bluetooth BMS?

[larsb]

I put liquid tape on the other connector already before as several wires wanted to slide out on that one. Should have followed the logic

 

[thundercamel]

Hi, newbie to bluetooth bms and still havent read whole discussion, but:

Has anyone come up with a way to increase range for the bluetooth?

I tried to mount this bluetooth on multi rotor drone, to properly see voltage levels, but the 'reception' is so bad, that the connection gets broken apart after like 5-6meters..

Has anyone else tested the bluetooth range for these bms'es? The model which im having seems to have really bad range or something is really interfering..

Was hoping for at least 10 meters of range or so..

Not sure whenever to look for other options (to remotely view cell levels) or just find a way how to improve the signal or change to 2.4ghz communication..

This is to see the cells dont go out of whack while in flight and also properly monitor temperature and voltage drop at various loads.

Lol, every bluetooth device I've ever used has been short range, which is all it was designed to be. I feel lucky whenever my BMS connects from the garage to my living room.

 

[wjr]

I've had about a 50% failure rate with the PC programmer boxes, so I would suggest buying one or two additional ones.
You can get them separately on Aliexpress just in case:
https://www.aliexpress.com/item/7S-24V-13S-14S-48V-Lithium-Battery-Protection-Board-Static-Balance-BMS-APP-Cell-Display-Smart/32870436486.html?spm=a2g0s.13010208.99999999.350.206e3c001Q0iSG

This link is outdatet: "Sorry, this item is no longer available!"

Searching for a replacement, I found this ad on IC GOGOGO store
https://www.aliexpress.com/item/33049139356.html
which has an "UART Box" - is this what I need?

I have this BMS:
https://www.aliexpress.com/item/32856349172.html
ANT Smart BMS 10s to 24s 300A w/ display

And where can I attach the serial box?
Do I have to pull the bluetooth module off?
Or can I use the display port, which looks like a serial connection as well?

I will try to get away without the PC software, but regarding the delivery time, I prefer to have the programmer box handy in case I need it.

 

[wjr]

hm. looks like they have changed the board.
I has printed on silk

RV24.1.4
ANT-BMS-24S
WWW.MAYIBMS.COM

The BT module is soldered to the board,so I don' want to unsolder this to connect a serial adaptor.
Can I connect a PC software at all?
Do I need one, at all?

I don't see any other serial port than the one to the display on the main board.
There is another serial connector unpopulated on the display, and a CAN as well,
But I don't hink that I want connect my PC to the display, do I?

anyway, the display board is labelled RV4.8 in silk, and "LCD/LED5VQ" on a paper sticker attached

 

[wjr]

looked up mayibms.com, but can't get very far there.
May be someone capable of Chinese language could go farther.
They have an "EN" button, but that seems just to translate the menu, not the content.

Their images still seem to display the old versions of the BMS.
So I don't see what all those unused connectors on my "new version" board might be useful for.

 

[artvk]

I just bought this BMS https://www.aliexpress.com/item/32840772926.html?spm=a2g0s.9042311.0.0.27424c4dWHUaFR

After connected all balance wire and connected to pc, the software in PC show wrong data in new Samsung 25R cell 1 (0.5V) and cell 2 (1.6V)
I already measure from the cell balance wire with multimeter and the data is same as other 3.5V.
also the cell 1 and 2 voltage even show less in Mobile version than in PC's.


Do I have to setup some parameter ? I order Li-on 20S version
Have anyone got it issue ?

 

[eee291]

You have to connect the B- on the BMS as well, only the balance wires is not enough.

 

[artvk]

You have to connect the B- on the BMS as well, only the balance wires is not enough.

Thanks a lot eee291. It works perfect right now.

 

[artvk]

JBD BMS
I have question when unplugged charger and leave it isolated without connected to other components around 12 hours , the total pack voltage bleeding is 0.11 V (from 81.68V to 81.57V)
Is this normal for this BMS ?

 

[krlenjuska]

I have 1 question about JBD bluetooth BMS.
Is android app enough for settings like charging voltage, balance start voltage and discharge cutoff voltage? I want to charge my pack to 4.10V. I dont wanna buy UART module if i dont need it.

Thanks!

 

[zipoman]

Yes, it is possible change settings only with app. But i cant set max voltage 3,5V for LFP, min 3.65V - I must set this voltage by pc. For li-ion I think no problem with 4.1V max voltage, problem is low value.

 

[zipoman]

JBD BMS
I have question when unplugged charger and leave it isolated without connected to other components around 12 hours , the total pack voltage bleeding is 0.11 V (from 81.68V to 81.57V)
Is this normal for this BMS ?

0.11 V it is normal voltage drop after unplug charger. When i charge li-ion to 4,2V , after 1hour voltage drop to 4,18V

 

[krlenjuska]

Yes, it is possible change settings only with app. But i cant set max voltage 3,5V for LFP, min 3.65V - I must set this voltage by pc. For li-ion I think no problem with 4.1V max voltage, problem is low value.

