On 1 May 2018 at 21:02, Hazem Sedra via EV wrote: > Crown CR 205 which is comparable to Trojans in quality will cost me $94.99/bat > X 18=$1709.82.
At Deepcyclebatterystore.com, I found prices and spec sheets for Crown batteries. The spec sheets are more complete than some I've seen. They give cycle life estimates at 100%, 50%, 40%, and 20% DOD. (I wish they'd include 80%.) CR-205: 205ah at C20, 105 minutes at 75a, 1050 cycles @ 50% DOD, $95 CR-220: 220ah at C20, 110 minutes at 75a, 1200 cycles @ 50% DOD, $120 CR-235: 235ah at C20, 125 minutes at 75a, 1200 cycles @ 50% DOD, $130 CR-260, 260ah at C20, 150 minutes at 75a, 1200 cycles @ 50% DOD, $157 With these data, we can compare the cost per kWh of use of their different models. First we compute the total kWh shifted by the batteries over their estimated lifetimes. We use the 75a reserve capacity since 75a is reasonably close to an average EV driving current (unless you're a real leadfoot). For example, the CR-205 would be 105/60 * 75 * 6 = 788Wh @ 75a / 2 (50%DOD) = 394Wh * 1050 cycles = 394 kWh Repeating the math for the CR-220, CR-235, and CR-260 we get 412 kWh, 469 kWh, and 563 kWh respectively. So now we can work out the cost per kWh shifted, and also estimate average cost per mile, assuming your car uses a typical 250 Wh/mi. CR-205 = 24.1 cents per kWh, 6 cents per mile CR-220 = 29.1 cents per kWh, 7.3 cents per mile CR-235 = 27.7 cents per kWh, 6.9 cents per mile CR-260 = 27.9 cents per kWh, 7 cents per mile When you look at the real life cost per mile, the results may not be exactly congruent to these numbers. For equivalent driving, the lower capacity battery will work harder which can shorten its cycle life. On the other hand, it's also pushing around a slightly ligher car. In a 3000lb car, the CR-205 will make the car 72lb (2.4%) lighter compared to a pack of CR-220s, and 126lb (4.2%) lighter compared to one with a pack of CR- 260s. I don't think it will make very much difference, but theoretically the peak acceleration currents could be slightly lower, contributing to slighly longer battery cycle life. All that said, if Crown's cycle life estimates are accurate across the different battery models, or at least similarly inaccurate :-), this gives you a good idea where the overall value lies within this one battery brand. 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)
