Thank God. I was running out of popcorn!
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Wow. Thoroughly entertaining! And informative. Tune in next week!
Oh yeah…Think this was entertaining? Try wrapping your head around this discussion! You’re going to need a lot of popcorn!
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I corrected the balance wires in the drawing, they now appear in the correct order.
The BMS I bought is a 60 AMP, I guess I posted the wrong link earlier in the thread. The BMS I am using is here.
Using the interface definition on the product page I used the following instructions, defined as (bms1) through (bms5), to make the POSITIVE & NEGATIVE connections as I understood them.
- (bms1) The Positive output on Battery Pack (22V + ) could connecting to charger positive pole (charger +)
- (bms2) Battery Pack (22V -) connecting with B- on board
- (bms3) Chip board P- connecting to Charger Negative Pole (charger -)
- (bms4) Chip board P- could be Negative output for charger, motor, controller
- (bms5) Battery B+ could be Positive output for charger, motor, controller
I used a mulimeter to check the cells of a Zippy 5000mAh 3s 30c LIPO Pack. With the negative probe on the BLACK wire and the positive probe on the WHITE wire I got 4.03v. Leaving the negative probe on the BLACK wire I then used the positive probe on the YELLOW wire and got 8.09v. Lastly Leaving the negative probe on the BLACK wire and moving the positive probe to the RED wire I got 12.13v. If I understand correctly, the results mean that WHITE is Cell 1, YELLOW is Cell 2 & RED is Cell 3.
I am not clear which is battery 1 (Cells 1, 2 & 3) and which is battery 2 (Cells 4, 5 & 6). Assuming the battery order is unimportant, though I dont see how it can be, I made the battery closest to the charging port Battery 1. I then made the balance connections Using the Balance Connector illustration on the linked product page.
I would assume if pin 4 on battery 1 and pin 1 on battery 2 were bridged, that would define the cell order. As there are only 6 balance connections on the BMS I am pretty much out of ideas. I hope someone can help me understand this.
Otherwise I think the diagram is accurate. Let me know if I missed something. Thanks again for all the help.
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Your getting close, you have the balance wires correct but the main supply wires are not. The negative supply wire should come from pack 1 The positive supply wire should come from pack 2
Like this? I have no idea why, can you explain? I am really trying to understand this, but the idea of multi cell power source has me pretty confused when it comes to the charging requirements :). Also, since it s a 60A BMS, do we need to bypass it while running? Is there a benefit to including the BMS while running assuming the ESC does its job and cuts off at 3.2V?
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All the wiring looks good now, assuming that the white balance wire is the first cell in each pack and the yellow wire is the second cell in each pack. As a precaution, you should check the voltage of each. The wire with the lowest voltage is cell one of each pack. The red balance wire is usually the last cell in the pack but it wouldn’t hurt to check that one as well.
Since you have a 60a Bms, You could discharge through it. Just set the Vesc max batt amps at 60 or less. I have measured current from the battery feeding dual motors going uphill and at 6s full throttle I was pulling less than 40a
I checked the cells with a multi-meter… With the negative probe on the BLACK wire and the positive probe on the WHITE wire I got 4.03v. Leaving the negative probe on the BLACK wire I then used the positive probe on the YELLOW wire and got 8.09v. Lastly Leaving the negative probe on the BLACK wire and moving the positive probe to the RED wire I got 12.13v. If I understand correctly, the results mean that WHITE is Cell 1, YELLOW is Cell 2 & RED is Cell 3.
Which of the POS/NEG wires do I move to discharge through the BMS?
You are correct with the balance wires Wht 1 Yel 2 Red 3 Your most recent diagram is also wired correctly to discharge through the BMS. Another advantage of not bypassing the BMS is that when you have regen braking the charge back to the batteries goes through the BMS. So you shouldn’t have to worry about over voltage when using brakes on a full battery.
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awesome, I really appreciate all the help on this.
Your very welcome
Im still a couple of weeks away from my BMS card getting here, but as soon as it does I am going to build this and post the results, with build pics and diagram, in a tutorial format. Thanks rpn314, Namasaki & VladPomogaev for educationg a n00b :).
For reference this is how I wired my 3x 4S Zippys up to my BMS (With help from @mccloed) and it’s been working perfectly.
Do you have any pictures 
Phew! Man physics is a bitch!
Hope I was able to actually be of help! Building up the community is what I’m here for, we all started as noobs at some point 
How do you develope this advanced whit 
couldn’t have said it better.
thanks for posting this thread i want to do the same
which charging port do you will use? someone can provide any ebay link to buy it?
please share photos of the process, thank you
I am planning on using the Razor charging port and charger.
36 Volt 1.5A Battery Charger
3 Pin Charging Port
It’s $21 shipped for both, looks fairly rugged and idiot proof.
That being said, I may salvage a charging port from an old notebook PC and use that and the charger that came with it. I’ll know more when I receive the BMS.
I’ll post pics and diagrams of the entire build process when I have the components.
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You gave me some great info that I didn’t have before, so I say +1 for rpn314 :).