Cost per PIP Charge

I'm pondering your response. I thought I read somewhere there was a constant charge rate but just couldn't find the actual number. Time to call Toyota. LOL I appreciate your feedback.

 

Here are some pictures.

So, I dont remember how far along the charge was when I took this picture, but here's a shot of the Charge Power screen on the MFD. At the time it was at 1.okw. (Edit: I see my MFD clock says 11:21AM. So I probably started charging at 1030AM the day I took this picture.. if I know I'm heading out for lunch, I start charging at 1030 for a bit of EV range).

I'm pretty sure my full charging at 120V is right around 2.5 hours because my commute is the same to and from work daily. I usually set the timer to start at 5:30AM. I usually try to leave the house at 8:10AM (need to drop the kids off at school so its fairly consistent). My car is always fully charged by the time I leave.



Here's a picture of my Kill-A-Watt. I only measured a full charge a few times. But it was usually around 3.2 kWh or so.



Maybe you should carry a Kill-A-Watt in your car. So next time you visit your friend, you can slap it on there and tell him exactly how much juice you used and pay him accordingly. Just be sure to carry a lot of coins.

 

Kewl pictures. Thanks for sharing. It's funny you are showing this because yesterday I purchased my own Kill-a-Watt. Your screen on the Kill-a-Watt is showing accumulative power used. Any idea what the "current" screen says? To achieve the answer I seek all one would have to do is multiply that number times 120 to give the power used. The formula for power is current times voltage. Does anything come to mind?

Cheers

 

Most definitely, when I took that picture of the Kill-A-Watt, it was after a full charge (meaning, the car was done by the time I looked at the Kill-A-Watt).

I have a picture of the K-A-W's current screen, IIRC at the time it said something like 11.8A or so (I have the picture posted here somewhere). Assuming 120V or thereabout, that should mean ~1.4 kw. But I dont remember the details of when I took that picture.

 

Very interesting. It would be cool to see if the current (in amps) changed over time as the charging session proceeded. That is one reason I purchased one. So much to learn. LOL

Cheers

 

Ok, I found one of my old posts discussing this. This may be of use to you.

New PiP Owners...More data please!!! | Page 7 | PriusChat

So I was wrong, that day I took that pic, I must have started charging at 11AM for lunch. It was reading 1.0kw on the Charge Power screen and when I checked the KAW it was reading 0.46kWh cumulative.

 

What is going on in my head right now is trying to figure out the relationship between what you see in the Prius and what you see on the KAW. The "power" screen is showing accumulative data while the "current" screen should be showing instantaneous readings. Not sure what the Prius is saying. accumulative or instantaneous.

 

The car doesn't keep necessarily keep the current (amperage) constant when charging. I've powered the car on at times and it will show 0.5 KW going into the battery, and then at other times it will show 0.9 KW or even 1.1 KW. All at 120V. Which means the current that's pulling from the wall will vary between 5 amps and 12 amps. I have noticed that as the battery approaches full, the amperage it's pulling gets smaller and smaller.

 

The Prius will always show instantaneous readings. A lot of us would like a cumulative reading when it finishes charging. Or a lifetime cumulative reading. Probably buried deep in the car's firmware it keeps track of the lifetime charging, but it's not available to us mere mortals...

 

That is consistent with my post a few back where I said "I recall charging a 12 volt battery which clearly showed high current at the beginning and near zero at the end of the charging." That suddenly makes my theory dead in the water that there is a constant charging rate that can be used to calculate the cost of charging. ARGH. LOL It was at the center of being able to compare the ultimate reason for creating my document which was to compare costs of gas vs electric and be able to show it using a simple formula. Fooey.

 

the other day, i was ready to leave for work, but the car was still charging. i hit the power button and it said ev range: 15.0 and time left to charge: .4h. i'm thinking wow, it must slow waaaaay down near the end if it's going to take 24m to put in another .1-.3 miles. but then, in about 2 minutes, it finished with 15.3 miles.

 

does this kill the 15% theory?

 

Of all the subjects about the Prius, this one fascinates me the most. Being able to understand and utilize battery technology to the most and be able to communicate it to others takes effort. I appreciate all the feedback in this thread. Bisco, have you concluded anything from that experience you just shared?

 

not positively, but i think it's why the engineer's can't put a kwh or battery capacity display in the car. it's not like gallons of gas, they really have no idea exactly how much 'fuel' the battery holds. and so i just think these computer estimates are a best guess scenario.

 

i know one thing, compared to my home a/c, the pip is a drop in the bucket on my electric bill. 3 days of high 90's last week cost me 145kw!

 

If you want to see some serious electrical usage, the new Tesla Model S has an 85KW pack, of course most won't be fully charging it every day, as that's about 265 miles of range. That's about 3 miles per KW... Not nearly as good as we are doing in the PiP, where most of us get 12-15 miles on about 3KW of pack (we are in the 4 or more miles per KW). Of course the Model S is a much larger, heavier car. A full charge on a Tesla in my area at .15 per KWH is about $12.75, not too bad for 265 miles... Even a Prius would get 3.7 gallons of gas (at $3.45/gallon), that would get a Prius about 185 miles (at 50 MPG). The point of this exercise? You don't buy a Model S to save lots of money on gasoline, at least not at current gas prices. There are other, more compelling reasons, such as not sending money to countries that want to kill us, etc.

BTW, a Model S can charge at 31 miles per hour on a 50A 240V outlet, or if you get the dual 10KW chargers, 62 miles per hour of charge on a 100A fed Tesla HPC EVSE. Your fully depleted 85KW pack could be charged in a little over 4 hours.

 

Holy cow Batman. How long is that charging cable? (giggle) 31 miles per hour and still charges. I'm totally impressed. Sorry, had to give ya a hard time. It's all good.

 

A better question is how thick; the 50A version uses #8 conductors, the 100A HPV EVSE uses #6 conductors, there are (3) conductors of that size in the cable (2 120V hots and the ground), and then. 2 18AWG wires for the Pilot and Proximity signals.

 

Any of you who saw what I wrote earlier that a friend refused to let me charge my new pip did have the last word. My wife and I took him to a restaurant. When we arrived he pulled a 9 volt battery recharger from his pocket and said "did you need a charge?" LOL