ALL POSTS about Charge Timer Failure

[TonyWilliams]

I have had the impression that Toyota is not really committed to this car. Perhaps they are selling it merely to satisfy the State of California mandates.

Not "perhaps". They "are" selling it to satisfy the CARB mandates. Toyota has about as much interest in EVs as Tesla does in gas guzzlers...

http://www.myrav4ev.com/forum/viewtopic.php?p=4143#p4143

 

[Dsinned]

I "see" it happening every single time I recharge via a "scheduled" charge. I have fully monitored "data logging" on my L2 EVSE charger, so I don't have to be present to know when its happening. I have posted my data here in the past to confirm my findings. Something must trigger it - I really have no idea what, but the lower charging rate characteristically associated with balancing, is VERY real and completely predictable, at least on my RAV4 EV. It always follows several hours after a bulk charging period, and always completes just after the schedule completion time, precisely 7 minutes afterwards. It has a consistently short duration of only ~27 minutes. (This too was clearly and consistently revealed in my data logging).

I don't have a good explanation for any of this stuff, but this is what I actually SEE happening!

Now, if "cell balancing" takes on a greater meaning and quite possibly involves cell "discharging", which involves internal shunting of cells, I have no way of monitoring that! Nonetheless, if this is what is taking place inexplicably for nearly 2 hours, after a bulk charge, and for technical reasons helps to promote proper cell aging/longevity, well okay then, that might help to explain some things. Why does this interact with scheduled charging operations? I've' seen plenty of empirical evidence that it does. So, why then is it not documented???

 

[fooljoe]

I "see" it happening every single time I recharge via a "scheduled" charge. I have fully monitored "data logging" on my L2 EVSE charger, so I don't have to be present to know when its happening.

About how much energy does this usually draw?

 

[Dsinned]

Not much. ~650Watt (240V) for 27 minutes on my L2 EVSE, so about 300Wh.

 

[fooljoe]

Not much. ~650Watt (240V) for 27 minutes on my L2 EVSE, so about 300Wh.

Probably a stupid question, but is your departure time set for charge only, or charge and pre-climate? That sounds a lot like a pre-climate event...

 

[miimura]

IMHO, it should remember the level 2 charging parameters for each location previously used for charging. Then it could make a reasonable estimate before it is plugged in. However, this is more of a feature request because there's nothing to indicate that it has that capability.

But what if you have 2 different EVSEs at the same location? This is what I have: 21a in the garage and 40a in the driveway.

Although Entunes emails you when the bulk charge is done, it will also e-mail you that it was interrupted if you unplug during cell balancing

I don't have any way to check whether or not cell balancing is occurring, but I get the "charge interrupted" email every time I unplug, so I think that email really just means "unplugged" rather than any interruption of charging occurred. I generally unplug at least 2 hours after "bulk charging" completes, so it seems at least sometimes the balancing would be done already. Also the EVSE relays are always open already when I unplug, so there's no active charging going on.

I don't think determining the amperage is the problem. The RAV4 EV is already looking at the pilot signal as soon as you plug in and that tells the available amperage. The problem is the voltage, like 208V vs. 240V. It would be very unusual for a GPS indistinguishable location to have both 208V and 240V EVSEs available. Well, I guess that's not the only problem. The RAV appears to also assume that anything below 20A is 120V. So, there's that too.

 

[miimura]

Not much. ~650Watt (240V) for 27 minutes on my L2 EVSE, so about 300Wh.

Probably a stupid question, but is your departure time set for charge only, or charge and pre-climate? That sounds a lot like a pre-climate event...

I doubt it's pre-climate. My schedule is configured for Charge Only and I see the same thing as Dsinned. Just this morning, it was doing its "Balance Charge" and it clicked off (finished) at exactly 7:07am while I was standing there. My departure time is set for 7:00am. Entunes e-mail says it started the "Bulk Charge" at 4:25 and finished at 5:46am. I had 76 miles showing before the standard charge and 104 miles after.

 

[fooljoe]

IMHO, it should remember the level 2 charging parameters for each location previously used for charging. Then it could make a reasonable estimate before it is plugged in.

