bluetooth BMS?

[Cowardlyduck]

Hey guy's, I recently got one of these for a house power wall project.
https://www.aliexpress.com/item/4000465536822.html?
I managed to wire it up and connect the basic xioxiang BMS app.
I'm a little disappointed at how basic the app is and was wondering if there are any alternatives that will work with this BMS.

I started reading through this thread, but at 59 pages now I was hoping someone might be so kind to give me a shortcut answer.

Thanks

 

[thundercamel]

What version of the app are you using? Android or iOS?

 

[Supersurron]

This is the English language app that I received today. It appears to be just a translated English version of the MaYi BMS app.

Do you have a download link for this app? Looking everywhere for it

 

[Manna]

Does anyone know where the Tx and Rx pins are located on the circuit mounted Bluetooth module ?

 

[amberwolf]

If you have a voltmeter, set it to 20vdc, put the black lead on any ground, then use the red lead to test all the BT board pins. The two that are about 2.5v are the serial pins. Which is which, can't tell like that, though.

 

[Cowardlyduck]

What version of the app are you using? Android or iOS?

I never saw a notification for this so assumed nobody had responded.

Anyway, I also reached out to the Alibaba seller and managed to get it through them. For anyone else looking, attached is the download of the app.
They also gave me this link: http://www.jiabaida.com/home-1.7-in...l?spm=a2g0s.imconversation.0.0.70c53e5fyveoU3

Cheers

 

[serious_sam]

Looks like version 3.1.1013

 

[Cowardlyduck]

Looks like version 3.1.1013

Is there a newer version?
I did notice it's a bit buggy and hangs when applying settings sometimes.

 

[mighty82]

[youtube]nBG5qz9Wm_s[/youtube]

What's going on here? Cell group 1 is jumping up and down and it's going in and out of high and low voltage protection mode.

I ripped the battery open to check the actual voltage of cell group 1, and it's at 4.1V thankfully. This is a little scary.

 

[Magsy]

This 3rd party iOS app for the LLT/JBD/xiaoxiang BMS is great. I have not tired the Android one.

I have altered just about all the settings at some point without issue. I also have the USB cable and PC software and they have feature parity for the most important things.

App Video

 

[Magsy]

[youtube]nBG5qz9Wm_s[/youtube]

What's going on here? Cell group 1 is jumping up and down and it's going in and out of high and low voltage protection mode.

I ripped the battery open to check the actual voltage of cell group 1, and it's at 4.1V thankfully. This is a little scary.

Can't say i have seen this on either of mine...but how is it balancing without charging and the mosfets locked? Have you changed the balance setting?

 

[mighty82]

Found the problem. Battery negative balance lead had broken.

 

[thundercamel]

What version of the app are you using? Android or iOS?

I never saw a notification for this so assumed nobody had responded.

Anyway, I also reached out to the Alibaba seller and managed to get it through them. For anyone else looking, attached is the download of the app.
They also gave me this link: http://www.jiabaida.com/home-1.7-in...l?spm=a2g0s.imconversation.0.0.70c53e5fyveoU3

Cheers

If it is version 3.1.1013 like serious_sam said, that is the new version that I've been using as well. For the 14s 60a unit at least, it has almost all the same parameters accessible as the PC software. What features are you looking for, that the android app is too basic to provide?

 

[Cowardlyduck]

What features are you looking for, that the android app is too basic to provide?

I was referring to the very basic one available on the Google Play store. It's next to useless unless the BMS is setup correctly prior.

I do like the features of the proper app. I like how it can show the variance of individual cell voltages compared to the average. Does anyone know if it can show a graph with all cell voltages?

The other thing that doesn't seem to be working is the ability to charge following a BMS low cell voltage trip. I'm using it with a powerwall battery connected to my inverter which needs to see voltage in order to charge it. Once the BMS trips it cuts voltage, so my inverter doesn't know to try charging it. I could set me BMS cut voltage lower, but I would rather have it keep presenting voltage if possible.
Does anyone know if this is possible?

Cheers

 

[newsky526]

Hi, this is a newer version of the program for Android (3.1.1015). It's work fine with 10Android. It is necessary to replace zip with apk.

 

[DrKraut]

Did anyone have a Problem with the new Elephant App V3?
Since i installed it, which asked me for a pin, the charge and discharge fets are disabled and cant be enabled. I can hear some sort of ticking or cklicking from the bms.
The BMS effectively doesnt work anymore.

Does anybody know why?

 

[john61ct]

The other thing that doesn't seem to be working is the ability to charge following a BMS low cell voltage trip. I'm using it with a powerwall battery connected to my inverter which needs to see voltage in order to charge it. Once the BMS trips it cuts voltage, so my inverter doesn't know to try charging it

You really should have "user space" LVC controls that prevent your bank being regularly drawn down that low.

You are drastically shortening lifespan if that is a routine occurrence.

Only use BMS as a failsafe backup for when those stop working.

Some chargers have a mode to recover too-low voltage packs at a very slow rate.

The BMS should have a manual reset function to open up the relays after a shutdown.

 

[john61ct]

The other thing that doesn't seem to be working is the ability to charge following a BMS low cell voltage trip. I'm using it with a powerwall battery connected to my inverter which needs to see voltage in order to charge it. Once the BMS trips it cuts voltage, so my inverter doesn't know to try charging it

You really should have "user space" LVC controls that prevent your bank being regularly drawn down that low.

You are drastically shortening lifespan if that is a routine occurrence.

Only use BMS as a failsafe backup for when those stop working.

Some chargers have a mode to recover too-low voltage packs at a very slow rate.

The BMS should have a manual reset function to open up the relays after a shutdown.

 

[Cowardlyduck]

The other thing that doesn't seem to be working is the ability to charge following a BMS low cell voltage trip. I'm using it with a powerwall battery connected to my inverter which needs to see voltage in order to charge it. Once the BMS trips it cuts voltage, so my inverter doesn't know to try charging it

You really should have "user space" LVC controls that prevent your bank being regularly drawn down that low.

You are drastically shortening lifespan if that is a routine occurrence.

Only use BMS as a failsafe backup for when those stop working.

Some chargers have a mode to recover too-low voltage packs at a very slow rate.

The BMS should have a manual reset function to open up the relays after a shutdown.

Ok, this is fair and I guess I was thinking about it backwards. I guess since these Bluetooth BMS are so capable now I thought it could handle it all, but it's good to keep it in perspective and let it only do it's job and not more.

Cheers

 

[serious_sam]

The other thing that doesn't seem to be working is the ability to charge following a BMS low cell voltage trip. I'm using it with a powerwall battery connected to my inverter which needs to see voltage in order to charge it. Once the BMS trips it cuts voltage, so my inverter doesn't know to try charging it. I could set me BMS cut voltage lower, but I would rather have it keep presenting voltage if possible.

To me, that sounds like correct operation of the BMS (correct LVC operation).

IMO the BMS LVC is effectively a last resort "fail-safe", just in case you accidentally discharge too far, to ensure that you don't damage the cells.

It would be ideal if you could program/set the inverter to stop discharging the cells at a certain "low" voltage, rather than rely on the BMS LVC for that purpose.

 

[john61ct]

Any circuit can simply be isolated by a standalone adjustable LVC, no need to expect load devices to have such functionality built in.

Entertainment circuits should cut out at a much earlier stage than say refrigeration.

Navigation and radio comms, safety devices may stay on until BMS kicks in, but that ever happening should be treated as a design failure needing fixing.

 

[Cowardlyduck]

To me, that sounds like correct operation of the BMS (correct LVC operation).

IMO the BMS LVC is effectively a last resort "fail-safe", just in case you accidentally discharge too far, to ensure that you don't damage the cells.

It would be ideal if you could program/set the inverter to stop discharging the cells at a certain "low" voltage, rather than rely on the BMS LVC for that purpose.

Yes. I realise that now, see my previous comment.

I'm trying to fine tune my LVC on my inverter and balance it with the BMS LVC. Inverter set to equivalent of 3.4V per cell and the BMS set to 2.7V with a release of 2.8V. Does that sound sensible?

Something else I need to consider with this pack is it is heated at low temps with 2 x 30W PTC heaters that kick in at 0c and 5c respectively. I need to leave enough buffer after the inverter LVC so that in a worst case scenario (very cold/long night) the heaters would still have enough capacity to run through the night...about ~650wh. That way my BMS LVC doesn't trip before the morning and my inverter can still 'see' the battery to start charging it off my solar.

Cheers

 

[serious_sam]

I'm trying to fine tune my LVC on my inverter and balance it with the BMS LVC. Inverter set to equivalent of 3.4V per cell and the BMS set to 2.7V with a release of 2.8V. Does that sound sensible?

As long as you can set the inverter LVC higher than the BMSs LVC, then it'll work.

It'll depend on your cells whether 3.4V is a good voltage to cut discharge at though.

 

[Cowardlyduck]

It'll depend on your cells whether 3.4V is a good voltage to cut discharge at though.

I won't go into too much detail here, but these are the cells:
https://batteryhookup.com/products/new-lg-chem-n2-1-3-7v-120ah-cell-module

It's still a work in progress, but this is the powerwall the BMS is part of:



I'm waiting on a few replacements to arrive under warranty, but so far they are performing well with around 15AH (out of 120AH) left at 3.4V...perfect for a worst case overnight heat needed scenario.

Cheers

 

[thundercamel]

I was referring to the very basic one available on the Google Play store. It's next to useless unless the BMS is setup correctly prior.

I do like the features of the proper app. I like how it can show the variance of individual cell voltages compared to the average. Does anyone know if it can show a graph with all cell voltages?

The other thing that doesn't seem to be working is the ability to charge following a BMS low cell voltage trip. I'm using it with a powerwall battery connected to my inverter which needs to see voltage in order to charge it. Once the BMS trips it cuts voltage, so my inverter doesn't know to try charging it. I could set me BMS cut voltage lower, but I would rather have it keep presenting voltage if possible.
Does anyone know if this is possible?

Cheers

If you go to the page where you can see all of the cell group voltages, you can tap on any group to see a graph of that group's voltage overlayed with average voltage, but I don't know of a graph for all groups. I thought for sure the data has to be stored in the Android/data/com.jiabaida.xiaoxiang/files folder, because it will only graph what data had been logged while the phone was connected via bluetooth, but all I find in mine are crash logs... If you could find that data, graphs could be logged using excel or such, but I'm guessing that's not worth your time.

I'm fairly certain on my JBD BMS that I've plugged in the charger while the BMS is in a state of chargen dischargeff (low cell voltage) and it does charge just fine. I am using the 14s60a version, and I did not use the P- connection as instructed.

With such big cells, balancing will take a long time. Let us know how it goes, or do you have a thread for this project?