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Battery balance lead

Posted: Wed Jul 22, 2015 3:53 pm
by Lee
I think it was Graham that mentioned somewhere, about how to recover a cell that has a higher, or lower voltage than the others.

Well if your charger isn't doing a good job of balancing the cells,
or you have a battery thats taking ages to charge because of one lazy cell,
here is a way to over come that.

This is a cable, I made up, for charging one cell at a time.
Its consists of two header pins, the cable and what ever end you need to plug into your charger.
I'm using a JST to plug into and existing charge cable I have, or you could just put bullets on the plug straight into your charger.
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To charge Cell 1, plug in the header pins with the neg pin going to the negative pin on the balance cable.
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For Cell 2, move the header pins along one pin. (always keep the negative pin towards the negative end of the balance plug)
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Then for Cell 3, use the last two pins.
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If this was a 4,5 or 6 cell, you would just carry on moving along one pin at a time.

Lets say, you have a battery that always finishes charging at 4.2, 3.9, 4.2.
You could plug this cable into cell 2 and top it up to equal the other two.
Its just as if you are charging a 1 cell pack instead of 3.
Charge at a very low rate (max of 1A)

Another scenario, is when a cell is too low for the charger to start. Or a battery arrive new, with one cell seemingly dead.
You can use this technique to try and recover the cell.

Hope this helps someone out.
Any questions, just ask.
Always be careful and never leave your battery charging unsupervised.
I'm not responsible for you burning your house down :D

Re: Battery balance lead

Posted: Wed Jul 22, 2015 7:47 pm
by Graham Lawrie
Thats it Lee:) thats what i do:) great pictures and thread:)

Re: Battery balance lead

Posted: Wed Jul 22, 2015 8:09 pm
by cml001
I don't understand why u move the negative pin... Should it not stay in the black lead?

Re: Battery balance lead

Posted: Wed Jul 22, 2015 8:12 pm
by Graham Lawrie
No:) as long as it is facing the negative side its fine. If you were to reverse it soit was to the positive side.........magic smoke:)

Re: Battery balance lead

Posted: Wed Jul 22, 2015 8:52 pm
by Derek
That's cool, Lee! Thanks for sharing that!

Re: Battery balance lead

Posted: Wed Jul 22, 2015 8:54 pm
by Tony
Cool idea Lee, thanks for sharing that

Re: Battery balance lead

Posted: Thu Jul 23, 2015 12:47 am
by cml001
I still don't get it.. Is the black wire off the battery not neg/ground/earth?

Re: Battery balance lead

Posted: Thu Jul 23, 2015 5:21 am
by Tony
cml001 wrote:I still don't get it.. Is the black wire off the battery not neg/ground/earth?
Because your cells are in series mate, as an example, get a few AA's or something similar and stack them on top of each other, say 3 of them... Now if you wanted to charge the middle one you'd have to put the charger straight across it which is the same as what Lee has done by moving the neg wire up...

Re: Battery balance lead

Posted: Thu Jul 23, 2015 11:12 am
by cml001
Ok, I see.

Re: Battery balance lead

Posted: Thu Jul 23, 2015 7:51 pm
by Graham Lawrie
Tony wrote:
cml001 wrote:I still don't get it.. Is the black wire off the battery not neg/ground/earth?
Because your cells are in series mate, as an example, get a few AA's or something similar and stack them on top of each other, say 3 of them... Now if you wanted to charge the middle one you'd have to put the charger straight across it which is the same as what Lee has done by moving the neg wire up...
Good explanation Tony:) using your knowledge and sharing:) Love it:)

Re: Battery balance lead

Posted: Thu Jul 23, 2015 7:55 pm
by Tony
Thanks mate