openrcforums

Right... anyone have any information on

1. How to connect up the various balance charge leads to the different batterie pack formations?
2. Where to buy the JST connections from?

I am sorry if I misunderstand your question. I am assuming that you want to build lipo packs.:

Building lipo packs is pretty easy. All packs are connected in a chain. Positive to negative. The JST balance lead should have one more lead than the number of cells in the pack. 4 leads for a 3 cell pack. 3 leads for a two cell.

The red lead of the balance contact is connected to the positive end of the chain. Each successive lead of the contact is connected to the next solder joint in the battery chain. The last lead is black and goes to the negative pole of the chain.

Solder the cells first, the power cables next and the balance lead last. Use tape to isolate the soldered cells. Be very careful not to short anything. I have shorted a lot of batteries and I consider myself as a careful person.

I buy my connectors from Hobbyking and always harvest power Leads and balance connectors from the lipo packs I discard.

Ok.... Do you have an easy to view picture/diagram so I can get my head round it?

Also.. How does wiring work when we end up with parallel cells rather than in series?

Rob


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like this?

http://scriptasylum.com/rc_speed/lipo.html


I like this one too...

https://sites.google.com/site/tjinguyte ... onnectors/


google lipo wiring

The second link was just great! I can not imagine there is anything more anyone would benefit to know about balance connectors.

As far as parallel lipo cells go : Don't do it. Just don't.

If you permanently connect two or more cells in parallell, you have created a new cell where the individual subcells can not be balanced. This is a really bad idea. It is a much better idea to make adapters that connect two or more battery packs in parallel. This way you can still balance each cell in the packs. Make sure to use packs that are well matched, that is has the same energy content, maximum discharge ratio and internal resistance. If not, you will not be able to get the maximum performance possible out of the battery.

Thanks.. great info!

parallel connected cells will automatically be balanced with each other.

A single cell that tries to go higher in voltage than another paralelled cell will automatically get less load current.
And this is exactly what a balancer does.

Reinhard

So.. all we need to do is connect up to the cells that are in 'series' with the balance leads.

Note the JST connectors can handle a maximum of 3 amps. Probably the same is true for the other types.
-Gohst

ReSt wrote:parallel connected cells will automatically be balanced with each other.

A single cell that tries to go higher in voltage than another paralelled cell will automatically get less load current.
And this is exactly what a balancer does.

Reinhard

Reinhard, I agree. In the Li-Ion camp, they routinely parallel up to 4 cells, then series these sub-packs, 99% of notebook batteries is connected this way. I have charged Li-Ion cells in parallel up to 100 cells many times over the last 15 years, zero problems.

With two cells in parallel, during charge or dis-charge, they balance them self as Reinhard said.

Ozzy

Rob Thomson wrote:

1. Where to buy the JST connections from?

The charging cables use JST XH series connectors. They are available from Digi-Key in the USA, but there are several sellers on eBay shipping from China, typically in sets of 10 including contacts.

Look for a seller called sammylam, he is extremely reliable.

These guys are good too....

http://www.ebay.com/itm/2S-6S-JST-XH-Ad ... 825wt_1080

or you can buy them in lots of 10 from Hobby king.....

2S

Found a superb tool online today...

http://scriptasylum.com/rc_speed/lipo.html

It shows you how to make each pack and wire it.. just select the config... picture showing wiring is generated.

Rob