No, It’s Real: EV Range Down

Well, I originally thought it was just the Toyota Guesstimatron estimating low. No, it’s almost certainly a very-real and pretty-substantial range loss!

I used to charge at work, ChargePoint saying that it put in 5.8KWh or so, typically, and I’d arrive home with a predicted 11ish miles left. Today, ChargePoint says it charged 4.8KWh, and if I had gone directly home, I most likely would have had only 2-3 miles left.

So, it sure looks like either the batteries are depleting in some sense, or the charger is just refusing to charge them fully.

My *best guess* as to what might be going on is that over the past couple months especially, although to a lesser degree before that, I have been doing considerably less scheduled charging. Instead, my wife and I have taken it up to the local mall, where we have quasi-free charging (and a pleasant walk together!), “filling ‘er up” there, and leaving it charged to 27ish miles over night.

Still, I’m kinda finding that a little hard to imagine being the cause of a 8-mile range drop, over the past 3-4 weeks. That is, 4 weeks ago, it was still getting 30ish miles.

The drop has been in two distinct steps, interestingly: 3-4 weeks ago, it dropped pretty suddenly from 30-31 down to 27-28, and then 5ish day’s ago it again dropped another 2 miles to 25-26. Very much a sudden, instantaneous drop in both cases.

Waddaya folks think?

I’m thinking my next move ought to be to go back to scheduled charging, mostly, for a few weeks and see if it recovers.

 

Referring to outdoor temperature, I presume?

Well, can’t say for sure, but it didn’t do this last summer.

 

Especially degradation in two distinct steps.

Highs here in the mid-to-high-90s F. If anything, last summer was hotter, and no such thing last sunmer.

Little over 20K miles on it.

 

I at least don’t remember it dropping particularly noticeably last summer.

So, you other folks who live in hot climates: Has your range dropped with increasing temperatures?

Its 20K miles have certainly mostly been in EV mode.

The fact that it has dropped in two distinct steps of 2-3 miles each ... well, that sounds a lot more like a computer making decisions than a battery electro-chemically degrading. (Actually 3 steps, but the first drop, from 34ish to 31ish was 3ish months ago.)

 

Thanks for the thoughts... Yes, the P.Prime uses forced-air battery cooling, where needed. That, pretty much always during charging, but pretty rarely while just driving.

To clarify, the temperature difference between last summer and this summer is not huge, as far as I can tell.

“ScanGuage” meaning an OBDII jobbie? It would be interesting to get a readout of the individual battery voltages. I bought a Carista a while back, but unfortunately, haven’t had a chance to try it out yet.

I’m pretty confident that what I’m seeing here is not just greater air-conditioner usage, since, according to ChargePoint, it’s actually charging considerably fewer KWh into the battery.

I’ve fairly consistently kept the A/C set at 80F since I got the car. That is, if the outdoor temperature is significantly above 80. If not, I just use forced-air cooling on myself!

FWIW though, thankfully, it rarely sits in hot parking lots; almost everywhere I go routinely has covered parking.

 

So, yes, thanks for the manual reference. Where is that in the manual? (I’d like to hear a little more context on that quote.)

Again, I’m pretty confident that it’s not mostly a matter of greatly-increased energy consumption, or of its estimate going down. That, since the real range is definitely lower, and ChargePoint clearly reports charging considerably less. Historically, I’ve seen as high as a little over 6KWh per charge, whereas yesterday ChargePoint said it only charged 4.8KWh into the battery.

 

Excellent info. Thanks.

As I mentioned, my current guess, based upon my recent charging habits, is that Toyota’s charge management is seeing that I’m frequently keeping the battery overnight at nearly a full charge, and it’s therefore trying to increase the time-average top charging margin by not charging as high.

Do you use scheduled, “just in time” in essence, charging more often than “charge now,” or the reverse?

 

Thanks for the thoughts!

In my particular case at least, it rarely sits out in the sun; almost all places I go routinely (thankfully!) have covered parking.

I’m thinking that’s true, but that it won’t adjust as rapidly as just one single charge cycle. I’ll probably have to change my charging habits for at least a week before the computer will react to them.

 

Again, I’m pretty confident that it’s not just the estimate going down, nor greater power consumption, because ChargePoint has been reporting only charging ~5KWh into the battery (starting very close to the HV threshold), where it has historically reported charging about 6KWh.