Bad mi/kWh after charging

[AScaLightning]

A few times now I will get horrendous range (1.4 mi/kWh) after charging. Prior to the charge I get around 2 mi/kWh.

Any ideas? The truck said charging to 90% but I stopped it at 80% - could that be it?!

Makes for hard trip planning.

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[invertedspear]

You will get slightly worse range when the battery needs to cool itself while you're driving. It's been 110+ here and I've been getting 2.1, when the temp drops to the low 90s I start getting about 2.5. After a DCFC session, your battery is going to be warmer than it's been, so it's going to be using some of your power to cool. A couple clarifying questions: is the 2.0 based on mixed highway and city, or only highway? What about the 1.4? I'm assuming charging in your post is referring to DCFC, so please correct me if that assumption is wrong. What are the external temperatures during each leg of your trip? Are there any other factors that could be at play like elevation changes?

The fact that you stopped the charge early could be part of it, only because the battery may spend some more "shore" power to cool towards the end of the charging process, but I don't know if this is the case. If you're going to stop at 80, try setting that one time charge limit to 80 in the truck and see if it makes any difference. It will be an additional data point to analyze anyway

 

[RocketGhost]

Over what distance did the horrendous 1.4 mi/kwh persist?

 

[Zprime29]

I assume you are referring to the "This Trip", which resets after charging. Consider the driving conditions before/after your charge. For instance, when I leave the DCFC in Benson, AZ, there's a BIG hill to drive up getting out of the town. So my initial "this trip" efficiency is always super low. Give it some distance and let it level out.

 

[JRT]

I see huge swings, especially short trips, I just know that if I'm going long enough to need charging to get home, plan 2 m/kwh and stop at 200 miles and recharge to 80%. Unless it is some crazy headwind or all up hill for hundreds of miles it seems to always settle at 2 m/kwh after a longer drive.

 

[hturnerfamily]

I've found out in 48,000+ miles of driving over the almost exact last TWO years, and many of that while towing our camper, that you CANNOT go by the 'guess o meter' for anything 'Exact' when it comes to your mi/kwh over ANY short range driving - but, only over the LONG range, and when you are at your destination...

and, interestingly... while at first you may see only .8 mi/kwh range, and have a sudden heartbreak and range anxiety, you might find the next time you look down, after 50 miles, it's back up to 1.4... etc. It takes a long while for the 'averages' to work in your favor, over the course of travel... what you averaged BEFORE you stopped to Fast Charge is MEANINGLESS, otherwise, unless ALL conditions and miles and terrain are EXACTLY the same.

so, for those who don't know:

when you see the mi/kwh range stated as the two digit 1.4, for example... that actually DOES NOT mean 1.4 miles per kwh of battery power: what it is saying is that you are averaging AT LEAST 1.4 mi/kwh, and since there is only ONE SINGLE DIGIT after the decimal, you won't REALLY know 'how much' more until you see it tick over, even briefly, to 1.5.
So, you may be sitting at 1.49 mi/kwh, which is extremely different, and better, than only 1.41 mi/kwh... or, said another way: potentially 5 miles or MORE of extra range, on a standard 100kwh battery pack.

 

[TaxmanHog]

A few times now I will get horrendous range (1.4 mi/kWh) after charging.

Do you shut down your truck after the charging session has completed to clear the [This trip] log?

I do just to clear the energy intake / consumed while idling with the AC/Heat running, these comforts also contribute to the distortion of lower MPK, doing this will allow the value of [This trip] to recover more quickly and give you a better idea how the truck is performing on the current leg of the trip.

 

[invertedspear]

Do you shut down your truck after the charging session has completed to clear the [This trip] log?

I do just to clear the energy intake / consumed while idling with the AC/Heat running, these comforts also contribute to the distortion of lower MPK, doing this will allow the value of [This trip] to recover more quickly and give you a better idea how the truck is performing on the current leg of the trip.

Is there any way not to? I have climate going full bore with the truck on while at a DCFC, but as soon as I disconnect from the charger the truck goes in to accessory mode and disengages the AC compressor. Then I have do the whole hold-brake-press-start which resets the this-trip measurements.

 

[John Becker]

I've been following the "Always Be Charging" (ABC) dogma.
Recently, I've decided that charging after a very short trip <10 miles is costing me considerably more MPK than after a longer drive.
I always wait a few hours for the battery to cool before I plug it in. For whatever reason, short charging cycles seem to cost more per kWh.
Well, that's been my experience.

 

[TaxmanHog]

Then I have do the whole hold-brake-press-start which resets the this-trip measurements.

I recall we've had an OTA that improved the way in which the This Trip values were reset, previous to the OTA it was in consistent.

It's been a while since I last DCFC'd, so I've likely forgotten the nuances, but I do recall in previous events that the values got severely distorted and persisted after the subsequent startup, so I got into a routine of fully turning her off while I unplugged and returned the cable, that seemed to help if I recall correctly.

 

[mb0220]

Is there any way not to? I have climate going full bore with the truck on while at a DCFC, but as soon as I disconnect from the charger the truck goes in to accessory mode and disengages the AC compressor. Then I have do the whole hold-brake-press-start which resets the this-trip measurements.

I have found that if you run climate (especially heat) while in accessory mode, and then go directly to startup and drive, then "This Trip" seems to include your accessory time in the efficiency calculation and it will initially show abnormally low efficiency because it's including that energy usage. Verified this by checking "where did my energy go?" in the center screen and the bar graph shows a LOT of usage for climate.

 

[Zprime29]

I recall we've had an OTA that improved the way in which the This Trip values were reset, previous to the OTA it was in consistent.

It's been a while since I last DCFC'd, so I've likely forgotten the nuances, but I do recall in previous events that the values got severely distorted and persisted after the subsequent startup, so I got into a routine of fully turning her off while I unplugged and returned the cable, that seemed to help if I recall correctly.

I think I got that update, though nothing since. My experience is the same as @invertedspear

 

[AScaLightning]

Thanks for all of the responses.

The 1.4 was for the entire drive of 2 hours and 20 minutes after the first charge. Conditions were the same before and after. Long drive from Minneapolis to south of Kansas City. Charged 2 more times and was back to around 2 mi/kWh after both of those. Closer to 1.8 though (going around 75mph).
The trick was reset prior to driving.

I will set the one time charge limit next time - that’s good advice.

also - I should do my own math. We did drive over 2 hours so perhaps we really got more.

appreciate all the advice and tips.

 

[potato]

Conditions were the same before and after.

I haven't really been following this thread but I'll chime in anyway. You have to be careful with statements like that... even a tiny bit of wind, just a light breeze, makes a huge difference to highway efficiency. So much that it's really hard to make any judgements about efficiency based on just one or two drives. In my opinion.

 

[AScaLightning]

So, I think it may have been how I stopped the fast charging. Using the truck to set the charging max and therefore stopping the charge rather than abruptly stopping the charger via the charging kiosk seems to may have been the difference.
Small sample size - but return trip home I was getting 2.0 mi/kWh going 78mph. Charged 3 times on return trip and not a single issue.
Thanks again for all the tips.

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