BMS board help please.

[billym1967]

so on building a battery put the BMS board in and it didnt work. output vault age was wrong and it wouldnt charge. changed the board and straight away no proble.

double checked the wiring diagrams on the board that didnt work and it didnt add up. contacted the seller and ended up more baffeled.

so ive added to pics one of the board and one of the wiring thats given.

help
B- to battery neg
P- the load out
C- to charger out
doesnt work

also heres the message i got
Hi
Sorry that was the wrong photo, I will remove it
Follow this diagram below, (manufacturers diagram)
B- to battery negative
Charging adapter: + connected to battery positive, - to c-
My recommendation for the load is to bypass this stage, so leave p- unconnected and wire motor controller direct to the battery
Sorry for the confusion

 

[Deleted member 4366]

On the back of the multipin connector, the pcb should be marked b0, b1......b10. Check between the cell-pack negative and each pin that the voltages correspond, so you have 0v on b0, 4v on b1, etc. all the way to b10.

 

[billym1967]

as its turned out, looks like its a faulty board as i had it wired right in the first place. it was only showing 36v output (40v) when bypassing the board. it also wouldnt activate the charger. when i put another board in it charged straight away. so looks like a faulty BMS

 

[Deleted member 4366]

as its turned out, looks like its a faulty board as i had it wired right in the first place. it was only showing 36v output (40v) when bypassing the board. it also wouldnt activate the charger. when i put another board in it charged straight away. so looks like a faulty BMS

The board won't work if you connect it wrong.

 

[billym1967]

ive replaced 1 BMS and this was battery 6, apart from my big accident and using battery of diffrent charges on the 1st one. ive had no problems till this one. for some reason i doubted myself. but after some messages and watching the utube vid he sent. well i had it right. apart from some having 10 small wires and others 11 all the BMS boards have been the same.
B- to battery neg
P- the load out
C- to charger out

on thios one he advised not to use the P-. but that wouldnt effect the charge.

 

[Deleted member 4366]

The problem is b0 to b10, not the main wires. Different BMSs require different connection sequence, so you can't just plug in the multipin connector to each one without checking the sequence.

 

[billym1967]

well i did check that, 11 wires, the black number 1 to b1 number 2 to b2 ect and the final wire to and the final 11th wire goes to the live. i have installed 10 and 11 wires so no the possitions change depending witch it is. also when i changed the BMS i changed it all including the wires.

 

[Nealh]

It appears from your last post you have wired up sense wiring incorrectly.

Usually when you have an extra sense wire the extra one ( the first wire ) is connected to the B- or cell 1 minus ( hence it is Black) as this is Gnd and allows the BMS to read 0v then all others often Red go B1+ is cell 1+ or 4.2v, B2+ is cell 2+ or 8.4v and so on etc ,etc.
If the BMS is expecting to see 0v reading and doesn't see it , it won't charge or give a correct output voltage reading.
BMS with exact number of sense wire use B- as a common Gnd most BMS with extra wire doesn't use a common Gnd via B-.

 

[Deleted member 4366]

well i did check that, 11 wires, the black number 1 to b1 number 2 to b2 ect and the final wire to and the final 11th wire goes to the live. i have installed 10 and 11 wires so no the possitions change depending witch it is. also when i changed the BMS i changed it all including the wires.

I told you how to check in post #2. Only a voltmeter and that test will show whether you got it right, but it sounds like you got it wrong. Normally, the black wire is B0, not B1.

 

[billym1967]

yes thats the way i had it wire 1 (black) was wired to the main negative, then the reds go b1 up wards the last red should end up on the battery live. like i said ive done 10 and 11 wires already and dont have a problem with that bit now. even though i doubted myself with the main wires. there was no reason to as i had wired it correctly.

 

[billym1967]

my post was a typo error i put the black wire on b0 witch is the negative terminals on the cells. same place as B- goes to.

 

[billym1967]

the BMS i replaced it with was 10 wires, the first wire was also black, but it didnt go to b0 it went to b1, i always check the wiring diagram to make sure before starting just in case there diffrent.

 

[Deleted member 4366]

I keep telling you. Only a voltmeter will tell you whether you got it right.

 

[billym1967]

so how can i use a voltmeter to test a BMS thats not charging, i would have thought all i could test is continuity

 

[Deleted member 4366]

You start by doing what I said in post #2.

 

[billym1967]

what should i expect to see on a healthy board. i'm guessing the same on all 10

 

[billym1967]

so would it be 4v 8v 12v ect

 

[Deleted member 4366]

Post the results here.
B0 = ?v
B1 = ?v
Etc.

 

[billym1967]

i will next time if it happens