PHEV vs. EV

For $50000 buy a new RAV4ev that goes 100 miles or wait until a purpose built EV with acceptable range is affordable. On a long trip the extra batteries in the PHEV are dead weight once they discharge. I believe the PHEV conversion market will continue even after they are offered by the manufacturers.

 

[Bold added] You have a point there. I don't make many cross-country trips, or even trips longer than 60-80 miles at a time. The few times I do, I should be able to remove the battery pack in a reasonable time, cap the wires, and drive as a standard hybrid.

 

From what I've read, unless you're in the Pacific Northwest, which has a lot of hydroelectric, you're putting out as much pollution with an EV (from the power plant) as you are from a Prius.

"Clean Coal" is relative to "Dirty Coal". If your main concern is pollution, I'd suggest getting real numbers -- there are a few threads in these forums that have mentioned numbers in the past -- and look closely. Until solar/wind/wave/etc are widespread, you may well not be reducing pollution at all, and you'll lose the flexibility of a hybrid over an EV.

 

Converting Prius to pure EV would be silly, a complete waste of the expensive hybrid parts. If you want an EV, sell the Prius and buy a new purpose-made EV, or buy a used Bug or Geo and have that converted. That way someone else will buy your used Prius and it will replace something with poorer fuel efficiency.

The specific question about CO2 is, how much coal does your electric utility use? If it's more than about 50% then an EV will create more CO2 than does a Prius. If you have the choice of getting 100% renewable electricity that would be far and away the most effective pollution reduction measure you can take even if you don't get an EV or a PHEV. If you're stuck with 85% coal electricity then you should keep the Prius as it is *without* a plug-in conversion, and *not* get an EV.

 

Talking about carrying dead weight and PHEV batteries.
In my last trip to Madison, Wisconsin for Hybridfest 2007 I covered a little over 2000 miles round trip, full PHEV with 3 extra TOYOTA NiMH packs plus all the amenities of a trip for 2 people (my wife and I) for 7 days plus a show tent and a 36" LCD for technology presentations during the event, the vehicle was full and heavy.
I recharged my PHEV Prius 15 times (thanks to rest stops and service stations courtesy) in this round trip, 2.5 to 3hs recharge time each time and made an averaged 82MPG in the total trip from Long Island,NY to Madison, WY.
Let me tell you that there is not a dead weight in a PHEV if you know how to take advantage of what you have.
By the way, I won the BEST car in Show at Hybridfest 2007 for technology and appearance

 

I got interested in the Prius when I was thinking about making an EV conversion. I ran into several problems, that the Prius solves. One major one is the regen/braking operation. The Prius solution is elegant. Another is AC, only the hybrids have electric AC. Power steering can be another problem, not many cars have electric power steering, or you can find a few cars without power steering. The Prius came up as the best solution. Then I thought about removing the ICE, and putting in another electric motor, (MG3). Then I thought about all the headaches of making the computer think the new MG3 was the ICE. Then I got the idea of leaving in the ICE and adding rear wheel drive with MG3 (and MG4?) with a seperate power system, and some kind of servo, so the Prius mostly thinks it is going slightly down hill when being pushed by the rear wheels. This gets around all the sillyness of having to turn off the car to go from pure EV mode to normal mode, plus I would have the fastest Prius ever! Thats having your cake and eating it! Of course, when the batteries SOC gets too low, I can always continue driving as a normal Prius seamlessly.

 

an EV only option only works if you can afford to have another car for longer trips. until i got my 2010, we had an EV that only did very short range trips (30 miles tops and with lead acid batts it was recommended to not discharge below 40% on a regular basis, so effective range was actually around 15 miles) mostly commuting to work 7 miles one way. i do plug in at work, so i run on the top of the pack only.

until we have companies like Better Place putting out public charging stations, neither plug ins or EV's will do much. now with 100 mile EV's on the horizon, that will make a greater market, but only for people who have the extra money to run two cars. as it stands, without being able to plug in away from home and not being able to double your range, it will simply not work financially for many people.

now, plug in kits are becoming more popular and competition, better charge storage options, and just better knowledge, period will make that option more affordable.

 

I have the Hymotion conversion. PHEV is very good for people who mostly drive around town. In that case, you can substitute electricity for gas for a large portion of your transport.

For an EV conversion at just $7K or $8K, you'd better ask if you're getting lead-acid batteries. If so, a) they are heavy, and b) you'll replace them every few (say 3) years, at fairly substantial cost, if you use the car regularly. Over a vehicle lifetime, that's going to be a pretty substantial cost in money and natural resources.

Here in Virginia, with about 50% coal-fired generation, my fairly exact calculation is that the electric miles in the PHEV reduce C02 emissions by just 30% relative to standard (gas-powered) miles in the Prius. That's based on 4 miles per KWH, 46 miles per gallon gasoline, charging off the grid, where Va Power generates an average of about 1.2 lbs of C02 per KWH. It's not even completely clear that I'm getting 4 miles per KWH, but that's what the US National Labs tests showed as average. One user here measured it and was getting just about 3 miles per KWH, but apparently had a rather tough commute.

