GerryAZ said:
... Therefore, it is necessary to charge the 12V battery or use a booster battery to get charging started. Once traction battery charging starts, the DC-DC converter will charge the 12V battery while the traction battery is charging.
On my 2011 LEAF, I recently observed that while L2 charging the main pack, that if the LEAF is ON, the DC-DC converter is inactive and NOT available to charge the 12V battery while the traction battery is charging.
I only discovered this because I left the LEAF ON to keep the 12V auxiliary outlet powered for charging my cell phone that had LEAF Spy Pro running creating a graph of the pack charging that I planned to Save.
I only discovered the situation when I turned the windshield wipers on to have the LEAF DC-DC raise the 12V buss voltage to check the 12V battery completeness of charge and saw that the buss voltage did not change.
Turning the wipers on is a simple way to fully charge the 12V.
With my AGM you know it is pretty fully charged once the current with 14.2 V on the buss drops very low to 0.86 or 0.67 amps.
I had done a similar thing a lot while using DCQC. And with DCQC charging the pack and the LEAF ON the DC-DC is active. But on my 2011 it is NOT while doing L2 with the LEAF ON.
There are also differences on HVAC availability with LEAF ON between DCQC and L2. HVAC works with DCQC, but usually NOT with L2.
One last note on killing the 12V. I killed it once with the headlights turned ON. With the headlight relay closed and 12V buss voltage very low, took a stout 12V source to be able to get the headlight relay to open.