bluetooth BMS?

Batteries, Chargers, and Battery Management Systems.
aethyr
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Re: bluetooth BMS?

Post by aethyr » Jul 06, 2017 7:30 pm

vipster76 wrote:where did you buy the bms from :) i wouldnt mind getting my hands on one!
from aliexpress, link is on 1st post

mattjrogers
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Re: bluetooth BMS?

Post by mattjrogers » Jul 07, 2017 7:24 am

I use the same APP and have found the lock function helpful in a few ways.
1 - I use the lock when I stop to cut off all chance of accidentally hitting the throttle when taking my one year old on and off the bike.
2 - It also helps when the bike is locked up in town to prevent anyone from knocking it down by accidentally hitting the throttle or just "trying" it out to see if ti works
3 - It shuts down any small voltage draws from the motor controller, indicator lights, etc so that there are no draws on the battery that might cause a low voltage failure if you forget about it.

Now - one thing to think about is that if your phone dies when you are out and have the bike locked, you can't turn it back on without finding a phone charger. I ordered a USB charger port board and need to hardwire it in to the battery so that I always have a place to charge my phone if I am out with the bike.

Another good thing is that I think the BMS is smart enough to prevent failures of the board during certain fault conditions. I am not experienced enough in circuits to know very much, but when researching a split pack, people like Ping told me that if the main battery wire between the two packs was disconnected while in use, it would fry the BMS because all the current would travel through the balance wires. Well....I was just riding and hit a bump and my bike shut off. The BMS showed weird voltages and an IC fault so I thought it failed. But when I got the bike home I found that the main battery wire had come apart. A quick soldering job later and the BMS functioned normally with no resets or issues. So in some way it much be better than other BMS boards because Ping told me this would fry a board.

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Re: bluetooth BMS?

Post by keyne » Jul 11, 2017 11:01 pm

I've just ordered a 24s 100A one myself. A few questions you may be able to help with:

Do you know what Balanced turn-on voltage is? Is this the voltage when it starts trying to balance any cells that are slightly higher than the rest?

Do you know how the sleep power consumption makes sense? 200uA when in sleep mode is great, but how do you get it in and out of sleep mode? With the bluetooth app? Wouldn't it already have to be in bluetooth mode to connect to the app to know you've just turned it on? I think I'm missing something here...

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Re: bluetooth BMS?

Post by DVDRW » Jul 11, 2017 11:15 pm

What battery monitor chip is used to read voltages in these BT BMS-es?
ISL94203?
LTC6804?

aethyr
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Re: bluetooth BMS?

Post by aethyr » Jul 11, 2017 11:55 pm

keyne wrote:I've just ordered a 24s 100A one myself. A few questions you may be able to help with:

Do you know what Balanced turn-on voltage is? Is this the voltage when it starts trying to balance any cells that are slightly higher than the rest?

Do you know how the sleep power consumption makes sense? 200uA when in sleep mode is great, but how do you get it in and out of sleep mode? With the bluetooth app? Wouldn't it already have to be in bluetooth mode to connect to the app to know you've just turned it on? I think I'm missing something here...
Yes, the balance turn on voltage is when balance charging begins. It's slower, so typically it's set later, around 4v or so.

My understanding is that the 200uA is used to detect a Bluetooth connection attempt, at which point it powers up fully. The Bluetooth module has a blue light that only lights up upon connection. When I turn off the phone app, the light turns off.

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Re: bluetooth BMS?

Post by keyne » Jul 12, 2017 3:01 am

Does it go into the sleep state by itself after a set time? Or is it only put into the sleep state if you use the app?

aethyr
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Re: bluetooth BMS?

Post by aethyr » Jul 12, 2017 5:26 pm

keyne wrote:Does it go into the sleep state by itself after a set time? Or is it only put into the sleep state if you use the app?
It goes into sleep if there is no Bluetooth activity for 10 seconds. The app polls the BMS constantly for real time data, so as long as the app is open, there is activity.

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Brandon314159
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Re: bluetooth BMS?

Post by Brandon314159 » Jul 18, 2017 7:56 pm

I purchased the 30A version from this same seller so will report my findings when installed on a 13S 15ah pack I'm assembling.

Any rough estimates on delivery to the states (time) for those that have purchased?

Also would love to check the software out if it's available somewhere.

Cheers.
-Brandon

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Re: bluetooth BMS?

