How to get your RAV4 to charge on time, every time

HD172 said:

I'll be experimenting tonight. We may need to start a how-to get your rav4 to charge on time every time thread when we find out what works and what doesn't.

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Consider the thread started.

For my situation, I have the Leviton 40A charger and a schedule to have charge complete by 5am daily. So far, no issues or missed charges at all.

I noticed something the last time I did a charge using my new Leviton 32A charger, with a 25' output cord to reach from inside the garage to my driveway. What I noticed is how sensitive the trigger switch is on the J1772 charge port connector!

At the time I set up a scheduled charge that night, it was nearly raining outside and since my RAV4 EV was parked in the driveway, I wrapped a terry cloth towel around the connector while connected to the charge port to keep everything dry should it start raining later that night. Sure enough I rec'd a "charge interrupted" alert on my iPhone. When I rechecked the charge port by jiggling the connector around a little, the trigger switch suddenly "clicked". So, by fiddling with a towel around it earlier, I had inadvertently actuate the trigger switch, disabling the scheduled charge.

If the charge cord connector is not "perfectly" seated while mated inside the charge port receptacle, and you never hear a definitive "click", or even if you do, but later put too much stress on the cable and/or side force on the connector, then there is a good chance your charge will never initiate. On the other hand if the charge does initiate, but too much stress is subsequently put on the cable connector or its trigger switch is inadvertently touched, like I did with a wrap around towel, even a charge already "in-progress" may become disabled. SURPRISE!

I agree with Dsinned on this. I talked about this in a different thread. The Leviton connector is touchy. When we first got the charger I would have turn on the lights in the garage to make Sure I seated the plug correctly. I do not have anymore problems now that I know how it should feel when it is correctly plugged in.

I schedule a standard charge to complete by 7am this morning (Monday). I made sure when I plugged in the charger (32A Leviton), that the connector latched and clicked properly. I monitored the charge all night with my home energy monitoring system, see attached for the results.

https://www.enerati.com/Electricity...=ODAwMDAxMDAxMDAwNDAwMjkwMDAwMDAyMDAwMjAwMDA=

Note, the total duration of the charge was 3 hours and 12 mins. It started at 1:15am and completed at 4:27am. Then, at about 6:42am there was another minor event where the car was using about 600watts of power from the charger for about an additonal 25 minutes. This event completed at about 7:07am this morning. All this information is recorded on the attached chart.

I do not know what this additional 25 minutes was for, . . . maybe a TMS cycle to keep the battery warm, as it was fairly chilly outside where my car was plugged in last night for the charge. As someone else has speculated on this forum while observing a similar belated, short duration charging event on his RAV4 EV, it might just be a "topping charge". I really have no idea.

Nevertheless, it does appear that the RAV4 EV has trouble keeping track of time during a scheduled charge even on a seemingly fully compatible Leviton EVSE L2 charger.

Could the second event be a pre-climate event? Did you program in charge only or charge and climate?

I agree that the Rav4 starts (and finishes) charging way too early. I have mine set for 7am every morning and it is always finished charging close to 5am. I wish it was a bit closer to "on time". I'm not sure if it is somehow calculating wrong or if it is just being overly conservative to ensure you are ready.

I have a 40A Leviton.

I scheduled "standard charge only", not climate contol system preconditioning.

When I do the same thing to my Chevy VOLT, i.e. a scheduled charge, using the same Leviton charger, it initiates charging so that it completes by 7am with a few minutes to spare. Scroll further back in time on the first graphs via the link in my original post, to early Sunday morning, and you will see what I mean . . . Remember that the VOLT can only accept a maximum charging rate, of 3.3kW, so even though it replenishes the battery with far less energy (up to 10.5kWh), it still takes longer to fully recharge compared to the RAV4 EV (up to 35kWh, standard charge mode).

Dsinned said:

... completed at 4:27am. Then, at about 6:42am there was another minor event where the car was using about 600watts of power from the charger for about an additonal 25 minutes. This event completed at about 7:07am this morning. All this information is recorded on the attached chart.

Click to expand...

The BMS (Battery Mangement System) will stop the the charge when the highest voltage cell reaches the peak voltage (3.7 volts). This is for any modern multi cell pack, and Tesla is not excluded.

Then, a series of shunts will discharge all the highest cells to match the lowest cells; in your case, this took 2 hours 15 minutes. Then it topped off the now "balanced" cells until 7:07am.

If you wanted a 7am departure, it seems very well done.

This, of course, does not correspond to the 15 minutes that the climate control would run, and suggesting TMS (Thermal Managment System) that just coincidently happens 1-6 hours after the initial charge completes and no other time doesn't seem plausible.

My car had a 4+45 balance yesterday, after running the battery all the way to "LO" on the GOM. The deeper the discharge, the higher likelihood that a longer time will be required to balance the cells.

Battery balancing makes a lot of sense. Thanks for explaining that.

