How To: Make a Y Balancer Harness

[BrianG]

The part you circled in greed is simply the bridge connection between each paralleled cell. A 5s2p pack is simply made up of two paralleled cells, with five of those pairs in series. The picture shows what looks like bus bars for the sake of example, but lipo cells are generally not shaped like that so the tabs would just the tied together to make the connection. A123 cells though, would have bus bars similar to that because of their shape. It simply comes down to the cell's physical shape and layout.

Yes, there is only one balance tap no matter how many paralleled cells there are. This is because the contact points for each paralleled cell are electrically the same point, so only one set of tap points are needed for each paralleled set. That drawing is only used if one wants to make their own lipo pack; it shows the electrical connections even though it might not look like that in the real world. This happens all the time in the electronics world where a schematic diagram never looks like the physical layout. A schematic is handy for the designer/builder/troubleshooter. A layout diagram would show the true physical layout of the components, but it is difficult to troubleshoot/build a circuit using this type of diagram. The diagram you circled is really a combination of a schematic and a layout diagram, hence the slight misunderstanding.

Now, on the Y adaptor diagram, it assumes the individual packs were wired correctly, so from a connector standpoint, it does not matter if the packs are 2s1p or 2s200p. This diagram is to show how to wire a series charging/balancing harness when using two packs.

I hope all that made sense!

Hi Brian,

I am still confused about the whole bridge thing. If these cells were regular rectangular lipo cells (not A123), what would the bridge physically look like (the green thing I circled). Also, when you say "the contact points for each parallel cell are electrically the same point," if I have two packs in parallel, what does this look like as well? I just never seen or heard of these concepts before and this why I am asking.

Thanks for your help.

Okay so going back to the 5s2p example, would all the + terminals of the first pack go on top of all the + terminals of of the second pack and the same with all the negative terminals and not just the + and - terminals at the ends of both packs, which make up the power/discharge leads?

[josh9mille]

Is this kinda the same thing? http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=9910&Product_Name=2_x_3S_->_6S_Splitter_JST-XH__(5pcs/bag)