thundercamel
10 kW
I just poke a wire through each hole and solder both sides generously.
bluetooth BMS?
- Thread starter aethyr
- Start date
cycborg
1 kW
I'm wrapping up a build with a 14s 100 A version of these, and I'm having a problem with only the even-numbered groups balancing. Here are some plots over 24 hours with the even groups clearly converging on a balancing limit, while the odd cells just drift down a bit. I'm leaving the USB connected with constant monitoring by the JBD Tools software, so I'm not worried about the drifting, but the balancing won't be very effective if only half the cells participate.
The plots show charging, then disconnecting the charger, then static balancing.
Has anyone encountered and/or solved this issue?
The plots show charging, then disconnecting the charger, then static balancing.
Has anyone encountered and/or solved this issue?
Compoundbike
100 W
okay where should i start.. i have builded the XiaoXiang BMS, with cheap cells to a skateboard (Lanzhd not very drainable).
unfortunately battery was damaged and started to burn.
But after repalcing the Batteries and limiting the discharge to 20A instead of 40A it caused no problems.
Overall im impressed with this BMS you can also shut off the Battery via Smartphone. :thumb:
unfortunately battery was damaged and started to burn.
But after repalcing the Batteries and limiting the discharge to 20A instead of 40A it caused no problems.
Overall im impressed with this BMS you can also shut off the Battery via Smartphone. :thumb:
cycborg
1 kW
cycborg said:
Argh, after two days of this, the BMS spontaneously started alternating between even and odd groups for no reason that I can determine. If anyone else runs in to this, I can't tell you what to do about it, all I can say is there's hope :?
Edit: My guess is that the alternation was triggered when the voltage of the highest even group fell to the level of the highest odd group. In the plots, you can see that these are groups 8 and 11, respectively. The only evidence I have is that these groups are now at the same voltage, and still higher than all the others.
Seems rational, bring the individual outliers toward the median before trying to get them all equalized.
Seems crazy to me they don't just go with 2+A balancing currents,
a bank that's not too far out of whack should take what 10-20min to get to within 1mV?
what would it add like $20 per unit max?
Seems crazy to me they don't just go with 2+A balancing currents,
a bank that's not too far out of whack should take what 10-20min to get to within 1mV?
what would it add like $20 per unit max?
cycborg
1 kW
I'm able to use the Xiaoxiang bluetooth app on Android with no problems, but not VBMS. I get the message "Auto Connect - Attempting to connect to the BMS" with a spinning indicator that just stays up until I hit the back button. Then I get a list of paired devices with a "Scan new device" button at the bottom, and when I tap this button, the button disappears but the list of paired devices stays up and no new devices appear, BMS or otherwise.
Is it necessary to pair the device in the bluetooth settings? When I try to do this, the adapter appears in the scanned list, but when I select it, I just get the message that the pairing request was declined, without being offered the chance to enter a PIN or anything.
If you're successfully using VBMS, what's the procedure?
I'm using the download link from this post, since I want to be able to test it before paying for it on the app store.
Thanks!
Is it necessary to pair the device in the bluetooth settings? When I try to do this, the adapter appears in the scanned list, but when I select it, I just get the message that the pairing request was declined, without being offered the chance to enter a PIN or anything.
If you're successfully using VBMS, what's the procedure?
I'm using the download link from this post, since I want to be able to test it before paying for it on the app store.
Thanks!
flippy
1 MW
- Joined
- Aug 12, 2015
- Messages
- 2,351
Yes. You need to pair it with your phone first. That is mandatory for every BT device. That is how it works. Pairing code is usually 1234 or 0000.
Sometimes you have to manually select the device in the list if it cant find it as vbms is programmed to look for a specific BT adress in your paired list. Manually selecting it solves that. But the BT has to be awake! It falls asleep after a few minutes of no current. You need to press the power button to wake it.
Never pay for vbms, just use the versions posted here.
Sometimes you have to manually select the device in the list if it cant find it as vbms is programmed to look for a specific BT adress in your paired list. Manually selecting it solves that. But the BT has to be awake! It falls asleep after a few minutes of no current. You need to press the power button to wake it.
Never pay for vbms, just use the versions posted here.
cycborg
1 kW
Thanks for the reply. So you haven't seen the behavior I've described?flippy said:
MJSfoto1956
10 kW
flippy said:
Well, you are "technically" right, but the advice above might lead to confusion for certain setups.