Thanks i ordered 6S-10S version.

 

[Tolkano]

How long does the bluetooth module last on these things? Mine seems to have killed itself after about 6 months

 

[tmho]

I finally finished my battery pack with the bluetooth BMS. But something strange that I cannot understand why.

I set the no. of cell (14s) and the capacity (13.5AH) of the pack. And I got the following readings from the app.

Voltage of the pack: 51.7V
Capacity of the pack: 7.006AH (52%)
Highest voltage of the cells: 3.691V
Lowest voltage of the cells: 3.688V

Then I started to charge the pack. I saw the voltage and capacity went up gradually and that was normal. After charging for about half an hour, I stopped the charging by unplugging the charger. And I got the following readings from the app which I think should also be normal. (Sorry, I did not take a screenshot)

Voltage of the pack: 55.1V
Capacity of the pack: 9.091AH (68%)

But after that, I found the capacity reading still going up. At about 40 minutes after unplugging the charger, I got the following readings.

Voltage of the pack: 54.1V
Capacity of the pack: 9.530AH (71%)
Highest voltage of the cells: 3.860V
Lowest voltage of the cells: 3.858V
Screenshot_2019-06-23-00-55-19.png


Why the capacity of the pack continue to increase after the charging had stopped? Is something wrong with the app?

PS: so far after the above screenshot, the capacity reading stays at 9.530Ah without going further up.

Further to my post above dated June 21, 2019, on September 21, 2019, I got the following readings.
Voltage of the pack: 50.2V
Capacity of the pack: 6.230AH (47%)
Highest voltage of the cells: 3.590V
Lowest voltage of the cells: 3.588V


After that, I have not used the battery (no charging and no discharging). Today, I have the following readings.
Voltage of the pack: 48.3V
Capacity of the pack: 0.836AH (7%)
Highest voltage of the cells: 3.452V
Lowest voltage of the cells: 3.450V


This time, it seems that the capacity should not decrease by that much even though the BMS may still draws some current during this storage period. Am I correct? Is there something wrong with the app or I did not set the parameters properly?

P.s. My battery is 14S4P. I set the no. of batteries to 14s and the battery physical capacity to 13.5AH. I have reset to factory settings and set 14s and 13.5AH again, but still got the above readings.

 

[tmho]

Also, I have downloaded the app for iphone hoping that it will be normal. But after opening the app, it just keeping scanning and cannot connect to the battery. Could somebody help me on this please?

 

[eee291]

Hey guys, I thought I'd make an announcement about the updated JBD App and PC programming software.
I know a few guys who don't update and then get issues with the newer Android versions and what not.

Here are the links:
Link to the App and PC soft.
http://www.jiabaida.com/home-1.7-info-id-104-catId-52.html
Direct link to the Zip file.
http://www.jiabaida.com/uploads/soft/xiaoxiangBMS.zip

Some pics:
https://imgur.com/a/lWp3iOA

When trying to connect to your BMS, the App will ask you to make a 6 digit password (there is no confirmation so be careful!)
It looks like you can change a lot more settings than before, looks like most people won't be needing the wonky PC dongle :thumb:

 

[tmho]

I finally finished my battery pack with the bluetooth BMS. But something strange that I cannot understand why.

I set the no. of cell (14s) and the capacity (13.5AH) of the pack. And I got the following readings from the app.

Voltage of the pack: 51.7V
Capacity of the pack: 7.006AH (52%)
Highest voltage of the cells: 3.691V
Lowest voltage of the cells: 3.688V

Then I started to charge the pack. I saw the voltage and capacity went up gradually and that was normal. After charging for about half an hour, I stopped the charging by unplugging the charger. And I got the following readings from the app which I think should also be normal. (Sorry, I did not take a screenshot)

Voltage of the pack: 55.1V
Capacity of the pack: 9.091AH (68%)

But after that, I found the capacity reading still going up. At about 40 minutes after unplugging the charger, I got the following readings.

Voltage of the pack: 54.1V
Capacity of the pack: 9.530AH (71%)
Highest voltage of the cells: 3.860V
Lowest voltage of the cells: 3.858V
Screenshot_2019-06-23-00-55-19.png


Why the capacity of the pack continue to increase after the charging had stopped? Is something wrong with the app?

PS: so far after the above screenshot, the capacity reading stays at 9.530Ah without going further up.

