Forums

Summer months

Summer months

I have read on this forum and articles about the battery losing efficiency when it's cold, which makes sense. Is the battery less efficient during the summer. I know the slight changes in mileage when it's cold is not huge but just wondering during the summer .

Bighorn | December 18, 2016

It's not so much the battery being less efficient, but that you're drawing power for needs other than locomotion--primarily heating the cabin, optimizing the battery temperature or cooling the cabin. Heating takes 3-6X as much energy as cooling, so winter shows the most obvious range decrease.

Jcastillo18 | December 18, 2016

Thanks Bighorn. I live in deep SouthTexas where the coldest it gets is 39 F and the rest of the year it's close to 100 F

Bighorn | December 18, 2016

In that case, I had some issues supercharging in the desert this summer. The system throttles back for temperature management purposes, so supercharging can take significantly longer.

cessna182 | December 18, 2016

I live in a "hot" state so my 3 will be white, and hopefully covered with solar panels to keep the interior under 80 degrees by thermostatic control, along with a direct power plug in to the environmental system. Either that or a self deploying umbrella!!!

topher | December 18, 2016

"Heating takes 3-6X as much energy as cooling,"

How does that work? If I cool the outside by moving heat inside, is that heating or cooling? What about if I cool the inside by moving heat outside?

"I live in a "hot" state so my 3 will be white, and hopefully covered with solar panels"

If it's covered solar panels, it won't be white.

Thank you kindly.

cessna182 | December 18, 2016

Tesla's roof panels were debuted in an array of colors...

Bighorn | December 18, 2016

@topher
I don't follow. AC draws 2 kW. Maximal heating draws 6kW in the cabin and 6kW for the battery.

cessna182 | December 18, 2016

My electric bill is far greater in summer than winter (total electric home). Guess Reddy Kilowatt is gouging me!

topher | December 18, 2016

@bighorn

That just means that they are doing heating inefficiently. Or that temperature ranges are symmetrical.

Thank you kindly.

Bighorn | December 18, 2016

@topher

Possibly, but it could be that the other night I was trying to raise the temperature of the car 100 degrees and air conditioning is seldom more than a 30 degree cool down. Same is true with houses around here--winter is much more expensive than summer.

Frank99 | December 18, 2016

topher -
A/C is done with a heat pump - moving heat from inside to outside. Heating can be done with a heat pump (moving heat from outside to inside), or using a resistance heater.

Tesla, as I understand it, uses a resistive heater. It's cheap and easy. EVs like the Nissan Leaf use a Heat Pump for heating - you get the same heating for about half the hit to battery life. Unfortunately, heat pumps stop working at a low temperature that depends on the system design - home heat pumps often stop heating when the outside temperature is below 25F or so. ICE vehicles use waste heat from the engine to heat the air, so even in a -20F winter morning in North Dakota, you can eventually warm up the car. For an EV, that means that you'd probably need to design in both a resistive heater for really cold days, and a heat pump for just normally cold days, for maximum efficiency. The Leaf does that; Tesla just designs in the resistivie heater, meaning for all of us who call freezing a "cold Morning" get stuck with an inefficient heating system to make sure that those North Dakotans can get some heat on what they call a "COLD" mornin".

There really isn't much of an excuse for Tesla installing only a resistive heater, especially on a car priced like the Model S or X. It's only a few bucks more to configure the existing A/C system as a heat pump, allowing it to heat the interior in less-than-Arctic conditions, while using the Resistive heating for really cold conditions. I live in a place (Phoenix) where Winter mornings are "cold" (minimum around freezing), and using a heat pump would solve 100% of my heating needs using half the energy of a Resistive heater. Even a North Dakotan would appreciate the heat pump, reducing battery usage on all those "cold" days that don't qualify as "COLD".

andy.connor.e | December 20, 2016

Theres a pretty accurate estimate for the Model S. On that specific webpage, you can choose outside temperatures and A/C or Heat on & off. That should give you a good estimate.

But it does depend how you drive. Lots of factors. Air resistance open windows, loud music, lights on?, running cabin fan (no heat/ac). Every single thing you operate in your car uses electricity, and reduces range.

andy.connor.e | December 20, 2016

@cessna

Probably because your heat is gas, and your A/C is electric. Currently, electric is more expensive than gas operated appliances.

Rocky_H | December 20, 2016

I don't like people to get scared off and worried by overly dramatic things like @andy.connor.e was saying, like loud music or lights reducing your range. That's not practically the case.

Energy usage by rank is kind of like this:
#1 Moving the car--your speed makes a huge difference here

#3 Heating--when it is really cold, the car can suck a lot of energy running heat. expect maybe 20-30% on a bad case

#10 Air conditioning--still kind of noticeable, but far less than heating

#3,656 Everything else--Seriously, headlights, wipers, stereo, touchscreen, everything else is so totally insignificant compared to the ones above that it will never make a noticeable difference on your range.

Red Sage ca us | December 20, 2016

Rocky_H: Correct. Sometimes it seems people believe that Tesla Motors products run on an array of three or four 6v batteries like a Power Wheels ride-on from Fisher-Price.

andy.connor.e | December 21, 2016

@Rocky

For the record, please recall when i said that the "#3,656" was significantly or noticeably making a difference on your range?

Rocky_H | December 21, 2016

@andy.connor
Quote: "For the record, please recall when i said that the "#3,656" was significantly or noticeably making a difference on your range?"

Ah, sure...a little copy and paste, and done.

"Lots of factors. Air resistance open windows, loud music, lights on?, running cabin fan (no heat/ac). Every single thing you operate in your car uses electricity, and reduces range."

Loud music and lights were factors you brought up as reducing range.