Take a closer look at the bms wiring diagram. There is no pin for a ground wire on the bms balance connector.
Yeah I did. The battery location/cells are flipped. I followed the diagram.
Not really, because they are designed for a balance charger not a bms
Why though? What’s the actual difference?
First of all, this is not about proving you wrong. Its about preventing a disaster. The battery supports bms like the Bestech bms do not have a ground pin on there balance ports. They use the main ground wire for that.
A balance charger is made differently and has a ground connection on its balance port.
Lipo batteries are not really designed to be used with a Bms. They are designed to be charged with a balance charger. That is why they are wired that way. To use Lipos with a Bms, you have to modify their wiring by omitting the ground wire on every pack.
I understand what you are saying, but if you look at the diagram and the way that the batteries are connected, the ground balance pin is NOT connected to the BMS. The “main ground wire” is!
A balance charger is made differently and has a ground connection on its balance port.
That’s why one of the batteries does not have a connection to the balance port from it’s balance plug!
one of the battery’s balance ground wires is not connected but the other battery’s is.
And neither should be.
That’s simply not true. The two wires are already connected together due to the two batteries being connected in series through the larger plug. And, these two wires need to be connected to the BMS according to the diagram which I highlighted here:
You are misinterpreting the diagram
No you are.
I’ve wired Li-ions and Lipos to Bms’s Have you ever actually wired a bms?
What brand of bms is that? There are some bms that use a ground wire on the balance port but battery supports or Supower, do not. In the diagram for battery supports, it shows only 6 pins for 6s battery a wire goes from the positive side of each cell to one of the 6 pins on the balance port. That is what the diagram shows.
Though all the cells and in both packs are connected in series through the main power leads. The balance wires isolate each cell so that the bms can monitor each cell separately.
It’s a Chinese brand, but my BMS is also a 6S, and it does not use a ground wire on the balance port.
@mmaner 's BMS also balances each cell, just like mine does. I don’t think you are correct in any of your claims. The plus and minus of the two batteries are supposed to be connected together, and to the balance port; the negative lead of the entire pack from the balance port is NOT connected; this system should work.
@mmaner The main power leads are connected in series but the balance wires are not suppose to be connected in series. They are suppose to be isolated. That is why there are 6 pins on the bms balance port. One pin for eace positive side of each cell. In a Lipo pack, that means the colored balance wires only. The black balance wire is connected to the main ground lead of each pack. and has to be omitted when connecting to a Bms balance port.
Here is my Lipo with bms build
Ok, after reconsidering this I realize that connecting the ground wire from the 2nd pack as shown in the diagram should not cause any problem. However, it is unnecessary.
Thank God. I was running out of popcorn!
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