Post by DirkB19 » Aug 07, 2017 5:38 pm

I purchased this 13s 30A Smart Bluetooth BMS from Aliexpress.
It arrived after 3 weeks.
:twisted: Unfortunately my unit doesn't work. It was DOA (Dead on Arrival).
Bluetooth & PC connection work, but the problem is that the first cell reads 1.8 V incorrectly while my cell 1 is at 4+ volts.

Seller thinks the problem is in my "weak" connections but I have checked and re-soldered everything and I am pretty sure the problem is in the PCB.
Anyways when I measure the voltage on the PCB header (where the sensor-wires arrive) it reads 4+ volts for cell 1 on my Fluke.
Any tips on what else I could try ?

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Brandon314159
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Re: bluetooth BMS?

Post by Brandon314159 » Aug 07, 2017 5:51 pm

My BMS has been functioning nicely and without issue here.

I think you can individually calibrate each cell so perhaps check that table on the PC software?
-Brandon

aethyr
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Re: bluetooth BMS?

Post by aethyr » Aug 14, 2017 6:54 pm

DirkB19 wrote:I purchased this 13s 30A Smart Bluetooth BMS from Aliexpress.
It arrived after 3 weeks.
:twisted: Unfortunately my unit doesn't work. It was DOA (Dead on Arrival).
Bluetooth & PC connection work, but the problem is that the first cell reads 1.8 V incorrectly while my cell 1 is at 4+ volts.

Seller thinks the problem is in my "weak" connections but I have checked and re-soldered everything and I am pretty sure the problem is in the PCB.
Anyways when I measure the voltage on the PCB header (where the sensor-wires arrive) it reads 4+ volts for cell 1 on my Fluke.
Any tips on what else I could try ?
Did you wiring everything, including battery leads? I had the same problem when I just plugged in my balance wires, but didn't wire up my main battery leads.

DirkB19
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Re: bluetooth BMS?

Post by DirkB19 » Aug 15, 2017 11:43 am

aethyr wrote: Did you wiring everything, including battery leads? I had the same problem when I just plugged in my balance wires, but didn't wire up my main battery leads.

Yes, I wired everything and checked and re-checked as advised by the Seller, but the problem is still the same.
So I started a 'dispute' for a full refund. Off course, for this I need to return the goods, which to China, costs more than the BMS itself ... :twisted:
As I leave on summer holiday in a few weeks with my E-bike, the seller leaves me no other option than to buy another new unit again, now hoping that it will work as advertised.
So I will probably pay 2x the price for 1 working unit :-(

The funny thing is that on there is a sticker which says "Quality check : OK"
I guess it has the same meaning as the other sticker which says "ROSH" :)

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Re: bluetooth BMS?

Post by cwah » Aug 17, 2017 5:13 am

Is it this seller?
http://s.aliexpress.com/Mb2AbyUv

I'm having a dispute with the 15s 30a bms too. Charging doesn't work and seller gives me random instructions to make it look like I did a mistake
Help me find my stolen electric brompton: http://bit.ly/1a0vbBC and Bosch Sinus B3 http://bit.ly/1eV0WQz

DirkB19
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Re: bluetooth BMS?

Post by DirkB19 » Aug 17, 2017 10:20 am

cwah wrote:Is it this seller?
http://s.aliexpress.com/Mb2AbyUv

I'm having a dispute with the 15s 30a bms too. Charging doesn't work and seller gives me random instructions to make it look like I did a mistake

Yes sir, that is the seller. And I have the exact same feeling that he is just giving instructions to make it look like I make a mistake.
I fear they have a major problem in their quality control department, and I think it is terrible how they treat us customers... :twisted:
Anyway I will start an Appeal procedure on Aliexpress, who via chat assured me that a good solution will be found ... let's wait and see. :cry:

DirkB19
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Re: bluetooth BMS?

Post by DirkB19 » Aug 17, 2017 10:22 am

Hi,

Is the same product available from a different (more reliable) seller ?

Nrgbod
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Re: bluetooth BMS?

Post by Nrgbod » Oct 28, 2017 2:06 pm

Has anyone managed to get the bms to record the pack Ah or seen the distance remaining field with anything other than zero?

The manual says it will log the Ah of the pack and in the app setting page there is a field for last cut off capacity. Mine is set to auto calculate but I'm on my 3rd cycle now and the last cut off capacity is still saying zero. The km remaining also hasn't moved from zero. Am I doing something wrong or are these not yet implemented?

