bluetooth BMS?

Batteries, Chargers, and Battery Management Systems.
john61ct   1.21 GW

1.21 GW
Posts: 3584
Joined: Dec 18 2018 2:06pm

Re: bluetooth BMS?

Post by john61ct » Feb 02 2020 2:45am

A graphic is not so helpful, even with detective work could end up here

https://a.aliexpress.com/_seWXIw

Where a review states they don't send out what's in the picture.

I meant an actual link, to a known-good (relatively) reliable supplier.

Thanks

User avatar
agniusm   10 MW

10 MW
Posts: 2393
Joined: Apr 16 2011 3:06pm
Location: Lithuania, Zarasai
Contact:

Re: bluetooth BMS?

Post by agniusm » Feb 02 2020 5:15am

I dont get it. It looks exactly like the one in photo i posted. How a link to an item would help you anyway? If you had asked pcb/bms version, manufacturing date, revision, that would be relevant. I dont think you have the answer

xmtx   1 mW

1 mW
Posts: 10
Joined: Jan 15 2017 7:30pm

Re: bluetooth BMS?

Post by xmtx » Feb 09 2020 5:39pm

Hello.
I've been happily playing with the XiaoXiang (yellow elephant) android App for quite some time now.
This thread helped me a lot to get a hang of the BMS, thank's a lot to all the contributors.

I recently updated my phone, for an android 10, and the apk that I got, I don't remember where, won't work on my phone.
The app launch, I get a blank screen for some seconds, then the app quits.
Does anybody have an apk working for android 10, or direction to get the app to work?

I don't know if it's relevant, but my phone is a Xiaomi mi9.

User avatar
eee291   100 kW

100 kW
Posts: 1042
Joined: Nov 05 2015 4:35pm
Location: Austria, Burgenland

Re: bluetooth BMS?

Post by eee291 » Feb 10 2020 2:00am


User avatar
serious_sam   100 W

100 W
Posts: 194
Joined: Mar 05 2017 8:07am
Location: Australia

Re: bluetooth BMS?

Post by serious_sam » Feb 10 2020 5:37am

I think I've got the opposite problem. I installed the latest version (v3.1.1013) - thanks eee291. But it won't see my BMS.

So I reinstall the older version (v2.1.1024), works again.

I'm on android version 6.0.1. Might be too old for the new app version.

Anybody else have a problem with the latest android app ?

xmtx   1 mW

1 mW
Posts: 10
Joined: Jan 15 2017 7:30pm

Re: bluetooth BMS?

Post by xmtx » Feb 10 2020 2:40pm

eee291 wrote:
Feb 10 2020 2:00am
viewtopic.php?p=1515412#p1515412
Thank you very much!
I went through the thread down to page 45, didn't saw your post. It should get more publicity!

User avatar
zeccato   100 W

100 W
Posts: 165
Joined: Jan 17 2019 8:16am

Re: bluetooth BMS?

Post by zeccato » Feb 10 2020 4:39pm

Hello, in one of these bms there's a high-voltage sound alarm when a cell exceeds, say, 3.55v.? (for charging the battery lifepo4).
I found this picture that looks like yes?
Attachments
HTB1QNVxRFzqK1RjSZFoq6zfcXXau.jpg_640x640q90.jpg
HTB1QNVxRFzqK1RjSZFoq6zfcXXau.jpg_640x640q90.jpg (26.64 KiB) Viewed 1571 times
Full susp. folding 20 swxh r. (2011),. 02 2020 MacT8. batt. 48v. 25A Life (2012), and 48 7,5A a123 (2018?). Controller programmable EB3 12 FET. Charger Balancer 14s: TP1430C. Gophert CPS-6011 60V 11A. Mercury (rarely). Buzzer. https://www.google.com/url?sa=t&source= ... 6dXxc9-lNW

quamau   100 mW

100 mW
Posts: 49
Joined: Jan 09 2009 4:35pm

Re: bluetooth BMS?

