TickTock
Well-known member
Tire pressure:
carcan msgId 385 : D3,D4,D5,D6 = pressure_x4
carcan msgId 385 : D3,D4,D5,D6 = pressure_x4
Active EV-CAN sampling: cell voltages, pack temperatures...
- Thread starter GregH
- Start date
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TickTock
Well-known member
Gids:
carcan msgId 5B3 : D5(?) & D6
Can someone who charges higher than 255 gids confirm the location of the MSB? It logically should be bit0 of D5 (D6 contains the LSBs).
carcan msgId 5B3 : D5(?) & D6
Can someone who charges higher than 255 gids confirm the location of the MSB? It logically should be bit0 of D5 (D6 contains the LSBs).
LEAFfan
Well-known member
TickTock, did you figure out how to get GIDs on the 2013?
TickTock
Well-known member
I just looked at the log file we captured from your car - I am reading gids from the same location as on my 2011 (5b3LEAFfan said:
5,D6). And I am sure I didn't get it mixed up with one of my own logs since I am reading 245 gids (I have not gotten that much charge since over a year).Correct. D7 bits 7,6,5,4 are valid bits for the corresponding data byte (D3,D4,D5,D6).TickTock said:
Correct. D5[1:0],D6[7:0]TickTock said:
D3[7:0],D4[7:5]= Remaining Charge time (120v)
D4[4:0],D5[7:2]= Remaining Charge time (240v)
GregH
Well-known member
So just tried a few of Jim's gems on EV-CAN with mixed results (as anticipated based on the ELM thread)..
797/79A works fine (main vehicle controller?) so VIN, L2/L1 count, DCQC count come in fine as well (I'm sure) as a bunch of other goodies yet to be discovered.
792/793 (OBC?) doesn't work as anticipated, but probably because I'm on a 2013 at the moment and the OBC is built in.. so to speak. I'm guessing 792/793 for EVSE info will work fine on my 2012 which is fine because all we really want is ampacity for Brusa control on 2011 and 2012.
745/746 (traction control?) for tire pressure doesn't work So I guess CAR-CAN can reach through the VCU to EV-CAN but not the other way around. Bummer.. Maybe this info is reflected in the VCU data somewhere..
797/79A works fine (main vehicle controller?) so VIN, L2/L1 count, DCQC count come in fine as well (I'm sure) as a bunch of other goodies yet to be discovered.
792/793 (OBC?) doesn't work as anticipated, but probably because I'm on a 2013 at the moment and the OBC is built in.. so to speak. I'm guessing 792/793 for EVSE info will work fine on my 2012 which is fine because all we really want is ampacity for Brusa control on 2011 and 2012.
745/746 (traction control?) for tire pressure doesn't work
So I guess CAR-CAN can reach through the VCU to EV-CAN but not the other way around. Bummer.. Maybe this info is reflected in the VCU data somewhere..You don't need to send any message. Message 0x5B3 is just there anytime the CAN-BUS is active. You just need to capture the message.sirfergy said:
Thanks Turbo3. How do all these things translate to ELM? For example, I tried getting L2 count but I couldn't figure out what sequence was necessary to get the correct message sent.
And for GIDS, how do you even listen on the ELM w/o first sending commands?
And for GIDS, how do you even listen on the ELM w/o first sending commands?
garygid
Well-known member
Great work everybody.
It is wonderful to see you all investigating and helping each other.
If only more of the world worked that way.
Merry Christmas to All.
It is wonderful to see you all investigating and helping each other.
If only more of the world worked that way.
Merry Christmas to All.
TickTock
Well-known member
Moving this discussion from the other thread
What makes us think these are shunt bits? I've tried both and neither looks right to me - looks random.
