Low cost / High performance universal BMS

[nlc]

Yes I heard about this board. But at my opinion this board is too much generic and cannot be used as is for automotive use. Need to add specific board for supplies, input/output interface, and so on.

I think a specific board is better for this kind of use. But yes I want to develop it in an open source way (hardware + software)
I already drew a first diagram for this board, opinions are welcome !! In some case some function will not be used (the precharge/main contactor part for example), but I take them into account to have a very generic board which can be used in all EV cases.

Here is the diagram :

[teraamper]

This is looks great!!
I can not wait to see the finished product.

[z704w40]

Have you seen the forum. There are several project focusing on interfaces. There is even a CAN bus interface project.
www raspberrypi .org forum projects-and-collaboration-general can-interface

[flores]

"But It have some flaws, I can list them if you are interested !"

I'm interessted.. what are the Elithon flaws?

[marcexec]

I have been following the Raspberry Pi project.
I wouldn't use it for the master board, it would only be possible to use it for display purposes, logging, connectivity etc. which means one level higher.

sudo bmsmaster --restart --force anyone?

BTW, the availability is not there yet - there are a lot of unhappy people who did get one and have to wait 58 days plus to get one each...

I'd prefer ATMEL or PIC, maybe an Arduino that you can interface to with whatever you want.
This is just my opinion, of course - what do you think?

[nlc]

Originally Posted by flores

"But It have some flaws, I can list them if you are interested !"

I'm interessted.. what are the Elithon flaws?

As you can see Elithion follows this topic, and its posts has shows that they have a sympathetic attitude, I am not sure it's really correct to do that now on a public forum :/

I send you a PM, but remember it's the opinion of a perfectionist developer

[flores]

I'm not an expert at this, but isn't 200mA a bit small for balancing? Is it possible to increase this by decreasing the resistor?

[nlc]

Originally Posted by marcexec

I have been following the Raspberry Pi project.
I wouldn't use it for the master board, it would only be possible to use it for display purposes, logging, connectivity etc. which means one level higher.

sudo bmsmaster --restart --force anyone?

I have the same opinion, no need of this king of board and operating system for the master board, which need to startup instantaneously when ignition turn ON. I use embedded linux on a lot of project, but I don't see the advantage here.

Originally Posted by marcexec

I'd prefer ATMEL or PIC, maybe an Arduino that you can interface to with whatever you want.
This is just my opinion, of course - what do you think?

Anyway, at my opinion there is absolutely no need to choose the microcontroller or other component now, the important step is to validate the general architecture of the board, to decide which functions the board must implement or not. The microcontroller choice is almost the last step

I need to add on my general architecture image that the digital outputs must have the PWM capability.

[nlc]

Originally Posted by flores

I'm not an expert at this, but isn't 200mA a bit small for balancing? Is it possible to increase this by decreasing the resistor?

The resistor is 1W, cannot lower the value. I don't want to have a bigger balancing current because :

- It's a generic board, no need to have a big current for small cell capacity
- The balancing algorithm can be improved, to have the balancing during the charge and no only at the end of the charge. For a 10h charge for example, it's almost 2Ah balancing at 200mA !
- A bigger current will perturb the on board temperature measurement

But for those which really want a bigger current, I put on the board 2 big and beautiful pad, to easily solder an external power resistor. The mosfet I put on the board can switch more than 4A, more that enough for everyone

[DJBecker]

Originally Posted by z704w40

Have you seen the forum. There are several project focusing on interfaces. There is even a CAN bus interface project.
www raspberrypi .org forum projects-and-collaboration-general can-interface

Only a single person on that thread has actual knowledge, and there is almost no experience with actually using what they are suggesting.

If you want to try socketCAN, you can buy existing boards that run Linux and have CAN controllers built in. I have a half dozen within arms length right now. But I still do all of my EV CAN work either directly programming the CAN controller (without trying to use socketCAN), or accept the bandwidth and functionality limits of ELM327 parts to get data to a laptop.