bluetooth BMS?

[izeman]

just for clearity: i got one of these here:

https://www.aliexpress.com/item/15S-60A-active-bms-2017-new-Li-ion-smart-bms-pcm-with-android-Bluetooth-app-UART/32833964039.html





15s 60a max for li-ion. interestingly, when i connected it to the bt module and installed the apk for the android phone, which worked flawlessly, i got pre-set voltages for some other lithium chemestry, but not li.ion.
i tried to raise max voltage cutoff to 4.250V, but couldn't set it above 3.9V.

i then tried the pc software, which worked fine as well. of course it has this awful chinese look, but who really cares as long as it works and got latin characters. with the pc software i was able to set it to correct values w/o problems. after that i was able to set the same high voltages through the android app as well.

these are the values right now:








.) anyone got an idea how to make it actively balance at any voltage i set - just to test. i set balance to 3.3v and set "active balance" but i can't see anything happen.

.) any idea how to use the "switch" feature?






.) led features are completely useless i guess, as i can't see any leds on the pcb. correct?

 

[andrew.box]

Interesting thread, but a bit hard to follow. There appear to be at least 3 different bluetooth capable BMS products being discussed here, and not always a clear reference to which one is being discussed in a given post. Like, which software screenshots go with which BMS?

Could it be valuable to the community to populate something like a google sheet with the various commercial BMS products (bluetooth and otherwise), their technical specs, links and notes to any associated software, and most importantly people's experience with them. I.e. who's actually got one in-hand and has tested it, and what did they find? Do we already have such a thing somewhere? Just an idea but of course a bit difficult to get going and organized.

I agree with you that this thread is a bag for information related to any "bluettoth capable BMS". I own of those myself.
I think that this information can be stored in the (somewhat hidden) ES wiki: https://endless-sphere.com/forums/viewtopic.php?f=32&t=46070

In the spirit of wikis, everybody is the editor, so feel free to add information and encourage others to do it.

What we can do in this thread is try to identify which models and sources of BMS we have around and make additions on the wiki. I think we should call these category "programmable BMS" instead of bluetooth. You know, any BMS that the manufacturer provides a way to program parameters by the end user (not the reseller). Usually these BMS have a serial port, and an optional Bluetooth adapter or USB2serial is attached.

I like the work of this guy https://github.com/simat/BatteryMonitor/wiki/Generic-Chinese-Bluetooth-BMS-unit-as-data-input
Using that information I propose calling those BMS (like mine), the "JBDTools BMS". I mean, calling by the canonical name of the most complete tool used to program it.

Ah, there's a wiki, very nice! Unfortunately I don't have one of these, so can't add much there, but for sure I've looked at them and wondered whether they work as advertised and/or are high quality and reliable.

That github page and associated software looks fantastic. Thanks for posting both of these things!

I guess if people posting here can try and mention what brand/model they have as Izeman has done, or at least what's it's being called on Alibaba or elsewhere, it would be nice for those trying to glean tips on how they're working and whether those who have them are happy with a particular unit.

 

[plateau]

Hi, people, is everything ok?

I'm from Brazil and here is very hard to find electronic stuffs related to eBikes.

To create a 14s7p battery, I have collected a lot of HP 62W laptop batteries (they had a bunch of Samsung 26F cells). The most part of cells are good (I have tested with an original IMax B6 and its capacities are between 2400 and 2600 mAh).

Now, I'm looking for a good BMS to manage the process of charging and discharging.

How about this BMS: https://goo.gl/RCoiuf

A friend of mine is visiting his relatives there in USA until Feb 15th. Thus, does anybody know if there is a good place to buy BMS there in USA?

I found a guy at eBay.com (in USA) but he only have 13s BMS option (I have bought a Bafang BBSO2 48v and everybody told me to use a 14s battery instead of 13s. Will I loose much power?)

If I don't find a bluetooth option, how to ensure does the battery life is good?

Thanks in advance.

Regards,

Pedro Rosa.

 

[izeman]

pedro, it will be hard do find stuff listed on aliexpress somewhere else. espescially not for that price.
does aliexpress ship to brazil? i know that many sellers don't ship to south america or africa and some other parts of the world.
if they do i'd order from aliexpress. i had really good expierience after several hundreds of orders. (506 orders to be precise 8) )

 

[plateau]

pedro, it will be hard do find stuff listed on aliexpress somewhere else. espescially not for that price.
does aliexpress ship to brazil? i know that many sellers don't ship to south america or africa and some other parts of the world.
if they do i'd order from aliexpress. i had really good expierience after several hundreds of orders. (506 orders to be precise 8) )

Thank you so much for having answered me too fast, Izeman.

