Is my DALY BMS bad?

[hondaman82]

Hello experts,
I am having some issue when building a pack using 4x272ah cells from Basen and Daly BMS. As shown in pictures attached, after connected the BMS to the cells, I check the voltage from BMS "P-" terminal to Battery "+" terminal and the voltage read only 3.11V , but when checking from B- to B+ it shows 13.14V . I already triple check the BMS wire connection and everything look right.
Questions:
1) I thought the voltage from P- to B+ should be 13.14 Volt also right? Is my BMS bad?
2) when connect the Bluetooth module and turn on the app, no device show, did I hook up t the correct port? I connected to the port mark "UART"
thank you everyone !

 

[Mgmuzza]

Have you activated the bms by charging?

 

[RemohDad]

I bought a 4s 150a Smart Daly BMS from AliExpress for the same batteries. I tried charging with it, as recommended, I shorted the B+ to the P+ lead, as recommended, and I got the same results that you've described. In other words, this Daly BMS didn't work.

I bought an 4s Overkill Solar BMS and connected it up and it works perfectly. Never again will I try a Daly BMS. I paid a bit more for the Overkill Solar BMS, but it was totally worth it. And the built in Bluetooth is very useful.

Just one man's experience.

 

[Gone]

I have three from Daly, 4s, 8s and 16s.
The 8s has an intermittent break on the 3rd lead, which caused occasional shut-downs.
When tested, it showed the low voltage like you reported.
I disconnected the sensor cable from the BMS and found the issue by testing the voltage for each pin.

Cables are not easy to source, so I'll try to get one from China.
Constructing a cable would be a minor pain.
The connectors for 4s and 8s are likely JST-PA, but I'm not 100% sure.
(The 16s looks more like the common JST-XH, but again, I'm unsure.)

 

[hondaman82]

thanks for your comments, when I short P- to B- nothing happen, when I hook up to the bench DC power supply charging at 14V the BMS seem to be on because I can detect the device from blutooth app, but after disconnect from the charger, the voltage drop back to 3V at P- again, so frustrating, should have gone with Overkill BMS

 

[hondaman82]

Great new
My BMS is activated now, that's a relief, after none of the methods above working, i saw a comment from another poster suggesting to short the "key" port, and that did the trick , thank you everyone

Short the "key" pins to wake up the BMS. The "key" is on the other opposite side of the BMS to the UART connector, look for a 2 pin connector, touch both pin with screw driver or something

 

[RRRRRRRRRRudy]

Great new
My BMS is activated now, that's a relief, after none of the methods above working, i saw a comment from another poster suggesting to short the "key" port, and that did the trick , thank you everyone

Short the "key" pins to wake up the BMS. The "key" is on the other opposite side of the BMS to the UART connector, look for a 2 pin connector, touch both pin with screw driver or something

Can you post a picture of the 'key' ... I am having a problem with my BMS. From the + of the battery and the blue wire of the BMS I have 14.5 volts. But between the + of the battery and the black wire of the BMS I only have 10.8 volts. Looks like the BMS is holding some voltage
That is a new battery and I tried the BMS yesterday and it worked. I 'top balance' the battery today and re-attach the BMS...and now nothing !
So I think I am going to try the 'key' thing !

***UPDATE: I found the 'key' and it worked !!! My BMS is back is business and working fine.