BMS wiring

[neokiller62]

Dear all,

I'm going to change my Goped battery charger to use lipo batteries

I want to connect a BMS LI-ion battery with balance function
As my Goped as only two wires + and - to be attached to the battery charger card, can i link C- P- B- on the same - wire?

Thank you

 

[d8veh]

No. That's dangerous. It will bypass the charging and discharging controls. Perhaps if you explain again what the problem is that you're trying to solve, we can offer a solution. I can't understand what your problem is from your description.

 

[neokiller62]

Thank you for your reply.

My Goped Iped II has got only two wires to plug in batteries to power controller board.
I want to add a PCM LI-ion battery with balance function

How can i plug in it?

I attached scheme and description bellow:

About BMS/PCB/PCM for 25.2V(25.9V) Li-Ion Battery Pack (7 cells with 50A +/-10A limit ) With Balance Function:

Describe

Model: BMS7LI
Protection Circuit Module Specifications For 25.2V/25.9V Li-ion or Li-Polymer Battery Pack, Different with normal PCB, it provides equilibrium function after battery pack is fully charged, e.g. PCM will detect each cell's voltage and trim higher voltage until other cell's voltage reach same,therefore allow Li-ion or Li-Polymer cell has longer service lifetime. Also the PCM will provide the following protections:
* Balance each cell at Max. 4.2/cell ( required voltage tolerance within 0.2V for each cell)
* Overcharge protection voltage for single cell: 4.35V +/-0.025V
* Overdischarge protection voltage for single cell: 2.40V +/-0.08V
* Continues working current: 30A
* Overcurrent detection protection: 40A ~ 60A
* Supply current: Max 30uA
* Short circuit protection
* Protection circuitry resistance: <=50mohms
Applications
Apply for 7 Cells Li-ion / Li-polymer Battery Pack with discharging current < 30A.
Internally Trimmed Voltage Limits to balance each cell. Please wait 30 minutes for this equilibrium function to take place after charger indicated battery pack is fully charged.
30A Discharge Current Limit.
Size: 3" x 2.4" x 0.4"

Net Weight: 1.50 oz

 

[dnmun]

connect it like they show in that picture.

 

[neokiller62]

If i connect like on the picture, i will connect B- C- and P- together because battery wires and charger wires are the same. Is it safe to do that?

Thank you

 

[dnmun]

that is not in the picture is it? why would you think it is safe if you are connecting wires together which are not connected in that picture?

 

[neokiller62]

Please i need to be sure, are you agreed with this diagram?

Thank you

 

[tahustvedt]

If you connect them together then you are bypassing the BMS.

 

[neokiller62]

If i connect each battery element to blanace port, how do i bypass BMS?

 

[dnmun]

C- goes to the charger, P- to the controller, you connect the positive terminal of the battery to P+ and to the charger + lead. B- goes to the negative terminal of the battery. the first sense wire goes to the top of #1 up to #8.

 

[neokiller62]

I've contacted Silviasol from forum, here is his answer:

p- is connected to the negative controller wire. B- is connected to the negative battery wire. C- is connected to the negative charge wire. This bms will not work with the stock charger in the pan since it connects thru the controller, you will have to use a different charger. For the balance connector use a 7 pin connector and connect the wires to all the battery terminal except the negative terminal. I had alot of problems when I used the stock sla charger anyways, it is not a good idea to use it. Sometimes it will not charge completely and sometimes it will charge over 4.2v and will charge too fast when it is above 4v.

Now i think to remove power supply from Iped because it is not necessary and connect an external li-ion charger (or internal if i found one) to BMS card.

 

[d8veh]

The diagram is correct, but a bit misleading. C-, B- and P- are not connected by the same wire. The wire running round the outside is the positive. It's separated from the negative by the load (controller P-), the charger (C-) and the BMS (B-).

Whatever charger you get, you need to get a matching socket and wire the positive to the battery positive and the negative to the C-.