Some year ago, I have bought a Samsung Galaxy S2 display from China at Aliexpress.com without any problem.

The biggest problem is the brazilian customs clearance. The package usually arrives here in Brazil with 2 weeks and the customs takes more than 40 business days to process it. So, sometimes it's impossible to build any electronic thing that you need to import a part.

Further, do you know any American seller?

One more time, thank you so much.

Regards,

Pedro Rosa.

 

[Inwo]

Hi, people, is everything ok?

I'm from Brazil and here is very hard to find electronic stuffs related to eBikes.

To create a 14s7p battery, I have collected a lot of HP 62W laptop batteries (they had a bunch of Samsung 26F cells). The most part of cells are good (I have tested with an original IMax B6 and its capacities are between 2400 and 2600 mAh).

Now, I'm looking for a good BMS to manage the process of charging and discharging.

How about this BMS: https://goo.gl/RCoiuf

A friend of mine is visiting his relatives there in USA until Feb 15th. Thus, does anybody know if there is a good place to buy BMS there in USA?

I found a guy at eBay.com (in USA) but he only have 13s BMS option (I have bought a Bafang BBSO2 48v and everybody told me to use a 14s battery instead of 13s. Will I loose much power?)

If I don't find a bluetooth option, how to ensure does the battery life is good?

Thanks in advance.

Regards,

Pedro Rosa.

Not supposed to talk about selling, but I have most models here in USA.
I did not get them to sell, but can help someone out if time is an issue.
12s_32s

 

[parabellum]

The biggest problem is the brazilian customs clearance. The package usually arrives here in Brazil with 2 weeks and the customs takes more than 40 business days to process it. So, sometimes it's impossible to build any electronic thing that you need to import a part.

Look out for courier company with US customer PB. I order to Miami address and they take all the hassle with customs, in 2 days after arrival I get my stuff in Dominican Republic, delivered if needed, all for ~4USD/pound fee.
May be little more complicated in your location as Brasil is not in CAFTA agreement. The shipping to US is a breeze compared to DR direct.

Sorry for OT.

 

[izeman]

i opened my bms yesterday. first of all to install a parallel 16pin jst-xh connector so i can connect 2 paralleled packs.
please ignore the small B- wire, it was for testing only. it is needed to get valid readings of cell voltage. if it's not connected the cells 1-3 show wrong values.

i still want to install an on/off switch, and there is a "switch" check mark in the software. maybe it's correlated to the K1 connection on the board?
anyone got an idea? when i measure voltage between pins i shows 3.3V. what could K stand for?

 

[plateau]

Hey, izeman , how are you?

Could you check if these pins have a pull-up resistor? If so, it could be to use a push button to switch between the charge and discharge.

Further, I really think it could be related to the "Switch" checkbox in the software because we usually use the work "K" to represent switches.

Regards,

Pedro Rosa.

 

[izeman]

Could you check if these pins have a pull-up resistor? If so, it could be to use a push button to switch between the charge and discharge.

how would i do that?
one pin is connected to GND, the other measures 1mOhm against ground (raising the longer you measure)

 

[plateau]

Could you check if these pins have a pull-up resistor? If so, it could be to use a push button to switch between the charge and discharge.

how would i do that?
one pin is connected to GND, the other measures 1mOhm against ground (raising the longer you measure)

I think 1M is a huge resistance for a pull-up or pull-down resistor.

My suggestion is: follow the PCB trace looking for other components. Is it possible?

Below, we have an example of Pull-up and Pull-Down resistors. I'm betting in a pull-up resistor because one of pads is a ground pin.

 

[ElectricGod]

Thought I'd add a little about these BMS. The android app works pretty well see below for screen shots. But first screen shots of the BMS.

I bought 2 of these BMS and both have this nice chunk of copper reinforcing, but they don't do much good since they are in the wrong place and don't reinforce the area where you would solder down a wire. I added copper to bridge the solder pad to the copper that's already there.

This copper reinforcing goes over to the P- solder pad, but fat lot of good it does with no reenforcing to the P- solder pad.

All the small components are covered in clear epoxy so if it gets wet, no harm will happen to them.

