Winter is around the corner; performance differences

[JeffRay]

So in NYC, the temperature dropped into the 30s over the weekend (Go Mets). As a result, I was reminded of last winters experience. In short what I remember was:

- in an urban setting of stop and go traffic, my performance drops from 1.8 mpkw to 1.2 mpkw.
- I park outside so what started at 98% charge dropped to 96% almost immediately.
- I put on the front seat warmers and the wired blanket for the back seat.
- In warm weather, I recharge 1-2 times per week.
- In cold weather, I recharged 2-3 times per week.

There were other performance factors posted by others. Feel free to repost.

 

[GlennD]

So in NYC, the temperature dropped into the 30s over the weekend (Go Mets). As a result, I was reminded of last winters experience. In short what I remember was:

- in an urban setting of stop and go traffic, my performance drops from 1.8 mpkw to 1.2 mpkw.
- I park outside so what started at 98% charge dropped to 96% almost immediately.
- I put on the front seat warmers and the wired blanket for the back seat.
- In warm weather, I recharge 1-2 times per week.
- In cold weather, I recharged 2-3 times per week.

There were other performance factors posted by others. Feel free to repost.

What is this winter you are speaking of? We do not allow it in Southern California!

 

[JeffRay]

OK. Rub it in. I guess you are not a Dodger fan so I can't gloat further about the Mets.

Take car to put on your sun screen!

 

[GlennD]

OK. Rub it in. I guess you are not a Dodger fan so I can't gloat further about the Mets.

Take car to put on your sun screen!

I live a mile and a half from the sorry Angles but I am not a sports fan.

 

[wtzouris]

Yes I am in NYC too and forgot how quickly things change, I drove 75 miles yesterday on a range charge, and had 18% battery remaining, so probably 89 miles total range, that's a far cry from 115 miles range in the summer. we had a high of 53 and a low of 33, most of my driving was at night. My outbound 40 miles averaged 2.4 mpkWh, the return 35 miles trip did 2.6 mpwWh,, 2.5 mpkWh average for the day. I was used to 3.0 average or higher all summer.
Things to remember:
Use the app to set climate control "time of departure"
Use seat heaters and heated windshield to quickly heat up the car, press MAX front windshield defrost and run down the fan speed immediately.
Keep the psi on tires up, 44 psi cold.
I don't remember what my lowest average mpkWh is for my 70 miles typical round trip in the dead of winter with wipers and wet roads. Maybe 2.2 mpkWh? I have to check my old screenshots.

 

[wtzouris]

OK I checked my old screenshots from February of this year when temps were in the 20s. My mpkWh after 28 miles travelled were 2.0, which after the 1.2 correction factor is 2.4 mpkWh.

The Mercedes display is wall to wheels which accounts for charger inefficiency. Chargers are only 80-85% efficient.
so,

2.4 x 28 = 67 miles range regular charge
2.4 x 31.5 = 75 miles range on extended range charge

 

[JeffRay]

Nice to hear from you wtzouris. Still have not seen you on Lafayette Street so we must be on different schedules.

So this week, rather than schlep to the dealer for a quick charge, I left it parked on the street near home and took the electric sewer instead. That way, I can have it charged over the weekend when I sport around in the convertible for the weekend. Probably last week I can make it through the week on one full charge. (I primarily drive locally with an occasional trip to the airport for an overnight trip).

 

[JeffRay]

This could have been posted under "range anxiety" but instead because it turned freezing overnight, it is here. When I got into the car this morning, the meter said 17%. I did use defrost to heat up car for my girls and yes, I put on the heated seat for me. It is about 5 miles to the dealer which was my destination for a full recharge. As others have noted, with a cold battery, performance takes a hit. I was getting 1.2 mpKw per meter, which implies about 5.7 miles at the start. Before I knew it, the battery reserve beeped. I was 3 miles to the dealer and down to 5% and 2 miles. Hm. I was too anxious to do the math in my head and was hoping that there was not too much stop and go traffic in the city. Bang, down to 1 mile with 30 city blocks left which is a little less than 2 miles. Starting thinking about what if I used up battery and decided to drive in the side lane just in case. One more obstacle, a four down to two lanes to get by, then smooth sailing. I pulled into the dealer with 2% left. When I told the service staff that I wanted a charge and a wash, they took one look at the meter and said they were going to charge it right away vs. taking a chance it would crap out in their shop.

