Simp BMS

[joromy]

Maybe the better way is SOC * Ah setting * #cells in series * voltage at 50% SOC (interpolated from whatever you chose your SOC settings to be)

That is a good idea, or maybe only use the SOC, shouldn't that be linear to the battery kWh?
Map 0-100% SOC to 0-60kWh

[joromy]

AmpSecond to Amp Hour

I'm a little less stupid now.

[Bryson]

Yes but battery kWh is calculated from the variables I posted above

[tom91]

Working on a new add-on, hint below:

SimpBMS CP test.JPG (19.89 KiB) Viewed 5042 times

Also updated the manual, got a section with coming updates with more hints. https://github.com/tomdebree/SimpBMS/bl ... 0V0.22.pdf

[mdrobnak]

Looks like J1772 support to me...

[Bryson]

Oh baby. Is this fast charging in the making?!

[mdrobnak]

Oh, that would be even better!

[tom91]

Oh baby. Is this fast charging in the making?!

Nope, CP is for AC charging. No fast charging support planned due to hardware limits.

Looks like J1772 support to me...

Yes Type 1 (J1772) and Type 2 current limiting for the chargers so the EVSE remains happy. It will require a small external circuit to condition signals.

[joromy]

I have Simp BMS and 14 Tesla model S batteries, but two of them are much higher voltage.
Is there a way to discharge (bleed) only these (6+6 cells)?
I would like to bleed them for long time instead of dissemble the whole pack.

I could probably do the changes in software, but need some hint

Have tried to use the standard balancing feature from 3.8V and up, this is discharging all cells except the low cell.
I "feel" that discharging only the two batteries all time, would be better...?

[tom91]

Balancing happens above the threshold voltage IF ANY cell is above the lowest cell voltage + the balancing hysteresis.

It also mentions it in the debug when balancing is going on.

So yes if you set the BMS into the mode where it is allowed to balance it will do it.

[joromy]

So I could set the threshold voltage very low, like 3.2V, and it will balance all time.
Is it a bad idea?

I think the two high batteries will never get down to average, if I just balance at the top.
They may be 5-10Ah higher. That will take months.

[SciroccoEV]

I think the two high batteries will never get down to average, if I just balance at the top.
They may be 5-10Ah higher. That will take months.

Just manually draw those two modules down to similar terminal voltage to the others.

[Bryson]

Charge the 12 low ones if your charger can support the lower voltage?

[joromy]

As I said: "I would like to bleed them for long time instead of dissemble the whole pack."

I just want to know If it's not good for batteries to balance at the hole voltage range?

I will use a hole weekend, maybe more (because I'm slow) to dissemble the pack.

It's built up in 4 layer, tons of connection and coolant pipes.
viewtopic.php?f=16&t=226

[celeron55]

Set the top balance voltage to whatever the level of the lowest cell is, and then just go do something else for probably many weeks if it's a lot off. This will work with any top balancing BMS.

[langoo]

Oh baby. Is this fast charging in the making?!

Nope, CP is for AC charging. No fast charging support planned due to hardware limits.

Looks like J1772 support to me...

Yes Type 1 (J1772) and Type 2 current limiting for the chargers so the EVSE remains happy. It will require a small external circuit to condition signals.

Any idea on when this function/module would be able to buy?

[tom91]

Any idea on when this function/module would be able to buy?

First batch is being produced right now, so hopefully next month.

[arber333]

Tom91

Can you tell me what happens with my Volt BMS?
I have 96s Volt cells, use original Volt BMS. I connected CAN cables and current sensor. It still shows -3A at 0 and i havent put it on the main cable.
I set max cell limit at 4.05V per cell.
Now if i connect charger and charge up to some 392Vdc charger still pushes 4A into cells when they are over 4V. I havent applied charger disconnect pin yet and i use my own CAN string source since i wanted to see what happens.

Now when i charged up to some 4.08V BMS throws ERROR and doesnt show any SOC, but shows Low and High cells in order of 3.889V and 4.085V.
I am not sure that is a good value because if i measure cells directly they are in 4.06V to 4.08V range. Is it possible that cells would show such discrepancy because of balancing?
When i left them to lay off for a day or so they got to 3.895V to 3.980V which is fime for me.

Tom could you maybe change "BALANCING" in the display menu so that it would show instead of error? Or would that be actual error?

[tom91]

Arber, without logs I cannot tell you what is going on.

Also are you running the charger not via the SimpBMS, so no idea what you mean by still pushing 4A.

[langoo]

Any idea on when this function/module would be able to buy?

First batch is being produced right now, so hopefully next month.

Any preview of the design and wiring between SimpBMS -> Module -> Type-2 socket?

Price idea?

[arber333]

Arber, without logs I cannot tell you what is going on.

Also are you running the charger not via the SimpBMS, so no idea what you mean by still pushing 4A.

Yes, well i wanted to see what happens with BMS outputs if i exceed the cell values. So i command the charger separately for now. I didnt expect error msg though. I will make som logs then...

[tom91]

Any idea on when this function/module would be able to buy?

First batch is being produced right now, so hopefully next month.

Any preview of the design and wiring between SimpBMS -> Module -> Type-2 socket?

Price idea?

viewtopic.php?f=13&t=815

All in this topic, will finalise the testing and then publish the wiring info.

[OutlandishPanda]

Tom, have you any plans to port SimpBMS to Teensy 4? I need the extra memory and CAN ports. I've tried myself but T4 (I think) uses a modified FlexCAN_T4 library and I quickly got out of my depth... I'll keep trying though.

BTW, your charger interface looks great - I'm sure will be very popular. Thanks.

[tom91]

Tom, have you any plans to port SimpBMS to Teensy 4? I need the extra memory and CAN ports. I've tried myself but T4 (I think) uses a modified FlexCAN_T4 library and I quickly got out of my depth... I'll keep trying though.

BTW, your charger interface looks great - I'm sure will be very popular. Thanks.

Yes that is the idea, however it is one of many things I am working on so cannot promise any time frames.

[Johaljaswant]

Do SimpBMS require always 12 V supply to save any changes.?