I don't think determining the amperage is the problem. The RAV4 EV is already looking at the pilot signal as soon as you plug in and that tells the available amperage. The problem is the voltage, like 208V vs. 240V. It would be very unusual for a GPS indistinguishable location to have both 208V and 240V EVSEs available.

Remembering the voltage at a location isn't going to help anything - the car needs both the voltage and amperage to calculate time to charge. Since you have to plug in to determine the amperage, might as well determine the voltage upon plug-in too, like just about every other EV does. Seems to me a software update to do that would be quite a bit easier than a new feature to remember the voltage based on GPS coordinates.

 

[fooljoe]

Just this morning, it was doing its "Balance Charge" and it clicked off (finished) at exactly 7:07am while I was standing there. My departure time is set for 7:00am. Entunes e-mail says it started the "Bulk Charge" at 4:25 and finished at 5:46am. I had 76 miles showing before the standard charge and 104 miles after.

I guess one of these days I'll just have to get up early and go see what's happening with mine around 7:00, as I usually don't make it to the car until at least 7:30. I can see my power consumption by the hour on the SCE webpage, and tried to look for a "balance charge" signature there, but the Rav4 draws so much power during the "bulk charge" it dwarfs everything else!

 

[Dsinned]

Not much. ~650Watt (240V) for 27 minutes on my L2 EVSE, so about 300Wh.

Probably a stupid question, but is your departure time set for charge only, or charge and pre-climate? That sounds a lot like a pre-climate event...

Charge only. I have never used pre-climate in my RAV4 EV.

 

[Dsinned]

Not much. ~650Watt (240V) for 27 minutes on my L2 EVSE, so about 300Wh.

Probably a stupid question, but is your departure time set for charge only, or charge and pre-climate? That sounds a lot like a pre-climate event...

I doubt it's pre-climate. My schedule is configured for Charge Only and I see the same thing as Dsinned. Just this morning, it was doing its "Balance Charge" and it clicked off (finished) at exactly 7:07am while I was standing there. My departure time is set for 7:00am. Entunes e-mail says it started the "Bulk Charge" at 4:25 and finished at 5:46am. I had 76 miles showing before the standard charge and 104 miles after.

Miimura, thank you very much, you have just independently confirmed my own findings. I think you are the only other forum member here to do so, so for a long while I was beginning to think I had dreamed all this stuff up.

The "7 minute over" thing is EXACTLY what happens to me on a scheduled charge, so I reset my departure time to 8:50am to fool-the-computer, so that my charge actually finishes just a few minutes before 9am at which time it is safe to unplug w/o receiving a "charge interrupted error messages".

The only thing I have yet to characterize is a scheduled - EXTENDED - charge, but I suspect it will behave exactly the same. However, plugging in well before midnight may be necessary (for a 9am schedule departure) depending on the S0C. With nearly a fully depleted battery, using a 7.7kW L2 EVSE, I will need every bit of those 9 hours to complete the extended charge plus subsequent cell balancing topping charge. If I do this with a SoC still above 30 miles range remaining, I think 9 hours should be sufficient and the charge will not automatically start until just after midnight.

 

[fooljoe]

Charge only. I have never used pre-climate in my RAV4 EV.

All the same, perhaps that's what this "balance charging" period is. It just seems too regular an occurrence to actually be cell balancing. Maybe the car is set to thermally condition the pack at or near the departure time, whether or not you're preconditioning the cabin.

 

[miimura]

I was beginning to think I had dreamed all this stuff up.

I don't see how you could think that. You have the monitoring data right in front of you. It doesn't tell you what the car is using the energy for, but it tells you exactly when and how much it's using.

 

[Dsinned]

Charge only. I have never used pre-climate in my RAV4 EV.

All the same, perhaps that's what this "balance charging" period is. It just seems too regular an occurrence to actually be cell balancing. Maybe the car is set to thermally condition the pack at or near the departure time, whether or not you're preconditioning the cabin.

Doubtful, but perhaps . . . but then again, I still fail to understand why Toyota has not documented any of this, especially if "charge interrupted" error messages will generally result because the owner has no idea this is what is happening or is "suppose to occur" during a scheduled charge.

