Reduced range in winter (merged)

[Lovemyev]

Why does zeroing the trip recorder affect the predicted range?

Resetting the trips removes all historical data stored by the car, it uses this data to PREDICT what it THINKS you should receive on a repeating similar types of journey and given the following criteria.
It is take from the previous data stored of driving style ( mode ) / ambient temp ( weather conditions ) / HVAC use etc etc.
It could be that over many previous weeks the car has been used purely for driving in town or on flat slow speed urban roads.
Maybe in Eco mode and with mild weather conditions and no use of the HVAC system.
Then out of the blue, the new EV owner(s) have a new long trip to make, that will be pushing the range of the battery.
The journey will be mage using an inclined motorway, at motorway speeds.
Also, the weather conditions have suddenly changed dramatically.
So, the car is fully charged for the journey and the predicted ( now over inflated range ) has been is calculated by using the historical data from the much different previous weeks of use.
It predicts that the new trip is achievable with a small margin to spare .
So, the new EV owner(s) then commences the journey and is shocked to find that as the journey progresses, the range is tumbling much faster than he / she expected, as the GOM is quickly recalculating the original prediction it first made based on previous historical data.
Of course for seasoned EV driver(s) they are not fooled by the over inflated GOM prediction at the start of the journey.
But the danger here is of course, that new EV driver can be caught out by believing the over inflated figure is totally accurate, then left scratching their heads when the car comes up short on range ?.
At least by resetting the trips before commencing this new longer journey, the prediction of range will be a LITTLE closer for when new EV driver(s) are taking on much longer trips for the first time.
Reset trips or not to rest trips, is a total personal choice of course.

 

[Belfastboy]

Throughout spring summer, charge the car overnight for 100% charge and usually gives estimated range of around 210 miles.

Now it is a bit colder, 100% is only showing range of around 130 miles when fully charged.

Surely the weather shouldn’t have such a wild affect on the range ?

Nearly due it’s one year service

Same here, 2020 MG ZS EV... I'm getting 126 miles on a full charge, really shocked by the depletion of it in the cold weather. I drove from Belfast to Dublin on a full charge, literally 0miles left in Dublin, lucky to be arriving at a friend's and its 100 miles by Google, so didn't even go the 126. On the way back lost the heater so stopped 80 miles in to re-charge, couldn't do it in the cold... roll on spring, don't want to be stopping every 80 miles for a recharge!

 

[Alb]

The difference between Summer and Winter consumption is well understood and pretty predictable. I've mapped this for my MG5 but relativity in the data will apply equally to the ZSEV and MG4. There's a whole thread covering this in the MG5 forum but for information, I'll show my latest graph:

This details monthly averaged consumption from March 2022 to present and very clearly depicts the maxima and minima that occur during hot and cold months. Using this real world data, the maximum range of my MG5 would have been 229 miles in August 2023 but only 161 miles in December 2022 (assuming a usable battery capacity of 48.8kWh). This is completely normal.

 

[Tangoed Man]

Same here, 2020 MG ZS EV... I'm getting 126 miles on a full charge, really shocked by the depletion of it in the cold weather. I drove from Belfast to Dublin on a full charge, literally 0miles left in Dublin, lucky to be arriving at a friend's and its 100 miles by Google, so didn't even go the 126. On the way back lost the heater so stopped 80 miles in to re-charge, couldn't do it in the cold... roll on spring, don't want to be stopping every 80 miles for a recharge!

Yup, and this is why my wife, (with her gorgeous Volcano Orange MG4 Trophy), will not let me sell our diesel E-class Merc, (it, too, suffers in the winter; summer range is 1000-miles, winter just 850-miles).

 

[tezzflyer]

380 miles in a MG4 Long range??? That may be what the GOM shows!

Whats the GOM? keep seeing it mentioned, no clue what it is!

 

[Susanna]

GOM - Guessometer

 

[Tangoed Man]

Whats the GOM? keep seeing it mentioned, no clue what it is!

Vernacular for the estimated range.

 

[profdraper]

Standard range model I guess ?.
If you are concerned about the predicted range after conducting a 100% charge, then try this.
Zero BOTH of your distance trip recorders before your next charging cycle to 100%.
"That's more like what I expected to see" :- I hear you cry .

Exactly right & for LFP battery chemistry in particular (& this has been written about extensively elsewhere; google it). One of the 'downsides' of LFP is that the Guessometer can be a bit wierd, depending. eg, the discharge curve appears to be not linear, but logarithmic, ie, much of the percieved GOM range appears to be lost early on, but then flattens out later. Of course this is 'not real' but more a symptom of the way the battery is treated in the charging phase.

So yes, always zero both trip meters before doing a full slow charge to 100% & battery balance on a home system like 240v or 7Kw (never DC rapid chargers). Another interesting recommendation from BYD - who use LFP 'blade' batteries arcross thier entire range - is to run the battery down to 10% every 3-6 months, then charge to 100% & balance. According to BYD, this also allows the GOM to work a little better.

Personally, I haven't been quite that extreme, but notice that the ZS EV battery level meter turns Red below 20% vs Orange below 50%. Every few months I charge to 100% from somewhere below 20% & together with the zero-tripmeter practice, this seems to be working quite well in terms of greater consistency with the GOM. Of course, in extreme cold weather & certain driviing conditions YMMV, but that is the nature of EV batteries in general.

