RavCharge, a solution to charge timer and entune woes

[Dsinned]

Joe, that's what I thought. I was just wondering, and doing a "what if" exercise. What Ravcharge is capable of doing already, is still certainly more than enough, since the vast majority of charges we do, should be "normal" charges. You have done a terrific job on Ravcharge! Toyota should have hired you as a consultant since Ravcharge has done more good to complement the RAV4 EV ownership experience than all the collective resources within Toyota have done to address our various charging issues combined.

THANK YOU! :mrgreen:

 

[Kohler Controller]

Fooljoe, just to let you know I did another ext charge after lunch (using 208V/30A). RavCharge said it would take 1:18 minutes to top it off, which coincided perfectly with what entune emails (start and stop) verified. Nice going.

 

[miimura]

I set my car to do an extended charge tonight. RavCharge says "To extended charge: 1:52 @ 235 volts 40 amps". So, it knows that I made that selection in the car and calculates the correct time on that basis from 79% Std SOC. ((1-0.79)*35 + 6.8 ) / (0.235*40) / 0.8 = 1.88 hr

Actual Entune e-mails showed 1:57. By car timer Scheduled Departure 6:50 - started 3:16 and ended 5:13.

 

[miimura]

I set my car to do an extended charge tonight. RavCharge says "To extended charge: 1:52 @ 235 volts 40 amps". So, it knows that I made that selection in the car and calculates the correct time on that basis from 79% Std SOC. ((1-0.79)*35 + 6.8 ) / (0.235*40) / 0.8 = 1.88 hr

Actual Entune e-mails showed 1:57. By car timer Scheduled Departure 6:50 - started 3:16 and ended 5:13.

So, on the consumption side, I drove 108 miles @ 3.3 mi/kWh today which indicates I took 32.7kWh out of the battery. I still had 4 energy bars on the gauge and RavCharge said I had 28% SOC remaining. This doesn't add up. 28% of 35kWh is 9.8kWh, which added to what I took out makes 42.5kWh total. We think it should be 41.8kWh total Extended.

Working it the other way, 41.8kWh - 32.7kWh = 9.1 kWh and 9.1 / 0.28 = 32.5 kWh, which would be what it considers to be the 100% Standard Charge, but we think it's 35kWh.

Yet a third way would be 108mi / (41.8kWh - 35kWh * 0.28) = 3.375 mi/kWh. Could they be "flooring" the value from 3.375 to 3.3?

Does this make sense to somebody else? I hit the Update button on the Energy Monitor and reset a trip meter before I left the house this morning so I could get a single efficiency number for the whole day. The 3.3mi/kWh reported is from the Average value in the upper right of the Energy Monitor history screen. Another significant digit would be nice...

 

[waidy]

I set my car to do an extended charge tonight. RavCharge says "To extended charge: 1:52 @ 235 volts 40 amps". So, it knows that I made that selection in the car and calculates the correct time on that basis from 79% Std SOC. ((1-0.79)*35 + 6.8 ) / (0.235*40) / 0.8 = 1.88 hr

Actual Entune e-mails showed 1:57. By car timer Scheduled Departure 6:50 - started 3:16 and ended 5:13.

So, on the consumption side, I drove 108 miles @ 3.3 mi/kWh today which indicates I took 32.7kWh out of the battery. I still had 4 energy bars on the gauge and RavCharge said I had 28% SOC remaining. This doesn't add up. 28% of 35kWh is 9.8kWh, which added to what I took out makes 42.5kWh total. We think it should be 41.8kWh total Extended.

Working it the other way, 41.8kWh - 32.7kWh = 9.1 kWh and 9.1 / 0.28 = 32.5 kWh, which would be what it considers to be the 100% Standard Charge, but we think it's 35kWh.

Yet a third way would be 108mi / (41.8kWh - 35kWh * 0.28) = 3.375 mi/kWh. Could they be "flooring" the value from 3.375 to 3.3?

Does this make sense to somebody else? I hit the Update button on the Energy Monitor and reset a trip meter before I left the house this morning so I could get a single efficiency number for the whole day. The 3.3mi/kWh reported is from the Average value in the upper right of the Energy Monitor history screen. Another significant digit would be nice...

100% is not necessary represented by 41.8 kWh. If you drain your battery pack to turtle, you may see closed to 50kWh electrons fed.

