TickTock
Well-known member
Tire pressure:
carcan msgId 385 : D3,D4,D5,D6 = pressure_x4
carcan msgId 385 : D3,D4,D5,D6 = pressure_x4
I just looked at the log file we captured from your car - I am reading gids from the same location as on my 2011 (5b35,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).LEAFfan said:TickTock, did you figure out how to get GIDs on the 2013?
Correct. D7 bits 7,6,5,4 are valid bits for the corresponding data byte (D3,D4,D5,D6).TickTock said:Tire pressure:
carcan msgId 385 : D3,D4,D5,D6 = pressure_x4
Correct. D5[1:0],D6[7:0]TickTock said: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).
TickTock said: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).
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:TickTock said: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).
What is the message you send on 5B3 to get the GIDS?
Turbo3 said:I guess GregH and Gary Giddings need to talk ;-)LEAFfan said:Turbo3 said:Correct value is 4821
Actually, Greg said it was 8421 and we had the incorrect one.
When everyone agrees on a single value then I can hardcode it. But it sounds like now is not that time.
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: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.
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: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: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.
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: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: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: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.
Good point...GregH 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.
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:Note this would also mean the car does NO BALANCING more than 15 minutes after a full charge.
drees 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 said:Also, keep track of which cell(s) were minimum at the end of the charge to see if those ever (later) get shunted.
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