the life of the battery or it's PCB at all?

It's not an "if" that should be contemplated. Simply make sure that under no circumstances can the battery positive and negative terminals be shorted together. Neither during partial insertion/removal of the plug or any other means. If the plug is of a kind where that can happen, then use a different design of plug.

As for your other point, that's what I'm worried about. Will the charger be able to read the two voltages independently from a single ground contact and separate (+) contacts?

In your diagram, you have Ch1 and Ch2 negative terminals of the charger connected together by the black wire. In other words, you have made a short circuit. You might damage or upset the operation of the charger by doing this. You should not do it unless you look inside the charger and determine that such a connection already exists in the internal wiring.

 

[eatkabab]

In your diagram, you have Ch1 and Ch2 negative terminals of the charger connected together by the black wire. In other words, you have made a short circuit. You might damage or upset the operation of the charger by doing this. You should not do it unless you look inside the charger and determine that such a connection already exists in the internal wiring.

So in essence two circuits sharing a ground connection are still independent? The ability to monitor voltage independently and charge independently is only limited by the charger electronics? As in, I can just build my own two channel charger.....and make it work.......?

 

[Mr Happy]

So in essence two circuits sharing a ground connection are still independent? The ability to monitor voltage independently and charge independently is only limited by the charger electronics? As in, I can just build my own two channel charger.....and make it work.......?

If you have two circuits that are completely isolated and independent from one another then making a one wire connection between them will not upset them. However, two charger circuits on the same power supply are highly unlikely to be independent. If two circuits are dependent and you connect them in the wrong place you will upset them.

I'm not saying you can't make the connection shown in your diagram, I am saying you must check it is OK to do so before going ahead. That check involves looking inside the charger to see how the circuits are arranged. The charger may internally have a common "ground" either on the positive side or the negative side of the batteries. You cannot tell without looking.

 

[xxgg]

Hello,

I am just wondering,

How much 'amp' do you guys use to charge your batteries?

Is it safe to charge at 1C rate ?

 

[benckie]

Depends on the cell I charge from 0.5 to 1 amp

 

[KiwiMark]

Is it safe to charge at 1C rate ?

Most cells should be OK with it, but I'm rarely in a big hurry so I normally charge at around 1/2 C.

 

[JargonGR]

I know this is a thread resurrection but I have wasted so much time looking for a ready made "perfect" cradle that would accept all types of LiPo cells for charging that I honestly fed up. The easiest most convenient method up to now is LuxLuthor's method but I am not good with soldering and this is because I have invested almost zero time on it.

Nonetheless I won't give up and will continue to look for a nice neat way to do this job done. Upon searching I stumbled upon these products which are not made for LiPos but it is some food for thought. I don't even want to think how much they will charge for those judging from the what they do but still it would be nice if someone could make something like this for LiPos.

Just an idea.

Here is the link to their site: http://www.muchmoreracing.net/us/sub/sub.htm

And some photos:

 

[Nisei]

Balance charge cRe: Tech Tricks: Homemade Balance Charging Cradles.

Thread Merge - Norm

thanks Norm
Doh, now my post doesn't make sense anymore. All the info seems to be in this topic 🙂
I'll post a pic when I've finished it.