[ SOLVED ] Bms cell order? does it matter? ANSWER: It absolutely matters

So I’m trying to connect two 5s lipos to a bms from Mboards and I have checked with others and my wiring for the b- and ch- ports on the bms are correct, with a negative lead going to my b- port and my negative charge port wire going to my ch- port. However what is concerning me is my order of balance wires. After reading a long thread about this, I am certain I have it wrong, and I was wondering if someone could tell me the order of the cells, because some color wires repeat. @mmaner @Namasaki I saw on the other thread that you guys have a lot of knownledge on this topic, maybe you could shed some light on this for me? Thanks

It definitely matters. Your BMS should have a diagram showing the cell numbers. The battery cell numbers are defined by voltage, the lowest voltage being cell 1 and increasing incrementally to the highest voltage being the last cell.


As @mmaner stated, it does matter and if you get it wrong, you will fry the bms.

I’m at work now but when I get home I will post a couple thoughts that I think will help. In the mean time could you post som picks of your Lipos’s wiring and a closeup of the bms balance port top and bottom with the wire connector in place and removed for clarity


Unfortunately I just left town for the weekend but I have a couple pictures I took before I left.imageimage

The top picture is how I connected the 10 pin connector to the two 6 pin connectors, I stuck the ends of the wires into the 6 pin connectors and hot glued them in place

My balance wiring starts with the pack that supplies the negative lead, and it goes 10-red 9-black 8-blue 7-white 6-yellow Second pack 5-red 4-Black 3-blue 2-white 1-yellow

I put them in this order because that is what order they connected in on the white plug

When you get back we need to start over by first removing the hot glue because you can’t just stuff wires in and hot glue them. They need to be soldered or crimped. Or else you will have intermittent connections that will cause a world of problems. Who ever told you that you could just hot glue the wires in place, Don’t take anymore advice from that source.


There should be some print on the bms circuit board that identifies the pins of the balance socket. Can you post a link of the 5s Lipos you are using?

With two 5s packs connected in series. The pack that supplies the negative main is Batt 1 (Cells 1,2,3,4,5) The pack that supplies the positive main is Batt 2 (Cells 6,7,8,9,10)

I need to see the balance wires coming from one of your batteries with it’s original balance connector to determine the cell order color code. There is no set standard for balance wire color code except that Red is always the last cell in series for each pack.

So, Batt 1 red balance wire is Cell 5 And, Batt 2 red balance wire is Cell 10

Lipo balance connectors always have an extra balance wire for ground which is always on the opposite end of the Red wire and is usually but not necessarily black.

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Ok starting to make a little more sense


This is where I got my batteries from. To see where the balance cables are coming from do I have to take off the shrink wrap?

No, don’t take off the shrink wrap. You identify the color code at the connector end.

image On the ten pin connector, the red wire on top with the black mark is 10, the top solder is my ch- port, and the bottom left solder is my b- port

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Are you sure this is a 10s bms and not a 9s? The original battery was if fact a 10s?

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Is the black wire on the bms identified as 1 or G

This is the bms and I used and 2x 5s lipos in series

What black wire? There were no labels, just a confusing diagram let me see if I can pull it up


Ok, no ground wire on the balance connector. The bms uses the main ground connected to B- as it’s ground source for balancing. So you only use 5 balance wires from each battery. You do not need to connect the balance ground wire from the battery

The ground wires are connected to the last cells negative side right?

You only connect positive wires to the bms balance connector

The balance ground of each pack is connected directly to the pack’s main ground wire.

I can’t find a clear picture of your battery’s balance leads to original connector. There is another option. We can identify them with a volt meter.

Ok thanks. I think I understand where everything goes, however I just need the order of the balance cells. I’m not a slacker, but I’m really inexperienced with multi meters and I was hoping that you might know which orders the balance wires go in