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Re: bluetooth BMS?

Post by Nrgbod » Oct 28, 2017 4:00 pm

DirkB19 wrote:Hi,

Is the same product available from a different (more reliable) seller ?
I got mine from greenbikekit.com

lukas999
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Re: bluetooth BMS?

Post by lukas999 » Nov 02, 2017 6:32 pm

mattjrogers wrote:I have one of these BMS units. Just installed it a week ago and working through its functionality.

I alway hate when a board has conflicting markings - such as a separate place to solder P- and C-, but they tell you to put both wires on the C- tab. Why?

I use that same phone APP and it occasionally cuts out and I have to re-connect the bluetooth, but it does not lose any data in that case. The BMS must have on board memory because it saves the number of cycles the battery has seen, fault data, and capacity info. The app asks for a lot of permissions, but it uses GPS location data to calculate your speed and distance so it can take a guess at the remaining distance your battery can go. You can pull up individual battery cell voltages in use to see voltage sag at max power and other info. It has a cool lock feature where one tap on the screen on the Lock icon turns off the output power. Nice for when you just run into a store and don't want anyone accidentally hitting your throttle. But I can imagine that you lock the BMS and then your phone dies and now you can't get it unlocked until you charge your phone. Guess I need to finish hooking up my USB port on my battery!

I have not loaded up the computer software, but it looks more powerful than the cell phone APP. You can change a lot form the phone and could save yourself by having a higher LVC and then if you really need, you can change it on the fly to a lower value to limp home. For my LiFePo4, the LVC is 2.7v. I would like it to be a little higher, but in reality it will only be at 2.7v under sag and the resting voltage will be higher. Balancing may or may not work well. I don't see any current flowing when it reaches its cell overvoltage cutoff. My charger is a standard no-name charger, but I do see 1 amp of current on other packs and BMSs when it is in balancing mode at top of charge. I can't feel any hot resistors, but they are under an AL cover plate and are small 50ma ones, so they may be working. My pack is a large 48v 45AH, so I don't expect balancing miracles. It does have a setting where I can tell it to turn on balancing at a specific voltage. I set it at a low 3.4v and when the first cells hit that voltage, a Chinese character appears next to them, so perhaps that cell resistor is turned on and reducing the current from that point until the first cell hits HVC.

Overall I really like its functions and being able to check individual cell voltages while riding really makes it a cool piece of tech. I just have to figure out how to wrap everything up so that I still get bluetooth signal but have a waterproof and protected pack. Any ideas? Also, how would you mount a USB port on a battery so that it is waterproof? I was thinking to just put the USB circuit board in with the battery and have a micro-usb cord already plugged in. Then I can run just the cord out through a waterproof grommet/caulked hole in the pack. Do they make a waterproof cover for the end of a micro-usb cable?

This is very early morning with a 1 year old, so it may not be written well, but I will update if I have any issues.

Hey man

''I alway hate when a board has conflicting markings - such as a separate place to solder P- and C-, but they tell you to put both wires on the C- tab. Why? ''

Shoud I connect wire to the P - ?

which one

I connected this bms like in the picture about

looks like is charging but not balancing

Thank You for Your Help

Lucas
Attachments
CONNECTION DIAGRAM BMS TO BATTERY.jpg
CONNECTION DIAGRAM BMS TO BATTERY.jpg (166.52 KiB) Viewed 282 times

lukas999
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Re: bluetooth BMS?

Post by lukas999 » Nov 03, 2017 4:19 am

Screenshot_20171103-090232.png
(94.93 KiB) Downloaded 6 times
hey guys

I set charge to 4,15 v per cell

after few hours this is my reading

this bms can't balance them or I doing something wrong ?

Thank You for Your Help

Lucas

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Re: bluetooth BMS?

Post by bl4s7er » Nov 04, 2017 8:40 am

lukas999 wrote:
Screenshot_20171103-090232.png
hey guys

I set charge to 4,15 v per cell

after few hours this is my reading

this bms can't balance them or I doing something wrong ?

Thank You for Your Help

Lucas
Hi, im specifically looking at this bms over the others purely for this one function - so I cant set the max V cutout when charging. I want to set it to 4.05V. In Lucas's case it appears the bms has not cutout when reaching the set amount, so the whole thing seems pretty pointless.

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Re: bluetooth BMS?