However, unlike Dsinned, I don't have a home energy monitor (yet) to see when power is being used. I have been going by the email notices that I get from Entune. Entune sends a "charge complete" notice hours earlier than my programmed departure time. Do you think the Entune notice is sent when the main charge completes and after that, the system balances the cells and tops it off??

SeaMonster said:

Battery balancing makes a lot of sense. Thanks for explaining that.
However, unlike Dsinned, I don't have a home energy monitor (yet) to see when power is being used. I have been going by the email notices that I get from Entune. Entune sends a "charge complete" notice hours earlier than my programmed departure time. Do you think the Entune notice is sent when the main charge completes and after that, the system balances the cells and tops it off??

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SeaMonster, yes, that appears to be the case. I get charging event alert notification emails sent to my iPhone from EnTunes as well, and for the last full charge, (as shown in the Enerati Dashboard link I provided above), I did not receive anything after the charge "complete" notification received at ~4:27am. The odd thing about the so-called "balancing" behavior that Tony speaks of, is the actual power consumed from the charger was limited to only 600 watts, with little variation, for that last 25 minutes.

Doesn't this imply the total number of cells being "actively" balanced with additional "top off" charging, was greatly reduced? If there was only 600 of 7700 watts of charging power being consumed, this implies only about 8% of the total number of cells were still charging. In which case a balancing charge ONLY applies the cell that are UNDER their full nominal voltage rating. I'm not sure there is any "discharging" going on to balance the cells. If so, that seems rather wasteful. Rather, it would seem the cells already at full charge are being "shunted" so that only the - NOT fully charged - cells remain connected to the charging system, and thus the total charging current is substantially lower.

I wish there was somebody from Tesla on this forum who could jump in here on these type of discussions and shed more light on what is actually going on "by design" inside these cars. Unfortunately, Tesla probably has entered into a NDA (Non Disclosure Agreement) with Toyota and is not permitted to reveal any relevant technical information about their involvement with the RAV4 EV's design.

Tony, do you think this "balance" charging is the same whether doing an extended charge vs. a standard charge?

The question in my mind is how does the battery know which type of charge it is getting and how does it thereby "control" the charge operation? Obviously, an electric parameter associated with the SOC of the battery, whether it be cell voltage(s), charging current(s), or some combination, such as the IR (voltage drop) accross each cell, while charging is in-progress, has to be measured by the internal battery charging control system. In order to standard charge the battery to only 35kWh, vs. 41.8kWh via an extended charge, something has to be constantly supervising the charge in-progress, and electronically in CONTROL. It also has to determine (or somehow predict) how long a charging is allowed before a "scheduled" completion. This is probably something a dedicated microcontroller does during any particular mode of battery charging in the RAV4 EV.

I have heard that in the Chevy VOLT, "balancing" employs shunting resistor across each battery cell as the charge nears completion. As can be seen in the Enerati dashboard for early Sunday morning, the nearly 4 hours of continuous, high power, charging ended by "ramping down" the power for the last 30 minutes or so. This "ramping down" while still charging is clearly visible in the realtime graph, sampling at one minute intervals.

The VOLT, however, has one and only one charging mode, whereas the RAV4 has two. Maybe, this somehow explains what is going on during charging that appears to be an added complication to how the latter is "fully" charged.

Dsinned said:

I'm not sure there is any "discharging" going on to balance the cells. If so, that seems rather wasteful. Rather, it would seem the cells already at full charge are being "shunted" so that only the - NOT fully charged - cells remain connected to the charging system, and thus the total charging current is substantially lower.

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The LEAF does both... While charging, there is a balancing routine, however at 100%, the cells can not be allowed to exceed their design voltage. So, yes, they do the "wasteful" method. That's why the 1-6 hours is spent just discharging, then the final very SLOW top off charge to bring them all up to design voltage, plus or minus 50 millivolt on the LEAF.

Dsinned said:

Tony, do you think this "balance" charging is the same whether doing an extended charge[100%] vs. a standard charge?[80%]

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Well, my hunch is the LEAF does NOT do a discharge / top off charge balance sequence at 80% since I've never witnessed that on either LEAF or with Rav4. It doesn't even seem required, since the real concern (amongst several) is making sure no one cell could exceed its design voltage limit. At 80%, a LEAF is at 4.05 volts per cell, and 4.1 at 100%. There is no fear of damaging the cell on an 80% charge.

Tesla is 3.7 volts per cell at 100%, but I don't know at 80%.

The question in my mind is how does the battery know which type of charge it is getting and how does it thereby "control" the charge operation?

Click to expand...

When a cell hits 3.7 volts? Seems simple enough, however I'm sure they monitor much more.

the nearly 4 hours of continuous, high power, charging ended by "ramping down" the power for the last 30 minutes or so. This "ramping down" while still charging is clearly visible in the realtime graph, sampling at one minute intervals.

The VOLT, however, has one and only one charging mode, whereas the RAV4 has two. Maybe, this somehow explains what is going on during charging that appears to be an added complication to how the latter is "fully" charged.

Click to expand...