Whew. I have to recalibrate my rules of thumb, 17% is cutting it too close, I have to head for a charge when down to 25%. If traffic was worse, I would have had to find a commercial charging garage.

BTW, if anyone has juiced out, please advise if there is any reserve like in gas cars when it hits 0 miles. A couple of weeks ago, I was driving my wife's gas car to a hockey game and discovered she had not told me that the gas light was on. At any rate, I was on 0 miles headed with a mile to go but got to a station and filled up with 19.95 gallons. The tank is rated to hold 21.10 gallons so there is a reserve in that car.

 

[wtzouris]

That's a good one, this winter weather really caught me by surprise -- even though I took delivery of my car last December.... I guess I did a lot of range charges last winter. Yesterday I swear I drove 4-5 miles and was down to 80% for a starting point of 97%. I noticed my car isn't charging to 100% anymore, only 97, 98 or 99% Again, I don't remember this because I often did range charges. Winter driving sucks when you do a lot of local errands and stop and go. It does better when you can cruise on the highway.
Looking forward to trying out my Nokia Hakkapeliitta R2 tires (Low Rolling Resistance ) winter rubber. Installed on another set of factory 17" rims just like the summer set. The TMPS sensors were read by the car without having to "re-program") Also I have to keep up on the tire pressures I put in 45 psi a few days ago (55 degree weather) and now in 35 degrees it's reading 42 psi. All measured on a cold tire, of course.

Oh and the Winter Formula washer fluid -- My B-Class hated the orange Methanol (Rain‑X® All-Season Windshield Washer Fluid) stuff -- kept saying the fluid reservoir was empty. So I found the Mercedes Summer Fit (soap) and Winter Fit ( Non-poisonous Ethanol) formulas online you have to mix with water. I have to use up (or drain) the summer stuff at the car wash and fill with Winter Formula. In December /January I go in for the Battery Warranty Certification (Desiccant Filter change) and maybe the recall firmware update will be ready by then. End of year 1 of a 3 year lease, I love the car, but I hope the next version will be ready in time and have AWD and double the range. And maybe a little bigger cargo area. And DC Fast Charge.

 

[Stretch2727]

Yes have noticed the drop off in efficiency with the cold weather. Probably one of the most annoying things is the regenerative braking does not regen so much when the battery is cold. This is kind of a double hit. Less efficient accelerating and less regained during braking.

If the MB follows the same cold weather strategy at Tesla most of inefficiency occurs at the beginning part of a drive. There are a lot of write ups on this on the Tesla forums.

Has anyone experimented with ways to keep the battery warm prior to driving? I am pretty sure if it is charging the battery is warm. I have a timer on my 240V charger I am going to time it so it is still charging when I leave for work in the morning. I will see if this helps. The 120V charger maybe better in this case as for sure the car is almost always charging in the morning if you use it for any reasonable distance each day.

My Focus Electric seemed to keep the battery warm when it was plugged in. There was a message that popped up all the time to plug in when you stopped the car in cold weather. I assumed it was for this.

I don't think the the departure time thing does anything with the battery.

Other ideas?

 

[wtzouris]

I think the departure time ( on the app) helps if you set it at least an hour in advance. Otherwise you start with a dead cold battery.

 

[JeffRay]

Well, while I don't mind charging twice a week, I was actually thinking of parking car overnight in an indoor garage. It is not heated but I doubt it gets colder than 55 overnight vs. 30s outside. I get 50% off overnight rate. The extra bonus is that it has a commercial Blink charger ($0.49/KwH) for charging. That way, I can skip the dealer which is a 15 minute walk from my office. More expensive but not that much more vs. multiple charging when you don't have your own garage and charger.

