bluetooth BMS?

[ElectricGod]

It sounds like the BMS is working, but the mosfets are turned off. In the APK on your phone, is the lock unlocked or locked? You want it locked to enable the BMS.

 

[EbikeAus]

I need your help guys!
I've wired the xiaoxang Bluetooth bms but having trouble pairing with my samsung phone.

Where do I get the app? Got no instruction from seller.
When I try to connect it says pairing rejected.
Any help would be great. Thanks

 

[EbikeAus]

I managed to install and connect on samsung tablet but can't connect phone??

 

[ElectricGod]

I managed to install and connect on samsung tablet but can't connect phone??

Look back on this page...like 2 or 3 posts and you will find the app.

In BT settings you don't pair to the BMS. You pair via the app only.

It is possible you can't pair. I have 3 android phones and my newest phone which is months old won't pair. My next oldest phone is from 2015 and the oldest from 2012 and they both connect to any BMS without issues. Go figure.

 

[EbikeAus]

I managed to install and connect on samsung tablet but can't connect phone??

Look back on this page...like 2 or 3 posts and you will find the app.

In BT settings you don't pair to the BMS. You pair via the app only.

It is possible you can't pair. I have 3 android phones and my newest phone which is months old won't pair. My next oldest phone is from 2015 and the oldest from 2012 and they both connect to any BMS without issues. Go figure.

Thanks for the response!
I think I've got it working on my s5.
I've ordered an s9 will have to see if that will work.
I ended up finding the app on a site called bmsbattery

 

[eee291]

The one on BMS battery is the old version.

Literally 5 post above yours I posted the link to the newest one.

Here it is again.
https://shouji.baidu.com/software/24043119.html

 

[EbikeAus]

The one on BMS battery is the old version.

Literally 5 post above yours I posted the link to the newest one.

Here it is again.
https://shouji.baidu.com/software/24043119.html

Thanks mate!
I did have a look...obviously not a very good one

Well I can see why this is a popular thread. These bms are great, especially for the $.

What voltage do you guys start balancing at?

 

[eee291]

I just left it at the default 3.8V. My cells don't really need balancing.

I wish I calibrated the shunt though, it shows 0.5A more when charging and discharging. The BMS is closed off and now I can't get to it without destroying the watertight seal



BTW, does the newer App work with your phone now?

 

[EbikeAus]

I just left it at the default 3.8V. My cells don't really need balancing.

I wish I calibrated the shunt though, it shows 0.5A more when charging and discharging. The BMS is closed off and now I can't get to it without destroying the watertight seal



BTW, does the newer App work with your phone now?

I'm still using the older app as I'm in the middle of the first charge on this pack.
I'll look into the shunt calibration.
Mine was set to balance at 4v, I think i'll change it to 3.8.
Thanks

 

[thundercamel]

If it's a good pack, then 4.0v is fine.

 

[xmtx]

It sounds like the BMS is working, but the mosfets are turned off. In the APK on your phone, is the lock unlocked or locked? You want it locked to enable the BMS.

Well, I can't even connect to the BMS, the connection fail each timeeither via BT or USB, there is no lock/unlock thing.

The seller asked me to brush the bms to remove any short, and to try to charge the battery via the BMS, maybe it will unlock it.
I'll keep you posted.

 

[ElectricGod]

The one on BMS battery is the old version.

Literally 5 post above yours I posted the link to the newest one.

Here it is again.
https://shouji.baidu.com/software/24043119.html

Thanks mate!
I did have a look...obviously not a very good one

Well I can see why this is a popular thread. These bms are great, especially for the $.

What voltage do you guys start balancing at?

There's a few things that play into how you set the balance voltage:
1. LION tends to stay balanced a good bit better than does LIPO.
2. Any pack can have a weak cell in it. That cell will get out of balance much more easily than the rest of the cells in the pack.
3. A cell with less capacity than the rest in the pack will discharge faster and charge faster than the rest of the pack.
4. The capacity of your pack will effect how quickly you can balance. A 10Ah pack will balance much more quickly than a 64Ah pack. A 10Ah cell will draw down more quickly than a 64Ah cell.
5. The current capability of your charger plays into things too. I charge at 30 amps. It would not be hard to charge much faster than the BMS can balance.
6. The resistors in the BMS are fairly small and can sink a few hundred milliamps at most. You need to account for the "speed" at which you can balance when you are charging and account for this by setting the balance start voltage appropriately.

IE: Hard and fast voltages aren't really applicable. Set the balance voltage conservatively low at first. Watch how your pack charges on your charger. If you see your pack balances just fine at that conservatively low voltage, set it a bit higher. Watch the packs cell voltages over 2 or 3 more charge cycles. If they stay balanced and the new higher voltage, set it a little higher and watch the cells over 2 or 3 more charge cycles. After probably 10 charge cycles at most, you'll find the balance start voltage that works for you best.