For that matter why hasn't Toyota issued a technical service bulletin to explain any of these idiosynchrocies to their dealer network. This in itself would go a long way toward pacififying all of us who continue to report our observations w/o receiving any confirmation in return from Toyota that what we are experiencing is REAL! :x

 

[waidy]

Charge only. I have never used pre-climate in my RAV4 EV.

All the same, perhaps that's what this "balance charging" period is. It just seems too regular an occurrence to actually be cell balancing. Maybe the car is set to thermally condition the pack at or near the departure time, whether or not you're preconditioning the cabin.

Doubtful, but perhaps . . . but then again, I still fail to understand why Toyota has not documented any of this, especially if "charge interrupted" error messages will generally result because the owner has no idea this is what is happening or is "suppose to occur" during a scheduled charge.

For that matter why hasn't Toyota issued a technical service bulletin to explain any of these idiosynchrocies to their dealer network. This in itself would go a long way toward pacififying all of us who continue to report our observations w/o receiving any confirmation in return from Toyota that what we are experiencing is REAL! :x

I never use time charge. The "interrupt" message also happens during non schedule plug-in charge. I often get the "interrupt" message few hour after the bulk charge is completed when I unplug the J-connector from the J-inlet.

 

[Dsinned]

Waidy, most likely "charge interrupted" is a direct result of unplugging while cell balancing is still in-progress, even during a manual charge.

Again, why doesn't TOYOTA document any this??? Why do the amber LEDs provide such useless information? Why are we all still discussing this ridiculous subject nearly 8 months after the first instances were reported to Toyota? Why hasn't Toyota figured out what needs to be done about it? Why? Why?? WHY???

 

[TeCKis300]

It irritates me too that a 'charge interrupted' message is sent after the core charging period is declared complete. Toyota's systems engineers should have definitely resolved this oversight before the release of the product.

I know these pet peeves frustrates us, especially those keen on understanding the car more technically. Though I will say that I've stopped worrying about most of these nits, so long as I can have a charged car when I need it. The car works as a great and frugal transportation appliance. And it even has swagger and personality to boot, which is much more than I expected from a RAV/EV. For that, I can overlook some of its flaws.

 

[waidy]

Waidy, most likely "charge interrupted" is a direct result of unplugging while cell balancing is still in-progress, even during a manual charge.

Yes. I understand that and that is why I am not concern. My message is to tell others that "no worry, be happy". The "interrupt" message does not ONLY apply to schedule charging.

Again, why doesn't TOYOTA document any this??? Why do the amber LEDs provide such useless information? Why are we all still discussing this ridiculous subject nearly 8 months after the first instances were reported to Toyota? Why hasn't Toyota figured out what needs to be done about it? Why? Why?? WHY???

They didn't document the cell balance in the 1st gen Rav4EV either. We found out ourselves that the 1st gen Rav4EV does its cell balancing after 10th charging insertion of the charging paddle (doesn't matter whether the charge was just a minutes or 4 hours). The cell balance on the 1st gen ONLY happens after 100% charge, and it happen right after the bulk charge (unlike the 2nd gen RAV4EV that cell bal happens also at 80% charge).

I spoke to a TESLA engineer who did the Rav4EV battery and BMS development for Toyota. I questioned him how do they determine the battery voltage at 80% SOC to do the cell balance. He said he has a chart for the battery voltage at different SOC. I expressed my concern about the cell balance doesn't happen right after the bulk charge and allow the battery pack self discharge (100% SOC) between bulk charge and cell charge. He said he will bring it up in his group. That was couple months ago, I should email him or drive down to Tesla's HQ to do a follow up.

 

[TonyWilliams]

I spoke to a TESLA engineer who did the Rav4EV battery and BMS development for Toyota. I questioned him how do they determine the battery voltage at 80% SOC to do the cell balance. He said he has a chart for the battery voltage at different SOC. I expressed my concern about the cell balance doesn't happen right after the bulk charge and allow the battery pack self discharge (100% SOC) between bulk charge and cell charge. He said he will bring it up in his group. That was couple months ago, I should email him or drive down to Tesla's HQ to do a follow up.

Can I get his contact info?

 

[waidy]

Can I get his contact info?

pm sent.