On 6 Mar 2015 at 10:08, paul dove via EV wrote: > Sure they [people who usually drive only 20 mi/day but now and then > need more range] might exist but it's not economical to own that much > battery for occasional use.
Well, now, that depends. If you only use 10% of your battery's capacity per day, you only have to charge every 8 days or so. That battery is likely to last the life of the vehicle, or longer, unless you're using lithium and the calendar-life-over-cycle-life restriction comes into play. That might be an appropriate and economical choice for some people. Let's say (somewhat optimistically) that the vehicle will last 15 years, and you drive 12k miles per year. That's an average of 32 miles oer day, and a total of 180k over the vehicle's life. So, maybe a range of 80-100 miles is plenty. But suppose you buy a bigger battery, with a rated range of 200mi, and you use 80% of it before charging (a good plan for long battery life). Thus most weeks, you'll charge only once every 5.6 days (rounding, every 5 days). You'll thus cycle your battery 1095 times over the life of the vehicle. I don't know enough about lithium to say, and I think it varies with chemistry, but at that point an NiMH battery (existing technology) will probably have used no more than half of its usable cycle life. So you probably do have more battery than you need for your normal vehicle mission. But wait. For one thing, this means you'll probably never have to worry about ponying up the cash for a new battery. That's comparable (in financial disruption even if not in exact cost) to having to replace the engine in your ICEV, something every ICEV owner dreads. I know quite a few people who live paycheck to paycheck, and simply don't have that kind of cash. For them, paying more upfront so they don't have to worry about buying a replacement battery later might be a reasonable choice. For another, what if you need to make a 180+ mile trip now and then? With an absurdly large battery, you have the spare capacity, and again - freedom from worry. If, for example, your daughter at college 90 miles away calls at 1am and says she's just been busted, you can go bail her out right now. (Not that this has actually happened to me, but you never know.) David Roden - Akron, Ohio, USA EVDL Administrator = = = = = = = = = = = = = = = = = = = = = = = = = = = = = EVDL Information: http://www.evdl.org/help/ = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Note: mail sent to "evpost" and "etpost" addresses will not reach me. To send a private message, please obtain my email address from the webpage http://www.evdl.org/help/ . = = = = = = = = = = = = = = = = = = = = = = = = = = = = = _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
