[DwainA]

Getting ready for a road trip and noticed that many (all?) commercial EV chargers charge by the connection minute, not by the power consumed. So I wanted to see where my paying to add battery storage break even is compared to paying for gas. Using rough estimates, I calculated that if I'm paying more than $0.02 USD per minute for electricity it's more expensive than $3.00 USD per gallon of gas. Does someone want to check my math?

Assumptions:
Y - gas cost $3 per gal
A - I get 2.5 miles per kWhr
B - I get 20 miles per gal
C - maximum charge rate is 3.7kW per hour
Z - calculated $ per minute charge to equal $/mile of gas

Formula: Z = (((Y/B) * A) * C) / 60

So, with our 45e if you pay $0.35 / minute to charge that's the equivalent of paying $45 per gallon!

Is this really true? Please run the numbers and let me know if I missed something. Thanks

[X5 45e]

Originally Posted by DwainA

Getting ready for a road trip and noticed that many (all?) commercial EV chargers charge by the connection minute, not by the power consumed. So I wanted to see where my paying to add battery storage break even is compared to paying for gas. Using rough estimates, I calculated that if I'm paying more than $0.02 USD per minute for electricity it's more expensive than $3.00 USD per gallon of gas. Does someone want to check my math?

Assumptions:
Y - gas cost $3 per gal
A - I get 2.5 miles per kWhr
B - I get 20 miles per gal
C - maximum charge rate is 3.7kW per hour
Z - calculated $ per minute charge to equal $/mile of gas

Formula: Z = (((Y/B) * A) * C) / 60

So, with our 45e if you pay $0.35 / minute to charge that's the equivalent of paying $45 per gallon!

Is this really true? Please run the numbers and let me know if I missed something. Thanks

I can simplify your math:

Charging takes 5-6 hours

0.35 x 60 x 5 = 105 $ that is ridiculous. For me on a pubic charger in Europe it is around 5-7,5 € for a full charge. Most destination / slow chargers are billed per kWh not per minute. Super chargers are billed per minute. Are you sure you are mentioning the price fir normal slow chargers?

Charging along the way on a round trip doesn't really make sense. You need to be plugged in for more that 2-3 hours to have some charge. I only do it on destination. It is not a replacement for a gas stop. That is why I chive a PHEV and not a EV.

That is. If I park somewhere for more than 30 minutes and I see a free charger I would plug in (if billed per kWh not per minute )

[PeterPuitG]

Originally Posted by X5 45e

If I park somewhere for more than 30 minutes and I see a free charger I would plug in (if billed per kWh not per minute )

At 3,7kw charging rate i would not go through all that trouble for less than a couple of hrs. Unless it would get me a parking spot that is reserved for cars that are charging.

[DwainA]

Originally Posted by X5 45e

I can simplify your math:

Charging takes 5-6 hours

0.35 x 60 x 5 = 105 $ that is ridiculous. For me on a pubic charger in Europe it is around 5-7,5 € for a full charge. Most destination / slow chargers are billed per kWh not per minute. Super chargers are billed per minute. Are you sure you are mentioning the price fir normal slow chargers?

Charging along the way on a round trip doesn't really make sense. You need to be plugged in for more that 2-3 hours to have some charge. I only do it on destination. It is not a replacement for a gas stop. That is why I chive a PHEV and not a EV.

That is. If I park somewhere for more than 30 minutes and I see a free charger I would plug in (if billed per kWh not per minute )

Definitely the same reason I own a 45e. BUT it appears that the charging infrastructure and business models are very different between Europe and US. Maybe this dialog will catch some decision makers eye. From my limited exploration of fees charged (by looking at quoted rates in several EV Charging apps) per minute seems to be the US business model. Definitely does not work for slow rate chargers like we have in the 45e. I love the car and want to use the electric capability as much as possible but am disappointed that the non-home charging cost in the US is so expensive because of our slow charge rate AND a per minute vs per kW business model.

[X5 45e]

Originally Posted by DwainA

Definitely the same reason I own a 45e. BUT it appears that the charging infrastructure and business models are very different between Europe and US. Maybe this dialog will catch some decision makers eye. From my limited exploration of fees charged (by looking at quoted rates in several EV Charging apps) per minute seems to be the US business model. Definitely does not work for slow rate chargers like we have in the 45e. I love the car and want to use the electric capability as much as possible but am disappointed that the non-home charging cost in the US is so expensive because of our slow charge rate AND a per minute vs per kW business model.

The only thing that charging per minute is good for is to clear the charging spot as soon as possible.

Some people park their cars in a charging spot for the night while the car is fully charged after a couple of hours.

It is a shame the business model is different. I did some city trips last week. And was plugged in for 3-4 hours making it possible to return home on electric. I did more than 100 km/day electric only.

[jad03060]

If the 45e had CCS capability, it would be more feasible to charge on the go. But, that would add cooling and other hardware needs in the vehicle, that is already pretty hefty! Same would be true if you wanted long long life on the batteries to charge it faster with an EVSE. Keeping the batteries in the safe temperature zone while charging helps them last longer.

[biterror]

Originally Posted by jad03060

If the 45e had CCS capability, it would be more feasible to charge on the go. But, that would add cooling and other hardware needs in the vehicle, that is already pretty hefty! Same would be true if you wanted long long life on the batteries to charge it faster with an EVSE. Keeping the batteries in the safe temperature zone while charging helps them last longer.

Well, the batteries are liquid cooled already..

[jad03060]

Originally Posted by biterror

Well, the batteries are liquid cooled already..

On my i3, when charging via CCS (high voltage, DCV), it can accept up to 50Kwhr...that’s a long ways from 3.7Kw the X5 can currently handle, and more than an order of magnitude more potential heat to deal with...it also has a larger electric motor by about 50%, so at max acceleration, would put a larger heat load on things. Scaling things can take up both space, add weight, and costs. The decision was made that it wasn’t worth it on the X5. Whether you agree or not, and would be willing to pay extra for that if offered is an open question.

[codex57]

On a plug in with such a small battery, it seems clear that charging on a road trip isn't reasonable unless it's an overnight charge like you would at home.

That said, I also don't think it's reasonable that BMW left such a weak charger at 3.7kW when they nearly tripled the size of the battery from the last gen. That alone should have told them they needed to bump up the charger, even just a little. Going to a 7kW likely wouldn't have needed much changes (if any) yet would keep the time to full charge close to what the last gen had and made it much more reasonable to charge on the go (or come home after running some errands, charge for a bit before going back out on electric power again.

They don't need to go full BEV 50kw rate, but 3.7kW is just ridiculous as well. They shouldn't have needed "feedback" to tell them they need to bump up the charge rate if they're gonna bump up the battery size.