 

[fooljoe]

So, on the consumption side, I drove 108 miles @ 3.3 mi/kWh today which indicates I took 32.7kWh out of the battery. I still had 4 energy bars on the gauge and RavCharge said I had 28% SOC remaining. This doesn't add up. 28% of 35kWh is 9.8kWh, which added to what I took out makes 42.5kWh total. We think it should be 41.8kWh total Extended.

The fits with the pattern I've mentioned of the Entune SOC value being predictably imprecise, in particular reading high for high SOC and low for low SOC. Your "actual" SOC is probably more like 30%, which would make it add up just about right. Do keep logging data like these, and perhaps we can figure out a correction factor at some point.

Another significant digit would be nice...

I might be able to get you that digit... Stay tuned.

100% is not necessary represented by 41.8 kWh. If you drain your battery pack to turtle, you may see closed to 50kWh electrons fed.

Miimura's just talking about consumption from the battery. Of course if you measure how much power it takes to charge from the wall you have to account for charging efficiency. I assumed 80% efficiency for RavCharge's time-to-charge calculator, which I thought was a bit conservative, but is so far turning out to be a pretty good estimate, and your 41.8/50 experience fits that pretty well.

 

[Dsinned]

The other thing that is not precisely known is the actual amount of battery capacity after a normal charge. 35kWh is what we all "assume" to be correct, but we have also been told that a normal charge corresponds to ~80% SoC, where a full (extended) charge is 41.8kWh. Thus, 80% of 41.8 = 33.44kWh. Obviously then, the correct value can be "assumed" to be either 35 or 33.44 kWh, or even less after accounting for some degree of battery degradation.

Unfortunately, the most ACCURATE interpretation of the RAV4 EV's true battery capacity, seems to be a moving target.

If only our cars were equipped with a battery consumption watt-hour meter. It would only have to function similar to a trip odometer and therefore be resettable, with at least 5 significant digits of accuracy (in Watt-hours). This would be similar to an RGM (Revenue Grade Meter) provided by utility companies to homeowners, but designed for EV applications. Such a meter, could have easily been added to the instrument panel as a digital LED readout with a reset button.

 

[fooljoe]

The other thing that is not precisely known is the actual amount of battery capacity after a normal charge. 35kWh is what we all "assume" to be correct...

For the record, 35kwh is the only number officially published by Toyota, and using it seems to work well with RavCharge's range and time-to-charge estimating features. I don't recommend changing this value from the default unless you've done your own testing against RavCharge's predictions and have good reason to believe your battery holds something less.

 

[Kohler Controller]

No one yet has definitively determined the capacity/SOC relationship yet. This is what I used when setting up my cycle life testing.

Assuming 3.6V and 3.1Ah per cell, and 4494 total cells in the pack, offers 50.1 kWh of total capacity.
Charging to 4.15V/cell, allows approximately 92% of total capacity, or 46.1 kWh.
Charging to 4V/cell, allows approximately 80% of total capacity, or 40.1 kWh.
If we assume 4.5kWh is reserved at the bottom (still in the pack after the vehicle has stopped), then our numbers become:
46.1-4.5 = 41.6 kWh available from extended charge mode
40.1-4.5 = 35.6 kWh available from standard charge mode
This 4.5kWh (~9% SOC) is not accessible.

So, the confusion comes in when we don't know what SOC we are referring to, the absolute or the usable.
For example, absolute values would be 92% SOC after extended charge down to 9% SOC where vehicle stops.
Absolute would also be 80% SOC after standard charge down to 9% SOC where vehicle stops.
Since the upper 4kWh and lower 4.5kWh are not accessible, one might want to make the SOC represent that range where:
41.6 (or 41.8 as published) kWh = 100% SOC and
35.6 (or 35 as published) kwh = 83.7% SOC of 41.8kWh
where 0% SOC usable is equivalent to 9% SOC absolute.

Now to make it more confusing, the 16 bars on the dash only correspond to the standard charge setting, so that 83.7%SOC is now divided into 16 segments, or ~5% per bar.

I have no idea what Entune uses as a % basis to fill up the battery display.

 

[fooljoe]

I have no idea what Entune uses as a % basis to fill up the battery display.

The best assumption for this is 100% Entune/RavCharge = full normal charge or 35kwh usable, 0% Entune/RavCharge = car won't drive anymore or 0kwh usable. From the RavCharge user perspective one should forget about all that's actually going on at the cell level and just work on this assumption.