Post by quamau » Feb 12 2020 6:25am

Same problem as serious_sam here: newest app version does not work on Android 9, older does. Is there an authoritative place to look at for app updates?

john61ct   1.21 GW

1.21 GW
Posts: 3584
Joined: Dec 18 2018 2:06pm

Re: bluetooth BMS?

Post by john61ct » Feb 12 2020 7:07am

Meantime be aware that older Androids can go for say $20 on eBay, cheap enough to dedicate one to a particular function.

User avatar
trazor   100 W

100 W
Posts: 158
Joined: Jan 13 2015 10:48pm
Contact:

Re: bluetooth BMS?

Post by trazor » Feb 12 2020 3:58pm

john61ct wrote:
Jan 23 2020 1:08pm
"cute elephant app"

Does that refer to what has been labelled the Xiaoxiang app?

are there lots of other bluetooth BMS that don't use that app?

And the Ant BMSs are completely different right?

And then there's the ones Em3v uses, any leads on how to get those?

I think it would be very useful, if we standardized some naming conventions?
I proposed having some naming conventions. While ago viewtopic.php?f=14&t=88676&p=1354972&hi ... e#p1354972

Two years later I still find this thread very confusing.

I think everybody means by now what "JBD" BMS are. (well labeled in PCB, same app, same chipset)
We don't have a name for the other ones.
I still miss a wiki to make this knowledge explicit :roll:

john61ct   1.21 GW

1.21 GW
Posts: 3584
Joined: Dec 18 2018 2:06pm

Re: bluetooth BMS?

Post by john61ct » Feb 12 2020 4:30pm

Yes too bad, no more wiki
viewtopic.php?f=32&t=94921

Each BMS type should get its own hardware thread, with links to top trusted quality ordering sources maintained in the OP.

And then each piece of the software they are all compatible with each getting a separate thread too.



verdulleme   1 µW

1 µW
Posts: 4
Joined: Aug 22 2018 12:34pm

Re: bluetooth BMS?

Post by verdulleme » Feb 16 2020 1:51pm

I'm building a batterypack for a friend, using the JBD smart bms (xiaoxiang).

I've run into what looks like a double problem.
First the bluetooth module stopped working. It does not build any connection with the app and the phone does not see any bluetooth device. It did work before. The led on the module is permanent on. Measured 3.3 volt over it.

Secondly, the uart-usb pc module does work, but only half. When I start the PC software I can start the connection. It reads all the cell voltages, total voltage, capacity etc. It also detects if the discharge fets are switched on or off (with K1). But it can't read the eeprom anymore. There is very quickly a connection error pop-up, or a 'the serial bus seems busy' error.
This also did work before, reading and writing to the eeprom. Trying a different baud-rate has no positive effect.
I found out about this problem after the bluetooth module stopped working, but am not sure if it is related to that.

What I measured is that without any module attached, the rxd is 0 volt, and txd 3.3 volt (constantly). When the uart-usb is connected, both led's inside the module flash intermittendly, rxd has pulses from 0 to 5 volt, txd pulses from 0 to 3.3 volt.
With the bluetooth module connected, no data on rxd or txd at all. Voltage levels stay the same as without a module.

Does anybody know if the rxd and txd behaviour and voltage levels are normal?

Has anybody run into a problem reading the eeprom after using the newest android app where one has to set a 6 digit passcode? That was initially what I thought had happened. The passcode has been set, but the pc software does not send it to the bms because that option does not exist there. Hence the bms rejects the eeprom reading.
If someone could tell me that in their setup the pc software still works after android has set a passcode, than at least I can rule out that possibilty.

Thanks

User avatar
eee291   100 kW

100 kW
Posts: 1042
Joined: Nov 05 2015 4:35pm
Location: Austria, Burgenland

Re: bluetooth BMS?

