Why the BMW i3-REx

First test drive:

The side view shows the low clearance with the receiver. There are inches to spare opening the hatch so I don't have to pull the quick-release pin to access the rear. I may experiment with some sort of strap to help raise the assembly as it appears to droop.


The back-up sensors complain but you can see around the chair. Raised a few inches, I still expect the warnings but better view under the rack. Once you go over 6-8 mph, the alarms turn off.


The rear view mirror view is not obstructed but will have to check again after getting a taller receiver.


The blue knob on the top adjusts an arm that holds the chair firmly in the rack. The small blue knob on the lower right is the quick release that tilts the rack so the big wheels touch the ground. Very easy to load or unload.


This is what it looks like walking up to the car.

I don't like this receiver (sold separately) because the chair rack is too low. When pulling out of the driveway, there is a gutter between the curb and driveway and it started to scrape. Driving at an angle worked but only because I knew it was there. In an unloaded car, it cleared the 'speed bumps' (i.e., sleeping policeman?) A few extra inches should do it.

I also bought a 5/8" x 2 1/2" bolt and locking nut as the original was too long to fully seat. I also don't care for lock-washers versus a locking nut with plastic insert. A general hardware bolt, I may look for a higher quality bolt and of course, replace the locking nut.

I was not trying to do handling or drag tests until I get the ground clearance right. When I took it off, keeping the receiver (the part that inserts) is the easiest way ... take wheel chair off first. <grins>

Bob Wilson

 

I may have found a solution: Shop Reese Adjustable Towing Ball Mount at Lowes.com


I suspect this means double the number of position by inverting the 2" receiver, draw bar.

Bob Wilson

 

Turns out to be fairly simple:

• Find insert for the vertical, square tube
• Drill new hole(s) offset from vertical by 8 deg

Reassemble so now the platform and vertical arm are 'normal' with respect to both horizontal and vertical. I have a drill press and bits for the holes are probably in my kit. Use lots of cutting oil, patience, and new bolts when done.

Bob Wilson

 

Well the week of 'no pay for play' ended with 352.0 miles and not one paid kWh. I arranged my normal trips to include 'free' chargers and the problem was solved.

It felt a little strange starting each morning with less than 100% SOC, sometimes under 80%. I was also surprised to find the Whole Foods chargers turned off at midnight. Also the 'broken display', Blink charger stopped working on Monday (someone finally turned it off?) But the others worked just fine.

Bob Wilson

 

Today I found a row of six, Huntsville utilities installed, 120 VAC outlets:



Our Level 1 EVSE is rated at 12A which limits the rate. However, the sockets appear to be NEMA 5-20R which should provide up to 20A, potentially a 66% increase in charge rate. So I'm wondering if anyone has a suggestion for a higher current, Level 1 EVSE?

I would like one that allows setting the current limit so it could provide more 'headroom' for the utility circuit breaker. For good measure, auto-step the current limit up measuring the dV drop to optimize loading on the circuit breaker.

So for dinner and a beverage, this is what happened at 12A:




Bob Wilson

 

Well they are using a standard NEMA 5-20 and I don't see anyone checking who is using them. For EV specific, we'd need an EVSE with a J1772 plug.

Bob Wilson

 

On my wheelchair carrier, I decided to buy an 8 degree, wedge shim, which I'll drill a 5/8" hole. Then I was just at Fastnal and bought a package of wedge washer that measured ~9 degrees. This will let the BIG bolt ride normal to hold the assembly together. With a generous amount of blue Loctite and properly torqued (a Big UGH!), it should work.

Bob Wilson

 

Planning a 700 mile trip from Huntsville AL to Stillwater OK turned out to be a little tricky. The nominal gas range at 65 mph is ~80 miles (40 MPG.) Trying to map fuel stops using either MapQuest or Google Maps was turning into a nightmare. Then I realized the answer, 24 hour truck stops.

Enter into Google "<highway> truck stop <state>" and you'll quickly get a list of truck stops, most are 24 hour but check. So far, they are running ~70 miles apart, well within the BMW i3-REx range. So I will make a Google Map trip consisting of segments between each truck stop along the routes. Then export the route to my iPhone and the car.

Bob Wilson

 

Another solution is to use GasBuddy and enter:

City_MPG = Highway_MPG = 40 MPG

This gives a nice map of stations with cheapest gas. However, it does not seem to show hours of operation. Still, a good start.

