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

ok i have two of those that i used for balance charging

@pat.speed I’m positive that b10 is on the left side

Also do you use lipos or li ions?

If this helps this is how I connect my batteries.

  1. connect them in series (red of one to black of other)

  2. Work out which balance lead is the first one (the lead also connected to the main black wire of the battery)

  3. Cut the bms wires to desired length

  4. One bms wire should be black that is the first one

  5. Plug that black wire into the first wire of the battery (in your case skip the first one and plug it into the second lead)

  6. Sequentially connect all of the next wires to the bms wires making sure to skip the first wire of the second plug (as that is already connected to the last wire of the first plug)

  7. Once all leads are connected, start from the first wire and check that all cell voltages increase by about 3.6-4.2v each time you move the second multimeter lead over a cell/ hole.

  8. Once verified that all cells are in the correct spots, solder the b- lead to the bms and c- or p- too if need. (It is very important to connect these first before the balance wires or it can fry the bms)

  9. Once it’s all connected and not smoking, charge the battery to full voltage while measuring each cell periodically though the charge, especially near the end to make sure they aren’t over charged. (I have noticed my cells being charged to 4.23v before but are then balance back to 4.2 shortly after)

  10. Go rip around your town and have some made fun on your new eboard that has a one plug charge system

Hope it helps a bit, and sorry if there’s any errors. @Namasaki could you plz just verify that sounds correct, I wouldn’t want to cause damage to anyone else property based on bad advise

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Lipos, 10s5000mah in 5x 2s and a 12s5000mah with 4s3s. Each pack gets me about 20km at 20km/h cruising speed, much more if I walk the dog, since I go about 10km/h

that all seems pretty accurate, it would be:

first pack (supplies negative lead to Vesc) b1-yellow b2-white b3-blue b4-black b5-red second pack (supplies positive lead to Vesc) b6-yellow b7-white b8-blue b9-black b10-red

negative lead to b- charge port negative to ch- charge port positive to positive lead

@Namasaki could you verify

Seems right except for that the red and black wire shouldn’t be next to each other, they should be at opposite ends of the plug

First pack supplies negative main to B- on bms

Second pack supplies Positive main to Vesc and positive lead to charge port

Abnormal color coding on these batteries. They have two black balance wires

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there are two black wires, the one next to red is a positive cable, the one on the end is the ground wire

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Ahh all g then

Looks like you have it all figured out now. Follow @pat.speed advice and test voltages at the bms connector after you have it all wired and before you plug it into the bms. Volt meter negative probe on the main negative wire from battery 1 Then check pins 1 through 10. voltage should increase by apx 4.2v at each pin in succession.

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Ok. @Namasaki Thank you so much for taking time out of your day to help a noob. I hope this thread can also help other people with bms and lipos.

Getting back from vacation on monday, will fix problem and post pictures when done.

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Wait @Namasaki Sorry to bug you, two small questions:

  1. since the bms/ charger is connected to my power leads, does my board need to be powered on for it to charge?

  2. my 42 volt Mboards charger has an led that is green when charge full or disconnect, and red is charging, will this work with lipos if all my wiring is correct?

Yes, the BMs needs to be in to charge. If the charger is the correct voltage and the +/- match you should be good.

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thank you guys for all the help

  1. Your board does not need to be powered on to charge the battery with that bms.
  2. Your 42v Mboards charger will work because lithium ion and Lipos both have the same voltage at full charge.

Connect the charge port positive directly to the positive main of your battery. The charge port negative goes through the bms to the battery.

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So is the post marked solution correct if I follow this?

Yes, that is correct

First off I would like to say thank you to the main contributors on this discussion as it cleared a lot of stress in my mind. I am however still running into charging problems with my diy build and I’m using the exact same setup and and I just followed your wiring guide. My brick still shows green when plugged in when the batteries are discharged. My balance wires are in the correct order from B10-B1 and so are the Ch- and B- ports. I would really like some help as this is the the very LAST problem I have to fix which is preventing me from enjoying my full diy build

image image

I would love to know if anything seems wrong with my BMS or the wires (too thin or something) I am still wondering if that extra black balance at the end of the first pack(negative main to VESC) port is still supposed to be connected to the B- port along with the negative main lead. I have tried both with and without to no luck.