Traction Battery - Volts, Amps & SOC%, kWh, Rated Range

Toyota Rav4 EV Forum

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TonyWilliams

Well-known member
Joined
Nov 14, 2012
Messages
4,131
Location
San Diego county, California USA
The Rav4 EV pack is almost exactly half the size of the Tesla 85kWh one. Actually, i might be fooled to think it is exactly half, except i think they used 2900ma cells, vice 3100ma.

When the car is fully charged, the cells (i don't know if this is individual, or groups of parallel cells) are 4.1 volts. At the "normal" charge of about 90%, the cells are about 4.05 volts. This, by the way, is exactly the voltages that the Nissan LEAF uses.

I drove tonight about 75 miles from Orange County to San Diego. I started around 54% SOC, with cells around 3.7 volts. I drove the car all the way to "Turtle", which occurred at 2.9% SOC. I continued to drive the car to 2.4% SOC, but the battery contactors did not open and i was in my garage.

For the 75 miles, the car reported that I used 21.993kWh, and regenerated 889kWh, for a net of 21.104kWh (yes, it actually gives all three values).

The cell voltages sagged significantly between 2.8xx volts and 3.2xx volts while driving at this low SOC%, entirely dependent on load. Once in my garage at 2.4% SOC, the cells reported 2.930 volts low to 3.122 volts high under no load.

We are compiling all the data as part of our "JdeMO" project, to offer CHAdeMO quick charging to Rav4 EV, Mercedes B-Class ED, and Tesla Model S (no adaptor required!).

More tidbits:

Low Battery Warning - 19.3% SOC
Very Low Battery - 13.9% SOC
Flashing gas can - 11.9% SOC
"LO" on the GOM - 8.4% (NOTE: cell voltages 3100-3190ma)
Climate Control Limited - 7%
Turtle - 2.9%
No cutoff by 2.4%
 
Tony,

Congratulations on breaking the Tesla codes and getting / reporting these values!
 
TonyWilliams said:
For the 75 miles, the car reported that I used 21.993kWh, and regenerated 889kWh, for a net of 21.104kWh (yes, it actually gives all three values).
Tony, what screen shows that information? Or a better question, how would I find this information from my RAV4 EV after a trip? Thanks.
 
red_stripe05 said:
TonyWilliams said:
For the 75 miles, the car reported that I used 21.993kWh, and regenerated 889kWh, for a net of 21.104kWh (yes, it actually gives all three values).
Tony, what screen shows that information? Or a better question, how would I find this information from my RAV4 EV after a trip? Thanks.
This is likely available from CAN-Bus decoding. It probably can't be shown on any of the car's screens.
 
TonyWilliams said:
This isn't available yet, but "next year", I suspect we will make this available to you. Lots of work to do.
Do you have a product form factor in mind? It would be amusing to use something like this: http://www.adafruit.com/products/1601
It's a 2.8" touch screen LCD that goes on a Raspberry Pi. Probably $100 of hardware all-in, except CAN-Bus interface.
 
miimura said:
TonyWilliams said:
This isn't available yet, but "next year", I suspect we will make this available to you. Lots of work to do.
Do you have a product form factor in mind? It would be amusing to use something like this: http://www.adafruit.com/products/1601
It's a 2.8" touch screen LCD that goes on a Raspberry Pi. Probably $100 of hardware all-in, except CAN-Bus interface.

Yes, that is popular for these types of things.

I'm thinking more "custom" and less generic.
 
One could simply get a cheapo wifi or bluetooth ELM327 OBD2 adapter and connect that to his smartphone to access the CAN data. I have an app for my Leaf that does this, and I've been working on decoding the Rav CAN and creating an app to do similar things for it. Tony's way ahead of me though - I've so far only found an internal SOC measurement similar to the "GIDs" from the Leaf world, and representations of time-to-charge and power consumption while driving. It's pretty exciting to finally have a way to see a measure of SOC in the "no man's land" between normal and extended charge!
 
For those interested in this kind of stuff, there is also a new smart phone app coming out called myEV by myCarma that logs SoC via a plug-in "device" in the car.

https://www.indiegogo.com/projects/myev-by-mycarma-electric-vehicle-logger-app

The most obvious thing lacking about the RAV4 EV is its minimalistic approach to instrumentation for real time electrical measurements from the battery pack.
 
TonyWilliams said:
I'm thinking more "custom" and less generic.
To my way of thinking, the case and the UI define how professional or "custom" it looks and feels. The guts don't really matter as long as it does the job well. Of course, showing the linux boot text going by on the screen when you power it on pretty much ruins the first impression...
 
miimura said:
TonyWilliams said:
I'm thinking more "custom" and less generic.
To my way of thinking, the case and the UI define how professional or "custom" it looks and feels. The guts don't really matter as long as it does the job well. Of course, showing the linux boot text going by on the screen when you power it on pretty much ruins the first impression...

It will have "factory installed" demeanor, not home built hack.

For inputs, I like one or two dedicated tactile feel switches / knobs / buttons. There's not much to input, and I'd like to keep it that way.

My desire for this type of device is that it COMPLETELY and professionally covers the existing fuel gauge and GOM.
 
Dsinned said:
For those interested in this kind of stuff, there is also a new smart phone app coming out called myEV by myCarma that logs SoC via a plug-in "device" in the car.

https://www.indiegogo.com/projects/myev-by-mycarma-electric-vehicle-logger-app

The most obvious thing lacking about the RAV4 EV is its minimalistic approach to instrumentation for real time electrical measurements from the battery pack.

