Recent content by simat

The comms protocol for these boards is explained in this thread Simon

Its been a while since I posted to this thread, amazing how time flies. Thanks @Aadamz5 for the spreadsheet, I will be looking at the calibration next, there is some interesting info on the calibration registers in that spreadsheet. I have written a little Python program to read and write the...

I don't know of any way you can get the Atmel processor that runs the BMS boards to send 'raw' commands to the TI chip. You could remove or disable the Atmel chip and talk directly to the TI chips via I2C bus if you wanted to. Simon

There are three variants of the BQ76940, the 76920 has five cell inputs, the 76930 has 10 inputs and the 76940 has 15 inputs. Any of the BMSs that handle more than 15 cells do indeed have more than one TI chip. The 'high voltage' chip has its I2C bus coms opto isolated so the Atmel processor...

This is where I got my latest batch of BMSs, https://www.aliexpress.com/item/15S-Smart-Li-ion-Battery-PCB-board-Bluetooth-Mobile-BMS-for-63V-Li-Ion-Ebike/32812066109.html I am fairly sure that any of the units using the xiaoxiang android ap or the Windows JBDTools program will be using the TI...

This link gives information on the 03,04,05 commands that give the information you want I have had limited success with switching the charge and discharge FETs on and off with the following. send DD A5 03 00 FF FD 77 DD A5 04 00 FF FC 77 DD 5A 00 02 56 78 FF 30 77 which is the same as getting...

I have done some further reverse engineering of the coms protocol for these BMS. I have decoded the majority of the Config settings that are displayed in the config tab. To read the config settings you first have to read the battery data information with these commands DD A5 03 00 FF FD 77 DD...

I have been using them on our E-Bikes for some time and they seem to work well. Only issue I have had is that connecting/disconnecting the bluetooth module can "glitch" the Atmel processor and hang the software. Only way to fix this is to toggle the reset pin on the processor or remove the...

If you click on the "spanner" button next to the "Post Reply" button you can subscribe. Interestingly I haven't been getting notifications via email recently, is there a problem? I agree. If you want to electrically isolate it you can use an opto isolated serial link and/or hook it up to...

I have been running Winston cells for over five years now. You are right, the cells in the photograph are a new batch of CALBs that I am using to put together a system for a friend. The black and red dots are the protective terminal covers that came with the new cells. I might reuse them when I...

These are screenshots from the software provided with the BMS And from my software reading the data from the BMS

No, the original shunts are 4mOhms and there are ten of them. https://www.aliexpress.com/store/product/48V-Smart-bluetooth-BMS-system-with-30A-discharge-current-for-54-6V-Battery-system-E-Bike/1379203_32733414980.html I started a tread a while ago detailing the communications protocol here...

There are a number Chinese Bluetooth PCBs that use the TI BQ76940 BMS controller/controllers connected to an Atmel 8 bit microcontroller looking like this. One of the main issues with these boards is the layout of the FETs that disconnect the battery from the rest of the world in the case of a...

There are a number of generic Bluetooth BMS units based around the TI BQ76940 BMS controller with a number of different configurations. I am not sure if they are manufactured by one or a number of different manufacturers. The thing they have in common is that they can be used with an Android app...

Thanks for posting the pictures on how to configure the boards for different cell counts. My first impressions like yours are that this BMS is very good for the money. Software is a little rough around the edges but gives all the information that one needs, nice that you can calibrate the unit...