HVB temperature and range

[GoHawks]

I searched the forum and could not find any specific threads on this topic. If I missed them, please point me that way. On a recent road trip I used DCFC multiple times at multiple stations ranging from max output of ~ 50kwh to 350kwh. This was the first road trip I had an OBDII scanner while driving. When using EA and charging at max rate of ~170kwh the HVB battery temp increased to the mid 80s F, but while using slower charges it only increase to the mid 70's which makes sense to me. Using level 2 chargers generally only show HVB temps in the 60's.

My question really is around those higher battery temps and range. Directly after using the EA station my range decreased by 28% for the remainder of my trip, which was about 2 hours. The first half of my trip was using my charge from home. The EA stop was the mid point of my drive. Same road, same speed (cruise control), but very different measurable range results. Should I expect reduced range with HVB battery temp of 80-85 degree? Should the range loss be that severe? I have read other threads about preconditioning and cooling but those generally only kick in with the HVB being around 93 degrees.

I have noticed this when using DCFC EA sessions prior but didn't have the data to verify it. On the return home, I used slower DCFC stations with max out of ~100khw and saw no range reduction. It was different day with different conditions (rainy and windy) which should have had a negative impact but did not.

Thanks for any input.

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[Maquis]

By “range loss” do you mean the range displayed on the GOM or the actual miles driven per kWh?

 

[GoHawks]

Miles per kWh. I don’t use the GOM.

 

[Maquis]

I don’t use the GOM.

 

[Grumpy2]

Perhaps there was more demand for AC on the remainder of the trip? Hot battery, hot truck??

 

[TaxmanHog]

Next time you do a DCFC charging session mid trip, do a full key cycle truck off then truck on, to reset the this trip value, see if that improves your MPK value post charging session.

 

[GoHawks]

Thanks for the replies. I did cycle the truck and was only using data from the obdii reader which matched the mpkhw the truck showed. It also was later in the evening so temperatures were ~60 degrees. Not too hot. However the HVB was much warmer post charge which I would expect.

 

[TomB985]

I don’t think your battery temperatures had anything to do with your efficiency. I’ve gone about 6,500 miles so far pulling my camper, and my battery temperatures spent most of their time between 80-95º F after the first DCFC of each day. I never noticed any difference in efficiency, which makes sense because the truck wasn’t spending energy to cool the battery once it got below about 92º. There was a huge difference with wind, elevation changes, and air temperature, though.

I think your efficiency differences had almost nothing to do with your battery temperature and everything to do with conditions around the truck.

 

[Adventureboy]

I'd lean toward the driving situation rather than the overall efficiency but keep it as a watch item. I do a 370-mile round trip fairly regularly which takes 2 DCFC stops due to the location of the chargers. The efficiency stays pretty consistent before and after the charge stops. If anything, I've noticed the efficiency increases slightly in the winter after a DCFC probably due to a warmer battery.
The bigger efficiency factor for me is wind direction which can have a pretty big effect on efficiency one way vs the other. I have seen that impact efficiency easily 30% or more sometimes, especially if the terrain funnels the wind down the highway on your nose vs your tail.

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