We have all the battery data, of course.

I have talked to the folks at this company in the past about their calculations about the LEAF, and I just got the impression that they were going to "educate me". I haven't even looked at whatever they are offering for Rav4, mostly because I have my own very specific ideas of what to display, how to calculate things, how it looks, what the interface is, etc.
 
TonyWilliams said:
miimura said:
TonyWilliams said:
I'm thinking more "custom" and less generic.
To my way of thinking, the case and the UI define how professional or "custom" it looks and feels. The guts don't really matter as long as it does the job well. Of course, showing the linux boot text going by on the screen when you power it on pretty much ruins the first impression...

It will have "factory installed" demeanor, not home built hack.

For inputs, I like one or two dedicated tactile feel switches / knobs / buttons. There's not much to input, and I'd like to keep it that way.

My desire for this type of device is that it COMPLETELY and professionally covers the existing fuel gauge and GOM.
Okay. That's much more ambitious that what I thought you were going for. I look forward to seeing what you come up with.
 
Tony,
Great job. Can you tell us what the vehicle charges to (total pack voltage) in both standard and extended modes? I notice that it abruptly stops when in standard mode (no taper). What current does it taper to in Extended Mode? It seems to simply stop after 15 minutes of taper rather than at a certain current value. Could you confirm? Or maybe Val?

Instead of covering the existing fuel/GOM gauge with your device, could you cover the display on the right side which is Completely Useless instead?
 
Kohler Controller said:
Tony,
Great job. Can you tell us what the vehicle charges to (total pack voltage) in both standard and extended modes? I notice that it abruptly stops when in standard mode (no taper). What current does it taper to in Extended Mode? It seems to simply stop after 15 minutes of taper rather than at a certain current value. Could you confirm? Or maybe Val?

Instead of covering the existing fuel/GOM gauge with your device, could you cover the display on the right side which is Completely Useless instead?
The idea I had was to take over the display on the right for our own purposes, but I have no idea how you would actually do that.
 
With 4.1 cells, and 74 cells per module * 6 * 16 (the same 96 cells in series as a LEAF) = 393.6 volts pack voltage in a Tesla Model S. Obviously, I don't yet know the configuration of our pack, but I'll bet it's still 96 cells in series.

The "80%" is about 4.05 volts per cell, and is actually about 89% SOC. I think it's about 83% in a LEAF.
 
http://www.teslamotorsclub.com/showthread.php/34934-Pics-Info-Inside-the-battery-pack/page11?p=739123&viewfull=1#post739123

The Rav4EV uses the 2900 mAh NCR18650PD with a C shaped vent designed to break the bond wire on the terminal when it opens. The C shaped vent is pictured in the Tesla patent but more recent patents also describe a circle shaped vent.

Pansonic recently released the NCR18650BE cell which is also an NCA cell rated at 2C max just like the PD cell, but rated at 3300 mAh! This cell has the same triangular postive terminal as the PD cell but has a circular vent. No other Panasonic cells besides the PD and BE have negative terminal vents! The nominal voltage of a NCA cell is 3.65V so a 3.3 Ah cell would result in a 85.5 kWh pack

The 3400 mAh NCR18650B is a high energy cell not suitable for EV use. The latest high energy cell is the NCR18650G rated at 3600 mAh. Neither of these cells has the Tesla vent on the neg terminal.

Tesla does not use the BMS to balance the pack. They use active impedance control to shuttle charge between bricks. It is always working and it much safer than a typical BMS (battery murder system)
 
Rav4 SOC meter

Loss of 5.4% SOC per bar until 51% SOC, then 4.5% SOC with variations per fuel bar below 51%

35kWh / 41.8kWh = 83.83% of usable capacity

Full "extended" charge - 96.5%- 98% SOC,
4112mv-4114mv

When car is turned on to READY, voltages drop to 4100-4106 with A/C pump running.

Normal charge - 88.9% SOC

FUEL BAR SEGMENTS:
16 gone - 83.4% SOC
15 gone - 78% SOC

14 gone - 72.6% SOC

13 gone - 67.2% SOC

12 gone - 61.8% SOC

11 gone - 56.4% SOC

10 gone - 51.0% SOC

9 gone - 46.4% SOC

8 gone - 41.9% SOC

7 gone - 37.4% SOC

6 gone - 32.9% SOC

5 gone - 28.4% SOC

4 gone - 23.9% SOC

3 gone - 19.4% SOC (LBW)

2 gone - 13.9% SOC (VLB)

1 gone - 7% SOC (CCL)

LBW - 19.4%
VLB - 13.9%
Flashing gas can - 12.9%
LO - 8.4%
Climate Control Limited (CCL) - 7%
Turtle - 2.9%
 
Great info Tony -

If you get a chance, do you think you could also correlate that internal SOC reading to the 0-100% of normal charge reading available from Entune? (i.e. what I use in RavCharge.) Or, if you can post what the ECU address, etc. is of where you're reading this stuff, perhaps I could log it myself using my OBD2 reader.

Thanks

Also, something seems to not quite add up: If an extended charge corresponds to ~97% SOC, and the lower limit to ~3% SOC, that means 41.8 kwh should be about 94% of the battery (so I guess our batteries are nominally ~44.5 kwh.) But then one would think a 35 kwh normal charge should be about 79% of the battery, or range from 3% SOC to ~82% SOC. The 89% SOC figure for a full normal charge seems really high, or am I missing something?
 
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