Help with charge only BMS wiring

Why does it go from 7 wires to 6 wires on the BMS connector? @stuxtruth @Jinra

Apologize if it’s a simpleton question, still figuring out BMSs and whether or not I want to use one or use it for charging only.

the 7th wire is effectly the pack main negative lead. “B-” on the diagram.

Ok, thank you!

Some of the BMSs I have looked at have a B- or B0 balance cable in addition to another spot on the board for B- which is why I was confused about dropping to 6 cables. The Evolve BMS is like this https://endless-sphere.com/forums/viewtopic.php?t=70435#p1064672

I guess the one the @stuxtruth must not be set up that way.

To bring this subject into light again…

I’d like to make a charge only BMS set up for my 6S2P setup with venom lipo’s (slightly nicer zippys) The single plug is going to be a must for me since I will be at college. I want to use the BMS to ONLY CHARGE, not for discharging, so I would end up getting a less expensive BMS.

I made a circuit diagram that you will see below. From what I can tell, this circuit is for both charging and discharging, which would require me to have a bms with a high discharge value so it won’t limit my motor power. How would I go about making it for charging only, with a bypass so I can avoid the BMS current limit?

Also, I am planning on using one of these adapters to connect my two lipo packs into effectively a 6s pack so the BMS will see it as a 6s. Would this work, or will I have to wire the balance connectors myself? http://www.hobbyking.com/hobbyking/store/_9910__2_x_3S_gt_6S_Splitter_JST_XH_5pcs_bag.html

And if I do have to wire it myself, is this diagram correct?

And finally here is the circuit diagram

Please check to make sure that diagram makes sense. The bms I am planning on using is something along the line of this: Ebay

It is cheap and probably has less than perfect build specs, but since it is (as planned) going to be for nothing other than balancing the cells while charging I do not see a problem. If there is one, let me know and I will pick up the same bms that strux had.

EDIT-

I should mention I have had all of this figured out by now, just haven’t updated this thread.

To run a Charge Only BMS you will need to follow the diagram above but run the negative from the esc/motor straight to the battery instead of to P-. You will still attach the negative to B-, but not P-. The charger does still attach to P- however.

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I’m having some confusion too with the wiring of these BMS’s.

I have ordered the 12s 60A BMS and am looking for pointers on the wiring.

This is the diagram that they provide:

This is a quick diagram that I have set up as I understand it (Excuse the rushed-ness!).

(I labeled it as 80A but I have ordered the 60A).

Is this correct? The balance cables took some mind bending but I think they’re correctly wired. If I wanted to use the BMS as charge only (incase the 60A limit is too low for my setup) how would I modify this wiring?

Also, does the AWG of the wiring to the charge port need to be low gauge? Or does it only need to handle the charge current coming in through the charger?

Hope someone out there has used something similar!

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I have also corrected your diagram for the Amp limiting wiring.

You could wire it the way you have it, but the main negative and the last negative balance wire are on the same terminal on the battery.

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Hi, I wanna buy a BMS too, but tell me, 45A isn’t low limit? Because a Skateboard can use more than 60A

Just curious, why did you go with two fuses?

I saw a wiring diagram, but after some advise I’ll live it with no fuse.

Yes you need to use a 60A bms for a 10s3p and 80A for 10s4p, nevertheless there are a lot of people running 60A bms for a 10s4p on Samsung 25R with no issues whatsoever

But I’m using a 6s1p 6300mah 35c, witch Bms I have to buy?

This should be the one you need

http://www.batterysupports.com/22v-24v-6s-60a-6x-36v-lithium-ion-lipo-battery-bms-pcm-pcb-p-478.html

Why? And Battery Supports do not ship To my Country! I saw some people using like 15A Bms with Sk3 Motors, How they do this?

Use it for charging only

Like Soldering the Vesc Cables in Charge Port of Bms??

No. You only use the BMS to charge the battery, and connect the battery straight to the esc (with a switch in between)

Like this?

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It depends on the BMS. There are a few threads here on how to do it, search how to bypass bms

Man, Wait, I want a Bms just for charging, How do I connect the Bms with the Battery? Because I don’t want to Burn My Bms