bluetooth BMS?

flippy said:

no, balance voltage is where it STARTS balancing. before that it doesnt do anything. as soon as a cell hits that voltage and the difference is bigger then the set voltage the bms will simply take the lowest cell and start getting all the cells that were above that to get them down to the lowest cell, it wont go lower then the lowest cell. so it continues to charge until the charger tops out.

generally you want to start at 3.8V depending how fast you charge. but 3.8 is a good start.

Click to expand...

Flippy...thanks for that clarification. I was wondering about that too.

Yeey, just got my 300A 8-24S BMC from IC GOGOGO, now begging them to send me a android APK.
I have noticed, there are different versions of BMS and APK discussed in this tread.
Can someone link, upload or send me an version that could work on my, please?
https://www.aliexpress.com/item/Smart-Display-300A-200A-150A-100A-70A-Lithium-Battery-Protection-Board-Balance-BMS-Coulomb-Meter-Li/32826820690.html?spm=a2g0s.9042311.0.0.3da24c4dHVtwZd

Got the android APK in English and Chinese today, in my spam folder and the BMS works and beeps and shows a bunch of strange numbers, voltages, warnings, settings and I am a happy man now!
I was getting mad yesterday, trying other versions of xiaoxiang without any success. This one has different Logo and called VBMS, did not found xiaoxiang inscription nether.
If someone needs this tier of APK to experiment with, PM me.
Does it make sense to make a tread with repository for different software, hardware versions, combinations for those BT BMSs, or is the evolution to fast?
Yay, I am in game again!

What is the major differences between this "Newly upgraded version (electronic components have been replaced with the best)" 8S to 24S BMS
https://www.aliexpress.com/item/6S-24S-smart-display-2-4V-or-3-2V-or-3-7V-300A-lithium-battery-protection/32741659733.html

How is it different than the 8S to 24S that is being discussed in this thread? Or did I miss a discussion in this thread about this "Newly upgraded version"?
https://www.aliexpress.com/store/product/Smart-Display-300A-200A-150A-100A-70A-Lithium-Battery-Protection-Board-Balance-BMS-Coulomb-Meter-Lithium/2856009_32826820690.html

I have been also looking at the BMS24 by Chargery,
http://www.chargery.com/balancer.asp

how does the Charger BMS24 compare to the 8S-24S BMS 300A - 70A IC GOGOGO Store BMS (link below)?
https://www.aliexpress.com/store/product/Smart-Display-300A-200A-150A-100A-70A-Lithium-Battery-Protection-Board-Balance-BMS-Coulomb-Meter-Lithium/2856009_32826820690.html

I am also looking for a Lithium Charger (Bench Charger) with variable DC Voltage so I can charge LiHV (4.35v), LIB (4.2v), LFE (3.65v), LiS (3v), LTO (2.75v) battery chemistries and different size battery packs (24v to 120v). And good direction or good threads here at ES?

Also is there cheap chargers that can be modified to work a range of say 48v to 96v and can be modified to work with different lithium chemistry voltages? I'd might even consider buying 50 or so and selling them on Kijiji.ca here in the London Ontario Canada area. So looking for one model that can be set to differnet voltages?


Bob in London.on.ca

there is no difference as far as i can see. the newer boards have SMD balance resistors and thermal band on them instead of tru hole resistors. that is the only difference.

the chargery BMS looks (and is) more expensive, has a higher balance current but not much more. probably a bit more accurate at the low voltage range.

you need a split unit to charge that voltage range.

get 2 of these units:
https://www.aliexpress.com/item/RD-DPS8005-programmable-constant-voltage-current-Step-down-power-supply-module-Voltmeter-Ammeter-buck-converter-80V/32849962454.html

and 2 power supplies:
https://www.aliexpress.com/store/product/Single-Output-Switching-Power-Supply-DC-90V-6-7A-600W-Transformer-220V-AC-DC90V-Power-Source/1260220_32850123866.html

you can set the units to the same current and voltage (half that) and then you can go up to 160V at 5A. or if you are under 80V you can parralel them up and get 10A charge. You can control them from a computer but you need to watch for making a ground loop with the usb.

i would recommend getting lots of fuses on the outputs to prevent blowing them up if you mess up the series/parralel connection.

