How Many kWh in a Full Charge?

Just to be clear here, are you in HV mode at this point? Do you have the segmented battery icon? I do. When it switches to HV mode, I have 6 battery segments visible and SoC is at 23.1%. When it gets down to 2 battery bar segments, SOC is at 18% and the ICE automatically comes on and stays on until 4 battery segments are visible again (I don't recall what the SOC was at that point). At that point the ICE will shutdown again if it is not needed.

Are sure you aren't looking at minimum SOC? I know you said you and I have same exact Xgauge programmed.

 

For me, SoC of 23.1% is where it switches from EV to HV mode. I can run in stealth mode (EV at slow speeds while in HV mode) all the way down to 18%, at which point the ICE is forced to come on.

I suspect some sort of subtle math error is going on here. I just don't know if the Scan Gauge is at fault or the Torque app. Or both. I'm tempted to pickup a cheap Android handset/tablet and get a bluetooth OBDII dongle and play with Torque.

 

at that point, is the distance traveled added to HV or EV ?

 

Ooooooh, good question. I'll have to try to setup an experiment to test that...

 

According to the spreadsheet that I think you and I are referring to, I am using State of Charge. Not minimum state of charge. And no my vehicle is still in EV mode. It is segmented and I am creeping along at 20 mph.

The prius looks at what are the battery demands. If you are pulling too many watts it will switch to HV much sooner.

 

Pretty sure EV miles are only counted when you're in EV mode and the EV car is showing. EV-boost, engine running with no gas in EV, as well as golf cart mode in HV all don't count.

 

I'm well aware of how the system works. But it's important to make a distinction between EV abilities available in HV mode (aka stealth mode), and true EV mode. True EV mode is when you have the green EV light on the dash, and the HSI screen shows a single icon of a car with the letters EV in it. HV mode is when the green EV light goes out, the HSI screen changes to show two icons, one with a smaller outline of a car that may or not have the EV letters, and the other with the letters ECO in it.

For me, the Scan Gauge shows that the SOC is 23.1% when it switches from true EV mode to HV mode. I can use EV capabilities at this point all the way down to SOC of 18% if I'm light footed enough, at which point the ICE comes on. I'm still in HV mode even though I'm using EV capabilities. That's the point I'm trying to make. It sounds like you are stating that you can be in HV mode, but use EV capabilities all the way down to 14.3% before the ICE is forced to come on.

 

Looks like it's added to the HV miles. I did a couple of loops around the campus. 2 miles, totally flat, no ICE usage, about 25 MPH. EV miles stayed the same, HV miles went up.

 

Ayup as I confirmed at lunch today. EV miles only counted if in EV mode with the EV car showing. Anything else, even if it's stealth EV in HV mode, gets added the HV column.

 

That creates a bit of a challenge for computing the EV only kWh/100 miles.

 

No, not really. Once you are in HV mode all your energy is coming from gas. Yes, the battery level goes up and down a bit, but the car tends to want it to even out. It will use a little, then charge a little. Every time you use a little (i.e. stealth mode) you don't really want it counting towards EV miles...not really an accurate accounting.

Mike

 

14.3 was a typo. Sorry. 24.3% soc is the minimum before ICE kicks on (HV mode). I have never taken the soc lower than 20% in HV mode.

And devprius, you are right, you can sometimes nurse it down to 23.1% soc before the switchover, but you have to be driving very slow.

 

I think you might have a E where F should be in your MTH function in the Scan Gauge's X-gauge programming for SoC. That might explain our different readings.

 

I finally had the time to measure the actual charging losses at 240V and 120V:

At 240V, the charging loss is approximately 16% to 17%. I measured 2.3 kW being drawn from the wall (well, seen at my utility's smart meter). The PiP's MID indicated that 1.9 kW was flowing into the battery. The Scan Gauge showed 9.3 Amps flowing into the battery. 9.3 * 207 (nominal voltage of the battery pack) equals 1925 watts which closely matches what the MID said. 1925 / 2300 = 0.83695652. Call it 0.837 or about 16.3%.

At 120V, the charging loss is a whopping 30% to 33%. I measured 12.67 amps from the wall (via a clamp-on ammeter), and 121 volts. This is 1533 kW. The MID said 1.0 kW was flowing into the battery, and the Scan Gauge showed 4.9 amps * 207 volts for 1014 watts, which again closes matches what the MID said. 1014 / 1533 = 0.66144814. Call it 0.661. or about 33.9%. Even if if the ammeter was off by 5% and the actual amps were just 12, 12 * 121 = 1452 watts. 1014 / 1452 = 0.69834711. Call it 0.698 or about 30.1%. Still rather large. Ouch.

SoC was around 28% when I started this experiment. The numbers could be different when the battery is starting to get full (at the end of the charging cycle). I'll try to setup that experiment later this week.

This should make it a little easier to measure how usable kWh we can get out of the pack.

 

^^^
The above losses aren't that far off from what people said about the Leaf at 240 vs 120 volts at My Nissan Leaf Forum • View topic - "typical" Miles/KWh figures for a couple scenarios?.

 

Your measurements are far off from the methodology I used...I measured total kWh input and compared to total kwh the EV ratio screen reports consumed. I found a 9% difference.

If in fact the losses were closer to 30% then when I charged with 3 kwh the battery only got 2.1 kwh and if I drove 14 miles that would mean about 150 wh per mile. Something just doesn't seem right.

Mike

 

With the PiP "On" during this actively monitored charging session, you may be adding another 200-300W load to the picture that would not normally be there in an unattended charging session.

 

Correct calculations. I've charged at many chargepoint locations, and their iphone app tells you how many kWs are being pulled from the station. It's usually 2.2 or 2.3 kW and as you stated the car only displays 1.9kW.

 

I wouldn't trust the EV/HV ratio screen to give you an accurate picture of the kWh consumed. We already know that the display truncates values. I.e 3 kWh display might mean 3.1 kWh, or it could mean 3.9 kWh.