Post by cycborg » Nov 04, 2017 10:36 am

lukas999 wrote:I set charge to 4,15 v per cell

after few hours this is my reading

this bms can't balance them or I doing something wrong ?
Your charger is set to 4.15 V/cell, so 58.1 V? The total of the cell voltages in your screenshot is 58.6 V; not an exact match, but probably within the measurement tolerance of the charger and BMS.

So it looks like your charger is holding at the correct voltage, but the BMS isn't balancing. Next step is to look at the BMS settings. I haven't used this BMS, so I'm somewhat guessing here. Referring to inwo's screenshot upthread, the relevant settings would seem to be:
  • Functions: Balance - should be enabled.
  • Base settings: CellOVP - should be higher than charger voltage per cell. 4.2 should work.
  • Base settings: PackOVP - should be higher than charger voltage total, so try 60.
  • Balance settings: Start Voltage: should be lower than charger voltage per cell. If you want 4.15 V, enter 4150. You might want to bump up the charger voltage a bit to give yourself a buffer. And if you do that, you might want to bump up the CellOVP and PackOVP.
  • Balance settings: Windows - Not sure what this is. Maybe how far it drains a cell before re-engaging the charger? If so, 50 mV seems reasonable.
So the basic rule would be:

Balance start voltage < Charger voltage per cell < CellOVP < PackOVP per cell.

And the gaps should be large enough to account for measurement inaccuracies. Make sense?

What are your settings for these parameters?

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Re: bluetooth BMS?

Post by lukas999 » Nov 06, 2017 3:44 pm

cycborg wrote:
lukas999 wrote:I set charge to 4,15 v per cell

after few hours this is my reading

this bms can't balance them or I doing something wrong ?
Your charger is set to 4.15 V/cell, so 58.1 V? The total of the cell voltages in your screenshot is 58.6 V; not an exact match, but probably within the measurement tolerance of the charger and BMS.

So it looks like your charger is holding at the correct voltage, but the BMS isn't balancing. Next step is to look at the BMS settings. I haven't used this BMS, so I'm somewhat guessing here. Referring to inwo's screenshot upthread, the relevant settings would seem to be:
  • Functions: Balance - should be enabled.
  • Base settings: CellOVP - should be higher than charger voltage per cell. 4.2 should work.
  • Base settings: PackOVP - should be higher than charger voltage total, so try 60.
  • Balance settings: Start Voltage: should be lower than charger voltage per cell. If you want 4.15 V, enter 4150. You might want to bump up the charger voltage a bit to give yourself a buffer. And if you do that, you might want to bump up the CellOVP and PackOVP.
  • Balance settings: Windows - Not sure what this is. Maybe how far it drains a cell before re-engaging the charger? If so, 50 mV seems reasonable.
So the basic rule would be:

Balance start voltage < Charger voltage per cell < CellOVP < PackOVP per cell.

And the gaps should be large enough to account for measurement inaccuracies. Make sense?

What are your settings for these parameters?
Hey

I did like You suggest

after several hours pack was pretty much balanced

I am using ICR 18650 26F in my pack and they are not brand new ( old laptops battery)

maybe that's why bms can't balance on the first balance charge

Looks like this BMS will work very good with all brand new batterys in the pack.

I am moving to the 2/24 s bms from chargery now
this bms has balance current 1,2 A per cell and that should be fine

I will keep You guys posted what is the progress :)

Thank YOu for Your Help

Lucas

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Re: bluetooth BMS?

Post by cycborg » Nov 06, 2017 4:34 pm

lukas999 wrote:I did like You suggest

after several hours pack was pretty much balanced
Glad to hear it worked. Can you post the settings you used? Also, your old settings, if you remember them, so we know what doesn't work.

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Re: bluetooth BMS?

Post by lukas999 » Nov 07, 2017 8:30 am

cycborg wrote:
lukas999 wrote:I did like You suggest

after several hours pack was pretty much balanced
Glad to hear it worked. Can you post the settings you used? Also, your old settings, if you remember them, so we know what doesn't work.
hey sorry I shipped bms back yesterday
I had set up 4.15 V over charge per cell
voltage relase was 4,08 V per cell as I remeber

Lucas

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shorza
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Re: bluetooth BMS?

Post by shorza » Nov 07, 2017 8:33 am

It looks like bmsbattery are selling a variety of these too.

https://bmsbattery.com/82-lipo

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