Most batteries are warranted for 8 years and 100,000 miles. 14 states mandate a 10 year 150,000 mile warranty.
The Chevy Volt limits the State of Charge of its battery not to exceed 80% and not to go lower than 20%. This significantly increases the life of the battery, expected to be many thousands of charge cycles.
I'm a private pilot. There's never any range anxiety...the ground is always less than 2 miles away in most light aircraft, and less than 8 miles in airliners! Better yet, fuel is not required to reach the ground! :)
@ck_02: All the accessories turned on at once is a fraction of what the traction motor draws. An A/C compressor motor might draw 3kW, the drive motor could be 50kW or more. Accessories can certainly impact range but if you work it out over any given trip they're only a minor percentage of overall draw. 10% difference in range would be a fair estimate unless you sit in the car for hours and hours at a time not going very far.
@ck_02: Traffic jams really aren't a problem. If you're not moving, you're not drawing (much) current. Going slowly actually increases your range. If the jam doesn't involve having to go any extra distance you're OK.
........ just make sure you don't have the radio, headlights, heat, defroster or air conditioning on, and resist the urge to find an escape route that would take you out of your way.
@patb2009 I don't think current alternative fuels have that much of an issue for "range anxiety". For instance, a 20 lb. propane tank can deliver approximately 250 miles. CNG or LNG are around 200-250 miles from what I've seen. Diesel is readily available at most current gas stations. I'm thinking an adapter or "pump" at home to fill LNG/CNG would be relatively viable and most towns (at least in my area) have abundances of NG available so to purchase for vehicles seems easy enough. Heck, the excess is currently being burned off as it is. (Wasteful, IMHO). Propane tanks can be exchanged all over town for around $20 or less. I think availabilty for using an alternative fuel is easily more readily found than current opportunities for "refueling" or replacing energy in an EV for the time being.
In addition to efficiency, what about battery capacity over time? The capacity of all the re-chargable batteries in my electronic devices decreases over time. That brand new laptop may run for 4 hours intially but after a couple years it only lasts for 2 hours. Has anyone ever evaluated the EV battery capacity over time? How much range is lost after a year of driving 30 miles five times a week in an EV with an intial range of 40 miles?
What about charge cycles? The example above would be equivalent to about 200 full charge cycles. How many charge cycles are expected out of these batteries? My electronic devices are reported as having about 1000 charge cycles and in my experience the capacity is only half of what it was when it was new. A twenty mile range after five years of use would be rather dismal.
I haven't really researched EV battery technology so pardon my ignorance. The higher initial price and range are way too far off for my needs so EV's aren't even on my radar.
In many engineering workplaces, there’s a generational conflict between recent engineering graduates and older, more experienced engineers. However, a recent study published in the psychology journal Cognition suggests that both may have something to learn from another group: 4 year olds.
Conventional wisdom holds that MIT, Cal Tech, and Stanford are three of the country’s best undergraduate engineering schools. Unfortunately, when conventional wisdom visits the topic of best engineering schools, it too often leaves out some of the most distinguished programs that don’t happen to offer PhD-level degrees.
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