One thing to consider when you downgrade battery capacity while the vehicle's daily mission stays the same: your battery cycle life will decrease, because you'll be using a greater percentage of its capacity each day.
I don't know what salvaged or new Leaf and Volt batteries go for, but IIRC the last time I checked, the best price I found for bare Chinese lithium iron phosphate cells was about $1.25 per amp hour. Thus a 100 amp hour, 3.2v cell would cost $125 plus shipping. A 34 cell, 108v battery would be something over $4200. Meanwhile, a new 108v lead battery will cost between $1400 and $2400, depending on brand, capacity, and your location. Most likely you'll be able to pick it up locally, so you won't have to pay to have it shipped. Since the LiFePo4 battery is apt to last at least 3 times as long as lead, it would seem that you're money ahead with lithium. This is what the several lithium proponents here on the EVDL will argue, quite persuasively, sometimes even rather stridently. But once you've bought your new lithium cells, youi're not done. You still have to pay for: 1. Shipping. This can add hundreds of dollars, and possibly weeks of waiting, to the lithium price. 2. BMS. You have to choose from different types. Which is best? The EVDL should be able to help.. 3. Probably a new charger. 4. Rebuilding or modifying your existing battery boxes or racks to accommodate the different battery shape and size. 5. Modifying the car's suspension, which is (or should be) tuned to a 1200lb lead battery. 6. Your own time and labor, or someone else's, studying how to do the upgrade, and installing it. OTOH, if you buy new lead batteries, it's way simpler. You remove the old ones and take them to the battery dealer as cores, pick the new ones up, bring them home, drop them in, connect them, and away you go. Here's an interesting lead vs lithium comparison written by US Battery, who of course want to defend their lead batteries: http://usbattery.com/lithium-vs-flooded-lead-acid-batteries/ I have some problems with it because they're trying to argue that three 12v, 150ah batteries will deliver 750 cycles. IMO that's way too optimistic. However, six USBMC 2200s are much more likely to return those 750 cycles with good care, and they're only about 10% more than the price USBMC give for the three 12v batteries. So even if you increase their bottom line cost per kWh for lead to 13 cents, and assume that lithiums aren't as expensive as USBMC claim, lead still costs about half as much per kWh delivered. Don't get me wrong, lithium has significant benefits, including lower weight, better range, and a flatter voltage curve on discharge. But lead batteries are still the cost-per-mile champs, though their margin has narrowed over the years. The bottom line is that if lead batteries meet your vehicle mission needs, and you've been satisfied with them, I don't see any particular reason for you to change to lithium. That said, I don't think I'd recommend downgrading your capacity, for the reason I gave above. Let us know how it goes. 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 Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