Second idea (lousy) is some kind of portable trickle charge as I live in an urban area with no place to plug in. When I walk the dog at 6 a.m., I can plug in and start charging and drain the portable battery. Maybe this will warm up the car battery, maybe not. The battery only has a limited capacity so it may not work and I would have to recharge it every night.

Like WTZ, I have had the car for a year and enjoy it. This time of the year is when the limited range tests my patience. Got through last winter so can get through this one too.

 

[Stretch2727]

I will try the departure time and see if it keeps the battery warm.

Jeff, I don't know how you do it without plugging in at home. This is one of the first questions I ask of anyone considering an electric car. Have you thought about a monthly garage rental that has some 120V plugs? My experience is you can keep the battery almost at capacity with a 120V charger as long as you are not driving more than 40 miles a day and have the overnight to charge.

Lugging batteries around for your second idea is likely not practical. A big computer UPS would likely work but these have about 3.0KW best case. Your not going very far on that charge and they are not cheap.

http://www.amazon.com/CyberPower-PR3000LCD-Smart-Sinewave-3000VA/dp/B00ANU8M3Y/ref=sr_1_5?s=electronics&ie=UTF8&qid=1448470467&sr=1-5&keywords=ups+battery+backup&refinements=p_36%3A1253507011

 

[wtzouris]

The UPS would not work anyway. L1 chargers draw too much power for each outlet. (Like a hair dryer) I think it would make the UPS trip its outlets .. If you got it to hold, it would run for about 12 minutes (half load). and the Weight is 124.0 (lbs.) Sealed Lead Acid (SLA) DC power into AC power into a 85% efficient L1 changer is not very sensible. 12 minutes of L1 is like 0.5 miles range added.

 

[Stretch2727]

Ok but this one has a 2700W output. If I remember correctly, level 1 on the highest amperage is 1500W.

Anyway, I agree not a good idea. Too heavy and expensive to be practical for such a small charge.

 

[JeffRay]

Thanks guys. I think the most practical idea for an urban owner is to find a friendly garage who will let me plug in overnight. The one my wife parks in might be willing. The manager actually pointed to where he could park me and I could charge. I completely forgot until now. I would get the benefit of a warmer battery and charging overnight like you guys.

In my defense, I thought I thought of all the charging requirements and was happy to charge twice a week in winters and once a week in summers. Obviously, it wasn't till a full year in did the actual reality hit me. Appreciate everyone's help.

BTW, I bought a small battery mainly to power my kids electric blanket in the rear seats so they could have "heated seats" like their parents upfront. The charge lasts 5 days and I recharge it on weekends at home. Agree the bigger battery is not a good idea even for warming up the battery in the morning.

 

[renault19]

How much more range do you get in cold weather on the East Coast if you "pre-warm" your B and its battery by letting the heater run while the car is still parked as opposed to driving off in a completely cold car? I remember having read something about battery efficiency versus cold temperature. Does the pre-warming only make sense while the B is still connected to a running charging station?

I've watched the battery gauge drop while driving in a cold (41F) and rainy night. Did hit the "extra reserve" mark/notification 3 miles before ariving at home.

 

[wtzouris]

On extended range charge, winter tires, I'm getting 75 miles range in 35 degree weather.

 

[wtzouris]

I think 5-6 miles worse if you don't pre-condition.......

 

[bcurious]

We've gotten as little as an indicated under 45mi for a full charge when it was cold here.
This is less than the daily commute that the car is meant to traverse for us.
Setting the departure time seems more effective at conserving range in that type of cold than the more mild 40s that the OP mentioned.
It was in the negative teens overnight and well below freezing during the sunny hours on the days that we experienced that short range here.
Dealers here shouldn't even offer the car without the range extender, in my opinion, and it was one feature we wanted but couldn't get with the available stock regionally when we selected the vehicle.