What is going on with my JBD BMS?

[ButcherCarl]

I have a 150amp JBD BMS on my DIY 4S 12v 302ah battery.
The voltage on the battery terminals is 13.36v. Voltage from +battery to B- on BMS is 13.36v. Voltage from +battery to C- on BMS is 8.67v.
I dont understand why this is happening. It wont allow current to flow out, or charge to go in.
Also, I have no clue how to use the App. A lot of it is in Chinese, not English, and I cant find anywhere that shows how to set up the parameters, or what anything means on the app. XiaoXiang app.
Is there a better App to use for these BMS's?

 

[Bob B]

What device are you using for the App? IOS or Android?

Overkill Solar has some very good documentation for this BMS .... and also has their own App. https://overkillsolar.com/support-downloads/

Can you post some screen shots of your App?

There are a ton of threads on here about the JBD BMS is you use the forum search tool.

 

[ButcherCarl]

Android.
I havnt found any threads on this problem.
What screenshots? The parameters, or just the main screen? What are we looking for specifically?

 

[Bob B]

For starters ..... is charge and discharge enabled on the main screen.

Were you able to enter the pack size into the BMS settings?
IOS or Android?
Cell voltages .... Temperatures.

If temps aren't working the BMS won't work. We need to see some of the screens and setting to have any idea what is going on.

 

[ButcherCarl]

I dont know if any of this is set up correctly.

 

[Bob B]

It looks like charge is enabled but discharge is turned off .... what happens if you turn it on?

 

[ButcherCarl]

Nothing.
discharge turns itself off after a little while.
It wont take a charge. nor will it allow discharge.
I have 2 150amp and 2 200amp BMS's and they are all doing the same thing. Im sure Im the problem, but dont know where to even start.

 

[ButcherCarl]

Does B- go to battery, or does C-?

 

[Rednecktek]

B- to battery, C- to loads

In the Functions settings, turn the switch to OFF.

 

[Bob B]

B- goes to the battery and C- goes to the load.



Sorry to be so abrupt, but if you can't answer a basic question like that for yourself, you shouldn't be building a DIY pack.

The diagram above is for a somewhat different BMS than yours, but shows the basic wiring. You need to study the instruction manual from Overkill Solar thoroughly. It is on the page I linked above and I will attach it to this post.

Edit: Well, I tried to attach that document but for some reason it didn't take .... You will have to download it from the Overkill Solar site.

 

[42OhmsPA]

I have a 150amp JBD BMS on my DIY 4S 12v 302ah battery.
The voltage on the battery terminals is 13.36v. Voltage from +battery to B- on BMS is 13.36v. Voltage from +battery to C- on BMS is 8.67v.
I dont understand why this is happening. It wont allow current to flow out, or charge to go in.
Also, I have no clue how to use the App. A lot of it is in Chinese, not English, and I cant find anywhere that shows how to set up the parameters, or what anything means on the app. XiaoXiang app.
Is there a better App to use for these BMS's?

I'm betting you have a wire flipped.
Check the voltage at the connector starting from the main negative, voltage should go up in sequence.

Edit, nevermind now I see the photos. Turn discharge on. You may need to hit it with a charger to get it to discharge.

 

[ButcherCarl]

B- goes to the battery and C- goes to the load.

View attachment 190777

Sorry to be so abrupt, but if you can't answer a basic question like that for yourself, you shouldn't be building a DIY pack.

The diagram above is for a somewhat different BMS than yours, but shows the basic wiring. You need to study the instruction manual from Overkill Solar thoroughly. It is on the page I linked above and I will attach it to this post.

Edit: Well, I tried to attach that document but for some reason it didn't take .... You will have to download it from the Overkill Solar site.

I did have it correct. And yes, I also double checked. but I asked the question to make sure Im not just confusing something.
Ive double and triple checked my wiring numerous times. Starting from the beginning when you are frustrated, helps to reset your brain.
Youve seen the pictures of this battery. Obviously, I have it set up correctly. I just threw something out there, to see if im missing something.

 

[ButcherCarl]

I'm betting you have a wire flipped.
Check the voltage at the connector starting from the main negative, voltage should go up in sequence.

Edit, nevermind now I see the photos. Turn discharge on. You may need to hit it with a charger to get it to discharge.

The discharge will not stay on.
As soon as I turn it on, I go back to the main screen to see if its accepting the charge, and its off. The charge switch stays on, but the discharge switch turns itself off, as soon as I leave the screen.
Do you have any idea why the B- connection would read the same as the battery, but the C- reads 4v lower?

 

[Bob B]

I did have it correct. And yes, I also double checked. but I asked the question to make sure Im not just confusing something.
Ive double and triple checked my wiring numerous times. Starting from the beginning when you are frustrated, helps to reset your brain.
Youve seen the pictures of this battery. Obviously, I have it set up correctly. I just threw something out there, to see if im missing something.

Your first post just made it sound like you didn't have any idea ..... seems like there has to be something basic wrong if you have the same problem with more than one pack.

The screen on my App doesn't look like yours .... at the bottom of the screen on mine, I have a list of "even counts." Do you have that on yours?

 

[Bob B]

Do you have any idea why the B- connection would read the same as the battery, but the C- reads 4v lower?

It's because the discharge mosfets are turned off for some reason ..... gotta figure out what the reason is.

 

[ButcherCarl]

Your first post just made it sound like you didn't have any idea ..... seems like there has to be something basic wrong if you have the same problem with more than one pack.

The screen on my App doesn't look like yours .... at the bottom of the screen on mine, I have a list of "even counts." Do you have that on yours?

I dont have any idea, what is going on with this issue.
Im trying to start at the beginning, to see what, if anything, I am overlooking. Sometimes, it is the most basic thing, and its overlooked, because it couldnt possibly be, "I have it backwards".
Can you drop a screenshot, so I can see what the differences are youre referencing?

 

[ButcherCarl]

It's because the discharge mosfets are turned off for some reason ..... gotta figure out what the reason is.

Ive had these batteries set up to my solar panels, running through my Victron 50amp/150v charge controller, and they had no problem charging.
Do you know if the BMS has a minimum amperage needed to accept a charge? Also, even if it does, that wouldnt have anything to do with the voltage difference across the BMS itself, correct?
The charger I have set up on it right now, is a 4amp Battery Tender, that has a 12v LiFePO4 setting. Is 4amps too low of current, for the BMS to allow through?

 

[ButcherCarl]

B- to battery, C- to loads

In the Functions settings, turn the switch to OFF.

Ill try that, see what happens.

 

[ButcherCarl]

B- to battery, C- to loads

In the Functions settings, turn the switch to OFF.

This worked.
The discharge switch is now staying on, AND it is allowing the charger to charge the battery.

 

[Bob B]

My app looks different ..... I'm using Apple. Also don't think I have that setting in mine. You can usually tell what is keeping it off by determining what protection event is triggered.

My home screen using the OverKill App looks like this at the bottom.