1.Is there an alternative app for Smart BMS with bluetooth? It would be nice to have floating window with cell voltage while using a map application. Maybe it wouldn't be hard to write?

2.How to setup all parameters like COVP, High Covp, pack max etc. for 54.6V? Is there any guide? The manual from chinese sellers are really crap.

Thanks!

The english app works fine. Just enterr the right number and hit set. Didnt have any issues so far.

What I meant is to have floating window from BMS app.

In the attached image you can see Locus Map as main app and EbikeX application for my custom controller (Barmal X2) which works in floating mode and displays data like power, voltage, speed via Bluetooth (when I took screenshot it was disconnected so no data is visible).

Here you can see it working with BMS app but I'm unable to view a map.

https://www.youtube.com/watch?v=VqCGcDerIrM&t=10s

Here's a video of Locus map with EbikeX app.So it's a watt meter with map. Pretty useful.

https://www.youtube.com/watch?v=wpEqwD8gvcQ

EbikerPL...good luck with getting that done. you'd have to convince the Chinese to rewrite the app and that's unlikely.

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.

parabellum said:

Yeey, just got my 300A 8-24S BMC from IC GOGOGO, now begging them to send me a android APK.
I have noticed, there are different versions of BMS and APK discussed in this tread.
Can someone link, upload or send me an version that could work on my, please?
https://www.aliexpress.com/item/Smart-Display-300A-200A-150A-100A-70A-Lithium-Battery-Protection-Board-Balance-BMS-Coulomb-Meter-Li/32826820690.html?spm=a2g0s.9042311.0.0.3da24c4dHVtwZd
IMG_20180621_223545.resized.jpg

Click to expand...

Hey

what is the balance current while balance charge ? app work fine ?

Luk

lukas999 said:

Hey

what is the balance current while balance charge ? app work fine ?

Luk

Click to expand...

Default setting is at 200mA. App works stable, but I only used it for settings, there is a bug in changing values in portrait mode, you must turn to landscape to be able to write. It was frustrating for 5 min before I figured out how to use it.

i am still pretty uncomfortable running 200+ amps tru that BMS. i got the 300A 32S version but those currents makes me a bit "yikes".
preventive upgrading to better mosfets something i should consider? i dont care about heat as the controller and bms is cooled by a fan and the battery is way overkill for the usage it will get. (4.4kWh, only pull 2 from it every day)

flippy said:

i am still pretty uncomfortable running 200+ amps tru that BMS. i got the 300A 32S version but those currents makes me a bit "yikes".
preventive upgrading to better mosfets something i should consider? i dont care about heat as the controller and bms is cooled by a fan and the battery is way overkill for the usage it will get. (4.4kWh, only pull 2 from it every day)

Click to expand...

Even if those HY045N10 fets have 4.5mO RDSon, (which is very strange for Chinese fets in given package and V rating) at 300A you will be pumping 67.5W of heat in to a tinny heat-sink on 1 side, not considering conduction loses etc.
I think there is a reason the over-current is set to 200A by default, along with 300A current sensor setting.
I also believe your(?) statement few pages ago, to divide specification claims by 2 is about right.
Are there HY045N10 used in 300A version.

yes, i know.

but i would like to get more input then my own reasoning that goes "those mosfets are crap but should do the job" and "i dont want to desolder and resolder 30 expensive ass mosfets" if you understand those little voices (some of them, others tell me other things ).

flippy said:

i am still pretty uncomfortable running 200+ amps tru that BMS. i got the 300A 32S version but those currents makes me a bit "yikes".
preventive upgrading to better mosfets something i should consider? i dont care about heat as the controller and bms is cooled by a fan and the battery is way overkill for the usage it will get. (4.4kWh, only pull 2 from it every day)

Click to expand...

