balance tap issue
 

Last weekend I had a bad collision and the balance tap on my neu lipo was smashed. I ordered Hyperion taps to replace it so I do not have to always change adapters.

I tested the voltage on each balance lead and put them in the order, negative, 3.7v, 7.4v, 10.1v, 14.8v. When I test on volt meter they test fine, when I test my other packs wired with hyperion adapters they are layed out the same way, but the voltages are displayed as -3.7, -7.4, -10.1, and -14.8.

If I plug the neu pack into the balancer no cells are detected and the balancer get real hot.

I know I've done something wrong but can't figure out what. I'd like to get this pack working again before I go to the track sunday, otherwise i only have a heavy trc pack to run.

Could you have reversed the volt meter by any chance? Looks like that's why it reading the negative voltages. And maybe the balancer was plugged in reverse as well.

the balancer only fits one way, it is keyed. The voltmeter was set the same for reading all packs. I had them in a line and went down the line.

If you measure negative voltages across the Hyperion taps on your other packs, then you have your ground lead attached to the positive side of cell 4. Then when you measure, you get the following:

Cell 4 + to Cell 3/4 junction = -3.7V
Cell 4 + to Cell 2/3 junction = -7.4V
Cell 4 + to Cell 1/2 junction = -11.1V
Cell 4 + to Cell 1 - = -14.8V

In short, you have your wires backwards in the balance tap.

Should I resolder the ground lead to + side of cell 4 on the Neu pack then or resolder the entire pack? The wires are layed out the same way in each tap, ground going to the slot with the arrow on it and counting up voltage each one over.

The only difference it the neu pack reads + voltage and the MA and TRC packs read - voltage.

to note, the MA and TRC packs are as they came from the factory and have never had the shrink removed or been modified in any way.

Here's what I would do:

Measure the tap wires and find which lead is your ground. Take that lead and it should go into the first slot on the balance tap. The next wire should be the junction between either cells 1/2 or 3/4 depending on how the ground is set up. Just make sure it reads +3.7V like your other packs do. Then repeat the process until you have all wires populated and the polarity is correct like your other packs.

I believe the ground setup is the issue. I have the ground and each junction marked. ground is going to slot 1, the 3-4 bridge is going to slot 5, 2-3 to 4, 1-2 to 3 and cell 1 lead to 2.

The only difference in the layout of the wires in the tap is the polarity. I tried putting the 3-4 junction into slot 2 last night and that made smoke come from the balancer (fortunately no damage and I balanced all my other packs afterward to verify).

I get most of it I guess what I'm not grasping is how to make them read -v at the tap rather than +v. the balancer recognizes no cells with the +v configuration. short of polarity all packs read voltages in the same tap locations.

I wish I were at home and not work so I could snap a picture.

I'm not a retard but I'm sure starting to feel like one. This is the first time I have ever had to work on a lipo other than balance and charge. and do to their potentially volatile nature I have my reservations.

I can slap together nimh packs in minutes, I feel real dumb that I'm just not grasping this.

Gimme a minute and I'll have you a diagram.

You should wire it like this:

Attachment 5866

If you measure with your meter ground on slot 1 and meter positive on slot 2, you should get -3.7V just like you did with your other packs. Every wire but the center wire in your balance tap needs to be reverse. Swap slot 1 and 5 and swap slot 2 and 4. You should then read the following:

With your meter ground on slot 1 and the positive meter lead on slot 2 = -3.7V
With your meter ground on slot 1 and the positive meter lead on slot 3 = -7.4V
With your meter ground on slot 1 and the positive meter lead on slot 4 = -11.1V
With your meter ground on slot 1 and the positive meter lead on slot 5 = -14.8V

That makes sense'ish. I'll dive into it when I get home and post pics from the hospital when I blow myself up! :angel:

If you match the polarity on all slots to your existing packs, you should be good to go. The pic I added will do that for you.

That's the way to go.

PS you don't have to rewire - take a small screw driver, and press into the top of the hyperion tap and you can slide the pins out ...

Do this a couple at a time to reverse them - careful not to short any cells.

I do this all the time when building packs...

That part I figured out :yes: it was the - voltage part... I think I got it now. I'll blow myself up when I get home. :whistle: