Info on BMW hybrid battery packs?

bobby_come_lately · Post by **bobby_come_lately** » Sat Nov 20, 2021 12:44 pm

5V for powering the modules? I use a dedicated little buck converter for that from the 12V.

bobby_come_lately · Post by **bobby_come_lately** » Sat Nov 20, 2021 12:50 pm

Question for anyone with these modules in a live vehicle: what sort of wh/m / wh/km are you seeing?

My range is pretty poor so far when compared to Jamie's bug with the VW battery pack. His is running 96s rather than 80s (I just have one 5 module pack in at the moment) but nonetheless he is seeing perhaps double my range.

For example, this morning I did 10.4 miles and the pack went from ~83% (4.025v) to 30% (3.625v) - 4.15 and 3.4 are my min/max. Quite a lot of stop/start but fairly light traffic and no real hills. It's in a Z3 with the Prius Gen 3 inverter and Outlander front motor/generator.

It's not outside the bounds of what I was expecting, but less than I was hoping for.

cloudy · Post by **cloudy** » Sat Nov 20, 2021 2:02 pm

The 7.6kwh pack only got ~14 miles range in the 330e when brand new - so using 53% to do 10 miles seems pretty good!

Also if anyone happens to have a spare high voltage connector socket from a bmw pack/electronics they would be wiling to sell - let me know!

bobby_come_lately · Post by **bobby_come_lately** » Sat Nov 20, 2021 2:18 pm

cloudy wrote: ↑Sat Nov 20, 2021 2:02 pm The 7.6kwh pack only got ~14 miles range in the 330e when brand new - so using 53% to do 10 miles seems pretty good!

Also if anyone happens to have a spare high voltage connector socket from a bmw pack/electronics they would be wiling to sell - let me know!

Yeah I probably shouldn't moan.

Is it the socket from the pack you need? I have a couple. PM me your details if so and I'll stick it in the post.

cloudy · Post by **cloudy** » Sat Nov 20, 2021 2:29 pm

Thanks! have sent over a PM...

I'd guess 300wh/m is a sensible figure to estimate with - that would suggest 53% of a pack should get you 13ish miles. With a lot of stop start and aged batteries, I'd say yours looks about right, even if on the low side. What temp were the batteries?

bobby_come_lately · Post by **bobby_come_lately** » Sat Nov 20, 2021 2:40 pm

cloudy wrote: ↑Sat Nov 20, 2021 2:29 pm Thanks! have sent over a PM...

I'd guess 300wh/m is a sensible figure to estimate with - that would suggest 53% of a pack should get you 13ish miles. With a lot of stop start and aged batteries, I'd say yours looks about right, even if on the low side. What temp were the batteries?

Not got any live monitoring or logging at the moment but they will have been pretty cold. Motor was reading 10.4 when I set off today.

[Edit: I do have the modules hooked up to Simp but no permanent readout in the cabin yet]

cloudy · Post by **cloudy** » Sat Nov 20, 2021 7:34 pm

I don't know how much these heat up through discharge, but perhaps in the warner months you'll get another few miles out of it!

celeron55 · Post by **celeron55** » Sat Nov 20, 2021 9:08 pm

3.4V seems like a rather high discharge limit. I'd happily discharge any lithium pack to 3.1V at least. Of course you'll have to limit your power down there, but range is range. I'd expect at least 10%, maybe 15% of capacity to be found below 3.4V.

cloudy · Post by **cloudy** » Sat Nov 20, 2021 10:13 pm

The BMW Datasheet suggests 2.8V - 4.14V for the SP06, so yes does suggest there is a quite a bit of extra capacity to play with

bobby_come_lately · Post by **bobby_come_lately** » Sun Nov 21, 2021 8:23 am

Thanks both. I need to do some more testing. Per previous comments on this thread, I found voltage dropped off very sharply below 3.4 so that's why I've set the limit so high.

mjc506 · Post by **mjc506** » Mon Nov 29, 2021 12:49 pm

Anyone playing with partial packs? I have a full pack of 6 modules here, but can't get balancing to work when less than 6 are connected (can't be a BMW limitation, surely, as some packs a 5 modules?). SimpBMS seems to be sending reasonable CAN messaged (although to all 6 modules, even if not all are connected), but the received CAN back from the modules appears not to have balancing status filled, and the CSCs don't get warm.

