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Discussion Starter #1
I’ve owned my 2014 ED for just over a year now and there have been a handful of times when the state of charge drops 10-20% while the car is parked for a few hours. The first time it happened, I thought I was just imagining it. It happened again today and I’m positive it is real. It was at 40% SOC when I parked at work in the morning. When I got In to go home seven hours later, the SOC had dropped to 30%. Any thoughts on what would cause this to happen? I am still on the original 12V battery.
 

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2014 Cabriolet bought in Sept 2016 with 6,470 mi
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The SOC can drop or rise due to the temperature of the battery. As you drive, the battery heats up and will show a higher SOC than after it has cooled back down - I've had it go down 5-10% when the weather is cold (I live in the Chicago area, so it can be very cold). I've also had it go up as much as 5% when it is cold in the morning but heats up during the day.

It could also be an actual drain of the battery pack if it is charging a weak 12V battery a lot.

If you don't live in an area that gets cold, you should definitely check the 12V. $100+ for a new battery is a lot better than $10000 for a new battery pack if it should fail completely and take the pack with it.
 

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I'd say if your 12v battery is the original, THEN GET IT OUT OF THERE NOW!!

Len
2014 EV Coupe 21.500 miles
2014 EV Cabriolet 22,000 miles
 

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Discussion Starter #4
I live in Des Moines, so probably pretty comparable temps to Chicago. We had a temperature drop last night and it was around 19 degrees this morning on my short ride into work, so maybe that is part of it.

I have a new MB battery ready to go, but the last time I checked, the diagnostic tool said my original battery is still good. I’ll check it again and maybe just replace it out of caution. I wonder if a weak 12v battery is also part of the reason I’m getting such terrible range in the winter? 35-40 miles average per charge, or less if I run the heater.
 

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2014 Cabriolet bought in Sept 2016 with 6,470 mi
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The cold temps are definitely at least part of it. Definitely recommend replacing the 12V battery sooner rather than later.

Your range loss is caused by using the heater. It eats around 10-15% of power all by itself - just watch the Power gauge when you are stopped and turn the heater on. If you have heated seats those are better to use than the heater. Personally, I never turn the heater on - I just dress for the weather and don't drive too far in the winter in the Smart
 

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Discussion Starter #6
No heated seats, unfortunately. I use the heater sparingly. I dress for cold weather, but there are still times when it’s necessary to run the defroster. Even when I’m not using the heater, I’m lucky to get a 40-mile range in winter. My HV battery has degraded about 10% and it’s more noticeable in the winter. Hopefully the initial rate of degradation has slowed down so it won’t drop by the same amount over the next seven years.
 

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2014 Cabriolet bought in Sept 2016 with 6,470 mi
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When my windows fog, I use the air down all the way at 60 and output to the windshield (AC off, just plain air). Works just as well if not better than the heated defrost.

I haven't noticed any degradation in range since I bought mine. I've actually gotten more maximum range in the summertime each year - it's mostly due to the tires getting older and less sticky I expect along with being better at maximizing range covering any loss in the battery capacity
 

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The cold temps are definitely at least part of it. Definitely recommend replacing the 12V battery sooner rather than later.

Your range loss is caused by using the heater. It eats around 10-15% of power all by itself - just watch the Power gauge when you are stopped and turn the heater on. If you have heated seats those are better to use than the heater. Personally, I never turn the heater on - I just dress for the weather and don't drive too far in the winter in the Smart
The hearter is a big contributor, but the range loss also occurs in cold weather even if you don't use the heater. With colder temperatures, the BMS raises the maximum allowed depth of discharge (ie. the "zero" SOC point) to prevent excessively low battery voltage under a load.
 
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