a123 2s3p ballance tap

[scott m lyons]

Hey guys need some help.I'm building some packs out of dewalt 1100's.I want to do 3 packs of 2 cells each so 6 cells in total.So I'll end up with 6.6 volt pack with 3300 mha's.My problem is how do you hook up the ballance tap for this application.I want to ballance each cell.Is it better to do it with a blinky with 7 wires or wire them as seperate packs within the 6 cells..So three ballance taps per pack.HELP!!!!

[mrdakota]

I haven't done 3 in parallel but I've done alot of two parallel with a servo y-harness to a blinky. Be sure to make the balance wire connection so the black is negative the red as the center tap and the white (organge-JR) the positive for the blinky connection. you then would have to make a custom 3-way harness or gang two of them, then all three batteries will be paralleled and balanced.
Make sure you do not connect this arrangment to the rx, just use another set of wires to the rx from the batteries.
On a side note: I've seen a few people connect the white (orange-JR) as the center tap right to the rx and have had a severe cell imbalance happen as the rx will constantly draw current between the neg(blk) and wht(org-JR), and that is bad.......MMM-ok

[paolime]

Picture says a thousand words Got any?

[mrdakota]

Sorry, I'm not an artist but I stay at a Holiday Inn often though

[wfield0455]

I'm a bit confused by your drawing. It looks like you basically cascaded a couple of Y harness to make a 3 into 1 harness and connected it to a single blinky??? Isn't that basically the same as tying all 3 center taps together and using a single balance tap and a single blinky? With the way you wired this, wouldn't you need 3 blinkys to balance all cells individually?

Wayne

[mrdakota]

	Quote: Originally Posted by wefcisco
	I'm a bit confused by your drawing. It looks like you basically cascaded a couple of Y harness to make a 3 into 1 harness and connected it to a single blinky??? Isn't that basically the same as tying all 3 center taps together and using a single balance tap and a single blinky? With the way you wired this, wouldn't you need 3 blinkys to balance all cells individually? Wayne

Wayne,
Yes, all three are connected together in parallel and therefore brought to the blinky as one big 3300mAh battery pack. Why would you want to balance them seperately.

[scott m lyons]

I'd like to ballance every battery not just the packs.I was thinking a seven wire ballance tap to a blinky.I think the blinky will take up to a 6 cell right?

[mrdakota]

That's fine. I thought you had three seperate batteries. My mistake. I'm not sure that would work with a 6.6v configuration. I'll give it some thought.

[wfield0455]

	Quote: Originally Posted by mrdakota
	Wayne, Yes, all three are connected together in parallel and therefore brought to the blinky as one big 3300mAh battery pack. Why would you want to balance them seperately.

I thought you were trying to balance all cells individually because you added 3 balance taps and 3 blinkys would allow you to balance them a 3 individual 2 cell packs. If you simply want to balance
the pack as a single large capacity 2 cell pack, you can eliminate 2 balance taps and the Y harnesses by simply tying the balance nodes in parallel right at the battery pack.. Actually the following webpage http://scriptasylum.com/rc_speed/_lipo.html in the A123 for dummies thread and it shows the wiring diagrams with or without balance taps for the various pack configurations.