The ramping down is not a balancing thing. It has to do with how fast the cells can be charged at higher SOC's. The LEAF can and does take 2C charge rates (48kW), but the power starts its "ramp down" from 120 amps at 50% SOC. Tesla, like LEAF, currently charges at 1C (about 230 amps at 386 volts!!!), and also must start quickly ramping down at about the half way point. The battery would heat up too quickly otherwise.

Slower charge rates, like the 1/4C of Rav4 (40 amps at 250 volt) can charge at full power until virtually fully charged.

Tony, the graph I am referring to showing the power consumption at my charger to recharge my RAV4 EV was in fact a "standard" charge (only to 80% of full capacity). Yet, there still was around 25 minutes of ~600 watts continuously consumed by the charger while still plugged in to the car. Again, I did not schedule any climate control preconditioning, so perhaps something else in the car was consuming that amount of power, like the battery's TMS, but not the battery itself.

From what you are saying now, a latent "top off" charge was not a result of balancing the cells, because it was a standard charge and therefore unnecessary to do any balancing.

No offense, and I do appreciate all your comments, but are you merely speculating here, or do you know for certain how the RAV4 (Tesla) battery is actually charged?

Dsinned said:

Tony, the graph I am referring to showing the power consumption at my charger to recharge my RAV4 EV was in fact a "standard" charge (only to 80% of full capacity). Yet, there still was around 25 minutes of ~600 watts continuously consumed by the charger while still plugged in to the car. Again, I did not schedule any climate control preconditioning, so perhaps something else in the car was consuming that amount of power, like the battery's TMS, but not the battery itself.

From what you are saying now, a latent "top off" charge was not a result of balancing the cells, because it was a standard charge and therefore unnecessary to do any balancing.

No offense, and I do appreciate all your comments, but are you merely speculating here, or do you know for certain how the RAV4 (Tesla) battery is actually charged?

Click to expand...

No, I don't know how the Tesla battery is handled. I don't know how many cells there are, or how they are sorted in modules, or a whole lot of stuff. I am describing things we learned with other EV's (mostly the Nissan LEAF) and hoping some of the holes line up.

For your 600w load, with no preheat and at 80%, I don't know. My only logical guess is the battery heater is on. It is physically located behind the "motor assembly" under the hood, on the passenger side. The cabin heater is in the middle front of the motor assembly. You could put your hand on either and see if they are running.

Again, as I stated, the LEAF does not do a "latent" charge at 80%.

It was relatively cold outside that morning, perhaps in the low 50F range, parked outside in my driveway all night while plugged in. The standard charge completed waaaay earlier than 7am, when I scheduled it to be completed. Then inexplicably, the 600W continuous "charging" began around 6:45am for ~25 minutes. It most logically could of been the TMS keeping the battery warm. I believe the two LEDs on the left rear side window were extinquished at the time, which supposedly indicates the battery charge had already completed.

The problem with some of these kind of things is there are no resident EXPERTS on the forums to turn to, and the dealers are generally clueless. I wish there was more technical information available on the RAV4 EV from a "design" standpoint. I'm sure there are a few Engineers at Toyota and/or Tesla reading this forum, but unfortunately are sworn to secrecy about "how things work" for our edification purposes. This is not rocket science but it sure seems that way sometimes! :roll:

So, I'm in an interesting situation. My Rav4's heater went out last week at some point and I took it into the dealer for service earlier this week. I've had the dealer's rental Rav4 EV since then. I set their car up onto the same charging schedule mine is on (5am charge complete, 8am preclimate). I came out to go to work yesterday and the car had not been charged. I was in a hurry and didn't look at the status window before it was cleared, so I'm not sure what the error was. However, it's the same charger and schedule as my car uses, and I got the alternating amber lights when I plugged in GE night before.

My conclusion, obviously based on a very limited sample set, is that there may be subtle differences between the cars in relation to either the charging port, the software, or something.

As a professional software developer in my past life, I know that all software is deterministic. Same inputs get the same outputs, unless designed specifically to not to be.

Anyway, is there a way we can compare "firmware" versions or something similar? There is something to this, we just have to figure out the pattern.

-Chris

Joyride, your situation is particular of interest, because most of us do delayed start scheduled charging as well, and expect the charge to be completed before we leave for work. If the charge never starts early in the morning, then we are unexpectedly faced with a RAV4 EV we cannot drive to work. Not a good situation!

Unfortunately, the easiest solution to this problem would be to do "immediate start" charging, but then we lose the advantage of off peak electricity rates after midnight, and cannot monitor remotely (via cell phone) when we are sleeping.

It sure seems like enough of us are having the same problem that Toyota needs to hear about it and figure out a solution.

I think you may be right, that it is the RAV4 EV's built-in battery charging firmware that supports the J1772 standard, that is most likely at fault.

My clippercreek cs-100 has been charging without any problems so far. I have been setting climate and charge times. I did get a climate start fail when I tried to turn on climate from the entunes app earlier than the departure time. I'm not sure if it was an app issue or if it was because there was a climate setting for later.