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For a more detailed analysis of how fast acceleration impacts my car, see the posts I made in this forum: EV Dynamics Physics Experiment - Page 2 - Energi Driving Tips & Tricks - Ford Fusion Energi Forum

The following is an explanation of why fast acceleration less efficient than slower acceleration. The plot below is the Electric Motor Map for a Prius. The x axis indicates rpms. The y axis indicates torque. The contour lines indicate efficiency. So at 20 Nm of torque and 3000 rpms, the...

Yes--I don't want to waste energy from the battery to heat the car. When the heater core cools down, I let the ICE warm it back up rather than drawing power from the battery to warm the heater core with the electric heater. I need to run the ICE anyway for my 60 mile commute. I might as well...

The car is pulling in cold outside air through the heater core to warm it up and direct it into the cabin. That quickly cools down the heater core. When the ICE is off, the heater core is isolated from the ICE coolant. The electric heating element is then used to heat the coolant isolated in...

If I were to buy a Model S, then I would need two cars. That is a great deal more hardware redundancy than in a PHEV. The range of a BEV is not going to suit my needs in the winter.

93% of the trips that I make with my PHEV are well within its 25 mile EV range. My commute to work is 8 miles. For such short trips, a pure hybrid looses much of is efficiency advantage to pure ICE vehicles. A PHEV is much more efficient for short trips. On my 60 mile commutes, I use about...

The last item that has a big impact on EV range is cabin heating. This plot shows temperatures for my 60 mile commute at -2 F. The car isolates the coolant in the heater core from the ICE coolant when the ICE is off and uses an electric heater to heat that coolant, if necessary. The red...

I have attempted blocking the grille with foam pipe covers. I monitored all the temperatures in the car for my commute when it was -10 F with and without the covers. The pipe foam covers had absolutely no effect at that temperature. All the temperatures (transmission, cylinder head, heater...

How do Prius owners preheat the power split device? The following chart shows the transmission fluid temperature for a 60 mile commute in the winter at -5 F (blue line) and in the summer at 68 F (red line). In the winter, the temperature never gets above 100 F even with the ICE running to...

The charts were not made driving a Tesla. But I would expect similar results. The max power output of the battery in my car is 68 kW. I don't know how things would change for a P85D. You would probably need a racetrack to properly measure the effects of fast acceleration. I'm doing this...

The chart from the link below shows the viscosity of transmission fluid vs. temperature. At 0 C (32 F), the viscosity is many times greater than what it is at 50 C (120 F). I would expect the transmission fluid used in EVs behaves similarly. This explains the significantly reduced mileage...

Of the total 0.009 kWh of additional energy for fast acceleration, 0.006 kWh is due to traveling the same distance in a shorter period of time. This is the difference between the dashed and solid green lines. But it is very difficult to measure such small differences accurately. But note...

The green lines take into account the additional friction (aerodynamic drag, rolling resistance, internal friction) associated with higher average speeds during fast acceleration vs. slow acceleration. The difference at the end of 0.25 miles is about 0.006 kWh more energy consumed from the...

I have attempted to measure the amount of energy consumed during slow acceleration vs. fast acceleration for an EV. Fast acceleration used more energy. The following chart shows my analysis. The dashed lines are fast acceleration and the solid lines are slow acceleration. In both cases, I...

I have been tracking the Energy Capacity and Temperature of the battery each morning for a year. The following plot shows how the energy capacity of the battery varies with temperature. The capacity of the high voltage battery (HVB) is 7.2 kWh. Capacity falls by about 8% as the HVB...

On Saturday morning, I measured the electric power consumed by the electric motor vs. transmission fluid temperature while driving over the same section of level road several times in EV mode with cruise control set to 30 mph. The outside temperature was 30 F and there was no wind. I did not...

$0.33 of electricity divided by $0.14/kWh = 2.36 kWh. Did charging really require 2.36 kWh of electricity? 2.36 kWh / 3.6 = 0.655 kWh / mi. That seems rather high. You will need to monitor the total miles driven and the total electricity consumed over a much longer period of time to get a...

Would the tire shop know hot to get the car to recognise the TPMS sensors?

As an example, for a commute in January when the outside temperature is -10 F, the transmission temperature starts out at 25 F (the temperature in the garage). After the 8 mile commute, the transmission warms up to 50 F. At 25 F, the additional power required to overcome cold internal...

After more analysis, it appears that approximately 25% out of the 36% total increase in kWh/mile consumed at 0 F vs. 70 F is due to increased internal friction. The transmission fluid is more viscous, the gears and bearings are harder to turn, etc. When the transmission fluid is at 0 F, it...

The car sends all trip data to the MyFord Mobile web site which provides a summary of data for each trip, including: date and time of the trip, plug-in energy consumed (kWh) from the battery, MPGe (which is converted to kWh/mi by 33.705/MPGe), trip distance, EV miles for the trip, brake...

I now have an explanation why the kWh/mile is so much greater in the winter vs. the summer. From the plot in the OP, kWh/mile is 0.225 at 75 F and 0.31 at 0 F, i.e. 1.38 times greater at 0 F vs. 75 F. The main reason for this increase is that cold weather significantly impacts the...

I am driving a PHEV in EV mode--no ICE and no gears are involved. Yes--I end up going the 1/4 mile in a short period of time with faster acceleration. 0.010 kWh of the difference is accounted for by friction with the faster overall speed of the 1/4 mile trip with faster acceleration. The...

If only conservative forces were involved, the amount of energy required to get the car to 60 mph is the kinetic energy of the car at 60 mph (0.5*m*v^2), regardless of how you got to 60 mph, i.e. fast or slow acceleration. But there are non-conservative forces involved in propelling a car...

