Cost of electricity in CA for Prius plug in

Great! Even less money for the charge.

Nexus 7 ? 2

 

It only takes 2.5 hours to charge at 120V and the last 10 minutes is at half power.

 

2 hours and 34 minutes here usually, and yes the last ten minutes is at half power

 

and the PIP charger in the car (not the brick) checks battery levels eight times during the charging process. (it does this by dropping the current to zero for 4 seconds)

 

Here in Alameda, CA, the electricity company pays me about $3/month to charge my Prius every day.

Really. The electric co is a small municipal utility, and they don't have time-of-day metering technology. In return for pledging to charge only off-peak and weekends, they give EV owners a $15 monthly credit, which works out to a positive for me if I stay in Tier II. The program was designed with electricity suckers like Leaf and Tesla in mind, but they include PiP, at least for now.

 

Charging is not full power the whole time.

 

So the book is stating worst case scenario?

Nexus 7 ? 2

 

I am not sure what the book is stating. But a charger will run at full current for some of its charging time, but not all. For example it is likely to charge at 20% current for the last 10% or so of the battery capacity. It will likely reduce the current if the battery gets too hot. This is done to improve battery life.

 

Check out my charts on "Attention Kill A Watt Nerds" thread. I tracked the current that the PIP draws over the whole time it was charging. The charger drops it's current to zero for seven seconds, Eight times during the charging cycle. The last ten minutes of the charge cycle the current drops to half it's full value.

 

The answer is that it kinda depends. If you are in Tiers 3, 4 or 5 by the end of your billing cycle, then count on about a dollar a full charge. Figure about $20 to $30 added to your monthly bill, depending upon how often your charge. If you are typically only in Tiers 1 or 2 at the end of the cycle, then it'll be about $10 to $15 a month.

 

I don't think that the battery gets too hot during charging, since the power during charging is much lower than the power during driving. I think it actually would take longer to charge in the cold since charging the battery is a chemical process and that process is less active at low temperatures, which would slow down the rate that the battery could be charged.

 

Battery charging is an exothermic reaction. It gives off heat. Batteries do not do well when they get too hot. A good battery charger will thus ensure that that doesn't happen.

 

From Micro Power Li-ion Battery Temperature Trends During Charge and Discharge:

Which means the heat comes from the charging electronics and battery resistance which depends on the charging/discharging power, not the chemical reaction.

 

After a few weeks of plugging in my new Prius at home I went online to PG&E's web site, logged into my account and looked up my 24 hour electricity consumption profile in "cost" mode before and after plugging in. By comparing the two curves it was easy to extrapolate the cost: .52-.54 for a charge. I set the charging timer for 3-6 am for lowest rate.

My situation is that I work on a community college campus that installed solar panels and was the first educational institution in the US that is 100% off the grid. As part of the build-out they installed panels over the staff parking spaces with electrical outlets on every supporting pier. So, I drive to work which is 13 miles from home and usually use up 90% of that morning's charge. I plug into the panels for FREE during the day and then drive home with enough charge to do a couple of errands like shopping, etc. Being able to plug in at work was an important part of my consideration on buying the Prius EV.

That averages out to about 27 cents worth of "fuel" on a 26 mile round trip per day. I purchased my car three months ago and still have half of the original tank of gas that came with the car. I drive my friends and co-workers crazy by telling them that I "roll on sunshine."

BTW: two work colleagues just bought Prius plug-ins after I explained the $4K in subsidy one is entitled to in California.

 

can you supply pic's of the solar panel/staff parking? It sounds interesting!

 

Perhaps you don't understand the difference between "off-grid" versus "grid-tied". I don't know which community college you're talking about, but the cost of going "off grid" is MORE than double the cost of "grid tied". PV can certainly be set up to supply 100% of any building - complex - institution - facility. We supply 100% of our home, and enough to charge - and still have about 10% surplus each year. But the cost of adding batteries to a PV system (for night time use) to run it off grid, and maintaining that huge bank (for a community college) of batteries, and then having to replace them every 4 to 7 years is HUGE and a waste of money that would make your local taxpayers flip out. Off grid is only practical for areas not easily serviced by the utility company.

EDIT:
That made me look up what the 1 time poster was talking about. The school is grid tied. The community college is in the farthest most north eastern corner of CA, namely, Oroville:

That's a blurb about their project found here.
Grading the Grid: America's First Solar-Powered College – ecomagination

.

 

Perhaps they have a genset rather than batteries. Quite a few university campuses have their own electric generation facilities and operate "off-grid".

 

A facility geared to be 'efficient' wouldn't burn gas or diesel all night long. Besides the pollution, there's a huge amount of loss converting gas to generator to inverter/grid quality power. That too would be a phenomenal waste of energy and capitol resources. Read up on the school, you'll see their grid tied. Anyone interested at looking at their PV can simply google the school - then go to Google satellite maps. It's quite a nice size PV farm.

 

PG&E has an interesting "Plug-in Electric Vehicle Calculator" at PEV Calculator. It's interesting in that I found, even with the EV-A rate plan, it will cost me overall more (gasoline plus electric) per month ($5.00) to drive a PIP than a regular Prius. This assumes my current Prius II gets 50 mpg and gasoline costs $4.00/gal and I drive 35 miles/day average; which are my averages now, and charging at the cheapest rate/off-peak hours. The calculator bases calculations off of your current home electrical energy usage and rate plan (without an EV). I don't know how accurate it is, but this was a bit of a shock to me.

 

The EV-A rate is Time Of Use. A simple comparison against your present account usage is a good start at a comparison but the next step would be to look at how much energy usage you could easily shift from expensive peak daytime usage periods to off-peak periods. This is difficult if you live in hot climates and have people at home during the day that need air conditioning. Examples of uses that can often be moved off-peak include pool or hot tub cycles and the dishwasher. Daytime off-peak periods on weekends can also be used for running laundry.