I've added Enginelink to my gauges and was very interested to watch the temperatures of the 4 sensors monitoring the air temperature of the cooling air over the HV battery. Temperatures here have been hovering around 110 deg F. I noticed that with A/C on and set on recirc the battery intake temperature hovered around 33 deg C and the no 3 sensor was at 36 deg C. when I changed the airflow to external, the intake temp gradually fell to 28 deg C and the No.3 sensor fell to 31 deg C. The A/C was set to Lo and fan was half speed. To me this demonstrated what I had long assumed, that recirc reduces air flow over the battery as the flow of air through the cabin is hindered. I usually use fresh air when cooling and only used recirc as an experiment.
Thanks for the experimentation. Sometimes I drive with all windows down on dry hot days in city. I wonder how this impacts the battery temp. I need to check that. BTW, I never use recirc setting. I see no point in breathing stale air. I actually modified the settings and recirc isn't a default anymore when AC is turned on.
I'd be very interested in how you achieved that? Unless outside temps are really crazy i.e. over 100 F I think the air flow over the battery is the most significant thing.
What about driving 30 mph (50 kmh) in the city? What are the temps like doing that on a longer period? You know what I'm getting at here. Get the car warmed up nicely and then drive rush hour for 2 hours and see how the temps are then.
great info, thanks feri! mine defaults to recirc, but after teh cabincools a bit, i switch to fresh. i have to keep my eye on it tho, it switches back every now and then. luckinly, we don't often see temps over 100.
It's possible that there is a design flaw that didn't present itself during design and research. I suspect that GenIII taxis may not be getting enough airflow due to stop start and variability of loads. Possibly many drivers use recirc in extremes of hot or cold, reducing airflow over the battery. Also how often does a large passenger's coat or a hand bag etc. cover the intake for instance? I don't have access to rush hours like that here so I can't test that effect but I can imagine the continual discharge and recharge would keep batteries hot.
Becoming too frequent here. We are getting apples flowering twice now. Used to be good apple and stone fruit region.
Not that often, but in a RHD the passengers would sit on the passenger side. On a LHD that could be a problem as they'd more often block the vent. Also, and similar to Oz here, but most individual male or younger female passengers sit in the front, with individual older women and couples sitting in the back. If the vent was blocked in the back, the battery would sit steady at 7/8 bars for some reason. No I don't believe cabbies will have recirc on - you want fresh air in your car! Often a/c doesn't work so well in start stop traffic on short journeys as all doors are opened and left open when passengers get in, then the a/c has to work double hard to cool the car on the journey, 2 minutes later they're all getting out with all doors wide open again! Often it's better not to use a/c in town in summer, but just have the windows down. I only used a/c if someone complained their hair was blown around or on a run that I knew would be over 1 mile. Might be different in Australia where it gets HOT.
I have found that it also helps to cool the battery when one or more of the dashboard vents are aimed up over my head and towards the right rear door where the battery ventilation intake is located. I usually have at least one vent aimed at the battery air intake during highway driving, and at least two during city or mountain driving in warm weather.
Is number 3 sensor always the highest? I need to know because my Scangauge II will only monitor 4 things at once, so I would like to only dedicate 1 of those slots to the battery temp, and would naturally choose the hottest bank of cells to monitor. Would you happen to also know whether the upper inverter coolant loop temp or the lower coolant loop temp would be the best one to monitor? Thanks in advance!
