MMR Blog

My Word: “Brrr” and “Whew” Hard on Batteries

Posted on March 27, 2014 Comments (0)

By Denise McCluggage

Anyone who lived 13 winters on a northern Vermont hillside as I did looking across to ski trails cut on Lincoln Mountain (known to the world as Sugarbush) has experienced what deep cold can do to a car battery. Just the usual car battery that urges your engine into a welcome roar sending a steamy shawl of exhaust to wrap your salty Land Rover. Or. Or grinds in a string of decelerating AR-Ar-rrrrs into silence. Every morning is an unwrapped present. What will it be today?

Most Vermont cars had peeking out from under the hood the prongs of an electric cord ready for connection to something they are apt to call a charging station these days. Then I called it my house. I had a heavy-duty red extension cord which at 50 feet was twice as long as needed but I liked seeing the extra length coiled beneath the outdoor outlet. Safe from snow because my deck with the curving wrought iron stair was over it.

Of course the Land Rover was plugged in every night, but I didn’t have an engine heater – just a heated dipstick to keep the oil more like soup and less like Jello and easier for the starter to churn it up. In the darkness of midwinter the dipstick heat might not be enough as the temperature stayed sub-zero for weeks. Fifty below overnight was not uncommon at the mountain. And if I was trying to stretch the battery’s life expectancy – costly damn things – I might get the AR-Ar-rrrrs and not the roar.

So I give up. To Kingbury’s Shell station for a new one for sure when the day warms up to three or four degrees. Or I opt for a jump start. Some folks just removed their battery and took it inside every night. Some had more serious plug-in devices, some had – Lord blessed ‘em – heated garages. But all of us well knew that cold was cruel to the electrics.

Now we have a new study from the AAA telling us just how cruel to these things called plug-in electrics. And it’s worse than they expected.

Using the three most popular pure electrics in the country – a Nissan Leaf (2013), a Mitsubishi i-MIEV (2012) and a Ford Focus (2014) -- the AAA Automotive Research Center in Southern California ran simulations to determine what extreme temperatures did to battery performance. The test started with fully charged batteries to no charge in “city traffic” in a climate-controlled room. The temperature of 75 degrees F was dropped to 20 degrees F for cold (that’s cold?) and raised to 95 degrees F for hot (not in summertime Phoenix.)

The results: more degradation than expected, according to Greg Bannon, the director of automotive engineering for AAA. The cold temperature reduced the range by 57%; the heat by 33%. (In miles that would mean cold cutting an expected 105 mile range to 43 miles and heat from 105 to 69 miles. Did you make it home?)

Not part of the study was how rather necessary accessories – heating and cooling, for instance – might add to the reduction in range. But keeping the car’s occupants comfortable costs miles too. As do headlights and electronic gadgetry like a radio.

Nor did the test include any other temperatures. I wonder what one should expect from, say, another 10 degrees in either direction. Is the slide a steady one or does performance step off a cliff at true extremes?

In any case it is probably safe to warn any Tesla owners not to take their lovely car skiing in Vermont or summer sight-seeing in Death Valley. I know they didn’t test Tesla, but lithium-ion batteries are affected by temperature variations too.

Do I sound pleased by this bad news? I don’t mean to. Electric is an important part of the power mix in our rolling stock. But I think to make electric cars work you have to live where the following applies: places you drive are rather close together; you have a number of choices in cars you can use, and you can match the choice to the task at hand with ease and delight. And you don’t mind having a car dictate when and where you, say, have lunch while it charges enough to get you on your way again. Electric cars are as needful – and dictatorial – as children.

I think an electric car at this stage of development needs a dinghy. GM learned that with its first brush with electric cars when precious few people actually wanted to buy an EV1 but everyone wanted GM to make them anyway and said nasty things about the General when he collected them up and crushed them. That 1980s experience is why GM in its later experience with electric vehicles designed the Volt and the Caddy ELR using a right clever system that will get most people to There and Back on electric only. And in case it doesn’t – or minds get changed as to where There is – GM throws in a dinghy. It’s an onboard, gasoline-fueled generator. It makes There any place a road goes and gas can be found.

As cold as it got in Vermont I could fill the Land Rover with gasoline. The problem was keeping the battery capable enough to spark the engine and get me down the hill to Kingsbury’s where the gas pumps were.

Did I mention deep cold is really unkind to batteries?