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Discussion Starter · #1 ·
Had the Zoe for 7 full months now, and absolutely love it. I haven't put petrol in the ICE for almost 3 months through a combination of lockdown and preferring to drive the Zoe. We had a really cold January here and the range suffered quite a bit. That wasn't a problem for us because we planned for that when researching buying a BEV, but I thought it would be interesting to plot a graph of battery performance vs monthly average temperature.

I just want to calculate real world number that someone looking to buy a BEV could use. My Chargemaster EVSE allows me to track how much energy flows through it and I have a receipt for all my public charging (mostly 22kW plus less than 10x 50kW). So I know exactly how much energy I've put into the car. That includes charging losses and extras like heating and pre-conditioning, so it's an all-in number that tells the true energy cost of running the car. The temperature number is the monthly average temperature for each month starting in August last year. January was really cold here, the av. temp. was only 1 centigrade!

Jan, Feb the Zoe only drove about 600 miles month each due to lockdown, but earlier months are 1300-2000 miles each so these should be solid numbers.

The graph shows a nice relationship between miles per charged kWh and temperature, clearly falling as the temperature falls:
141981


I'm posting this here rather than the Zoe forum so that anyone researching for information can find it more easily, but also to see if anyone else has similar data for their car? Would be curious to see how the Zoe stacks up.

Note that you can't use this data to accurately estimate the car's range - it includes charging losses which don't end up in the battery, and some of the pre-conditioning was done while the car was plugged in to the mains so that didn't reduce the range of the car. I reckon, however, that in the cold January our range while doing mainly short trips was down to around 120 miles vs 180 when the weather was warmer.
 

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Had the Zoe for 7 full months now, and absolutely love it. I haven't put petrol in the ICE for almost 3 months through a combination of lockdown and preferring to drive the Zoe. We had a really cold January here and the range suffered quite a bit. That wasn't a problem for us because we planned for that when researching buying a BEV, but I thought it would be interesting to plot a graph of battery performance vs monthly average temperature.

I just want to calculate real world number that someone looking to buy a BEV could use. My Chargemaster EVSE allows me to track how much energy flows through it and I have a receipt for all my public charging (mostly 22kW plus less than 10x 50kW). So I know exactly how much energy I've put into the car. That includes charging losses and extras like heating and pre-conditioning, so it's an all-in number that tells the true energy cost of running the car. The temperature number is the monthly average temperature for each month starting in August last year. January was really cold here, the av. temp. was only 1 centigrade!

Jan, Feb the Zoe only drove about 600 miles month each due to lockdown, but earlier months are 1300-2000 miles each so these should be solid numbers.

The graph shows a nice relationship between miles per charged kWh and temperature, clearly falling as the temperature falls:
View attachment 141981

I'm posting this here rather than the Zoe forum so that anyone researching for information can find it more easily, but also to see if anyone else has similar data for their car? Would be curious to see how the Zoe stacks up.

Note that you can't use this data to accurately estimate the car's range - it includes charging losses which don't end up in the battery, and some of the pre-conditioning was done while the car was plugged in to the mains so that didn't reduce the range of the car. I reckon, however, that in the cold January our range while doing mainly short trips was down to around 120 miles vs 180 when the weather was warmer.
Have a look on Battery University
Discharging at High and Low Temperatures

At -5C you only have about 80% of the capacity of the battery compared to a temperature of 25C. On top of that you will be using the heater which is a heat pump and this consumes about 1.9kW* compared to nothing in the summer or about 0.6kW for cooling if you have it on. It's a bit perverse but the percentage drop in mileage is worse for lower speeds because the heater is on for a longer period of time for a given journey. At 20mph the winter range is 48% of the Summer range. 30mph it is 60%, 40mph it is 70%, 50mph it is 80%.

** The Renault Kangoo EV doesn't have a heat pump, instead it has a 4kW resistive heater running off the traction battery. Given an COP > 2 for the heat pump this reduces the heating load to less than 2kW for a Zoe.

Peter
 

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Discussion Starter · #3 ·
Have a look on Battery University
Discharging at High and Low Temperatures

At -5C you only have about 80% of the capacity of the battery compared to a temperature of 25C. On top of that you will be using the heater which is a heat pump and this consumes about 1.9kW* compared to nothing in the summer or about 0.6kW for cooling if you have it on. It's a bit perverse but the percentage drop in mileage is worse for lower speeds because the heater is on for a longer period of time for a given journey. At 20mph the winter range is 48% of the Summer range. 30mph it is 60%, 40mph it is 70%, 50mph it is 80%.

