Charge mode while speeding/maybe worth it?

i think you would have to do some controlled testing, but you may be on to something.

i assume charge mode puts an extra lode on the engine, but how much at those rpm's is a great question.
something like scan gauge measuring rpm's and mpg's would be helpful.

 

Whenever our charge drops low enough that the ICE kicks on, we always start CHG'ing.

If you remember years ago on MythBusters they tested vehicle mileage with windows open and with A/C running. What they found was the extra drag on the engine caused by the A/C had no effect on mileage. Yes it is an extra drag, but it is so tiny that they could not detect it. On the other hand, windows being open causes so much turbulence that it did hurt mileage.

The ICE generates electricity, putting some of that electricity into the battery does not harm mileage.

Roughly 30-miles of driving while CHG'ing gives us 15-miles of EV range.

 

i think you're incorrect, but neither of us has data

 

We have discussed this topic before. Here is the link.
Can using CHG Mode be more efficient?

While I have never tested your scenario of driving 88mph with CHG mode, at moderate speed up to 65mph or so, CHG mode + using EV mode from the traction battery charged during CHG mode offers neither benefit nor penalty on the overall mpg when compared to driving the same distance with HV mode only in the same condition. Your mileage may vary depending on a lot of factors, so there can be a case that using CHG mode and utilizing the traction battery charge for EV mode later may make sense.

However, one good reason not to abuse the CHG mode is that it is akin to using DC Fast charging on the traction battery. You may be shortening the life of the traction battery by repeatedly using CHG mode. Remember that the PP has no active cooling mechanism other than just taking AC air from the cabin. You are generating a lot of heat during the CHG mode.

 

At sustained speed above 72mph, the PP normally neither charges nor discharges the traction battery. I have shown that fact in this thread.
Engine only MPG

Now, if you are driving at a sustained speed of 88mph and force the CHG mode to engage in charging the traction battery. That extra energy has to come from somewhere. You may not be seeing an mpg difference with or without CHG mode in your few cases, but I am almost certain that the extra load required to charge the traction battery must have reduced the overall efficiency. You are just not seeing it because it is buried under lots of noise from many variables.

 

if charge mode didn't hurt mpg, there would have to be another reason toyota didn't implement it permanently in the software management. that could be sal's charging rate scenario above.

 

i didn't mean that, i meant all the time.

 

it would be nice to see one go through the epa testing, with and without.

 

Well, if you are comfortable with the idea of getting a free lunch in exchange for a much more costly early traction battery replacement, then enjoy your lunch.

 

yeah, and the epa test is all at normal driving speeds. but it would be nice to know in those situations as well.
might be worth using charge mode more. or not.

 

is there a warning in the manual?

it might be worth monitoring battery temps

 

Was there a warning in the manual for early Leaf for using a Fast DC charge too frequently is detrimental to the longevity of the traction battery? At least, Toyota warrants the battery for 10 years 150kmiles, as long as it is not just degradation.

I wonder if anyone has actually measured the traction battery temperature during CHG mode? If it is not substantially higher than the high temperature during L2 charge session, it may be fine.