GerryAZ wrote:Turbo3 wrote:Keep in mind that the 96 battery voltages are not all read out at the same time by the BMS. They are read out serially at 19,200 baud. Which means the load on each cell can be very different for each voltage read out. So a higher voltage could be because there was a lower load at that time and a lower voltage on another cell because a high load was applied making it hard to see the effect of the shunts which draw very little power. The shunt resistors appear to be 430 ohms each. So about 10 ma of current when active.
Until someone reverse engineers the BMS code we will not know for sure the order.
The cell lose test done by LeafSpy when the Leaf is in park and below VLBW is the best way to detect bad cells.
My battery is fine, but I wanted to make sure I have LEAF Spy set up correctly for the 2015 because I am meeting a fellow LEAF driver this weekend to take readings on his battery (which he suspects is low on capacity). If no one knows the correct shunt order, I will just leave it programmed the way it has always been.
I misspoke a little. It is possible that the group of four voltages that make up the shunt group could be measured at the same time depending on the architecture of the IC that measures the voltage. There are 24 ICs one for each group of four cells. Data passes from one to the next until it gets back to the CPU. If each IC has a dedicated A2D for each cell and all sample the cell voltage at the same time the voltages will be in sync but if it only has one A2D that gets switched then each cell will be measured with a different time offset.