Tracking MPG with EV

[broski499]

I registered every fill-up with my 2008 Prius for 10 years on this site.

I recently switched to a Chevy Bolt and am trying to figure out how I can register the energy use.

Do you calculate how far you went and then how much energy you used on the odomoter trips? Charging up resets it. So each fill up with whenever you charge?

Curious how some of you are going about this.

[ECO-AKJ]

When I had a C-max Energi, it would show me how much fuel used and how many kilowatts used, I would imagine on the Bolt that you could take your total miles and divide by the amount of kilowatts to charge back to full.

*Of course this could be slightly skewed due to temperatures!

[Piotrsko]

Dont know about others, but even when I was commuting in the ranger my recharges were different amounts for pretty much the same drive. Sometimes significantly different. Since they weren't significantly different all the time I just noted those odd ones and averaged them out. Kinda like buying fuel at a different pump or station.

Some days you're the only one on the road, you catch all the lights red or green, there a truck in front while going uphill..........

[aerohead]

Originally Posted by broski499

I registered every fill-up with my 2008 Prius for 10 years on this site.

I recently switched to a Chevy Bolt and am trying to figure out how I can register the energy use.

Do you calculate how far you went and then how much energy you used on the odomoter trips? Charging up resets it. So each fill up with whenever you charge?

Curious how some of you are going about this.

Member AeroStealth has a BOLT, and has posted all his MPG-e data at the 'Garage & Tools' Forum.
I believe that he uses his phone to photograph both the in-car energy display, plus his EVSE screen to capture all the numbers.And there's about a 10% in charging efficiency difference, between the 120-V 'Granny' charger, and a 220-V home charger, plus DC fast chargers.

[Hersbird]

Seems like it's untrackable for most because they charge at home and most chargers don't tell you how much they have actually used. So you can go by what the car says it used. Sort of similar to trusting the MPG readout on a modern car. You won't see the charging losses for sure. I vote for kWh/100 miles or km as the standard, but have no idea what people are actually using.

[Piotrsko]

I suppose you could use a kill-a-watt style device to measure actuals, but, like I previously indicated the actuals vary a lot. Prolly need a year's history to determine whatever averaging method to use, and it would still be an average.

Suspect the same problem exists for fuel vehicles, but we don't get that granular

[JSH]

Originally Posted by broski499

I registered every fill-up with my 2008 Prius for 10 years on this site.

I recently switched to a Chevy Bolt and am trying to figure out how I can register the energy use.

Do you calculate how far you went and then how much energy you used on the odomoter trips? Charging up resets it. So each fill up with whenever you charge?

Curious how some of you are going about this.

I have a 2017 Bolt. Charging does not reset my trip meter or efficiency ratings. I record trip meter mileage, efficiency (miles / kWh), and overall odometer reading the 1st of the month and then manually reset Trip A and the efficiency.

For actual kWh consumed I get that from my WallBox charger each month.

I don't track the charging I do at work for free but that has dwindled to almost nothing now that we have about 175 EVs and 24 free chargers. I don't use paid DC fast charging enough to bother and the ones near work are no longer free so I don't use them.

I have found that charging efficiency can vary wildly based on temperature, charger rate, and SOC when starting and finishing charging. I generally charge to 90% as that last 10% is very slow and inefficient.

In general:

• Charging with the 120V EVSE that came with the Bolt is inefficient - about 20% charge losses
• Just topping off after driving 5-10 miles is VERY inefficient. 42% charging loss
• Best efficiency (6% losses) comes when I charge from about 30% to 80% with my 240V WallBox.
• Colder ambient temp = more charging losses

[Slipstream88]

I've seen Wh/mile(km) as a common tracking standard. You could substitute gal. for Wh and at least have a "Fill-to-fill" Chart to reference.

[Piotrsko]

freebeard or aerohead probably has a WH to gasoline equivelant energy formula, but I suspect the result is abysmally small numbers