Mom is flying to Phoenix over the Christmas Holiday to visit my brothers and I'm thinking about driving our BMW i3-REX for technical reasons. There are two routes: via Albuquerque - about 100 miles shorter, <1%, there appears to be significant grades to Phoenix. via Las Cruces - fewer grades and likely warmer and dryer but a little longer. Right now, I'm leaning towards the Las Cruces route on the way over and decide at Phoenix on which route back. But I'm interested in suggestions and why. The technical reason is to test expanding the 2 gallon tank, ~80 miles, to 3-4 gallons, 120-160 miles. The larger tank lets us run 2-3 hour legs with fewer fuel stops. This significantly improves the cross-country, block time. Suggestions? Comments? Thanks, Bob Wilson
Find it hard to respond in the way desired. For you, NM is a barrier in terms of distance and elevation. This seems pretty joyless. I would instead choose a route based on anticipated wonderful things along the way. Surely internet now allows one to create elevation profile maps. You probably know 'the price' of elevation changes in the i3. So just minimax the thing. Might find snow on the N route and not the S. That becomes known only within a few days of launch.
Me? I'd do both, but that's just me being me again. Albuquerque has the advantage of being more visually rewarding (sans Memphis) and probably has more charging options during stops. You can whistle the Route 66 song while you're driving, and you almost completely avoid the state of Texas, which is always something that I try to do on longer trips. You will also bypass DFW. Lost Crutches, as you already pointed out, will be the less exiting route during the winter months...actually less exiting all the way around. You'll have to deal with the Lone-Star state's billboard-sized speed limit signs and there might be some places where the speed differential between a hypermiler and a PSL+5 driver will be greater. Life's a journey, not a destination. Take both. Post pics. Good Luck!
Both makes sense because it is a round trip. In terms of tourism and engineering data collection. Bob (rocketman) would have a lot to see in White Sands area. Find a string to pull; get a VIP tour.
Neither route sensibly goes by my house, (drat!) but I took the northerly route one thanksgiving to Seattle. That was the farthest north we could get and avoid foul weather. At Flagstaff we finally passed the storm and went north via SLC to Seattle. We passed the time via conversation.
Watch the weather closely no matter which route you take. They close I-40 in Arizona and NM on occasion. Also I-10 if it gets bad enough in NM and West Texas. To add between Flagstaff and Phoenix you go through the Verde Valley. A rather steep downhill into the valley and a steep up hill out of the valley. Then a steep downhill into the Phoenix area 30 or so miles south. Just the reverse going north bound.
Thanks everyone, great suggestions. So using Google Earth, I mapped both routes: The southern route goes no higher than 4700 ft which given the small size of the REX, ~32 hp, hurts but not as bad as the 7500 ft peaks of the northern route. Expected altitude effects: 2800 ft 91% ~= 29 hp # I-40 pass, NC-TN 4700 ft 85% ~= 27 hp # I-10 route 7500 ft 78% ~= 25 hp # I-40 pass, AZ-NM I'll check with the BMW i3-REX forums to see if anyone has experience on these routes and suggestions. Right now, I'm thinking an electric supercharger would be a great addition ... or take the Gen-3 Prius. Bob Wilson
"or take the Gen-3 Prius"... A data-gathering project forgone But not our call. Speaking of which, how would you log parameters en route? Prevailing winds are W to E and might help you get home over the northern mountains. My default would be a clockwise loop unless some other factor supersedes. This is thinking like back in ye olden days of Prius. Mildly exhilarating
Garmin GPS or iPhone recording GPS for speed, time, altitude OBD scanner ... have already used Scangauge but it has no data recording ... but the iPhone can take time lapse Receipts Hummm, mount a mast and . . . <grins> I agree with the clockwise loop. Hold off on the worst case route until we try the 'easy' one. But I may get some tire chains in anticipation of unexpected foul weather on the northern route. +++ Bob Wilson
I bicycled Deming -> Las Cruces on I 10 (not strictly illegal) with strong following wind and it was a memorably fast trip. Choice was peddling or siting up straight and 'spreading' my jacket. Would definitely not buy chainage before Phoenix at earliest (Payson?). Carry XS weight for 3200 mi? You may already own them though. OBD scanner that cannot be further engineered to 'write to disk'? Sounds like something that a technical person could create in a month (insert smilie here with flames coming out of eyes)
This is an interesting test, my Volt has a mountain mode that maintains 40% reserve in the HV battery to supplement power needs going up long grades. I'm not really sure how much of the REX hp is needed for electric power generation. For the i3 what is the total Hp of the electric motor and extender? Is the extender ever used to supplement power demand over what the Electric motor has or is it just for sustaining the electric motor? Sorry for Newby questions. I'm not familiar with how the i3 system works. iPhone ?
168 hp - electric motor, rear wheel drive 33 hp - range extender only drives a generator, no mechanical connection to wheels "Charge sustaining mode" - means the REX will maintain the battery SOC at the time it starts. By default, at 6%, but I've modified mine to allow starting at 75% SOC. It will not put a higher charge on the battery. The question you wanted to ask,'What sustained speed on the REX?' - It handles 70 mph in ideal conditions with ~36-37 MPG but given head winds, climbs, or AC/heating, less. A better cruise speed is 65 mph, 39-40 MPG, which is ideal for following semi-trailer trucks that run at 65-67 mph. At 75 mph, it loses ~20% SOC with each tank and gets 32-33 MPG. More details here: Why the BMW i3-REx | PriusChat Bob Wilson
Thanks for all info, that's very interesting. The trip you are planning will go up hill slowly over several hundred miles, but as long as you have that 75% reserve, I'd think you would have plenty to get over rapid elevation climbs and regeneration on the down grades. I've driven out to Phoenix the past 2 years over the Xmas holidays from the upper Midwest in my Gen 2 Prius. I took the OKC to ABQ route and was surprised how much my mileage fell off. It dropped to 35-37 heading west at 75 mph until I got to ABQ. Then it was largely down hill from there but did need to still need to go over the divide at a 5500 ft level in western NM. I'll be making the trip again this year too. iPhone ?