FYI, in Utah, it's 1.9 2 lbs C02/kwh. See here:
http://tonto.eia.doe.gov/ftproot/environment/e-supdoc-u.pdf

So, by my calculation, electric miles in my PHEV Prius would actually raise C02 emissions (slightly) if I were charging off the Utah grid.

The plain old gas-powered Gen II Prius sets a pretty high standard of efficiency. You'll see a lot of literature on efficiency of EVs that uses (e.g.) the US average vehicle as the comparison. OK, compared to 21 MPG, yes, electric looks good. Compared to 46, in some areas (like Virginia) it's a modest improvement, in coal-intensive areas, it probably is no improvement at all, relative to driving a standard gas Prius.

When we bought the Hymotion kit, we were able to buy power from a wind farm. It was the last big step in a fairly intensive attempt to reduce carbon footprint. (And, truth be told, both my wife and I thought it would be just basically pretty cool.) But that clean power option has since ceased in Virginia, and we are back to charging it from VA Power's standard generating sources.

When all is said and done: At Utah's C02/KWH, it's not clear you are even coming ahead by substituting a Prius-sized EV for a Prius. At least, not if the performance of the current generation of PHEV Prii is a guide. And if you upsize it - get an electric SUV -- that just makes it that much worse. I'm pretty sure that the Cal Edison tests of the RAV4-EVs showed about 3 miles per KWH.

The upshot is that if you want to spend money to reduce your carbon footprint, you can get much better bang-for-the-buck elsewhere. At least if you charge off a grid that uses a lot of coal. And if you're in a really coal-intensive area, it's possible you're spending money to raise your carbon footprint.


Edit: I should have read Richard Schumachers' comment first. He got to the point in a lot fewer words than I used. I'd guess closer to 75% coal for C02 break-even but that's a quibble.

 

the ePrius is real, No engine, top speed 52mph. cost 10k plus battery.
for example a 5k dollar Pack will go about 15 miles and last 3500 cycles.
Plug In Hybrid Electric Vehicle PHEV

 

I agree with the others in the fact that converting from a petrol powered car (prius) to a coal / petrol hybrid (PHEV prius) is not often environmentally sound. It is certainly sound from an energy independence stand point though.

For what it's worth I have a spreadsheet that calculates MPGe based on the numbers that Google.org came up with. I've checked their work and it's very sound. I actually think the 50% coal cut off is a bit optimistic. I found that most states have a very narrow margin if any in the comparison.

I'll try to attach the spreadsheet, but it was intended for and mentions another forum. If that's a PC policy flag, feel free to axe the post.

Personally I'm more for energy-independence than clean air, so I'd to the conversion if money were no object.

11011011

 

Add me to the list of people that decided on a Prius after researching BEV conversion options.

Some people call PHEVs a temporary solution, or stepping stone as if that is a bad thing. I think they are a critical step on the road to BEVs. In my opinion we have been caught in a paradox since interest in BEVs renewed in the late 60s/early70s.

1. Batteries are too expensive to build BEVs with the range and reliability to get buyers attention.
2. Batteries could easily be built cheaply enough to do so, if they were being produced in large quantities.
3. Batteries won't be produced in large enough quantities to drive down costs until there is significant demand.
4. Return to 1 and repeat.

I think the progression from HEVs to PHEVs to BEVs provides us with a serious opportunity to break the cycle. It allows for gradual shift from gas to electric, rather than the existing all or nothing problem. Starting with HEVs, gas use is cut between 1/3 and 1/2, with fairly small batteries at a reasonable cost. This provides financial motivation for battery research and production cost reduction, bringing the cost of batteries down. This reduction in battery cost makes short range PHEVs financially feasible, cutting fuel use in half yet again. The cycle of cost reduction continues, making long range PHEVs and short range BEVs cost competitive and so on.

I spent about a year researching and designing a BEV conversion of a standard car, before coming to the conclusion that it just wasn't practical for me. For about $6-8k (DC, lead acid) I could have gotten about 40 mile range and a max speed of 80mph or so (with reduced range), but would require a great deal of tinkering, maintenance and upkeep, as well as recurring battery replacement costs. In an ideal world I really would have like to do it anyway, but I just couldn't justify the cost and effort given how poorly it would match our young family's needs. At that point we bought a salvaged Prius to eventually be converted to PHEV. A year or so later, we decided that replacing our second car with another Prius would be a bigger bang for the buck than a PHEV conversion on the first one. Hopefully in another year or two I'll be able to do our first PHEV conversion.

