How Does Outside Temperture Affect Regen System?

My work route has a rather steep hill, about a half mile or so in length and I noticed that on mornings where the outside temp is less than 60 degrees I get only one regen dot and if the temp is greater than 60 I get two and on rare occasions I get three.

Here are Drive Parameters ...
1) ECO Mode
2) Cruise set at 55
3) No Braking, coasting down hill

So why does the outside temp affect the regen system in this way?

For what it is worth, it cost me 10 to go up and I have an average gain of 3-5 when going down.

^Short answer: Yes. Regen is dependent on temperature (as well as state of charge, of course: "100%" = little or no regen). But I believe that it is the battery temperature that matters, not the OAT. So OAT affects regen to the extent that it lowers the battery temperature.

How much regen you get when the battery is cold likely depends on the model year of the car and the battery management software it is using. At very cold temperatures, say 10ºF and below, there is essentially no regen — even at low SOC levels — on 2011/2012 models. Whether that is true for 2013 and later models I couldn't say.

Thanks for the info.

I have a 2011 and the hill in question is approximately 12.4 miles from my starting location. From my driveway to my office parking spot, the entire trip is 26.? miles. This winter I will have to pay more attention, as I do not remember it not ever regenerating going down this hill.

D3Leaf said:

Thanks for the info.

I have a 2011 and the hill in question is approximately 12.4 miles from my starting location. From my driveway to my office parking spot, the entire trip is 26.? miles. This winter I will have to pay more attention, as I do not remember it not ever regenerating going down this hill.

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Be aware that even if it is cold outside your battery may be quite a bit warmer from charging and driving. So you might not notice the reduced regen unless the battery gets cold. It also depends on whether or not you have had the P3227 software update. It drastically reduces regen at cool battery temperatures, for reasons unclear.