• Have you tried out dark mode?! Scroll to the bottom of any page to find a sun or moon icon to turn dark mode on or off!

diy solar

diy solar

JK BMS WIRING

raffy323232

New Member
Joined
Apr 10, 2024
Messages
5
Location
MANILA, PHILIPPINES
good day to all. just bought the new jk bms. 16s 150amps with 2amps active balancer.
my question is... why there is 2 "B8" Terminals. which one should i use?
and is the first red wire from below will connect to main negative terminal?


thanks to all....
 

Attachments

  • 434156454_439854461893855_9192323136078154940_n.jpg
    434156454_439854461893855_9192323136078154940_n.jpg
    99.1 KB · Views: 175
Here is a link to the description and wiring diagram found on the JK BMS website. Its a little blurry but looks like the B8 pin next to NT3 on the 3rd connector is not used. Just leave that particular red wire disconnected.

 
On mine both paths have the resistor in place so either could be used, other boards only have the resistor on the early path. Look above the 5th 8 pin chip in from the top left and you can see the unpopulated position for the 2nd R01 resistor, no other 8 pin chip is fed from 2 pins.
 

Attachments

  • BMS Borad pic from internet.png
    BMS Borad pic from internet.png
    2.4 MB · Views: 101
On mine both paths have the resistor in place so either could be used, other boards only have the resistor on the early path. Look above the 5th 8 pin chip in from the top left and you can see the unpopulated position for the 2nd R01 resistor, no other 8 pin chip is fed from 2 pins.
thanks!...i wonder whats the point of the manufacturer of this bms in creating this confusion on B8 terminal
i have another question... will my bms be destroyed if i connect the B8 on the leads without that resistor?
 
Last edited:
thanks!...i wonder whats the point of the manufacturer of this bms in creating this confusion on B8 terminal
i have another question... will my bms be destroyed if i connect the B8 on the leads without that resistor?
No, it will report a cell count issue and throw an alarm but no damage. Your JK reported total voltage will be short by the missing cell.
 
What if you use both B8 wires on the B8 terminal? Like in the picture. A guy told me it's fine and he been using it that way.
 

Attachments

  • Messenger_creation_eea7fde7-e551-4e3f-abf5-01c81f960be1.jpeg
    Messenger_creation_eea7fde7-e551-4e3f-abf5-01c81f960be1.jpeg
    161.5 KB · Views: 77
What if you use both B8 wires on the B8 terminal? Like in the picture. A guy told me it's fine and he been using it that way.
Using both to the one cell would share the current so no issue other than the two 2.5A resistors mean you would need 5A total for one to blow followed quickly by the other. I would only use one as you lose the 2.5A protection using 2 wires.
 
I took JK's image, sharpened it and added clarification which should be there by default.
Before anyone asks... I will not be editing or reviewing their materials/manuals or guides again. This image is only to support our fellow members.View attachment 217915
Thank u for doing this ... their site was killing me with all the confusing blurriness....
 
1721329182621.png
B1 (+) Sense lead on B1+ terminal
B(-) Lead is on B1 NEG
B8/B16 (+) Sense Lead
BMS (+) (thicker silocone wire with plug) also on B8/B16 Terminal
Main (+) to Breaker on B8/B16
 
Considering that a small mistake can cost me a hole BMS , I rather as the question here.
BMS-Balance Wire.jpg
Is the above sketch correct and as I understand it I leave the second B8 wire disconnected?
Best regards
Paul
 
Hello all,
Just to give here the lessons learnt from my brand new JK BMS PB2A1620P wiring w/ 14s.
As mentionned on the post above, i had to let B8 unconnected.
In my case i have only 14 strings.
And what worked was to leave the 2 last extra wires unconnected too.
In other words for who wants to connect JK BMS PB2A1620P with less than 16 strings,
1/ Connect everything up to B8 from B- to B7+
2/ Leave B8 unconnected
3/ Continue from B9 to your last string +, which should be B+
4/ Power on the beast
5/ Configure the beast through Bluetooth app so as you enter the right type of batteries (in my case Li-Ion) and the right number of cells (in my case 14)
This worked for me. Hoping it will for you!

BTW, JK support seems to be non-existent. No way to send email through their web-site support page. No reply from the contact email address (even in Chinese). Has anyone managed to get in touch with them?
 
My JK PB2A16S20P was working fine on initial wiring and testing. i did not connected the 2nd B8 wire and left it loose.
after testing, i reorganised the wires and tested again. this time B8 and B9 failed to show in the list and an alarm was generated!
the entire system failed, as the BMS wouldn't give any output in this state!!

this is when i started looking up things and came across this thread.
after going through the knowledge shared, i disconnected the BMS and pulled it out. after removing the covers i started to check for the status of the R01's shown in the photo posted earlier on this thread by kommando. there are 8 on one side of the PCB and another 8 on the other surface, connected to staggered pins of the connectors. both the B8s have resistors connected to them in my board, and both the resistors are now showing open!!

i have ordered another BMS and have been scratching my head as to what led to this situation.
my best guess is that the loose 2nd B8 must have touched some battery terminal while rearranging the wires, and burnt out both the R01s.
(i did attach a ring lug to the 2nd B8 too, which was a mistake i now realise!)
Hopefully i should be able to source the 0402 R01s and replace them, and have a ready replacement BMS for future!
it was nice lesson learnt, and im sharing it here in hope that others reading this thread may avoid it!
 
You can fix the BMS, simplest method is to remove the burnt resistors and replace them with a solder bridge. Now on the two balance wires add in a 2.5:A fuse to give the protection the bridged resistors used to give. I soldered in new resistors but I have a microscope.
 
Is it allowed to cut the sense wires? so that not all wires have te same length.
Yes, my PCB based sense system has different lengths, the JK detects this and reports increasing resistances the further the cell is away from the BMS.
 

Attachments

  • Cell pack assembly used for reset.jpg
    Cell pack assembly used for reset.jpg
    139.8 KB · Views: 6

diy solar

diy solar
Back
Top