You would have to use a 2s align balancer - Unless you wire the packs in series for charging and in parrallel for running...

This no longer makes it 2am proof IMO. If you go this route just use Brian's guide for wiring the adapter

wiring
 

could you double up the wires on the 2s plug? the paired cells(ie one from each pack)would probably equalize if I am thinking about this right - I know its not Ideal but I have no space for a harness and want to solder both batteries output leads to the one deans plug (paralell) They are small packs so charge time wouldnt be an issue

No - it is not possible to wire a pack as a 2s2p and then try to balance it as a 4s. Since you have paired cells the balancer would not be able to "see" the cells as separate.

if you could reconfigure the pack to 2p 2s vs 2s 2p you'd have more options....

Gibberish...

Anyways, it is not possible to wire a pack as a 2s2p and then try to balance it as a 4s. Since you have paired cells the balancer would not be able to "see" the cells as separate.

If you left the cells configured as 2 2s packs you could make an adapter to charge them as a 4s, but you mentioned lack of room to do that.

I would just wire them as a 2s2p pack and use a 2s balancer harness. As long as the cells are similar in age and usage they should be fine. The paralleled pairs of cells will naturally equalize voltage. If the cells were different in age by alot you may have issues with one cell in the paralleled pairs taking voltage faster during the charge, that would be the only issue that I can think of.

Don't know what that linc guy is on - That what I was saying...

i.e. This is why it won't work

This is a 4s battery

Tap 1 Battery 1 Cell 1 (-)
Tap 2 Battery 1 Cell 1 (+) / Cell 2 (-)
Tap 3 Battery 1 Cell 2 (+) / Cell 3 (-)
Tap 4 Battery 1 Cell 3 (+) / Cell 4 (-)
Tap 5 Battery 1 Cell 4 (+)

This is an attempt at a 2s 1p as 4s and why it doesn't work

Tap 1 Battery 1 Cell 1 (-)
Tap 2 Battery 1 Cell 1 (+) / Cell 2 (-)
Tap 3 Battery 1 Cell 2 (+) / Battery 2 Cell 1 (-) / Battery 1 Cell 1 (-) - because the batteries are in parallel i.e. you will short the battery
Tap 4 Battery 2 Cell 1 (+) / Cell 2 (-)
Tap 5 Battery 2 Cell 2 (+)

Man, Do you just want to send me your posts to proofread before you throw them up on the forum? I can do that for a small fee, just to help out... Or is it too early for you?

and the consensus is
 

so if ive got this right and I use my balance charger to charge through both packs main leads siultaneously with the 2 2s taps converted to 1 2s tap I should be right (the packs are identical)
thanks for the input pls correct me if I'm wrong

"Lipo batteries make everthing better!"

PS i'll check your answer in the morning got to get up in5 1/2 hours

Yes.

Yep, that is correct.

Maybe I should add a parallel charging/balancing diagram to my site...

Brian,

I have some questions regarding your schematic under "Lipo Wiring" @ http://scriptasylum.com/rc_speed/_lipo.html. The example I will use is the 5S2P lipo configuration. I want to know what is represented by the wiring where the positive and negative junctions of each pack seem to be bridged to another adjacent pack?

I also noticed that there is only one balance tap for this entire configuration. It seems to be independent of the number of packs that are put in parallel provided that each pack has the same number of cells since I changed the parameters just to makes sure for myself. This seems to contradict your instructions on how to make the Y harness.

Hope you can clarify this for me.

Lipo Configuration Question
 

Brian,

I have some questions regarding your schematic under "Lipo Wiring" on your website. The example I'm using is a 5S2P lipo configuration. I want to know what is represented by the wiring where the positive and negative junctions of each pack seem to be bridged to another adjacent pack? In the attached photo it is circled in green if you can make it out lol.

I also noticed that there is only one balance tap for this entire configuration. It seems to be independent of the number of packs that are put in parallel provided that each pack has the same number of cells. I changed the cell parameters just to makes sure for myself. This seems to contradict your instructions on how to make a Y harness, where there are two balancing taps, one for each pack.

Hope you can clarify this for me.

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! :smile:

lipo configuration
 

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.

With a regular rectangular lipo cell, a parallel pair would be made by simply putting the cells on top of each other so both + tabs are touching and both - tabs are touching. Then you just fold them together and solder.

If you have two seperate packs in parallel, you'd have two seperate balance plugs. There is no current drawing for that specifically.

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?

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)

Yes, that is the same thing.

I wish they made one for 2s batteries, or can you just plug 2s batteries into that?