----- Original Message ----- From: "Roger Stockton" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, September 24, 2002 11:15 PM Subject: RE: Conversion Concept Musings
> Jon "Sheer" Pullen wrote: > > > QM is 3100 lbs - does anyone have any suggestions for > > 'testing 0-60 with equipment you can find in your own home'? > > A stopwatch and a clear section of flat road? ;^> Tests done tonight indicate you are correct.. after driving the car 90 miles today, I did a 0-60 test and got about 13.5s with just me in the car. There may be some error in that number, as the road was not exactly flat [maybe 1% uphill grade], but it's probably close enough to validate your point. I genuinely thought she was faster. Ah well.. > > But one can safely assume that if a automaker were to mass > > produce a car, they would use components rated for much > > higher weight stress and thusly the vehicle would not be over > > it's GVWR. > > Ummm... I'm not sure I'm following you here; are you saying that an automaker would build the car with a higher GVWR in the first place, or that surely the automaker overbuilt the car you choose for conversion such that actually loading it to or beyond the GVWR really isn't over taxing it? I'm saying that a automaker making a production EV would use bearings & whatnot rated for the increased weight, and would still be able to achive the range I've achived while having a higher GVWR. > > That's a interesting point and one that I will definately > > consider. However, I have already put improvements in place > > to compensate for the additional weight (thicker sway bars, > > stiffer shocks, regen, etc) so I don't think the handling is > > severely compromised. > > Ah yes, but what about where all these various bits attach to the frame of the car, or where the unibody 'frame' attaches to the sheet metal, etc.; do you know what effect overloading might have on them in terms of accelerated wear, and fatique failure? (These are especially important considerations when one gets into aluminum construction vehicles, by the way, since aluminum has some rather unforgiving behaviours relative to steel.) I don't have any idea how far I am stressing the frame of my car. I can only say that if Victor's CRX hasn't folded in half yet, I feel pretty comfortable driving my Accord around. I figure his will fail first, then I'll know what to beef up on mine. ;-) > > The batteries are good to -15.. > > Like I said... most (or at least much) of the [North] American mid-west. I'm curious as to what the degradation is below -15. I suspect much of the degradation in range would not be so much because of diminished capacity as it would be because of the enormous amount of power needed to keep the cabin warm enough that the driver didn't turn into a human popsicle. > But they do warm up somewhat on discharge, and if they start off in a 90-100F+ ambient, you could very well require some cooling before you could > safely plug them in to charge immediately upon reaching your destination. I still don't follow you - if you're exceeding the temp limits for the pack while driving, that's a problem while driving, not while charging. The batteries cool off pretty quickly once you take a load off them - 40 lbs just isnt that much thermal mass - so I really don't see this as a issue. > > > 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 > > > > Um, no. 200-230. > > Really? Back on March 6, 2002 you wrote: > > > QM [with 4AWG interconnects, remember!] gets 160 - 200 > > wh/mile on the streets (average over ten days of driving) - > > the wh goes up dramatically with hills (hence the large > > variation), proof that regen isn't a perfect cure just yet.. > > throw another person in the car, and the wh goes up to about > > 230 with hills. [grins] Yes, and, I state 200-230 as my current average wh. The car has had some changes since March 6 - the same wheel alignment that made the car not tend to feel like it wanted to latirally oscilate did bad things to my wh/mi. I apologize for any confusion this may have caused. I regret having to give up my uberlow wh number, but I suspect it was in part because only a small portion of the drive wheels were touching the ground, and I prefer having the car handle stably. In particular, the camber and toe in values were so far off as to amaze the alignment tech - I suspect this is the result of taking apart the front end of the car three times.. > So, you are now reporting that QM is getting less efficient as it is used? Yes. The suspension upgrade also increased my aero losses slightly. I'm hoping that adding a belly pan will get me back some of the loss, but I haven't gotten that far yet. > > I wouldn't be getting the range I am except > > that Evercel overspec'd their batteries. (i.e. I can get more > > than 84 AH out of them) I'm told that as they age, I will > > lose some of this 'excess' capacity, so probably by the end > > of it's life QM will be a 80 mile range car. I can live with that. > > You reported previously having been informed that the Evercels would deliver ~89Ah for the first 50 cycles, then drop to the rated 83Ah after that; surely you are into the 83Ah portion of their life by now?. Those are the numbers I was givin by evercel. Real world testing has not bourne them out - I am getting well above 83 AH out of the batteries before their voltage under load indicates they are 'empty'. In addition, the 'cliff' comes later than it should, from a AH standpoint, so I stand by my statement that these batteries are delivering more than their rated capacity. Whether other batteries purchased from evercel would do so, I can't say. > It is not so much that Evercel over-spec'ced their batteries you know: even Bob Brandt's book illustrates similar behaviour from the much maligned lead-> acid battery; the flooded PbA starts off at less than rated capacity, cycles up to >100% of rated, stays there a while, then starts dropping off at an > increasing rate until plummeting shortly after hitting the 80% of rated capacity end-of-life point. It just happens that you don't appear to have to cycle > the Evercels up to their max capacity point; they do it 'out of the box'. I will keep that in mind.