Turbo3 said:
What makes us think these are shunt bits? I've tried both and neither looks right to me - looks random.
garygid
Well-known member
There appear to be 96x2 data bits, and 96 are occasionally on,
with the other 96 always off. So, it is a guess, but one that
seems to fit with the Battery data, and we have no other
reasonable explanation at this point for these 96 bits of data.
with the other 96 always off. So, it is a guess, but one that
seems to fit with the Battery data, and we have no other
reasonable explanation at this point for these 96 bits of data.
TickTock
Well-known member
On page EVB-26 of the April, 2011 rev of the SM, it states that the highest cellpairs are discharged until they reach the target level. I see random cellpairs getting selected - sometimes even the low ones. Under no condition should the lowest cellpair get shunted. Also, others have shown captures with lots of CPs highlighted. I really doubt more than a half dozen or so are ever shunted since this would reduce the available pack voltage.
Attachments
GregH
Well-known member
If the BMS is not very intelligent and only tries top side balancing without considering the SOH at low SOCs, then it is entirely possible at a low SOC to see a low cell have balancing prescribed hours earlier when it may have been much higher.TickTock said:
TickTock
Well-known member
That's another thing - it makes no sense to me for these to be active while driving. It's been a while since I had the conversation, but I am pretty sure the Nissan engineer told me they only do top-side balancing (which is consistent with the description in the SM). There is no reason to shunt the cells while driving - it should only be done while connected to the charger so the remaining cells can, then, be charged more.GregH said:
GregH
Well-known member
When we did the first lithium PHEV Prius conversions I would do exactly this. The iron phosphate batteries really pop up at the end of charge so it was really easy to identify the fullest cells and bring on balancing... shut off the (1kW.. 5A, 200V) charger and balance for 10-20 minutes (@40mA) then turn off balancing, turn on the charger.. repeat.. This of course required being plugged in for hours after a full charge.. not optimal.TickTock said:
If you know which cells you'd like to remove a few mAh from then it really doesn't matter much what the voltage is at the time the balancing is done. You just need to keep the shunt on for X minutes or hours.
If my Leaf is balancing, it always seems to be off when I turn on the car then I can see the shunts turn on over a few seconds from left to right (lowest cell to highest cell). I can see the same pattern come back on over a few seconds every time I turn the car back on. This indicates to me the car does NOT balance when off.. but it certainly does when on or when charging. As a matter of fact it could be balancing in the middle of an L2 charge based on an assessment made the day before at the end of a previous L2 charge. Note this would also mean the car does NO BALANCING more than 15 minutes after a full charge.. ie when the 3 blue LEDs turn off and the car goes to sleep, the balancing turns off.
I'm not sure why they don't balance with the car off, perhaps to make sure no shunts get stuck on.. more likely the LBC shuts down when the VCM goes to sleep seconds after key-off and doesn't have the ability to leave shunts stuck on while sleeping. For better or worse, I designed my battery management systems so that I could leave balancing on when the processor powered down. I had LEDs on each shunt visible from outside the pack so you could see at a glance which shunts were on.
Good point...GregH said:
It would be nice to confirm this since most have assumed (including Phil/Ingineer) that balancing can happen at any time - hence the recommendation to charge to 100% and let the car sit for up to 4 hours to help encourage pack balancing.GregH said:
Should be easy enough to test - can we read CP voltages up to 15 min after charging stops? Record them then, wait a few hours and turn the car back on and check again...
TickTock
Well-known member
Also, keep track of which cell(s) were minimum at the end of the charge to see if those ever (later) get shunted.
GregH
Well-known member
drees said:
Unfortunately no... When the LBC is asleep we can't ping it for cell data.
My only evidence for this is that when I first turn the car on I see no shunts on, then over the course of 5 seconds or so they turn on.. I'll try to capture better video of this in action. It's pretty clear when you see it.
TickTock said:
Yes. Wasn't there some post from an Android user who had a very low cell then showed a screenshot of all the shunts on except that one? I guess that would indicate it does take into account voltage at low SOC.. although it could also be that cell was really low at a full charge as well.