Personally, I am hesitant to give you a balance start voltage and to tell you "this will work for you". Having said that, I have multiple LIPO packs that are fairly new and they start balancing at 3.9 volts. However as those LIPOs age, I'll want to set the voltage lower as some cells will lose capacity faster than others. I have a 20S LIPO pack that is made of 5 4S multistar packs. Some of the 10,000mah packs are older than the others. I set the balance start voltage to account for the older packs and their somewhat lesser capacity. This brings the entire pack to 4.1v per cell, but I start at 3.7 volts so the lower capacity or older cells can be kept from over charging while the newer cells continue to charge.

 

[EbikeAus]

Thanks for the detailed response!

This pack is 14s5p of recycled 25r. They look like they will balance up nicely.
I'll do as you recommend and cycle them a few times

 

[trazor]

I just left it at the default 3.8V. My cells don't really need balancing.

I wish I calibrated the shunt though, it shows 0.5A more when charging and discharging. The BMS is closed off and now I can't get to it without destroying the watertight seal



BTW, does the newer App work with your phone now?

I purchased 3 JBD BMS and all of them had 20% discrepancy to inline multimeter at around 10 amps. I think shunt calibration is a must in these BMS. I don't know why. Voltages are very well calibrated though.

 

[ElectricGod]

The one on BMS battery is the old version.

Literally 5 post above yours I posted the link to the newest one.

Here it is again.
https://shouji.baidu.com/software/24043119.html

Thanks mate!
I did have a look...obviously not a very good one

Well I can see why this is a popular thread. These bms are great, especially for the $.

What voltage do you guys start balancing at?

FYI...this link is to version 2.1.1022

https://shouji.baidu.com/software/24043119.html

I'm pretty sure I got that exact version from the battery BMS site.

Either that or they have the 2.1.1011 version.

 

[Doit]

Has anybody used a BMS like this: https://www.aliexpress.com/item/20S...-app-UART-correspondence-bms/32809939362.html?

Its bluetooth enabled with an android app so you can configure everything in software, as well as monitor pack voltages.

I think I'm going to order it and try it out, but I'm curious if anyone else has seen/used a BMS like this. The only problem is that 50A is below my needs, so I'll use this just for charging. This should be fine, since my controller has LVC and I can actually monitor individual cell voltages from the phone app.

Guys, I enjoyed reading your thread. Is it possible to modify the discharge current through its software? my 84v pack has a maximum 40A discharge couldn't go more than that. as above BMS specification, it has 50A continuous discharge not sure if I can change that?

 

[eee291]

You can with the PC software and adapter.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.13010208.99999999.263.4fdc3c00Fx15aD
Select UART Box wire

The software can be found some pages back
You can increase the Current limit to whatever you want but mind the BMS temp.
You can always do what ElectricGod and others have done and mod the BMS.

 

[Doit]

You can with the PC software and adapter.

many thanks

 

[ichiban]

I really wish there were some "conclusions" for this thread, completed with references (to page # + links). Since this is very lengthy, 32 pages up to here with tons of detail.

The gurus here talked about deep techs based on their long experience. Half of which I don't even have a clue what the heck they are. BMS is a crucial device we all need to take good care of our precious packs. However, it works complicatedly and with variations among models and makes - not to mention those with newer BT function to ease (or to complicate) the operation even more, especially for newbies.

The experts will say most BMS simply work straightforward as it can get... :?

 

[ichiban]

And I have bought one 14s BT BMS from JBD (AliExpress) waiting for my new 14s7p & 14s5p packs assy soon.

Hopefully, there wouldn't be much problems connecting to them.

 

[ElectricGod]

I had a couple of odd things happen with a smart BMS this week.
1. Cell voltages were all in the 3.5 to 3.7v range. There was no over current or low pack or cell voltage condition, but the P- mosfets shut off anyway. It was kind of weird. They turned off once and then right back on again. A minute later they did it again 3 times in rapid succession. I then stopped and tried the throttle once more, which worked for a second and then the BMS stayed off. checking the BMS status didn't show anything wrong.

2. Last night, same BMS, on the dashboard it was displaying LT and the P- mosfets were off. Since the BMS is on LIPO packs, I had the HVC recovery voltage set to 4.2 volts. No cell was above 4v. I then set HVC to 4.1 volts and the LT disappeared and the mosfets enabled.

This BMS has been working well for quite a while now.

 

[trazor]

Non important observation: the xiaoxiang app that connects to these BMS stole the logo from a more prominent project: https://hadoop.apache.org/ :lol: China shameless programmers.

 

[ElectricGod]

Non important observation: the xiaoxiang app that connects to these BMS stole the logo from a more prominent project: https://hadoop.apache.org/ :lol: China shameless programmers.

You never know...maybe inside those atmel 328 processors these BMS use is a subspace link into AWS.

 

[trazor]

Non important observation: the xiaoxiang app that connects to these BMS stole the logo from a more prominent project: https://hadoop.apache.org/ :lol: China shameless programmers.

You never know...maybe inside those atmel 328 processors these BMS use is a subspace link into AWS.

Yeah, probably there is a bitcoin miner working at nights. That will explain last weird behaviour of your bms and the strange efficiency measurements :lol:

 

[EbikeAus]

Just reporting that the app seems to connect perfectly fine with my new Samsung s9, seems to connect quicker than my old s5