This is an interesting detail. Those bridged solder connections are a bit of a gimic. The BMS is actually a 20S BMS, but these connections on the balance connector bridged like this makes it work for 16S. Unbridge them and viola, it's 20S.

The android app...just a few of the many pages of stuff in the app.

 

[izeman]

i don't have those copper bars on my BMS. should i add them?
electricgod: did you find a way to add an on/off switch? i'd like to get rid of my inrush limiter (one component less to fail) and use the BMS instead. any ideas?

 

[ElectricGod]

i don't have those copper bars on my BMS. should i add them?
electricgod: did you find a way to add an on/off switch? i'd like to get rid of my inrush limiter (one component less to fail) and use the BMS instead. any ideas?

I'd add copper to the power traces. Some 14 or 16 awg wire ought to do it.

I don't know anything about the inrush limiter or an on/off except for what I read in the thread. I got the BMS's a few days ago so I don't know much about them yet.

The mosfets are HY3410's which are really low grade...100 mOhm, 17 amp...meh. I'll be replacing them with something better.

Thinking more about the on/off...the 2 charge controller IC's are going to have a pin that disables the mosfets. Or the cpu will...I think it's an atmel 328, but I may be remembering wrong. All BMS will have some kind of gate control for the mosfets so that the charge side or load side can be turned off in over load conditions. One of the two IC's is going to have what you want. Of course an SPDT switch would work connected the the gates. Connect it to batt- and a resistor so that you can pull the mosfet gates to ground and turn them off. It's not quite the same as a push button that has a logic latch, but close enough to not matter.

 

[Inwo]

Maybe turning the bms power off.
The 24s and 32s smart bms have a jst pin that powers the electronics.

 

[ElectricGod]

Maybe turning the bms power off.
The 24s and 32s smart bms have a jst pin that powers the electronics.

differnt BMS...

The one you are referring to has the LCD and we are talking about the 16-20S smart BMS that does not use and LCD.

This one has an on/off button.

This one does not.

 

[flippy]

The mosfets are HY3410's which are really low grade...100 mOhm, 17 amp...meh. I'll be replacing them with something better.

With what mosfet would you replace them? I got 3 bms here with shitty mosfets.

 

[Inwo]

Was using that as an example.
Disconnecting B+ or another lead should turn off mosfets.

 

[izeman]

Was using that as an example.
Disconnecting B+ or another lead should turn off mosfets.

no. battery positive i not even connected to the BMS. the BMS takes it's power from the balance wires (which of course ARE connected to B+).

 

[izeman]

The mosfets are HY3410's which are really low grade...100 mOhm, 17 amp...meh. I'll be replacing them with something better.

Mine got irfb 3607. Even if they are genuine (what i doubt) those have an internal resistance of 7-9mOhm which is quite high.
Replacing them with some 3077 will help a lot and boost max current as well.
Still there are a lot of FETs (10 pieces !!) in parallel so it should work fine. I can swap them anytime it's needed.

 

[flippy]

i am looking for a mosfet that can do more then 75v. my next battery is ~115v charged.
and takers for a solid mosfet choice for these voltages?

 

[izeman]

i am looking for a mosfet that can do more then 75v. my next battery is ~115v charged.
and takers for a solid mosfet choice for these voltages?

first to mind would be IRFB4115 capable of 150V, but resistance is very high (~10mOhm)

 

[Inwo]

Discharge testing:
Quite an arc disconnecting a 25a 25v load.
I used the manual disconnect in the app. Worked perfectly.
Is it easy to do with the 12s bms too.
That’s one anti-spark solution.

Turn off disch mos when done riding.

 

[izeman]

YES!!! i works!

just connect a latching switch to K1, enable SWITCH in eeprom (windows software) and voilá! you can switch the BMS on/off with it.
if you DISABLE the SWITCH checkmark in the software it will be ALWAYS ON.

edit: it's a bit strange: i can easily connect with my redmi note 3 android, and i could connect with my mi mix2 an nougat firmware, but it's not working with oreo. any ideas why this could happen?

 

[flippy]

first to mind would be IRFB4115 capable of 150V, but resistance is very high (~10mOhm)

would the IPP048N12N3G be a better alternative? (4.8mOhm)
https://www.infineon.com/cms/en/product/power/mosfet/20v-300v-n-channel-power-mosfet/120v-300v-n-channel-power-mosfet/ipp048n12n3-g/

i still plan on putting like a dozen on the board to replace the chinesium mosfets to get decent current capabillty.