Further to my post above dated June 21, 2019, on September 21, 2019, I got the following readings.
Voltage of the pack: 50.2V
Capacity of the pack: 6.230AH (47%)
Highest voltage of the cells: 3.590V
Lowest voltage of the cells: 3.588V
Screenshot_2019-09-21-10-17-13.png

After that, I have not used the battery (no charging and no discharging). Today, I have the following readings.
Voltage of the pack: 48.3V
Capacity of the pack: 0.836AH (7%)
Highest voltage of the cells: 3.452V
Lowest voltage of the cells: 3.450V
Screenshot_2019-12-09-16-06-50.png

This time, it seems that the capacity should not decrease by that much even though the BMS may still draws some current during this storage period. Am I correct? Is there something wrong with the app or I did not set the parameters properly?

P.s. My battery is 14S4P. I set the no. of batteries to 14s and the battery physical capacity to 13.5AH. I have reset to factory settings and set 14s and 13.5AH again, but still got the above readings.

I just found out why I got such readings. They calculate the capacity (or state of charge) based on the voltage of the cells. From the latest version of the app, I can see that they set 3.405V as 0% and 3.477V as 10%. Therefore, my cells at 3.45V will be treated as 7% (7% of 13.5AH is 0.945AH). I understand such method (state of charge based on the voltage) is not that accurate. However, if somebody know the most appropriate voltages for various state of charge (for lithium ion cells), please let me know so that I can change the settings in the app.

 

[john61ct]

I just found out why I got such readings. They calculate the capacity (or state of charge) based on the voltage of the cells.

There are three factors there, which are only loosely if not barely related to each other.

SoC, at least between 100% and 0%, is only very roughly related to voltage, and even then only after isolated and resting for some time.

Capacity, aka State of Health, can only be determined accurately through precisely timed discharge tests with a CC load. Roughly with an Ah / coulomb counter, but need to cycle completely from standard 100% Full to 0% empty SoC benchmark points.

Getting the actual SoC very precisely can be done using similar tests once the Ah capacity has been determined.

I do not know of any BMS I would trust for any of these.

Other than voltage of course, but that accuracy needs to be verified, calibrated against separate known good instrumentation as well.

 

[SilverLine]

Hallo

If i buy the cheapest model, the one with lowest Amp rating (like the JBD 20s 30a), and only use the BMS for charging, and bypassing discharged. Will I still have most of the cool features, like cell monitoring via app, cell ballancering, and manuel ballancing if a cell drift ?
Thanks

 

[john61ct]

You mean controlling external relays rather than running power through the FETs?

Yes, all the voltage based stuff is fine.

You just lose OCP

 

[SilverLine]

No, just only using the BMS as "charge only".. And connect the main negative wire directly from battery to speed controller. I am aware, that I loose some safety.
But thanks... And its also possible to se how many aH i put back in the battery when charging ?
Does it show how many mAh you put back in each cell ?

 

[thundercamel]

Hey guys, I thought I'd make an announcement about the updated JBD App and PC programming software.
I know a few guys who don't update and then get issues with the newer Android versions and what not.

Here are the links:
Link to the App and PC soft.
http://www.jiabaida.com/home-1.7-info-id-104-catId-52.html
Direct link to the Zip file.
http://www.jiabaida.com/uploads/soft/xiaoxiangBMS.zip

Some pics:
https://imgur.com/a/lWp3iOA

When trying to connect to your BMS, the App will ask you to make a 6 digit password (there is no confirmation so be careful!)
It looks like you can change a lot more settings than before, looks like most people won't be needing the wonky PC dongle :thumb:

Thanks eee! I wonder how far the functionality of the 6 digit passcode extends to, but I did get the new software up and running.

I now own three of the 14s 60a JBD units from here. They turned out to be a v1.3, v1.4, and just now a v1.6 which seems to be a pretty big revision. Two of the mosfets and two of the shunt resistors are gone to make room for more balance circuitry, but at least these mosfets are rated at about half the RDS of the old ones.

KNB3308A 80V 9mOhm 80A
145N08A 80V 4.8mOhm 145A

I forgot to look at what values came programmed with this v1.6 unit, and pasted in the settings I was using from the v1.3 unit that it's replacing. If anyone reads the default settings from a v1.6 unit, let me know if the shunt resistor is still set to 0.2 mR please.

Open images in a new tab for full resolution. V1.4:

V1.4:

V1.6:

V1.6:

 

[thundercamel]

No, just only using the BMS as "charge only".. And connect the main negative wire directly from battery to speed controller. I am aware, that I loose some safety.
But thanks... And its also possible to se how many aH i put back in the battery when charging ?
Does it show how many mAh you put back in each cell ?

As far as I know, the JBD BMS only shows instantaneous voltage and amperage readings. Wattage on the smartphone app is calculated on the fly I believe, and anything showing capacity levels or mAh are estimated from the current voltage. There are adjustable parameters for what voltage your cells are at for every 20% of their capacity level to adjust that calculation it gives you.

 

[john61ct]

IOW really nowhere near accurate SoC.

Even the most accurate BMs at hundreds of dollars get maybe 4-6% accuracy at best.