To wit: Neither my PowerVelocity app nor Xiaoxiang app should ever be directly paired via my iPhone's BT settings -- the apps themselves will do the pairing for you when you launch them. In fact, the PowerVelocity app will remember the pairing even when disconnected or turned off.
YMMV.
M
eee291
100 kW
flippy said:
You're wrong.
Go back a few posts I've mentioned how to connect to Xiaoxang BMS more than once and it does not involve pairing it in the Android Bluetooth settings.
cycborg
1 kW
flippy said:
Maybe this is one reason why the app isn't on the app store and must be installed from the APK.
Anyway, no one else has my issue of not being able to pair the device via the system BT settings?
izeman
1 GW
Imho you can't pair through "Settings", and this is NOT how it's intended to work. You open the app, it connects, and then it disconnects again after you close the app. No code needed ever.cycborg said:
cycborg
1 kW
izeman said:
I'm trying to use VBMS on Android. Is that what you're talking about?
izeman
1 GW
Not sure what the name of the apk was. The "official" Xiaoxiang app on Android.
eee291
100 kW
cycborg said:
We were talking about the Xiaoxang BMS or JDB BMS.
I have experienced something similar to what you are saying. When I bought a 24S BMS that could do 20S-30S I connected only 12S to see if I can change the parameters. The Bluetooth module was flashing but I couldn't connect to it not even with the PC module, not until I connected the full 24S.
larsb
1 MW
I use the 24s Smart BMS together with the VBMS app on android.
Works for me. I sometimes have to search for the BT, confirm with password 1234
This BMS to avoid any confusion:
https://www.aliexpress.com/item/32826820690.html
Works for me. I sometimes have to search for the BT, confirm with password 1234
This BMS to avoid any confusion:
https://www.aliexpress.com/item/32826820690.html
cycborg
1 kW
larsb said:
I'm using the one pictured below from LLT Power (purchased via the JBD Store). I think the problem is that these are shipped with a proprietary BT module that only interfaces with the "official" Xiaoxiang app. This post indicates that these BMSs were previously shipped with generic BT modules, but the modules included now are not programmable.
So likely your model, and possibly older models like mine, allows pairing through the system settings, which then allows them to work with VBMS. It's looking like VBMS isn't an option with my proprietary BT module, though.
cycborg
1 kW
Headrc said:
Other than the issue with proprietary bluetooth described above, I've been happy with them, although I've only had them installed for a week and a half. The 100 A one has not yet been on a vehicle, just monitoring and charging the battery, but I also have a 30 A version that I've installed on my bike with PhaseRunner and 9C motor. They both seem to do what they're supposed to in terms of basic function (HVC, LVC, balancing).
The ability to monitor things at the cell level is a huge advantage over BMSs without comms capability, and the ability to configure parameters as you like them is also a big deal. I like being able to control the FETs through the app, which eliminates the need to disconnect the battery or install a switch, with the consequent sparking or anti-sparking workarounds.
I've had some interaction with the specific vendor linked above and they're fairly responsive.
thundercamel
10 kW
I totally agree with and emphasize the cell level monitoring. Now why didn't I think of using the switch before I bought my XT90 anti-spark connectors? Oh well, one less stepcycborg said:
Inwo
10 kW
ElectricGod said:Back in May I got 5 of these BMS/balancers and an LCD. Over this past weekend I finally got time to set them up. The 4 pin JST connectors are labeled COM1 and COM2. They are the communications interconnects between each board and how you program via a USB adapter too. The right hand 7 pin connector goes to the LCD. The left hand 8 pin JST is the 7S balance connector.
https://www.aliexpress.com/store/product/112S-35S-Lithium-Li-ion-LiFePO4-LTO-Lipo-Battery-Protection-Board-BMS-Balance-Bluetooth-APP-7S/2856009_32861093603.html?spm=2114.12010612.8148356.39.29213de2sfucrn
They can be daisy chained together up to 16 in a row. When you use them as a single 7S board, the mosfets can be used for up to 30 amps. When you chain them together, they become balancers. This is the boards on 32S, 16,000mah LIPO packs before and after securing them together with nylon spacers. The "stack" is about 1" thick. Board 1 is on top and board 5 is on the bottom.