** The Renault Kangoo EV doesn't have a heat pump, instead it has a 4kW resistive heater running off the traction battery. Given an COP > 2 for the heat pump this reduces the heating load to less than 2kW for a Zoe.

Peter
Thanks Peter, hadn't seen Battery University before. That's an interesting article and I'll be sure to check out the rest.
 

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Thanks Peter, hadn't seen Battery University before. That's an interesting article and I'll be sure to check out the rest.
To complete the list of loads on the traction battery, what I call Auxiliary Services (runs everything else electrical on the car) comes out to about 1kW. So summer time running with no cooling is 1kW. Summer with cooling is 1.6kW. Winter with heating is nearly 3kW. The last one is a significant factor as it will discharge the battery in about 14 hours without even moving the car.

Another 3kW is used by the motor to drive the car at 30mph, 8kW at 40, 15kW at 50, 26kW at 60, 41kw at 70, 61kW at 80 and 71kW at 84 (speed limiter). The power goes up as the cube of the speed. The energy consumed per mile goes up as the square of the speed and this is why high speed has a disproportionate affect on range. These are all theoretical figures but they are calibrated with respect to the official NEDC mileage of 250 miles for the ZE40. The reason why this is so high is the the New European Driving Cycle is based mostly on low speed stop/start city driving with one short high speed 'dash' at the end. The NEDC figure is also summer driving with no air con.
Peter
 

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That’s interesting stuff. It’s obvious when you point it out, but I hadn’t clocked that cabin heating and base load will be there for longer at lower speeds.
 

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Seems quite a different profile to the older Zoes. My Q210 was higher mpkwh at 0 degrees, but not by much, think I averaged 2.9. However when the outside average was 12 degrees or above you hit the sweet spot for the older chemistry and would go from low 3mpkwh to an easy 4 or above. (y)
 

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Have a look on Battery University
Discharging at High and Low Temperatures

At -5C you only have about 80% of the capacity of the battery compared to a temperature of 25C. On top of that you will be using the heater which is a heat pump and this consumes about 1.9kW* compared to nothing in the summer or about 0.6kW for cooling if you have it on. It's a bit perverse but the percentage drop in mileage is worse for lower speeds because the heater is on for a longer period of time for a given journey. At 20mph the winter range is 48% of the Summer range. 30mph it is 60%, 40mph it is 70%, 50mph it is 80%.

** The Renault Kangoo EV doesn't have a heat pump, instead it has a 4kW resistive heater running off the traction battery. Given an COP > 2 for the heat pump this reduces the heating load to less than 2kW for a Zoe.

Peter
I have an update for the battery capacity at low temperatures. I found out that the ZE40 uses LG Chem E63 cells and the product data for that shows that the capacity at -5C compared to 25C is 87% which is a lot better than the cells tested by the Battery University. It is possibly a better cell chemistry optimised for transport applications.This would mean the vehicle electronics takes about 0.9kW, heating 1.6kW and air con 0.9kW.
 

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some people here miss the fact that the heater is not on 24/7. even if you have a 2/4kw heater, the heater is working along the thermostat, turning it on and off as required
 

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some people here miss the fact that the heater is not on 24/7. even if you have a 2/4kw heater, the heater is working along the thermostat, turning it on and off as required
You are absolutely right but it depends how much heat leaks out of cars which are probably the worst insulated enclosures ever.

I have a question for Zoe 41kWh owners, when it is -5C outside does the heater struggle to keep the cabin temperature at a reasonable level such as 20-22C? If it struggles to do that then it is probably producing about 4kW of heat and the thermostat is a lot more on than off.
 

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You are absolutely right but it depends how much heat leaks out of cars which are probably the worst insulated enclosures ever.

I have a question for Zoe 41kWh owners, when it is -5C outside does the heater struggle to keep the cabin temperature at a reasonable level such as 20-22C? If it struggles to do that then it is probably producing about 4kW of heat and the thermostat is a lot more on than off.
on -5 or lower, anything more than 21C on the controls would make mine too hot for comfort. Note that you cant have eco mode on though
 

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on -5 or lower, anything more than 21C on the controls would make mine too hot for comfort. Note that you cant have eco mode on though
That's useful information. It sounds like Zoe can get the cabin much warmer than 21C. Thanks
 
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