Excellent post by the way Kohler - this will hopefully help to clear up the confusion between whether the normal charge figure is 35kwh or 80% of 41.8kwh. Seems pretty clear that 35kwh is the right number (or very close to it) when you realize that any talk of 80% probably means 80% of the absolute battery capacity. So again I'll reiterate that you should not change your RavCharge setting from 35kwh unless you're reasonably certain that your battery has measurably degraded. Don't change it because you think the 35kwh quoted figure is somehow inaccurate (even if it is, 35kwh is what works best in RavCharge.)

 

[TonyWilliams]

The numbers that work:

45.0kWh total - 100% SOC
41.8kWh usable- 95.1% SOC = [( 41.8 + 1.0) / 45]
35.0kWh usable- 80.0% SOC = [( 35.0 + 1.0) / 45]
1.0kWh unusable- 2.2% SOC = [1.0) / 45]

 

[Kohler Controller]

The numbers that work:

45.0kWh total - 100% SOC
41.8kWh usable- 95.1% SOC = [( 41.8 + 1.0) / 45]
35.0kWh usable- 80.0% SOC = [( 35.0 + 1.0) / 45]
1.0kWh unusable- 2.2% SOC = [1.0) / 45]

These numbers work out the same as my previous post if one assumes a 3.6V/2.9Ah cell (like the ones I am testing). The only difference being the upper and lower keep out areas are smaller (2.2 to 2.5kwh at the top end and 1 to 1.5kWh at the lower SOC).

I can't wait to definitively find out exactly what capacity cells (and quantity) our vehicles use.

 

[fooljoe]

Just made a few more improvements to RavCharge:

In the climate section, by request I've added in 4 recurring timers, under the start/stop buttons. The interface for these is just like the charge timer interface, and like the charge timers they'll continue to execute every day you select as long as they're left on.

On the status page there's now a link to open a larger, dynamic map in a new tab or in your google maps app. Below that your raw latitude and longitude coordinates are also displayed now, in case you want to use them for any reason.

 

[boredcleaner]

thanks fooljoe!

 

[yblaser]

You've probably already thought of this and while I probably don't need this as I haven't really pushed my range, it might be nice to incorporate Tony's data so that you have a complimentary display for the slider setting of mi/kwh to display average speed required to reach that efficiency. You could either input efficiency or average speed to compute your range.

 

[fooljoe]

You've probably already thought of this and while I probably don't need this as I haven't really pushed my range, it might be nice to incorporate Tony's data so that you have a complimentary display for the slider setting of mi/kwh to display average speed required to reach that efficiency. You could either input efficiency or average speed to compute your range.

Done. The idea did occur to me before, but I never got around to it. Thanks for the reminder! And thanks to Tony!

 

[miimura]

I've never thought of "feature creep" in such a good light before. The improvements just keep coming. Thanks fooljoe!

 

[Dsinned]

Early this morning, just after midnight, I used Ravcharge to do a normal charge with initial S0C at 64%. According to Entunes email notifications charging took approximately 2 hours and 6 minutes, between 00:09 and 02:15am. Ravcharge's prediction was fairly close at 2 hours even. Ravcharge's predicted range (100 miles) is significantly higher than Entunes (91 miles) with CC off, even with the sliders for battery capacity and efficiency adjusted conservatively to 33.4kWh and 3mi/kWh respectively. The actual in-car average efficiency (after ~2 weeks) was still at a constant reading of 3.1mi/kWh.

As per usual, I recorded a battery equalization, post bulk charge at a substantially lower charging rate (~640W) that took place for 27 minutes from 06:30 to 06:57am. In-car departure time was set to 06:50am.

 

[TonyWilliams]

As per usual, I recorded a battery equalization, post bulk charge at a substantially lower charging rate (~640W) that took place for 27 minutes from 06:30 to 06:57am. In-car departure time was set to 06:50am.

I doubt that any power pulled through your EVSE that starts EXACTLY 20 minutes before your scheduled departure is a "battery equalization".

That is simply pre-conditioning the battery (heating it) and your cabin (if selected).

 

[Dsinned]

Nope, no pre-conditioning was selected/scheduled in the car or Ravcharge. This behavior is ALWAYS the same for EVERY charge. Other than the bulk charge itself, this additional "charging activity" is the ONLY other time the charging station is activated.

I have documented this unexpected "event" numerous times here on this forum, and by way of pure speculation, have referred to it as an "equalization" charge, "topping off" charge, "balancing" charge, but in reality, I have no idea what it is, or why it occurs when it does.