I did find a small bug(?) that meant the code assumed that all 6 modules were always connected - this affected display (the unconnected modules just showed 0V etc) and calculation of average/min/max voltages, fixed that in my copy. @tom91, do you want a PR for that? (just moving a bracket at the end of BMSModuleManager::decodecan in BMSModuleManager.cpp so that Module[CMU].setExists() etc are within the if statement)

mjc506 · Post by **mjc506** » Thu Dec 02, 2021 11:59 am

Ahh. It is a limitation of the BMW CSCs - the first (white) CSC contains a uc that does know how many modules should be present.

On the plus side, everything works using SimpBMS with fewer modules, apart from balancing it seems. Also, I've found the datasheet for the actual BMS chip, and it seems reasonably do-able to interface directly with them in the first CSC (replacing the controller uc, which does the CAN interface). This will require some (hopefully small) hardware mods, but looks like it would allow larger packs... I'll attempt to write a library for talking to the BMS chip(s).

cloudy · Post by **cloudy** » Sun Dec 05, 2021 4:10 pm

Yes the previous gen (all black BMS) would balance just one module fine. The latest gen has master that emulates the can from the slaves whilst using simple serial? to communicate with them. It will only enable balance current with all 6 attached. There is probably a way to decode the serial side Comms to make single modules work.

Gregski · Post by **Gregski** » Sat Dec 18, 2021 5:07 pm

maybe you'll find this exploded diagram useful

Gregski · Post by **Gregski** » Sat Dec 18, 2021 5:29 pm

my 2018 530e battery pack came with the signal connector pig tail so I decided to unwrap it to see if it would hep any of those who are metal case cover removal averse

and considering it was covered with honey or molasses or both, which now I have successfully transferred to my hands and now to the keyboard, I really hope someone on here appreciates it

mjc506 · Post by **mjc506** » Wed Dec 22, 2021 10:03 am

Now managing to speak to the CSCs directly (without the BMW layer)

https://github.com/mjc-506/bmsSerial

cloudy · Post by **cloudy** » Wed Dec 22, 2021 10:15 am

Great work! Thanks for sharing

Gregski · Post by **Gregski** » Thu Dec 30, 2021 4:15 pm

I thought someone may be interested in how the battery cables are built, so I went out and bought two of the #1 cell module main negative leads part # 61 27 8 621 016, this is the longest cable in the pack, I plan to modify the ends on these and use them as my to and fro to the pack

these are keyed, meaning they plug in a certain way

more excruciating detail can be found here: I bought a BMW 530e hybrid battery pack - Now What?

Gregski · Post by **Gregski** » Fri Dec 31, 2021 5:20 pm

thought you may enjoy this BMW i8 BATTERY TEARDOWN video, appear to be same modules but in yet a different form factor

saman195 · Post by **saman195** » Tue Jan 18, 2022 11:36 am

Jack Bauer wrote: ↑Sun May 17, 2020 2:08 pm Yeah the 3 series packs seem to be 5 module. Five and seven series have 6.

have you used SIMP BMS with these modules? I need a BMS that works wit these modules and the monitoring/balancing circuit inside the module. could you please advise?
Kind regards

bobby_come_lately · Post by **bobby_come_lately** » Tue Jan 18, 2022 4:10 pm

I'm using SimpBMS with these modules. You need this version: https://github.com/Tom-evnut/BMWPhevBMS

mjc506 · Post by **mjc506** » Thu Jan 20, 2022 10:00 pm

Yup, SimpBMS works great with these, so long as you use a complete pack.

Gregski · Post by **Gregski** » Sat Jan 22, 2022 4:41 am

I finally fandangled with my 2018 530e HV Battery Pack Safety Box today and think some of you may find these pics useful, as I was perplexed by all the German zigging and zagging inside of this box