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NutmegCT

NutmegCT

Great Pumpkin
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So let's say you go out and get a GM Volt (or similar plug-in electric vehicle). As you'll drive *at the most* just 40mi/day (just for local trips, shopping, etc.), you won't likely use the 1300cc gas engine much, if at all.

Of course, you're saving $$$ because you're not buying gasoline. But you still plan to recharge the battery at home, from your residential electricity provider.

How do you figure the KWH needed to recharge the battery system? Here's a quote from the GM-Volt website:

<span style="font-style: italic">The Volt can drive for 40 miles on a single full electric charge of its battery pack. It is a known fact that the battery pack will be allowed to drain down from 80% to 30% before the gas-generator kicks in. Since the battery pack holds 16 KWH of energy, that means 8 KWH will get you 40 miles.</span>

https://gm-volt.com/chevy-volt-reasons-for-use-and-cost-of-operation/

I don't understand the reasoning for using 8 KWH instead of 16 KWH. But to figure "average" recharge cost, do you just take the 8KWH times your local KWH charge?

Here in Connecticut, we pay 20 cents/kwh. So a Volt recharge would be 8 times 20 cents, or just $1.60? And if it's recharged maybe twice a week (8 times a month), that's a monthly "fuel cost" of only $12.80?

Obviously, other costs include initial purchase, maintenance, insurance, etc. That applies to any new car. But the "fuel" cost seems very inexpensive - almost too good to be true.

And you know what that means ...

What am I missing?

Thanks.
Tom
PS - if there's another BCF topic area that's more appropriate for this post, just let me know and I'll move it.
 
I think the "fuel" costs <span style="text-decoration: underline">are</span> that cheap, but only in a narrow set of circumstances (although those circumstance fit my commute perfectly).
If you live in Wyoming or have a long highway commute, this car won't work for you.

The <span style="font-style: italic">kicker</span> is that the car will cost $40,000. You could get a Chevy Cobalt for under $15,000 and could do the same driving more cheaply for for 3 or 4 years, even factoring in the extra gas cost.

I am not sure about the battery life on the Volt but I think it is about 7 years. Other than that, the drivetrain needs very little maintenance compared to a piston engine (which, after 7 years, might need a cam belt, filters, a number of oil changes, etc).

So it might be possible that the Volt will be better in the long run <span style="text-decoration: underline">if</span> you keep it for a fairly long time (say, 7 years) and use it <span style="font-style: italic">only</span> inside of that narrow "operating window" where it is most efficient.

I watch the Chevy Volt team talk about all of this on Facebook. It's pretty interesting.
 
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]<span style="font-style: italic">The Volt can drive for 40 miles on a single full electric charge of its battery pack. It is a known fact that the battery pack will be allowed to drain down from 80% to 30% before the gas-generator kicks in. Since the battery pack holds 16 KWH of energy, that means 8 KWH will get you 40 miles.</span>

I don't understand the reasoning for using 8 KWH instead of 16 KWH.[/QUOTE]

The full charge is 16KWH. They say it will use 80% to 30% of that before the generator starts. It seems they take the mid-point of that (80+30/2 = 50%) to get the 8KWH (50% 0f 16KWH) that's the estimate of the power that's been used to drive the 40 miles.

I'd doubt that simply multiplying what you're charged for electricity by the amount the car uses is appropriate.

There will be losses in the charging process so that you'll almost certainly need more KWH input to get the battery up to its full charge.

You should be able to get them to estimate how much input KWH is needed to charge the battery.
 
Gentlemen - very good points.

I think that even if the Volt were to be available at $30K, it wouldn't make economic sense for the individual buyer.

That Volt webpage actually does calculate the dollar costs for recharging, altho' the averages they use are several years old. I plugged in (no pun intended ...) my own kwh cost and still found the "fuel" charges quite low.

I agree with Nial on the possible long-term benefit of the Volt type car. However, one other aspect of course is the warranty and/or life of that massive battery unit itself. If it has to be replaced in 7 years (or whatever), it's going to cost a bit more than replacing your run-of-the-mill DieHard Gold.

Onward through the fog!
Tom
 
I've wondered as well if you need to be in a primarily warm climate as well. For example, even if you have a short commute, does the range hold up if you're parked at work all day and it's 10 degrees out, or if you don't have garage space and it sits out all night. Since batteries tend not to react well to extended cold exposure might you be always running on the gas generator.
 
Big Dodge 5.9LV8....Mercedes 380V8, my favorite 2 get out & go cars!!

.....& I'm building a Corvette: 5.7L TPI V8 for a daily driver!
 
Seems the comments on electric vehicle and cold weather are all over the map.

To be expected, some EV owners are defensive of their vehicle's ability to function "in the cold". Myself I don't doubt the functioning ... just the battery life.

https://www.econogics.com/ev/evcold.htm

On the other hand, many folks report that, while their car does still run, the battery life is quite reduced in the cold.

https://gm-volt.com/2009/12/28/mini-e-electric-car-performance-in-cold-and-ice-is-not-good/

I'd imagine however that there are many factors at play (aren't there always ...). In cold weather the battery itself will be "weak", but an external battery heater could improve that issue. But in cold weather we tend to use things like heaters, wipers, etc.; unless the heater has a separate power source I can see cold weather simply causing increased "draw" on the battery.

Seems that for several reasons, having an ICE (internal combustion engine) onboard to charge the battery when needed, will be a necessity. If you're stuck in traffic on a cold day, you turn off EV, but the battery continues to go downhill due to temperature. Not the same in a gas car. As Nial said earlier, why not just get an economical gas engine car in the first place.

Tom
 
NutmegCT said:
How do you figure the KWH needed to recharge the battery system? Here's a quote from the GM-Volt website:

<span style="font-style: italic">The Volt can drive for 40 miles on a single full electric charge of its battery pack. It is a known fact that the battery pack will be allowed to drain down from 80% to 30% before the gas-generator kicks in. Since the battery pack holds 16 KWH of energy, that means 8 KWH will get you 40 miles.</span>

https://gm-volt.com/chevy-volt-reasons-for-use-and-cost-of-operation/

I don't understand the reasoning for using 8 KWH instead of 16 KWH. But to figure "average" recharge cost, do you just take the 8KWH times your local KWH charge?
Click to expand...
The 16 kwh capacity is for a full charge to zero on the battery. The 8 kwh is the practical limit for the system, and therefore the <span style="font-style: italic">de facto</span> "zero charge" state.

Hybrids and electric cars don't use the full capacity of their batteries either to 100% <span style="text-decoration: underline">or</span> 0%. To do so would drastically reduce battery life, as anyone who's ever re-charged a 24V toy car can tell you. The key to making an electric drivetrain feasible is to make the battery pack an essentially permanent part of the car, and all such cars a programmed accordingly. I've been driving a Prius now for almost 5 years, and their batteries <span style="text-decoration: underline">ARE</span> permanent. Replacing one that hasn't been physically damaged in a wreck almost never happens. You're easily more likely to need to replace your engine block.

The cold weather definitely effects battery output, however. The Prius ECM is programmed to run the engine much differently (more) in cold weather, with a resulting loss of about 10 mpg for me here in Ohio. However going from 45 to 35 mpg in a mid-size car for 1/2 the year isn't exactly a burden! :cooler:
 
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