Rob

 

I would highly encourage anyone considering PHEV or BEV to look at adding solar. For example, here is the situation here in AZ:

Mile per Year: 7300 (PHEV 20 *365 days)
Annual E consumption: 1825 kWh AC (250 AC Wh/mi assumed)
Required Solar Capacity: 1.14 DC kW (AZ ~1600kWh/yr per DC rated kW)
Upfront Solar Cost: $7,984 (assumed $7/DC Watt installed)
Util Rebate: -$3,422
State Tax Credit: -$1,000
Federal Tax Credit: -$2,395
Net Solar Cost: $1,167
Lifetime Energy Production: 36,500 kWh
Net Cost per kWh: $0.032
Net Cost per mile: $0.008

Equiv Gas cost per mile: $0.07 (46mpg, $2.63 to start, increasing 2% per year)
Equiv Grid cost per mile: $0.028 (9c/kWh to start, increasing 2% per year)

Even if you roll the system into your mortgage, roughly doubling its cost but making the upfront cost zero its still much cheaper than gas, and competitive against dirtier grid power.

Rob

 

I couldn't agree more that PHEV's are an important step on the road to BEV's, and I sincerely hope that you can realize your dream soon.

As you know from reading my thread about our BMS+ PHEV http://priuschat.com/forums/prius-p...1-one-year-driving-our-bms-plug-in-prius.html, I am a fan of Norm's system of multiple salvage Prius battery packs. There are certainly difficulties in implementing a safe charging method, but the payoff is a battery system with 1/3 the internal resistance and 1/3 the input/output load per pack of a stock battery (or 1/4 if you use 3 add-on packs plus the original).

Plus, the actual cash outlay can be kept about as low as possible with any PHEV conversion (roughly the same as the Enginer system that everyone seems so excited about), around $2200 total (I did save a lot by building my own charger).

Although I end up doing most of the actual "plugging in" ( I still watch it like a hawk while it's charging), our whole family loves the car--my wife drives it whenever she can, our teenage son also likes to use it as much as possible (it must have a certain "cool" factor going for it), and our 10-year old helped me design the charger and comparator circuits. An important factor in our enjoyment is how well the PHEV capacity fits our driving situation (mild climate, short distances, and fairly light local traffic).

Thanks for all the knowledge you have added to the PHEV community over the years.

NW BMS+ Driver

 

Perhaps a little off topic... But, I highly recommend solar panels as a source of clean energy. I have a 3KW system installed in a grid-tied configuration (no battery bank). While not independent from the grid, this config allows me to sell power to the utility.
Perhaps in future, a V2G capable PHEV conversion, will make it possible to use my car as the battery bank to supply power even during a grid outage.

 

Unfortunately, I can not say for sure since costs can vary greatly from region to region and fluctuate over time. Some regions offer some great discounts, incentives and rebates. It can often cost ~$10/Watt. So a 3KW might cost about $30K minus whatever incentives you might be able to get. If you do it yourself, instead of hiring a contractor, you would probably be able to do it cheaper. But you will probably still need some assistance from an electrician at some point, especially if you go grid-tied.

You might want to do a search for "solar rebates" or "solar incentive" for your region to get some idea. Or check sites like "Database of State Incentives..." DSIRE: DSIRE Home .

 

Since it seems more people might be interested, here is some info I was sharing with a few folks over PM regarding solar costs:

Smallish systems can be a challenge, as a lot of installers charge a premium for smaller systems. For example, here is a turnkey installer here in Phoenix:

http://www.americanpv.com/pdf/res_on/prices.pdf

Their 6.3kW system is $6.07/W installed before incentives, but their 2.34kW is $7.70/W. From what I've seen with small setups in particular your best bet is probably to find an internet seller who sells complete kits, and then DIY as much as you can and pay an electrician to do the hookup. From folks I've talked to this can be as cheap as $3-500. As I understand the system needs to be "professionally installed" to qualify for all the credits and rebates, but as long as the electrician does the final inspection and hookup you are ok. Here is a site that seems to usually have good deals on kits:

Residential Grid Tie Kits

Their 1.6kW kit is $7,685, or $4.80/W. Their 1.8kW expandable kit is $6.13, but has an oversized inverter so you can add panels later to expand up to 5.4kW. Under "panels by the pallet" they have additional panels as cheap as ~$3/W in quantities of 20-30 or so. Here in AZ the $7,685 1.6kW kit should be under $1000 after incentives (30% federal tax credit, $1000 state tax credit, $3/W util rebate up to 50% total cost). Obviously incentives vary considerably state to state so you'd need to heck the dsire website to see what your states deal is. Also the numbers I posted assume you are using a grid tied system and have net metering. To get a good idea of how much output you can expect from your system in your area, the site below is really handy:
PVWATTS v. 1

We're trying to get our house ready to sell, we'll see how it goes. If we can get it sold, we're hoping to do an Energy Efficient Mortgage on our next house to pay for solar (and maybe geothermal cooling), and then do a PHEV conversion on one or both of our Priuses.

Rob