False economy

[2000mc]

Originally Posted by RedDevil

A gallon of gas may deliver 33.7 kWh worth of energy, but most of that is transferred to heat and goes out of the tailpipe. More heat is lost through the radiator.
So only about 8 kWh is available to power the alternator belt - assuming 75% efficiency in that; only 6 kWh of electricity can be had from that gallon.

If you remove the belt and obtain 6 kWh worth of electricity (over time, at 200/300 W per hour) to power the 12V system from the battery and you lose 50% in charging that, you'd still need just 12 kWh from the mains.
That's a gallon saved for, what's your rate, a dollar and a half at 12.5 cents per kWh?
Well worth it!

So for every gallon of gas a car tries to turn into electricity, it puts out around 3kwh? So you replace buying a gallon of gas with 35 - 40 cents from your outlet. Sounds like it works out pretty well then.
Or saying you need 12kwh? Or more like $1.50/gal break even?

[California98Civic]

Originally Posted by cosmick

You guys trying to go beltless, what you save on fuel you spend on the 110-volt battery charger in your garage. Plus you can't do roadtrips, and if you can't enjoy your car, then why own one? Then again, how can you enjoy anything under 200 HP?
Likewise, you guys trying block heaters, what you save on fuel you spend on 110V in your garage.
If you're using a good synthetic oil, then the block heater doesn't actually help reduce cold start friction.

Aren't you kinda...



... trolling. I love my 106 hp, 17-year-old car.

[RedDevil]

Originally Posted by 2000mc

So for every gallon of gas a car tries to turn into electricity, it puts out around 3kwh? So you replace buying a gallon of gas with 35 - 40 cents from your outlet. Sounds like it works out pretty well then.
Or saying you need 12kwh? Or more like $1.50/gal break even?

I meant the latter. About $1.50 cost of electricity for saving a gallon of gas.

At traditional gasoline engine is about 25% effective in turning gas into mechanical power, max.
Now most of the time it is on partial load, that's less than 25% effective, but I assume the extra load of running the alternator makes the engine work slightly harder, so slightly more efficient; the difference between both may well work out to 25%, a tad over 8 kWh.

The 75% belt and alternator efficiency for turning motion to electricity is a bit on the high side maybe, just to be sure. -> 6 kWh
50% efficiency on charging the battery from the mains is probably way low, again to prevent pro bias on the alternator delete side.
You need 12 kWh from the mains then to get those same 6 kWh of battery power.

The fact stands that charging the battery from the mains rather than the alternator is much cheaper.
Imagine how it works out with our ridiculously high European fuel prices

The OP may have been trolling, never mind we'll turn it into an exercise of getting the math right.
There are lots of reasons why it can be impractical to do an alternator delete, but energy efficiency is not one of them.

[Chrysler kid]

The 2.5 in my fusion has over 200hp im sure but the things still drives like a Buick lesabre.

It's not about horse power it's about being content with what you drive. My 2011 fusion is boring and Un interesting and highly irrelevant when it comes to talking about cars.

My camaro makes 388whp on stock heads ls1. It's fun but not daily driver fun

My civic I can hop in and go anywhere and not worry about scrapes and dents

[Xist]

I enjoy riding my bicycle!

I will keep my 0 HP toilet, thank you very much!

[niky]

I'm still trying to digest this one:

Originally Posted by cosmick

If you're using a good synthetic oil, then the block heater doesn't actually help reduce cold start friction.

Which is sort of like saying: If you use birth control pills, you don't actually need condoms to prevent STDs.

Uh...

[Fat Charlie]

My 250 hp AWD turbo was fun. Great in the snow and the twisties, great at blasting down the straight. Cruising at 70 and want to make a quick pass? No problem!

My 117 hp econobox is fun. Great in the snow and the twisties and goes down the straight just as fast as my old turbo did. How? I commute. Rush hour traffic sucks, and a couple brilliant passes gets me... two car lengths ahead when we get to the next bottleneck. And that only if everything else goes well. Now even in the worst traffic I'm still doing high performance driving.

And that barge that was rudely and dangerously riding my a... courteously filling my wake for me back on the straight? I don't need 250 horses when we get into the hilly curves- he can't keep up with the 117 I do have even though I keep to the same speed.

So by outside performance metrics, it was a move up. I leave home at the same time I always did and get to work at the same time I always did. I still leave people behind in the twisties and pass Jeeps in blizzards. Gas mileage? My worst tank ever, in winter while I was still learning the car and wasn't the driver for half the tank was almost 2 mpg better than my best ever Subaru tank in August under ideal conditions.

You know what the most fun thing about the performance I'm getting is? It's mine. I got it. No 16 year old with the ink still drying on his license can swing by a dealership and come out duplicating my performance because I'm the one turning out these numbers. I bought a pretty efficient car and made a few tweaks to it, but the real numbers come from my driving. That's fun as hell.

[samwichse]

My 1.0L Insight has 66HP on tap (72 incl the electric motor) and will go over 110mph no problem.

Getting caught over 100 gets you "reckless endangerment" here.

It's more than enough car to have fun it (nimble traffic jockey), and gives you the option of something you haven't even considered: challenging yourself to get high MPG is its own fun.


QED

[drainoil]

Originally Posted by niky

I'm still trying to digest this one:



Which is sort of like saying: If you use birth control pills, you don't actually need condoms to prevent STDs.

Uh...

Lol

[Ecky]

I miss my Integra-swapped Del Sol sometimes, but there's a reason I replaced it with my Insight.

If I could have the economy and utility of the Insight in a targa/convertible, and the grip/handling of sticky tires with the economy of LRR tires, I definitely would. Priorities though.