Post by eee291 » Feb 16 2020 2:24pm

I had a similar issue it was before the new app though, all I did was disconnect the balance wires for a while and it worked again.

verdulleme   1 µW

1 µW
Posts: 4
Joined: Aug 22 2018 12:34pm

Re: bluetooth BMS?

Post by verdulleme » Feb 16 2020 2:55pm

Good to hear you solved it that way.
Unfortunately, mine have been disconnected for more than a week already. No change....

User avatar
eee291   100 kW

100 kW
Posts: 1042
Joined: Nov 05 2015 4:35pm
Location: Austria, Burgenland

Re: bluetooth BMS?

Post by eee291 » Feb 16 2020 4:35pm

I guess you could try to flash a new firmware to it, I've seen a post with the file attached to it.

Here it is:
viewtopic.php?f=14&t=88676&p=1517242&hi ... e#p1517242
DISCLAIMER! Only try this if you have no other option. Randomly updating and hoping for more features might leave you with a bricked BMS.

qwerkus   1 kW

1 kW
Posts: 473
Joined: Jul 22 2017 4:00am

Re: bluetooth BMS?

Post by qwerkus » Feb 18 2020 4:00am

Hello,

I've run into a recurring issue with those smart bms. Got mine from jbd / aliexpress and there seem no way to make the switch work. (see attached pics) Altogether, I got 3 of those bms, and only one has a working switch. Any chance to fix this ? Or is it just very bad build quality.

Thanks for your time.
Attachments
20200217_102420.jpg
20200217_102420.jpg (437.46 KiB) Viewed 1315 times
20200217_102448.jpg
20200217_102448.jpg (436.32 KiB) Viewed 1315 times
switch.jpg
switch.jpg (470.74 KiB) Viewed 1315 times

qwerkus   1 kW

1 kW
Posts: 473
Joined: Jul 22 2017 4:00am

Re: bluetooth BMS?

Post by qwerkus » Feb 18 2020 1:29pm

Well, problem solved it appears: I soldered the switch wires on the wrong side of the bms! I simply added more solder tin to have it flow all the way through the holes and make contact on both pcb sides, and now it seems to work.

User avatar
thundercamel   1 kW

1 kW
Posts: 328
Joined: Jul 23 2018 2:58pm
Location: Round Lake, Illinois

Re: bluetooth BMS?

Post by thundercamel » Feb 19 2020 1:24pm

So you installed a switch to have the BMS ignore the temp sensor inputs, or is the BMS acting as a switch output?
My Ebike builds - Existing bikes, affordable motor kits, self built 14s6p batteries - Now with more recumbent!

qwerkus   1 kW

1 kW
Posts: 473
Joined: Jul 22 2017 4:00am

Re: bluetooth BMS?

Post by qwerkus » Feb 19 2020 3:57pm

thundercamel wrote:
Feb 19 2020 1:24pm
So you installed a switch to have the BMS ignore the temp sensor inputs, or is the BMS acting as a switch output?
Those JBD BMS come with a "weak electricity" switch - as they call it - which basically cuts off power, though the tension is more like 15V, not 0. What it does it toggling the main output MOSFET, which is good enough to act as power cutoff. On the plus side, it sits behind the overcharge protection, so no risk of short circuit. This and the possibility to manually limit the max. charge per cell is actually the only reason I got those expensive BMS. In my experience, the whole BT + smartphone App hype is quite counterproductive, as a well built pack will rarely unbalance itself to a point where you'd need to monitor it constantly, yet it will discharge faster because of the additional BT drain, which might not be an issue during everyday use, but certainly is when putting the battery away for storage...

I kept the temp sensors, but had to solder them directly to the pcb, as my box is not wide enough to fit the jst connectors.

john61ct   1.21 GW

1.21 GW
Posts: 3584
Joined: Dec 18 2018 2:06pm

Re: bluetooth BMS?

Post by john61ct » Feb 20 2020 4:46am


qwerkus wrote:Those JBD BMS
Are there BMS models featured in this thread with BT comms, that you would say are outside that "JBD" categorization?

