Charging costs and EV costs/mile

Absent real metering data, I estimate that about 8.5 kWh of utility energy is required to bring the battery from zero miles to full charge. This is based on measuring 9.4 or so amps at 120V with a clamp-on amp meter, and the eTRON app telling me it will take 7:35 hours to charge. Audi customer support tells me that the charger is 10A at 120V and 16A at 240V so 9.4 is in the ballpark. (Has anyone measured the actual kWh it takes to recharge the car?)

My home's marginal off-peak electric rate is US$0.37/kWh (I'm in the highest tier on a TOU rate). So that's about $3.15 per charge (8.5*0.37). At a 15 mile electric range that's about $0.21/mile So now I'm looking for any Chargepoint station I can find, regardless of the cost.

I'm also earnestly investigating getting a second electric meter at the house for charging with an EV rate that will be about $0.12/kWh off-peak. That should save me over $500 annually in EV electric costs, assuming 250 home charges per year. A 240V connection would also be a little more efficient.

BTW, gasoline at $3.00/gallon and 35 MPG is $.086 per mile (that's 40 percent of the $0.21 electric utility cost per mile :shock. It might just be cheaper to use the car's Charge mode and gasoline to charge the battery than to do so at home right now.

My word, $0.37/kWh, off peak? We are so spoiled here in the Pacific NW, I pay $0.08+ per kWh here, no tiers. So maybe 0.65 to 0.70 per charge here. That's about 0.035 per mile for me (yes, I do average about 20 miles per charge).

BLink network charging stations in Oregon charge .39 per for members, like you, I don't know that it is worth the effort.

Everything I've read says our battery has 7.6kWh usable capacity.

My condolences for the $0.39/kWh. Holy moly, that's high! I pay $0.12 and get free weekends out of that.

Why not set the timers to have the car charge overnight, during off peak hours? (if you can't do it through the app, use the web interface). I have the same peak rate as you, I'm in Southern California, but the off peak hours are half the peak rate.

RKD2":38q6whfx said:

Why not set the timers to have the car charge overnight, during off peak hours? (if you can't do it through the app, use the web interface). I have the same peak rate as you, I'm in Southern California, but the off peak hours are half the peak rate.

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RKD2":38q6whfx said:

Why not set the timers to have the car charge overnight, during off peak hours? (if you can't do it through the app, use the web interface). I have the same peak rate as you, I'm in Southern California, but the off peak hours are half the peak rate.

Click to expand...

US$0.37/kWh is the winter marginal off-peak rate on my time-of-use rate... Sigh

However, I've just had my first chance to use a commercial charger that will tell me the AC energy supply it takes to charge the car. From full electric charge-empty to full charge they sold me 6.74 kWh at 3.2kW and 240V for 2.5hours at a "bargain," US$0.19/kWh (about half my home's rate!).

More interesting is the charging station report of only 6.74 kWh delivered -- AC. I'd expected it to take more. Audi's said that their 8.8 kWh battery has 7.0 kWh usable, with a footnote stating that the battery is maintained bewteen 25 and 85 percent charge. I need to do some arithmetic around all this when I get home.

But, I certainly can't get 7.0 kWh DC into the battery with only 6.74 kWh (or even 7.0kWh) AC input. 6.6 is (100-25%)=75% of 8.8 kWh, but what about the 85% upper charge range figure? That might imply that only 60% (85-25%) of the 8.8, or 5.28 kWh DC is actually available, and maybe the 7.0 is the "usable" kWh from the AC source? I'm so confused.

Does anybody else have measured AC kWh readings to do a complete recharge? The car would barely leave the traffic light at idle under electric power when I connected to the charger. Seemed out of juice to me.

Has anyone finally discovered how much of the 8.8kWh A3 e-tron battery is available for use? I would love to have the software updated to allow greater use of the battery pack, since I have noted about 6.8kWh as the top my A3 e-tron battery is able to receive. I also wish that Audi had added the new Golf GTE batteries which would have pushed my A3 e-tron up to 13+kWh, but they chose to end production and use the name on the all-electric e-tron instead. We still like our A3 e-tron very much, but are upset that the app has not been updated since before we purchased our car in Feb. 2017, and there has been no talk about support for owners who wish to upgrade their battery packs (the new batteries are the same size as the original ones, but higher amp hours, thus the extended kWh and resulting increase in range).

My commute is nearly equal to my electric range on my 2017 A3 Etron. When I first got the car last month I was charging on 120V and it took around 7 hours. My range would read 19 the next morning. My battery would run out 2 blocks from home on the way back and the gas engine would kick in.

Then I installed a 240V outlet and it now charges in less than 2 hours. The range reads as 21 or 22 in the morning. The battery lasts all way home now, although the range reads zero when I get there. Luckily the last block is down hill.

According my my power meter graphs, I'm putting about 5.5 KWH into the car during the midnight charges. 3.5KWH the first hour and 2KWH the second hour.

Range improves when temperatures aren't as cold so is it possible that your increased range coincides with winter fading?

What is the web portal address to update the timer for my 2017? I have the old app, but it stopped working with the updated phone. Would be nice to be able to make adjustments, if needed. No one has ever been able to point me to such a place, which seems ridiculous.