Sheer wrote: > My hunch is that even at 80% DOD I can do 0-60 in 14 fully > loaded. (well, it depends on how heavy the passengers are.. > but four people my weight? Sure.)
Nope, the numbers disagree. We've been through this before; with the NiZn voltage sag at 3C as soon as you get more than about 5% discharged, your available battery power is about 77hp. Assuming QM is about 2500lbs with you (alone) onboard, Jeremy's acceleration spreadsheet predicts about 14.8s. Now add 3 more people and try it at 80%DOD... You'd have to do a test to tell for sure, of course. > My car has 500 lbs of 'legit' overhead in the GVWR, which is > enough for 3.1 passengers my weight. However, I've driven it > with four people in it and the sky did not fall. I don't > think the extra 1-200 lbs is significant, because I think > that if I know Honda, they designed in a 'safety factor' of > about 500 lbs beyond the weight rating for the inevitable > college-student-moving-experience the car was bound to experience. > > Now, with all due respect, please drop the weight issue. Or > I'll start pointing out many, many successful EVs in the EV > photo album that appear to have completely ignored the GVWR > and seem to still be rolling. My comment was worded as a question specifically because I could not recall how close your particular conversion was to GVWR, but was reasonably sure that with 4 people onboard it would be at or over. The weight issue isn't going to go away anytime soon; it is a legitimate concern. One must assume the manufacturer assigns that number to the vehicle for good reason(s), and any conversion that ignores it and consistently operates at or over the GVWR cannot be considered an example of something acceptable for widespread use by the general public. I'm glad to hear that you have planned your conversion to allow for a driver and passenger or two or cargo without exceeding its GVWR, however, as you note, it is all too easy to point out examples of conversions that are at or over GVWR before the driver even gets in. Sure, they work and don't fall apart imeediately, but I suspect part of what lets them sneak by is that most of them are not capable of highway speed operation for the distances QM is, so they may tend to operate mostly at lower speeds or on surface streets, or for shorter distances, so that the greatly reduced safety margins with respect to handling, braking, acceleration, etc. have less opportunity to contribute to a tragedy. > About the only place I can think of where battery temp > management would be essential with NiZn, from what I've seen > of it, would be Las Vegas and places with similar weather. I think most of the [North] American mid-west would require thermal management: the winter temperatures are well outside of the operating range for NiZn, and even when they aren't the pack capacity would be reduced; summer/daytime temperatures can easily get high enough to require cooling in order to permit charging. IMHO, it just isn't plug-and-play unless you can plug it in anytime, anywhere and safely charge. > With a NaNiCl pack, I think we can safely say a 100,000mi + life. I thought so too, but when I ran the numbers it came up short. The problem is that MES-DEA only rates it at 1000 cycles to 100%DOD, even though they have lab data indicating 1600 cycles (and counting). They say they will only update the rated life when they have more statistical data. > I don't know about you, but I don't want to drive a car that > does 0-60 in 24 seconds. It would probably be acceptable in > most of europe, but in many U.S. cities you would get run > over. ;-) Well, okay, I exadurate a little bit, but it > certainly wouldn't be very much fun to drive. You've never driven a Type 2 VW have you? ;^> I replaced my '70 Type 2 with a newer, characterless North American car a year or two ago and miss the VW terribly, even though it probably couldn't do 0-60 in even 24s. Can a [stock] Beetle even do 0-60 in much under 24s? Lots of these cars (Type 1 and 2) on the road worldwide, and their owners generally seem to find them very fun to drive... it is certainly a different experience, but still fun ;^> > It would still, however, have less range than QM. Perhaps, but not necessarily by much. I WAGged 250Wh/mi for the NaNiCl Sprint to get >60mi range, but I notice you report 160-200Wh/mi for QM (with you alone onboard). The lighter Sprint with its slightly higher pack voltage would likely get similar efficiency, and this pushes the range up to a similar 80-100mi usable range as you report for QM. Please understand that it is not my intent to bash QM here; it is certainly the closest conversion to meeting the stated requirements that I know of, however, it does still miss by more than just expected pack life. Cheers, Roger.
