Wiring of the 6S BMS

Yeah, for that BMS this diagram looks correct

And why wouldn’t that work on mine? Because it is the same right?

That is your BMS

Okay, so my diagram should work?

Your diagram needs a loop key in the fat black cable

Okay thank you. What is its function?

It turns the skateboard on and off. Make sure it’s an antispark XT90 not just an XT90

warning: if you don’t plug it all the way in every time you will burn up the key

Okay but I have an on/off switch so I guess that means I don’t need the XT-90 connector right?

If you use an electronic anti-spark switch, you won’t need the loopkey but you’ll still need an XT60 or XT90 connector internally so the battery can be disconnected if needed. Make sure it’s the kind where you have to hold the button for {number} seconds before it turns off. That’s so if a pebble or stick hits the power button, you don’t lose brakes.

Okay thank you

@b264 I was wondering, what batterypercentage is safer, if you charge with the BMS for the first time?

Maximum of 4.2V per cell, as measured with a multimeter

Hey I’m about to hook up my bms for charging purposes and want to make sure I do it right. I am using two 3s lipos in series. Also would you recommend soldering or just putting the wires into connectors and hot gluing. I also plan on using 10 gauge wire to attach directly to the p- b- and positive charging input. is this correct?


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Okay, first of all lets run through the balance port cables.

Since it is a hobby lipo it probably has a (-) (cell1 pos) (cell2 pos) (cell3 pos) so four cables total. If it does NOT have 4 pins, disregard everything below and let me know.

The BMS has 6 pins total.

For claritys sake, when I refer to the “lower battery” I mean the battery that has it’s positive terminal connected to the negative terminal of the “higher battery”

Your lower battery will use 3 of the 4 cables. The (cell1 pos) (cell2 pos) (cell3 pos) terminals will be used. Do NOT use the (-) balance cable on the lower BMS.

Your higher battery will use 3 of the four cables. Like the lower battery, the higher battery will use (cell1 pos) (cell2 pos) (cell3 pos). Again, do not use the (-) terminal on the balance port.

So here’s the sequence for the BMS balance port cables

BATTERY CABLES _______ BMS PORT (low batt, cell1 pos)________1 (this pin may be labeled as B1) (low batt, cell2 pos)________2 (low batt, cell3 pos)________3 (high batt, cell1 pos)_______4 (high batt, cell2 pos)_______5 (high batt, cell3 pos)_______6 (this pin may be labeled as B6)

You may have noticed that there is no (-) pin used in the port. This is because the ground pin is pulled directly from (B-) on the BMS.

Here’s what you should do. Lay everything out on a floor. Verify the correct orientation of the plug for the BMS.

Clearly label your high batt and low batt.

Connect low batt + to high batt -. This should use the main battery terminals, not the balance port.

Once that is connected, connect the low batt - to B- on the BMS. Also connect P- to the charge port, and the other charge port pin to the main battery positive terminal. Again, this is using the main battery cables, NOT the balance cables.

After this is done begin working out the balance port. Make sure you have it in the correct orientation, if you connect it backwards to the battery and hook it up to the BMS then you’ll release the magic smoke :wind_face:

Here are things you need to keep in mind.

NEVER disconnect low batt from high batt while the balance port is connected. ESPECIALLY when the VESC is still on and connected. This will release the magic smoke. :wind_face:

NEVER connect the balance port when either the P- or B- cables are disconnected. This will release the magic smoke. :wind_face:

Always cover live wires while working. If you have a cable or wire with an exposed plug temporarily tape it up with electrical tape. This includes the balance port plug that goes into the BMS, it has live contacts on one face face. If it touches anything grounded or any other cells voltage it will release the magic smoke :wind_face: and possibly the magic light. :cloud_with_lightning:

BESIDES THAT everything looks good! I just wanted to clarify some pins and let you know the hazards associated with these kinds of batteries and BMS’s. Your diagram looks correct enough. It just doesn’t look like it has the balance cable connections labeled.

I’ve personally used that exact model of BMS before and I can vouch for the information I’ve provided above.

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wow thanks a ton for that explanation! It helps a lot! I will update on how it turns out.

If you have any questions feel free to ask! The community takes care of everyone :wink:

Should it look like this?


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I was wondering if this configuration also works since all I need to do is cut off the black balance cable on my series balance connector


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Yep, that all works fine :slight_smile: