Questions about Xiaoxiang App

[Mako74]

Hi guys. I'm trying to get grips with the Xiaoxiang BMS app. I'm using the version 3.1.1026 on Android to view and set parameters and function for a 12V 150Ah LiFePO4 battery. I've been searching and Googling but haven't found a source that would explain all the parameters and functions. I'm familiar with the basic ones, but then there's some that I don't know and I'd be super happy if you pros could help me out:

• PARAMETER VIEW / Nominal Capacity (of the battery pack): Do I need to know this or will the BMS figure it out after some cycles and if it does, how many cycles does it take?
• FUNCTION SETTING / RESET CAPACITY: What does it actually do? I've clicked it, but can't see anything changing in the parameters view.
• Is there a User Manual or Guide for the Xiaoxiang app?

Many thanks in advance!

 

[Banszi]

Nominal capacity - enter the rated capacity of battery (ex 280ah)

The BMS will show a projected capacity based on the cell thresholds that you set (20,40,60,80% voltage values) and with each discharge cycle will evaluate the projected capacity

The reset capacity resets the calculations made by the BMS during multiple discharge cycles.

Instructions attached

 

[WingNut]

FUNCTION SETTING -> RESET CAPACITY is useful if remaining capacity reported has drifted to the point of being inaccurate. This can happen with very low current being missed, measuring accuracy cumulative errors, calibration errors, repeated partial state of charge cycling etc.

The App lets you set 20%, 40%, 60%, 80% & Full voltage set-points. Full is when the meter reset to 100% SOC occurs. That doesn't necessarily mean that the battery is full. It just means that the battery reached the voltage you chose as being full and meter in the App resets to full. If the error accumulation has grown to where it's noticeable then resetting the pack's capacity is a quick way to force a SOC reset to be within the voltage check points (20%, 40%, 60%, 80%) you entered.

I did full discharge tests on my batteries stopping at every 10% capacity used and then letting the battery rest and recover to a resting voltage. You could allow 20 hrs or so rest each step of the discharge test. The 20%, 40%, 60%, & 80% voltages I entered were rested voltages. Now, if the App SOC doesn't look right because of the reasons mentioned and the battery has been at rest, I'll use RESET CAPACITY to make it closer to what is accurate.

If you are using the battery often and also recharging to Full often then SOC errors shouldn't be very noticeable as the coulomb counting is accurate enough but I think it's worth the time to do the discharge test so you can enter accurate voltages for the 20%, 40%, 60%, & 80% check points.

 

[techguy22]

I did full discharge tests on my batteries stopping at every 10% capacity used and then letting the battery rest and recover to a resting voltage. You could allow 20 hrs or so rest each step of the discharge test. The 20%, 40%, 60%, & 80% voltages I entered were rested voltages. Now, if the App SOC doesn't look right because of the reasons mentioned and the battery has been at rest, I'll use RESET CAPACITY to make it closer to what is accurate.

I'm curious, how do you determine you've discharged 10% in order to stop charging and let it rest? Do you go by the percentage numbers shown on the app? Or did you do a full discharge, check the amp hours, then discharge out 10% of the Ah you measured? I would like to do what you suggested on my pack but I'm not totally sure how to get started.

Also, if you click the "Reset Capacity" button in the app, should you do it at full SOC or does it matter what SOC you do it at?

 

[Mako74]

Thank you guys!

@WingNut, I'm currently doing charge (Victron Blue Smart Charger 12V/15A but I also have 30V/10A Adjustable DC Power Supply available) and discharge (Aliexpress 180W adjustable load tester) for these two Bely 12V 150Ah batteries (see attached screenshots) and the whole parameter setting is a bit overwhelming for a newbie like me so i do greatly appreciate your help!

As I'm doing this all with a ready-made battery pack I assume the BMS settings have been done at the factory and should be 'correct'. I'll post a one picture compilation showing the factory settings for 'Battery #1'. Here what catches my attention is the Nominal Capacity of 168.54AH (170.14AH in 'Battery #2'), as well as the Cycle Capacity of 80.0AH, which, according to the app should be set at 80% of the Nomical Capacity, i.e. ~134AH for Battery #1 if that 168AH is actual capacity, correct? Also, how does the Charge overcurrent of 160A and discharge overcurrent of -160A has to be set based on the nomical capacity? Regarding the 20,40,60 and 80% Voltage, how should I actually set these or should I just trust the factory settings and let them be as they are?

At the moment as I'm charging Battery #1 and discharging Battery #2 (attached screenshots), I've set the values as follows for both batteries:

Nominal Capacity of 150AH
Cycle Capacity of 120.0AH
Charge overcurrent 150A
Discharge overcurrent of -150A

Regarding the usage of these batteries, I'll be connecting them in parallel for a 12V 300Ah bank to be used in a camper van with 600W of solar, Victron Multiplus, DC2DC charger etc. I'm happy to have the batteries working in the range of 10-90% SOC and don't need to either charge or drain them fully so I might be just stressing for nothing, but I'd be very greatfull if you could scan through the attached parameters from Battery #1 and let me know if you see anything alarming in these settings.

Many thanks!

 

[WingNut]

I'm curious, how do you determine you've discharged 10% in order to stop charging and let it rest? Do you go by the percentage numbers shown on the app? Or did you do a full discharge, check the amp hours, then discharge out 10% of the Ah you measured? I would like to do what you suggested on my pack but I'm not totally sure how to get started.

Also, if you click the "Reset Capacity" button in the app, should you do it at full SOC or does it matter what SOC you do it at?

I did a few near full discharges first to confirm capacity then used a discharge tester with a specified load. I set notifications on my phone to remind me to go to check the setup based on elapsed time. I stopped the testing at each 10% used then let voltage recover/stabilize before the next 10% discharge. My three batteries have less capacity than typical so the testing was quicker than large capacity batteries. They're cylindrical cells, not prismatic so the curve looks a bit different. It looks similar to the curve that a Battle Born battery would have for example. You can see the recovery after each 10% discharge below. I use "Reset Capacity" when the battery is less than full. My batteries sit unused most of the time as I don't have a specific daily or weekly need for them.

 

[WingNut]

@Mako74 - We'll all have different opinions as to best settings and how hard to push the batteries etc. so my ideas & settings will be different than others.

For 20%, 40%, 60%, 80% & Full, I currently have:

Full: 3.45V
80%: 3.332V
60%: 3.293V
40%: 3.29V
20%: 3.24V

Undervoltage: 2.9V
Pack undervoltage: 11.6V

I'll change settings as needed or if my opinion or understanding of it all changes though.

 

[Mako74]

@Mako74 - We'll all have different opinions as to best settings and how hard to push the batteries etc. so my ideas & settings will be different than others.

For 20%, 40%, 60%, 80% & Full, I currently have:

Full: 3.45V
80%: 3.332V
60%: 3.293V
40%: 3.29V
20%: 3.24V

Undervoltage: 2.9V
Pack undervoltage: 11.6V

I'll change settings as needed or if my opinion or understanding of it all changes though.

Thanks @WingNut - unlike you, I really have no understaning (but I'm educating myself), hence no opinions and therefore I'm at the mercy of the factory and others. I appreciate your input! Looking at the other parameters, is there something you'd question from the factory keeping in mind my intended use?

 

[WingNut]

Your JDB 150A BMS is newer than mine (v1.3). Yours has the heating function so must be V1.5 or newer & settings would be different if the BMS has also other different components. I mentioned 20%, 40%, 60%, 80%,Full, Undervoltage & Pack undervoltage as things I'd adjust.
Also, maybe take a look at:

Balancing precision: I used 0.002V and the app accepted that.
Nominal capacity: It might be a bit high. You mentioned it is a 150Ah battery and I think you previously posted it tested at 155Ah.
Cycle capacity: looks low, you could use 80% of nominal capacity for example.

 

[Mako74]

@WingNut - many thanks, I'll try to set these but as we speak, the Xiaoxiang is working randomly. It might ask me 1-10 times the password and when it finally opens, it seems to freeze before it actually crashes when trying to access the Parameters View or anything else. I've tried v21 and v26, but same issues. The view-only v21 of the app works fine.

I'm a bit all over the place with my batteries, sorry for that. I will try to compile main findings HERE, where I also posted results on the first charge and discharge results.

 

[WingNut]

Maybe try 3.1.1015 from Google Play: https://play.google.com/store/apps/details?id=com.carplounge.bms

 

[Mako74]

Maybe try 3.1.1015 from Google Play: https://play.google.com/store/apps/details?id=com.carplounge.bms

Same issue. On Battery 1 all these versions work really slow. On Battery 2 all work well.

 

[WingNut]

There's the old xiaoxiang 2.0.1006.4.apk here: https://diysolarforum.com/attachments/xiaoxiang-protection-enterprise-apk.4224/ that gives access to settings.

When I switched over to the new green color Bluetooth modules that old app no longer connects to any of my BMS. It worked with the old blue color Bluetooth modules. The new green color Bluetooth modules work better for me overall so I won't switch back to the old BT modules.

I mention it because there's a slight chance that you have one battery with the newer BT module and one battery with the older BT module. If the old app works with one battery and not the other that might confirm it.

 

[Mako74]

There's the old xiaoxiang 2.0.1006.4.apk here: https://diysolarforum.com/attachments/xiaoxiang-protection-enterprise-apk.4224/ that gives access to settings.

When I switched over to the new green color Bluetooth modules that old app no longer connects to any of my BMS. It worked with the old blue color Bluetooth modules. The new green color Bluetooth modules work better for me overall so I won't switch back to the old BT modules.

I mention it because there's a slight chance that you have one battery with the newer BT module and one battery with the older BT module. If the old app works with one battery and not the other that might confirm it.

Thanks. The thing is that both batteries connected fine with the v21 and v26 apps, but since this morning all BT apps seem to hang and crash with the other battery, The other battery works fine with all versions I've tested.

The only thing that has changed in this particular battery that has the apps crashing and asking password several times is that I plugged in the 180W load tester to house AC outlet while it was connected to the battery and the output was set to 180W, so there was a ~15A peak when that happened. Could this have caused some damage on the BMS or its BT module?

EDIT: After finishing the discharge, the BMS kicked on the undervoltage protection, stopped discharging and APP is working fine. Go figure, but all is good now and the battery gave out 161Ah.

 

[WingNut]

The BMS would handle a 15A load easily. I've put instantaneous 100A load (toaster oven) on mine no problem. You can add or change the password, might as well try that.

 

[hilndr44]

Dumb question : on the Xiaoxiang app, is cell#1 the closest to the positive terminal, or the closest to the negative?

 

[Sky-HHI]

Closest to negative

 

[hilndr44]

Thanks! How does one go about purchasing the full-blown version of the app?

 

[Sky-HHI]

Overkill Solar web site, in the support/download section, free

 

[hilndr44]

Overkill Solar web site, in the support/download section, free

I was looking for the "Pro" version that allows me to actually change the settings.