openinverter forum

Do you think i can rearrange the module as shown. The order of the boards remains, but the HV part is different. The reason for this is that I want to stack the short modules on top of the Long ones so that they fit between the frame rails.

muehlpower wrote: ↑Thu Apr 23, 2020 8:49 am Do you think i can rearrange the module as shown.

We're not currently aware of any limitations that would prevent you from doing that

Getting close ...

Nice, any way of grabbing SPI data logs? So we can start looking at doing some decoding.

These simulated or done on actual hardware?

Thats a simulation on Xilinx ISE. Hope to start actual hardware tests next week. Once proven any data logger like a Saleae or Analog discovery can connect to the spi or uart ports on the board and grab data. Initial release will be receive only. If it works out on the bench I'll pop one in the post to you Tom.

First tests with the Spartan 6 FPGA. Looks like we can detect the long pulses in order to decode CS. Now onto clk and data.

New board just arrived from JLCPCB.

I can't wait to see how you get on with it

Good news is our new pcbs with the Xilinx FPGA onboard work a treat.

Do your boards work with each battery module board, or require the main Model3 BMS?

retrEVnoc wrote: ↑Thu May 21, 2020 12:21 am Do your boards work with each battery module board, or require the main Model3 BMS?

Damien's board generates the Tesla version of the isoSPI bus that connects the battery modules. It's possible this hardware will be enough to implement the BMS functionality but we just don't know today.

Another great video Damien

You say in the video that you are not sure what you are going to do with this development. My advice is to sell the board as a closed source, tested and supported solution that simply converts isoSPI to SPI and nothing else. Basically a board that does one thing really, really well.

You are entitled to make a financial return for your efforts and I have no doubt that you'll end up using the funds to undertake even more open source projects that we all benefit from

Time for a little update on the M3 BMS isospi board development.

As of today we have successful decode of the Tesla variant iso spi into normal spi that can be read by a (fast!) microcontroller. When connected to just one slave the data rate is very fast. There is just enough block ram in the fpga to buffer it so I'm leaning towards having to put some external fast ram on the board once we get talking to a full pack.

Work on transmission has now commenced so once we get something running on the bench I'll make a video.

I have nothing useful to say, other than general praise and excitement at yet another milestone being achieved. Great work.

New Keysight scope purchased with Patreon donations. Now I can get back to work on the Tesla Model 3 BMS. Lack of a 4 channel fast DSO with SPI decode meant this project has been on hold since I had to give back the demo unit. As I don't get any sponsorship, things like this need to be purchased at normal price so delays happen. Thanks to the kind assistance of those on Patreon (and elsewhere) we can get back to hacking and publish a beta design for the M3 bms decoder.

I hope you take that with you to Lanzarote

Are the PC based DAQs not good for this sort of thing? (PicoScope I think is one of the more well known ones)
-Matt

Lots of options out there. My experience with pc based scopes is that unless you get a good one (expensive) and a good pc (expensive) then its no use. Plus I prefer to have physical buttons to push:)

MattsAwesomeStuff wrote: ↑Mon Jun 29, 2020 12:42 am I have nothing useful to say, other than general praise and excitement at yet another milestone being achieved. Great work.

Same here, great work Damien, please unlock these awesome batteries for everyone!! Heading to your Patreon now...

I thought I would share this here, as an aside replying to the prior discussions about using edge connectors with the flex pcb cables on these modules. This is a photo of a partial solution, tested on a spare flex PCB from eBay.
As excited as I am following the developments towards decoding the Tesla model 3 BMS, my final pack assembly is happening in the next month, and therefore I am going with an off the shelf BMS... in order to simplify the wiring process I have been searching for a solution for connecting to the flex PCBs directly, and this is what settled on.

The blue connector is an Amphenol Flat Flex Connector (digikey PN 609-2193-ND). The contact is ideal, a very secure flat crimp insulation piercing design, but they are only available in 2.54 mm spacing connectors, while the Tesla flex PCB is 3.5 mm spacing. Therefore my plan is to remove the contacts from the connector and solder the pins into a PCB laid out for the correct spacing, designed to connect the flex PCB pads to a board mount connector for the BMS cell tap wires. The PCB will slide in behind the flex cable and provide a rigid backing for carefully crimping each contact.

Hopefully this helps someone! When I finish the pcb layout and test the boards, I will post the eagle and gerber files online somewhere to share them.

I would prefer to solder additional cables to the original board to use any BMS. Later, when the BMS has hacked, you can remove the cables and reactivate the tesla boards.

Ken_S wrote: ↑Tue Jul 28, 2020 6:20 amI am going with an off the shelf BMS...

muehlpower wrote: ↑Tue Jul 28, 2020 8:50 am I would prefer to solder additional cables to the original board to use any BMS

Not a topic for this thread but be extremely careful with "off the shelf" BMS systems and Tesla batteries. We have seen several examples of destroyed modules and very poor support by a 'reputable' supplier.

If you wish to discuss further then the BMS sub forum is the place to post;

viewforum.php?f=13

Kevin Sharpe wrote: ↑Tue Jul 28, 2020 9:36 am

Ken_S wrote: ↑Tue Jul 28, 2020 6:20 amI am going with an off the shelf BMS...

muehlpower wrote: ↑Tue Jul 28, 2020 8:50 am I would prefer to solder additional cables to the original board to use any BMS

Not a topic for this thread but be extremely careful with "off the shelf" BMS systems and Tesla batteries. We have seen several examples of destroyed modules and very poor support by a 'reputable' supplier.

If you wish to discuss further then the BMS sub forum is the place to post;

viewforum.php?f=13

Thanks for the warning. I will continue the discussion there.

Right, back to the hacking. The next phase of this op requires a battery and slave board. Fun though it would be to haul around a full size model 3 brick, I decided to make a bench version from 25 x 18650 cells. This has the added advantage of allowing individual cells to be connected and disconnected allowing us to observe the data changes.