The documentation is not overly clear in some regards of wiring these BMS so in the end, I just ignored the manual and wired them with the balance connections only. I'm not using B-, C- or P- at all. Probably the LCD won't display charge or discharge amps as a result. Oh well. My LIPO packs are 4S each so I pulled out 9 4S JST male connectors and started chaining together the 5 BMS balance connections so they could span my 8 LIPO packs. The high pin in the first balance connector is common with the lowest pin in the second BMS balance connector. The second BMS high pin is common with the third BMS low pin...and so on. The LCD is plugged into the lowest BMS, but I don't know if that matters or not. With just the lowest 4S pack plugged in, a few seconds later I was seeing cell voltages on the LCD. There's an LED next to the COM2 connector that flashes randomly. As I plugged in more 4S sections, after a few seconds, they too would be added to the list and their LED would flash. Once all 5 boards were plugged together and had the full 32S connected, they all flash their LEDs at seemingly random intervals. I'm guessing the LED indicates data on the 4 wire buss. I don't know why, but the LCD won't display more than the first 28 cells. Maybe there's a setting in the BMS that tells it to scroll through the entire 32S or maybe I need a second LCD? The manual doesn't say and ICGOGOGO was clueless. They just wanted to sell another LCD...so that's on it's way and more boards too.
The manual is horribly incomplete and even though it's supposedly in English, all the screen shots are of the Chinese config app and then the actual settings are not explained at all. This is the first step in programming the BMS and that's literally all the better it gets for the rest of it.
This is the English config application. Based on the pictures in the documentation, you enter commands in that lower left pane that tell the BMS what do to. However, the manual does not explain what you type there.
This sequence of pictures is what the LCD shows. It sort "cycles" at random, but then the only thing that changes is the voltage at the bottom. As you can see the cell voltages are the same. So much for showing all 32 cells. There's no physical buttons to press on the LCD and no solder connections that could possibly be connections for buttons. I really wish it was back lit! Notice the temp reading (20C), I have no idea where the thermistor is. It's not on the LCD and looking at the boards closely there's not one on them either. I don't see in the STM32 docs that they have an internal thermistor. I'm wondering if this is fake data. In messing around, I couldn't get it to go up or down.
I want to mention the balance connector some more. Silk screened on the back side of the board is this battery layout. It is accurate for the BMS.
On the top side of the board, notice the orientation of the balance connector. This is exactly opposite of an actual balance connector on a battery pack. If you attempt to plug in a batteries balance lead directly into this connector, you will destroy the BMS. Where B- is silk screened on the board, in an actual battery balance cable, that's B+. DON'T plug a battery pack directly into the BMS!!! I didn't do it, but a friend who also has these boards did and fried at least one of his boards.
Notice the balancing resistors. 3R3 or 3.3 ohms at 4.2 volts per cell that's 1.27 amps. The specs on ICGOGOGO say "balance the current 60mA-1.2A (4.2V)". OK close enough to V/R=I, but then look at those 7 tiny mosfets or transistors on the board. They clearly connect to the resistors and source to drain across each cell. Do you seriously think they can handle 1.2 amps? My guess is that "1.2" amps is more like momentary drain and reality is more like 500mA continuous. The 4 pin packages are KPC357NT opto-isolators. I think the lowest mosfet is controlled directly by the STM32 CPU and the other 6 channels are behind the 6 opto-isolators.
IMHO, the mosfets are pretty useless and I'll never use them. I bought this board purely for it's daisy chain balancing ability at 112 cells. I intend to use 48S. The mosfets are NCE1540's. They are good for virtually nothing I'm likely to ever do where I need mosfets. I seriously doubt I'd ever build an EV that maxed out at 30 amps.
This is in the manual. Currently I don't have it jumpered at all on any of the boards. My theory, is to set this up in programming and NOT use these jumpers. That's how every other smart BMS works. It is cool that it will support LTO and LION. Most BMS won't do the full range of lithium chemistries.
I have this system connected to 4 x 10s lto 60ah modules. 40s total.
5 cells on each of 8 boards. [Keeps each module on its own section in app]
A second LCD displays over run from first LCD.
New boards have 10ohm shunts.
Balance current settings have no effect on duty cycle of shunt current.
30% balance, rising to 40% when current is sensed.
Hvc and lvc can be set..
First board in string is master, and c- output controls charger from all 40s. 150v fets should work great for my 100v charger.
Drive a relay or connect small charger and load direct.
View attachment 1
Hope these are correct screen shots.
I have questions to go go, but clueless. Balance works, settings for current do not.
Might need uart to pc, but I'm not smart enough for this Chinese nightmare.
Love these boards as they work for most any string and chem. Smoke one? Throw it out keep the other 7. Smoke the Mosfets? Shift it out of the master position.
Have parallel modules? These don't care. Each 7s section is isolated. In theory, use one bms system for 2 or 3 discrete batteries. Read up to 112 cells on 1 app.
