2x5s balance leads into 10s balance leads

[Massy]

Hi!

So I finally have everything to get my board together. However I'm not 100% certain how to hook up the balance leads.

Right now I have 2 5s packs each with 6 balance wires. I need to merge these into a single 10s balance lead with 10 cables.

I think I almost got it but I want to be sure it's correct before accidentaly starting a LiPo fire. I feel I have one cable too much but I guess that might be because this goes into a BMS rather than regular balance charger? I beleive that I do not need the first negative as this is connected via B- cable to the BMS, correct?

So if someone could help me fill in the blanks here it would be greatly appreciated.

BMS using: http://www.batterysupports.com/36v-37v-42v-10s-60a-10x-36v-lithium-ion-lipolymer-battery-bms-p-267.html

 

[Ianhill]

No it is nit as above that wrong, start at the negative end off the pack with the 5s balance lead and place the negative of blance plug with the first cell negative then so on to the 5th cell that is the end for one balance lead and the start for the other so cell 5 + is the end of one balance cable and the - of the next 5s balance lead start at the same spot so the potential difference across the leads is always the voltage of one cell. Iam poor at explaining sorry

 

[Massy]

No it is nit as above that wrong, start at the negative end off the pack with the 5s balance lead and place the negative of blance plug with the first cell negative then so on to the 5th cell that is the end for one balance lead and the start for the other so cell 5 + is the end of one balance cable and the - of the next 5s balance lead start at the same spot so the potential difference across the leads is always the voltage of one cell. Iam poor at explaining sorry

I think I understand this. However I have 12 cables supposed to merge into 10. I understand the ones in the middle should merge into one cable leaving me with 11 cables, not 10. Can someone bring some sense into this?

 

[WeeChumlee]

Just to correct your drawing to reduce confusion.
The 10S balance plug will have 11 leads, just as the 5S plug has 6 leads.
Then do as Ian said.

 

[Massy]

Just to correct your drawing to reduce confusion.
The 10S balance plug will have 11 leads, just as the 5S plug has 6 leads.
Then do as Ian said.

My 10s BMS has only 10 pins which is what confuses me to the point where I'm close to becoming crazy.. :? If that wasn't the case I would probably have it all wired up by now...

 

[Ianhill]

I can not see what is going on with BMS pin 1 from that drawing its been cropped to much it looks to have 9 cells if u count them

 

[Massy]

I can not see what is going on with BMS pin 1 from that drawing its been cropped to much it looks to have 9 cells if u count them

Haha, ooops I have updated the picture to be smaller, the image is not cropped but you might have a smaller screen than me

 

[WeeChumlee]

In this case the 'missing' 11th pin is just the minus connection.
That diagram pretty much says it all, can't really improve on that.
Google 3S to 6S balance leads as they are common. 5S is obviously the same.

 

[Ianhill]

As chum Lee said
I can see the whole picture now shitty android phones

 

[Massy]

In this case the 'missing' 11th pin is just the minus connection.
That diagram pretty much says it all, can't really improve on that.
Google 3S to 6S balance leads as they are common. 5S is obviously the same.

Thank you! So just to double check, does this mean the black (negative) cable from the negative batteries balance lead is left disconnected (since this is connected via the P- anyway)? This would mean that when I measure the voltage from pin 1-10 I'd get only 34 instead of 38 volts, correct?

As mentioned before everything would be 100% clear it's just this "missing" pin that confuses me.

 

[Massy]

Now I've soldered the balancing cables. Could anyone confirm that pin 1-10 should measure ~34 rather than ~38 volts and that the last cell will be connected by BMS from P-? Is it safe to measure from negative terminal to the positive balance pin? If so, this should equal 38 volts, correct? That is measuring pin 1 and 2 should actually be the second cell?

 

[WeeChumlee]

Indeed, per the drawing above measuring between terminals 1 and 10 would measure 9 cells.
Sure you can measure between B- and terminal 10 - this would give you full battery voltage.

 

[Massy]

Indeed, per the drawing above measuring between terminals 1 and 10 would measure 9 cells.
Sure you can measure between B- and terminal 10 - this would give you full battery voltage.

Thank you so much, will do the last soldering to the BMS tomorrow and hopefully all will be well!

 

[WeeChumlee]

Good luck dude. Post a few picks of your boards when done.

 

[Hwy89]

In your drawing you have one of the balance connectors reversed. The most positive terminal on the bottom pack connects to the most negative terminal on the top pack. This point corresponds with wire 6 (s5) of the 11. Wire 11 will be s10 and will be the most positive of the top pack referred to as B+.

 

[Massy]

Good luck dude. Post a few picks of your boards when done.

Sure will, might have a video coming too Although I might put it together with duct tape initially until I have time to make it look good

Here's a benchtest with power supply before I connected up the BMS and batteries to keep you happy for now
[youtube]QJt321varlY[/youtube]

In your drawing you have one of the balance connectors reversed. The most positive terminal on the bottom pack connects to the most negative terminal on the top pack. This point corresponds with wire 6 (s5) of the 11. Wire 11 will be s10 and will be the most positive of the top pack referred to as B+.

Thanks for looking out for me, that would have been disastrous but I actually did it correct once actually measuring with a multimeter etc. Charging the batteries right now, so far so good after 30-40 min.

Edit: Success, all cells at ~4.22 V and the whole battery at 42.1 Volts

 

[WeeChumlee]

Glad you got it sorted.
Hope to see the complete build once done. Have a blast.

 

[Redfire]

Hi anyone I have 2x5s cont get my bms to work I want to used them for charging but it’s not working like I want to con you send me a diagram