On a hot sunny day, occasionally I have to be stopped for extended periods with the A/C running which means the engine will come on for a few minutes out of every 10 minutes or so. to charge the traction battery. Engine comes on at 2 bars and goes off at 3 bars. As engine efficiency at idle is low, would it be better to put it in D with the brake firmly pressed and push the accelerator so that the engine speed is in the high efficiency range so as to produce more charge for the fuel burnt and maybe also I could charge it to a few more bars on the battery indicator? Is this line of thinking correct?