Bob Wilson

 

Someone make a rude comment about the India Engineering practices from a photo of my EVSE installation. You'll have to take that up with the tree:


Bob Wilson

 

I had this problem of an 8 degree droop:

Leaving the driveway, the rain gutter at the curb caused the rear of the carrier to scrape. No problem with local speed-bumps.

I bought an 8 degree, wedge shim used by off-roaders who lift their suspension. A wedge shim handles the new body-to-spring-to-axle angle. After re-drilling the mount hole to 5/8", here it is installed:

Notice the platform is now parallel within a degree or so of a line drawn axle-to-axle of the wheels.

Here is the wedge shim in the assembly:

The tow ball mount droops a little then you can see the small end of the steel wedge. On top of the wedge is an alignment part that comes with wheel chair carrier to keep it from rotating around the bolt and shifting to the rear. The wedge actually over-corrects a little but the 'slop in the system' lets the carrier droop to level.

Now one potential problem is the bolt holding everything together has to deal with an 8 degree angle. Cocked at an angle, one side of the bolt-head would be have all of the stres and the other side, unloaded. Over time, road vibration would lead to a crack and the head separating ... not good. So I used a 9 degree, wedge washer:

Annealed, the washer conforms so the bolt-head is evenly loaded. It also means stress will in effect keep the bolt-head from any rotation.

Now the only metric for fuel consumption has been 40 MPG @65 mph between Knoxville TN and Cleveland TN on my first drive home. But I've added a receiver hitch and now the wheelchair carrier and wheelchair with a rain cover. So I replicated the benchmark @65 mph, +90F and AC at 74F:

So loaded, it is running 73 miles / 2 gallons ~= 36 MPG. This is the mileage needed for trip planning. Here is the electrical version (after coming to a stop) of the benchmark:

These were taken at the Shell station right off of the Interstate. And then the flap for the gas tank would not open and I was completely out of gas.

So I drove over to the BMW dealer and they showed me the manual over-ride. They also showed it is not a one-time use and then go to dealer. For now, they asked that I do a power-on, RESET of the software which is in progress. I'll back out the 'code' and if it doesn't work, I'll schedule an appointment. The major technical issues have been addressed.

Minor issues:

• Safety chain ... bolt failure would be bad ... dragging on road, less bad.
• Fitting 1 gallon spare can in front trunk (frunk).
• License plate replica behind chair carrier with light.
  
• Left-turn light is blocked but that may not be a problem.
• Rust protection and lock-nut the bolt.

Suggestion? Thoughts?

Bob Wilson

ps. I suppose we should alert the usual suspects that "Bob Wilson ran his hybrid out of gas, AGAIN. The world is ending!" Of course I did have about 60 EV miles left to drive to the dealer and home. <GRINS>

 

I am thinking one of those plastic covered, bike cables with a lock. That would prevent things from 'walking off' too.

Bob Wilson

 

Posted from Stillwater OK:

	From	To	mph	MPG
1	Huntsville AL	Tuscombia AL	45.3	47.3
2	Tuscombia AL	Cornith MS	56.8	34.5
3	(meal) Cornith MS	Memphis TN	31.6	40.6
4	Memphis TN	Lehi AR (biology)	27.0	41.3
5	Lehi AR	Carlisle AR	40.3	39.2
6	(breakfast) Carlisle AR	Conway AR	25.7	39.8
7	Conway AR	Clarksville AR	49.8	40.0
8	Clarksville AR	Roland OK	41.9	40.6
9	Roland OK	(lunch) Webber_Falls OK	23.2	41.5
10	Webber_Falls OK	Broken_Arrow OK	43.6	32.0
11	Broken_Arrow OK	Stillwater OK	39.7	41.4
12	Huntsville AL	Stillwater OK	37.2	39.6

• Me, Wife, and two dogs
  • three meal breaks
  • one extended biology break
  • one driver
• Normal cruise speed 65-68 mph
  • following trucks using auto-cruise control
• Spare gallon
  • Pulling off in Memphis found 24 hr station
  • Closed truckstop in AR, used spare gallon

Started with 100% SOC; enabled REx at 75%, and; arrived Stillwater at 54%. When using 'coded' range extender, need to enable it when car is first turned on. A couple of 'OPPS' eroded the SOC a couple of percent and slowly reduces SOC over trip. Some evidence that slowing for refueling can regenerate 1-2% SOC to bring it above the running value.

The Prius is obviously a better, cross-country car. However, the BMW i3-REx meets our requirements, especially with the spare gallon can.

• Eating during the drive can save a lot of time, hours. Requires passenger commitment and planning.

Bob Wilson