> the whole BT + smartphone App hype is quite counterproductive, as a well built pack will rarely unbalance itself to a point where you'd need to monitor it constantly, yet it will discharge faster because of the additional BT drain, which might not be an issue during everyday use, but certainly is when putting the battery away for storage

Yes I agree. But many sub-optimal packs (and all top-balanced ones IMO) do benefit from such monitoring while in use discharging.

Yes that extra parasitic drain is an issue while sitting not in use, but personally I think that is true for **all** BMS

My solution is to not "embed" them fully inside the pack shrinkwrap, but bring the balance leads out and design the physical connectors and case so the BMS is easily removed and (when needed not if,) replaced, without disassembling the pack wrt the cells themselves.

I would do this even if the BMS featured a "completely off" switch.

And I definitely want a good BMS active, not only for HVC protection in case the charge controller fails

but also in use while **discharging**, so the LVC / alarms are based on the weakest cell/group voltage rather than that of the overall pack.

Especially critical if you top balnce, and might want those last few miles of range to get home some days
Last edited by john61ct on Feb 20 2020 4:46am, edited 1 time in total.

User avatar
agniusm   10 MW

10 MW
Posts: 2393
Joined: Apr 16 2011 3:06pm
Location: Lithuania, Zarasai
Contact:

Re: bluetooth BMS?

Post by agniusm » Feb 20 2020 12:54pm

What should be idle consumptuon on this bms? We are getting 18.1mA with notging connected and no coms over BT? Seems excessive

john61ct   1.21 GW

1.21 GW
Posts: 3584
Joined: Dec 18 2018 2:06pm

Re: bluetooth BMS?

Post by john61ct » Feb 20 2020 2:00pm

That's why - and just one good reason - to easily be able to fully isolate the cells from everything else.

Some extremely crappy BMS actually pull more current from some groups than others, the accumulative effect on pack lifespan will be a huge hit on overall longevity.

To the point in some contexts if possible it wohld be worth using a buck converter from the full pack and feeding the BMS power input from that.

Or get a better BMS.

User avatar
thundercamel   1 kW

1 kW
Posts: 328
Joined: Jul 23 2018 2:58pm
Location: Round Lake, Illinois

Re: bluetooth BMS?

Post by thundercamel » Feb 21 2020 9:18am

Thanks qwerkus, that's the first time I'm hearing about the switch feature.
john61ct wrote:
Feb 20 2020 4:46am
qwerkus wrote:Those JBD BMS
Are there BMS models featured in this thread with BT comms, that you would say are outside that "JBD" categorization?

but also in use while **discharging**, so the LVC / alarms are based on the weakest cell/group voltage rather than that of the overall pack.

Especially critical if you top balnce, and might want those last few miles of range to get home some days
I've also seen Ant BMS units on this thread and AliExpress that seem like a good option. I have two of the JBD smart BMS units, and they drain so little they've barely made a dent over two winters of storage. I definitely want to monitor voltages just in case, and the LVC of each cell group I totall agree with. My packs are both uniform batteries, I top balance and I used a nickel strip per cell for series connections. At bottom capacity for max range, the groups vary greatly in their voltages, but always line right back up after charging.
My Ebike builds - Existing bikes, affordable motor kits, self built 14s6p batteries - Now with more recumbent!

john61ct   1.21 GW

1.21 GW
Posts: 3584
Joined: Dec 18 2018 2:06pm

Re: bluetooth BMS?

Post by john61ct » Feb 21 2020 3:08pm

OK it does look like Ant is a completely different setup, firmware components etc

Badger1666   1 µW

1 µW
Posts: 1
Joined: Nov 25 2018 8:48am

Re: bluetooth BMS?

Post by Badger1666 » Feb 23 2020 4:58am

Hi
I have an ant bms that need current calibration
I have the the pc tools software , what USB adapter do I need and where does it connect?

Thanks

Post Reply