First of all, I'd like to thank everyone for their comments on this important issue. I'm in the middle of my first conversion, a Honda Insight, so it helps to have a list of things to check, or at least be aware of the issues/risks.
I also have a '94 US Electricar S10 with 52 Hawker 42AH batteries, for a total of 1710 lbs. Since it is a from-scractch EV, it has the original GM S10 sticker, as well as an additional sticker certifying that it meets all (US) federal safety regulations in effect in '94. The original GM GVWR is 4600 lbs (2087 kg), with a front GAWR of 2500 lbs (1134 kg), and rear GAWR of 2700 lbs (1225 kg). The US Electricar GVWR is 5400 lbs, with a front GAWR of 2500 lbs, and rear GAWR of 2900 lbs. Not being an automotive expert, I notice only that the rear leaf springs have 4 segments (is this more than the stock S10?). I also note that the frame near the battery box (which is made of 3/4" steel in the front and 1/8" steel for the sides), is reenforced as appropriate for the copious amount of lead that it carries. Any other improvements have escaped my amateur eyes. It does seem curious that the GVWR went up by 800 lbs, while the rear GAWR went up by only 200 lbs and the front remained unchanged. Now on my insight, the GAWR is 1040 kg (~2244 lbs), the front GAWR is 600 kg (~1320 lbs), and the rear GAWR is 450 kg (~990 lbs). The vehicle weight is 1878 lbs (I have air conditioning). I took out a mere 218 pounds (74 of it gasoline!) mostly from the rear. While I haven't weighed the ICE/IMA/clutch/flywheel yet, I expect it will be pretty close to the the 92 lb small Siemens AC drive and its 57 lb (short) inverter--maybe even a bit less! Two Evercel NiZn battery options would be 26 MB50-12-8 at 23.4 lbs for a total of 600 lbs, or 20 MB80-12-8 at 36.2 for a total of 728 lbs. These fit nicely in the gas tank cavity and the IMA inverter / existing battery areas. I guestimate the center of gravity to be 1/5 of the way from the rear axle line to the front axle line. So this would be an extra 382 or 510 lbs of batteries. (Side note: I'll be using 20 Hawkers until evercel's are available at 34 lbs each). So I assume that it is safe to assume that the rear tires (same as the front) are ok for GAWR of 1320 lbs. Clearly the suspension (ride height and resulting oversteer from additional rear weight) and brakes are issues (yes, regen is great for normal driving in non-winter conditions, but you need to be able to do it all with regular brakes. And, yes, there is an interesting ABS/regen control integration possible/required here). I guess some LiIon batteries at 400 lbs for 240V would make this a lot simpler! Gary ----- Original Message ----- From: "Otmar" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, September 24, 2002 2:50 PM Subject: Re: GVWR > >The concept of 'legit' overhead in GVWR is interesting. I > >think we all agree that the GVWR of a vehicle can be > >exceeded a bit. > > This is an interesting issue. > > I believe the important things to consider are: > Braking ability on long downgrades. > Wheel and tire load ratings, > Ride height, > Strength of the remainder of the suspension and frame. > > I have run many vehicles well over GVWR. I regularly load VW busses > 2000 lbs Over the GVWR with reinforced springs. It requires careful > mountain descents, tends to wear on the suspension mounts, and after > many years a couple of the suspension arms started to take a bend. I > always stay within the tire ratings and keep them properly inflated. > > I wonder what the manufacturers use for the weak link determining > GVWR. I suspect it's primarily the braking ability and then they > design the springs to take what they want it to take. Or maybe it's > by decree, and then they build the rest of the car to fit. > > -Otmar- > > http://www.CafeElectric.com/ Home of the Zilla. > http://www.evcl.com/914 My electric 914 > > NEV. It stands for "Not an Electric Vehicle" > Remember the 70s, just say no to NEVs on arterials. >