I'm using mine at 210 battery amps and it doesn't seem to heat at all.
So I'd say no problem.

Dui said:

I'm using mine at 210 battery amps and it doesn't seem to heat at all.
So I'd say no problem.

Click to expand...

how long are those peaks?

I did connect a battery to BMS yesterday and balanced a 24s battery, which happened to have 1 cell low or at least BMS thinks so.
My observation:
If more then 13 cells are draining, BMS gets to 60C and switches a bunch of lower cells off to cool, at 45C it resumes on those cells.
At ~12-13 cells draining it leveled at ~58-60C in free air 30C room temperature, thermistor squeezed to heat sink with a cooling pad.

Considering, I have 200mA balance current set it mathematically must be ~ 12x4.07Vx0.2A=9.7W of heat and it is about the limit of where I am comfortable with, in unconfined space, open to convection, no forced cooling.

150A constant will make 16.8W on fets only + whatever conduction loses are.

This thing really needs forced cooling over 120A constant, otherwise, I risk the over temp protection switching it off at any moment.

P.S. My BMS will go inside a metal ammo can and surprisingly BT module connects to the phone from there.

flippy said:

Dui said:

I'm using mine at 210 battery amps and it doesn't seem to heat at all.
So I'd say no problem.

Click to expand...

how long are those peaks?

Click to expand...

Pretty long, It stays between 180 and 210 Amps from 50 to 110kmh usually. Once passed 110 the current goes down to 120Amps and stays around there.
The only time where I see the BMS heating is at the end of the charge, I guess that is whenever its doing the balancing.

Dui said:

The only time where I see the BMS heating is at the end of the charge, I guess that is whenever its doing the balancing.

Click to expand...

Do you know what mosfet's are used in your BMS? Link to the BMS?

parabellum said:

Dui said:

The only time where I see the BMS heating is at the end of the charge, I guess that is whenever its doing the balancing.

Click to expand...

Do you know what mosfet's are used in your BMS? Link to the BMS?

Click to expand...

The 32S BMS uses 150 volt IRFP4115's in it on the P- side and I forget what the C- are but they are 100 volt mosfets.

Probably that heating you are seeing is not the mosfets at all, but rather the resistors balancing the cells and heating up in the process.

parabellum said:

Do you know what mosfet's are used in your BMS? Link to the BMS?

Click to expand...

Sorry I don't know what mosfets they are using, but the BMS is this one:
https://item.taobao.com/item.htm?spm=a1z09.2.0.0.55692e8dxUTQtX&id=548548418029&_u=s23vfsu8d21

I'm using the 300A version, 32S.

I'm really not an expert when it comes to BMS, but I don't really think mosfets matter that much. From what I understand their only purpose during discharge is to cut the power in case either the load is too high, temp is too high or if one cell reaches its bottom voltage. So they basically act like a simple relay.

The rest of the time they should be ON, which means that the only way for them to heat would be through their internal resistance. Since I guess these mosfets are mounted in parrallel, then their total resistance should be extremely low, so there shouldn't be much heat to dissipate.
But maybe I'm wrong about that, I'm not entirely sure.

the internal resistance adds up with current. this is why you get massive heatsinks on say for example a cpu or graphics card. those thave billions of mosfets running at hundreds of amps. gross simplfication but shit adds up when you push dozens of amps.

Dui said:

I'm using the 300A version, 32S.

Click to expand...

Thanks for your info.
Your BMS is very similar but not same, theoreticaly you should have worse fets if going linear on V ratings but they could potentially be better fets if they are some original reputable make.
Do you have access to fet sink? (the balance sink is apposite one)
What is the max temp you did see at discharge? (the app shows temp at discharge, I believe)
How long(seconds in average)you are over 120A?

Not confronting your experiences, just need data to understand the whole picture.
Thanks again.

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.

Click to expand...

Did you asked them for any kind of main disconnect board, or alternative BT programming APP?