 

[Simon John]

Resetting the trips removes all historical data stored by the car, it uses this data to PREDICT what it THINKS you should receive on a repeating similar types of journey and given the following criteria.
It is take from the previous data stored of driving style ( mode ) / ambient temp ( weather conditions ) / HVAC use etc etc.
It could be that over many previous weeks the car has been used purely for driving in town or on flat slow speed urban roads.
Maybe in Eco mode and with mild weather conditions and no use of the HVAC system.
Then out of the blue, the new EV owner(s) have a new long trip to make, that will be pushing the range of the battery.
The journey will be mage using an inclined motorway, at motorway speeds.
Also, the weather conditions have suddenly changed dramatically.
So, the car is fully charged for the journey and the predicted ( now over inflated range ) has been is calculated by using the historical data from the much different previous weeks of use.
It predicts that the new trip is achievable with a small margin to spare .
So, the new EV owner(s) then commences the journey and is shocked to find that as the journey progresses, the range is tumbling much faster than he / she expected, as the GOM is quickly recalculating the original prediction it first made based on previous historical data.
Of course for seasoned EV driver(s) they are not fooled by the over inflated GOM prediction at the start of the journey.
But the danger here is of course, that new EV driver can be caught out by believing the over inflated figure is totally accurate, then left scratching their heads when the car comes up short on range ?.
At least by resetting the trips before commencing this new longer journey, the prediction of range will be a LITTLE closer for when new EV driver(s) are taking on much longer trips for the first time.
Reset trips or not to rest trips, is a total personal choice of course.

I reset my trips the other day and this helped settled my range back to some normality now we're in winter, thanks for the tip.

 

[Coulomb]

I reset my trips the other day and this helped settled my range back to some normality now we're in winter, thanks for the tip.

? But it's probably just lying to you. If that soothes your nerves, I guess that's OK.

Or if you had unusual driving conditions recently (bad head wind, unusually hilly terrain), then that's fair enough, but realise that the BMS will be starting with no information, so it will start off assuming default conditions (summer weather, average hills, etc).

Honestly, I don't understand this obsession with resetting the trip meters, unless you have changed driving style or conditions recently. Otherwise, just let the guess-o-meter make its best guess, based on past driving.

 

[ozzz]

I am so happy to live in Australia, although Friday is looking to be 40°C and today a nice 27°C my MG 4-51 is loving life.

 

[Susanna]

I never reset my trip meters, as my driving ‘style’ doesn’t really vary.
I find the miles/kWh a much better and more accurate way to estimate my range. Of course the outside temperature and use of HVAC has an immediate effect, together with short journeys not allowing the battery to warm up, which can easily be seen on the driver’s screen.

Multiplying one’s miles/kWh by usable battery becomes second nature if range is an issue on a particular journey.

 

[Ruislip Resident]

I never reset my trip meters, as my driving ‘style’ doesn’t really vary.
I find the miles/kWh a much better and more accurate way to estimate my range. Of course the outside temperature and use of HVAC has an immediate effect, together with short journeys not allowing the battery to warm up, which can easily be seen on the driver’s screen.

Multiplying one’s miles/kWh by usable battery becomes second nature if range is an issue on a particular journey.

Likewise. Though I have to multiply battery percentage x 70 x current m/kwh, then knock a tad off. I can't multiply by 68.2. My mental maths isn't good enough. Although on a long journey If I start at 100% I will also see how many miles I have done at 25% and 50% battery used also.

 

[pollenface]

Surely the weather shouldn’t have such a wild affect on the range ?

It absolutely does. Cold affects all EVs.

 

[DB Go Rex]

It absolutely does. Cold affects all EVs.

As it does ICE cars.

 

[Lovemyev]

I never reset my trip meters, as my driving ‘style’ doesn’t really vary.
I find the miles/kWh a much better and more accurate way to estimate my range. Of course the outside temperature and use of HVAC has an immediate effect, together with short journeys not allowing the battery to warm up, which can easily be seen on the driver’s screen.

Multiplying one’s miles/kWh by usable battery becomes second nature if range is an issue on a particular journey.

Other factors including driving style will vary the prediction of course.
It’s purely a personal choice thing really.
How many times have we seen new EV owners panic and question if their traction battery is faulty, when their reported range after a change, has reduced dramatically just when the temperature drops.
Resetting the trips is no magic fix, it was never intended to be so.
It just reassures them that the car is capable of displaying a figure more closely associated to the WLTP range they believed possible when buying the car.
Therefore it offers less anxiety over the condition of the HV battery is totally unfounded.

 

[Susanna]

@Lovemyev - I totally understand what you are saying, and the reasons behind it. Personal choice as you say.

My concerns are that some drivers appear to think that merely resetting the trips has magically given them more range, when in fact the figure on the GOM was more accurate!

 

[pollenface]

As it does ICE cars.

And butter

 

[Belfastboy]

Yup, and this is why my wife, (with her gorgeous Volcano Orange MG4 Trophy), will not let me sell our diesel E-class Merc, (it, too, suffers in the winter; summer range is 1000-miles, winter just 850-miles).

ahhh the comfort of slow burning diesel consumption ?

 

[Brian]

Throughout spring summer, charge the car overnight for 100% charge and usually gives estimated range of around 210 miles.

Now it is a bit colder, 100% is only showing range of around 130 miles when fully charged.

Surely the weather shouldn’t have such a wild affect on the range ?

Nearly due it’s one year service

Mines shows 110 but that's in Scotland the frozen north.