mgroves

Some enterprising guys have invented this EDrive thing, which is a simple technology that allows you to charge up your Prius at home instead of just being limited to Synergy charging while in operation. They say you can get 100mpg with a hacked Prius, for a mere $12,500 more (dropping to $6500 soon, I guess).

So, 100mpg seems like quite a lot, but I think the cost alone of the modification negates any economic benefit of 100mpg. Certainly any environmental benefit would be negated because that electricity comes from evil corporations burning fossil fuels anyway. So, let’s look at the cost over, say 20 years or so. Well past the normal lifetime of a typical car. How does the Hacked Prius stack up to the Prius and other similar sized cars?

Recall these calculations from Sithlet:

2006 Honda Civic Hyrbid : MSRP $21,850. From Honda’s site.
Also potential tax savings if you buy a hybrid.
This is versus $14360-$18260 for a Civic Coupe or $14560-$18260 for for a Civic Sedan.
Then, you’ve got 49/51 MPG for the Hybrid, 30/38 MPG for the Coupe or Sedan.

At $2.10 per gallon (~current prices), this means you’ll need to get about 2638 gallons worth of savings. The average ratio of MPG for Hybrid MPG : non-Hybrid MPG is 1.4877… so you’re basically getting an “extra” half gallon per gallon you use. So you’d need to use ~5250 gallons to get your money back.

The tank holds 12 gallons, so 439 fill-ups — I guess it really depends on your car and how bad gas prices get, but that seems like a lot to me! Even once a week, that’s 7 or 8 years. With gas prices normally rising, I suppose that would go down some — but that’s still a while to break even on your investment.

I thought I could take these impressive calculations, and expound on them with a full analysis to determine whether the Hacked Prius was a good buy, and how a regular Prius stacks up to similar cars. I cobbled together a quick Excel sheet with the following assumptions:

• I compared the Priuses to 3 cars: Honda Civic, Toyota Corolla, Hyundai Accent. All cars are similarly sized and have pretty decent gas mileage of their own. I tried my best to compare apples-to-apples; no Hummers or cement trucks here. Sithlet’s comparison of the Civic to the Civic Hybrid was very good, but I want to evaluate the Hacked Prius, and there is no Non-Hybrid Prius.
• MSRPs from the vendor’s websites. I tried to be conservative with my pricing. I went with prices toward the ceiling for the non-hybrids, and floor prices for the hybrids.
• Fuel economy from HybridCars.com. I don’t know if this is highway or what, but that’s the number I’ll be using.
• 13000 miles of driving per year.
• Gas price of $2.819, which is what it is right now in my zip code according to GasBuddy.com
• Hack kit cost of $6500, and 100mph fuel economy for the hacked Prius
• $0 in electricity usage for the hacked Prius (maybe you’ve already bought a bunch of solar panels or you can just steal from your neighbor)
• Gas price stays at $2.819 for the next 20 years (this makes it simpler to calculate).
• No maintenance costs or anything like that–let’s assume they are the same for each car, though I have no idea if that’s a fair assumption one way or the other.
• Tax break for the Prius is $2000. I think this is accurate.

Please feel free to download my Excel sheet and play with my assumptions. I’ve made it as dynamic as possible so all you have to do is plug in your own numbers.

You can see on the graph below that the Hacked Prius just about (but not quite) converges with the normal Prius at the 20 year mark. Add in electricity costs, and the Hacked Prius is a terrible idea–even from a purely environmentalist-hippy standpoint (unless you have solar panels all over your roof and the roofs of places you go to).

Also note that with gas prices at $2.819 (up from $2.10 in Sithlet’s calculations), the Prius breaks even with regular cars at about 4 years of ownership. Just for fun, get the Excel sheet and see what happens if gas went up to $10, or see what happens if you drive 26000 miles a year.

If one were to assume that gas prices are going to go up, the Prius is certainly a good buy, but only because of the tax break from the government. Without that break, the Prius wouldn’t break even with other cars until around 7 or 8 years of ownership. Is this a good thing? I’ve always been in favor of just about every tax break ever conceived, but in this case, the tax break might act as some sort of innovation stifling crutch. Toyota only has to be X-$2000 good, not X good.

Anyway, Hacked Prius conclusion: bad idea. The up-front cost vastly overpowers the gas savings.

And then there’s this: Hummers consume less energy from start to finish than hybrids. Certainly they will cost you, the driver more than a hybrid (or other low-cost car) to own and operate, but if one is basing their decision on pollution, energy consumption and what not, the Hummer may be a good choice. Something to think about.