That does not take into account real world effects. The energy from the battery is not transmitted as efficiently to power the wheels with faster acceleration. With fast acceleration, you are traveling more of the trip at higher speeds. Higher speeds have more aerodynamic drag and friction...

Fast acceleration reduces range in the following ways: 1. Your average speed over the entire trip will be faster if you accelerate fast. The higher your average speed, the more friction and aerodynamic drag, and hence the more energy used. 2. During acceleration, the electric motor operates...

In general, you will get better mileage driving on level roads vs. driving on hills. To go up the hill you need to convert electrical energy from the battery to potental energy required to climb the hill. This conversion is not 100% efficient--it is perhaps 85% efficient. However, you get all...

My EV range is 25 miles, so my commute to and from work is generally entirely EV. I discard any trips that are not EV.

I think that you will find for any car, including EVs, significantly more power is required to overcome internal frictions when you first start out when its cold. The wheel bearings are much more stiff and hard to turn. The transmission fluid is much more viscous. It will probably require...

When the coolant temperature falls below 15 F, the ICE will turn on. I use the engine block heater at home to prevent that. But I can't do that for the return trip. So when it is below about 10 F, the ICE turns on for the return trip. I don't include trips when that happens. Otherwise, I do...

I used the same tires all year round and maintained tire pressure around 40 psi throughout the year. The tires are Michelin Energy Saver A/S. --- To estimate the amount of energy used by the heater (not included in the plot above), the heater consumes a max of 5 kW of power. At 0 F, it would...

I am continuing my original query about mileage in the winter in this thread: http://www.teslamotorsclub.com/showthread.php/46208-Cold-Weather-Impact-on-EV-range

I am interested in the impact of cold weather on EV range of the Model S and the reasons why cold weather has such an impact on EV range. The range calculator at Tesla's web site seems to be extremely optimistic--I don't think I trust it. I do not have a model S, so I am providing data I...

Has anyone analyzed in some thread why it takes so much more power in the winter to propel the car? I observe for my car that it takes 40% more energy for the commute to work in the winter vs. the summer even with the heater off. When it is below 0 F, it takes more than three times as much...

So apparently it takes 268 (feb) / 172 (jul) = 1.55 times as much energy in the winter vs. the summer to drive the car, i.e. range is reduced by this factor. I assume you use the heater in the winter. Do you also remote start or precondition the car in the winter before starting out? Do you...

Thank you for your reply. Are the kWh's that you are using reported by the car or do you meter the actual electricity consumed by the car from the power company?

I would be very interested to see how kWh / mi energy consumption varies based on the season. Have you computed the kWh/mi for each month of the year, or each season. I would expect kWh/mi to be significantly greater in the winter vs. the summer.

Does anyone know how PerformanceBox provides accurate speed information from GPS. GPS location accuracy is around 5 meters. So speed it not going to be accurate if computed from GPS location alone. Does it use doppler, i.e. frequency shift, of the GPS signal to determine speed? It must have...

Yes, this is only one data point. In order to compare with another car, you would have to drive that car under similar conditions. Cold winters greatly impact the amount of energy used. It can take almost twice as much energy to drive in the winter vs. in the summer. I have no idea how the...

In a post elsewhere today, it was indicated that the Model S averaged 447 Wh/mi over a two year period including vampire losses. For the best state, Vermont, CO2 emissions are 0.77 grams/kWh. For the worst state, Kentucky, CO2 emissions are 957 g/kWh. So emissions are going to range anywhere...

To put this into perspective, suppose that you leave your computer on 24/7. A rather inefficient one might consume 200 to 300 watts of power. If coal is used to generate electricity, that amounts to 2 to 3 tons of CO2 into the atmosphere each year. Assume a gas-powered car generates 320...

About 40% of the fuel's energy at a power plant is converted to electrical energy. There are also transmission efficiency losses of electricity of about 7%. Thus the efficiency of the conversion of fossil fuel energy to usable electricity at one's home is approximately 35%. The car is maybe...

Generating electricity requires power, fossil fuels in many cases. The efficiency of power generation using coal is far less than conventional cars. You would produce less emissions driving a conventional car burning gas than driving an EV if electricity were generated by coal. Fortunately...

This report may be of interest to you: http://assets.climat...eport_Final.pdf If you consider lifecycle emissions, PHEV emissions are less than Teslas. - - - Updated - - - Note that some electric companies allow you to select how your electricity is generated. All my electricity comes from...

However, Tesla states that you should not leave the car in temperatures below -30 F (I am not sure of the exact temperature) for more than one day. I am assuming that the car cannot properly heat the battery when it is that cold (especially if not plugged in). So the battery temperature could...

There is no heater for the battery in my PHEV. Chemical reactions occur at a slower rate when it is cold. I don't see how the battery can produce as much power when cold. Tesla uses a battery heater to prevent this from happening.

If the battery is cold, it can't produce as much power. On my PHEV, when the battery temperature is below 0 F, the maximum power output is significantly reduced from that at 70 F. I can monitor the maximum discharge power of the battery.

Using Tesla range calculator at their web site, the estimated range of an 85D at 65 mph at 70 F is 295 miles. The maximum energy you can get from the battery is about 75 kWh. 75 / 295 = 0.254 kWh/mile. So you are getting the expected mileage for the car.

<sarcasm on> The gas savings is shown very prominently in the design studio and I don't see any fine print. Thus if I order the car, Tesla must be guaranteeing me that I will save about $10,000 in fuel costs over five years, and if I don't they will have to make up the difference to keep their...

I have tracked my fuel consumption over the past two year for my PHEV (both electricity and gas). I average 11,500 miles per year and have spent $550 on gas and electricity per year. That is not even close to the $2000 per year quoted at Tesla's web site. Many people trading up to a Tesla...