Can anyone explain the air path to cool the HVB. It appears to me that the fan in the back blows air into the battery pack. The warm air probably comes out of the battery pack just above the fan inlet and is ducted out down through the floor to outside. However, where does the fan get its air supply from, perhaps the side top vents? If the fan gets it's supply from inside the car and blows outside, then where does the makeup air come from? What if the inside cabin temperature is very hot, does it still take the air from the inside? I seem to recall reading that it can take air from the outside but does it also exhaust outside. Then what are the two top side vents for?
Can anyone shed some light on this? I read all the posts but still can't figure it out.
There are two cooling fans in an C-Max Energi. The one above and to the right (as viewed from the rear of the car) of the 12V battery is for cooling the electronics. The second fan is located on the left side to pull the air from the fan duct outlets at the rear of the HVB.
The air intake for the cooling fans are the two top vents behind the rear seats on the left and right sides. To check this, when the fans are running, place a sheet of paper above a vent and the negative air pressure will pull the paper tight to the vent. The vent provide input to the lower front of the HVB and the air outlet is in the lower rear of the HVB.
The HVB fan is rather interesting. I have monitored the inside air temperature, HVB air temperature, and fan speed with a ScanGauge to determine how the fans function.
The Fan speed is variable speed. Minimum of 1500 RPMs To a maximum of 2725 RPMs. As the car speed in increased the fan speed increases. The minimum fan speed is also increased as the HVB gets hotter. The fans will not come on at all if the interior temperature is less that 8 degrees cooler that the HVB. The fan speed increases as the car speed increases. At 65MPH the fan reaches to maximum speed. In a cold climate I suspect that the fan will come on if the interior temperature is significantly warmer than the HVB but I am not able to accurately test this theory in my climate.
So where does the fan exhaust heat go. I have found no evidence of the heat being exhausted to the outside. The best documentation I have found related to HVB airflow is in the document http://elvsolutions....Guide Final.pdf
Hope this information helps,