Monday, October 31, 2016

An Electric Orange

Watch those wayward thoughts- this is a family-friendly blog!
This particular electric orange is a Smithco Sand Star E-Plus from 1996.
Smithco makes the word's premier grooming equipment for golf courses, baseball diamonds, and similar surfaces.  They began producing a battery-electric version of their SandStar bunker rake in the early 90's to answer demands for quiet on the course, and chose a 36 Volt golf car transaxle that would be familiar to any course mechanic.  This one had developed an internal short in the motor, and was donated to me for educational or EVenturous purposes.
This orange ATV comes with two linear actuators, one for the mid-mounted sand rake, and the other for rear-mounted attachments like scrapers and brooms.  It's powered by a 400amp Curtis controller and in impressive condition, save that little issue of a short in the motor....
The battery pack was DOA, and quickly pulled by my experienced battery-shuffling students. 
360 lbs of very dead lead, RIP
We then proceeded to clean up and repaint the corroded battery tray and pull the motor.  To fully diagnose the motor (aka: take it apart and see how it works) we popped off the end bell and pressed out the armature, which was the first hydraulic press experience for these students.  The short was where a field winding wire was attached to a terminal bolt, so we removed that bolt and ground off the old brazing.  A more experienced hand than I will be called upon to braze that bronze.  oh, Dan- got yer eyes on?
The students are eager to see me popping wheelies reminiscent of those 1980's 3-wheeled Honda suicidal ATVs, but it looks like this design topped out at 12 mph.  The math for higher revs has yet to be done....

Re-Motivating the KurbWatt

The most persistent problem in the Grumman KurbWatt has been a significant stutter at low throttle settings.  I first thought this might be pitting on the potentiometer wiper surfaces, but analog measurement of the pot didn't show any stutter as it was cycled, and testing the drivetrain with a known good pot didn't cure it either.  Theory #2 is a bad spot on the motor commutator, like a burned com bar or two.  This seemed confirmed when the trucklet failed to move after a stop, only giving the tiniest hint that the controller was outputting any current (barely an amp on the meter and an inaudible 'thump' in the driveline as I planted the go pedal).  Pushing the truck forward a few inches in gear to rotate the motor resulted in a normal restart.  
So, I turned to good buddy Tim Ritchey, who had salvaged an identical General Electric 5BT1346B51 from a cancerous Jet Electric pickup, which looked good and "ran till they parked it", and it also spun smoothly on 12 Volts.  

Pulling the Grumman motor was a bit challenging due to the tight clearance between the flywheel and the transmission output flange.  VW's solution to this problem was to machine a scallop out of the side of the flywheel so that the engine could only be pulled out at one point in a rotation, and then only by snaking the engine around that output flange.  It was quite the wrestling match with a 200 lb motor and flywheel.  I imagine a big greasy engine would be much more fun indeed!  

Once we got the motor out, the mysterious 'riveted on' brush covers slid right off after removing a draw bolt, so we could inspect the brushes and commutator bars.  They are shiny copper instead of the expected dark patina, but with no visible defects, and the brushes appear to be in good order.  To add insult, the rusty old motor spins just fine on 12 Volts.  

Oh well, we have a replacement motor all painted up, and are going to test drive it, by gosh!  

Pulling the 1980 Jet Electric motor hub was quite a challenge, apparent in the end due to the liberal amount of red Locktite that had been not only applied to the bolts, but also slathered all over the motor shaft!  A weekend of penetrating oil and four guys on prybars finally popped it loose.  Here's hoping that we didn't damage the motor bearings in the process, but they 'feel fine'. 

The whole exercise will not be for naught, as the clutch was worn down to the rivets, the pressure plate was deeply grooved, and the flywheel was pitted from its years of immobile exposure.  With all new/resurfaced components, we can at least eliminate a few more variables. 

Just test-fitting components, obviously some learning left to go and not ready for installation yet!

We considered going clutchless, going as far as to procure a spare transaxle that was specifically modified for clutchless EV use, but the two provided adaptor hubs and transmission profile plate don't match my spare motors, so we'll hold off on any custom machining until after a test of the replacement GE motor with a new clutch.  

Thursday, October 20, 2016

The i-MiEV is a workhorse

Owners of the deceptively diminutive Mitsubishi i-MiEV quickly discover it to be the "little car that can", as it has 50 cubic feet of flat-floored storage when the rear seatbacks are folded flat.  That's enough to carry for example; two 55 gallon drums, a dozen nested 32 gallon garbage cans, a 50" LED TV, or an adult bicycle on the inside.  More intrepid owners add roof racks for items such as rooftop tent camping, bicycles or, perhaps a boat.

Really intrepid owners add the 2" receiver hitch from Torklift Central, enabling both towing and cargo platform use.

Virtually Started

Thanks to collaboration with Mr. Thompson, four leading students of introductory engineering are taking on a real-world project in Computer Aided Design, in which they are taking measurements of the Ranger EV battery box, modeling it in the computer, and then modeling the fitment of our different battery pack options!
For suspenders to compliment this virtual belt, students in Mr. Culpepper's Wood Shop are cutting and gluing wooden blocks as stand-ins for Nissan Leaf modules.  With just two wooden dummy modules, it should be easy to check lid clearances and tape off outlines or even create wire frames of how the battery will fit in the box.  

As an added bonus, both techniques were started today, so we get to have a race of old-school craftsmanship versus new-age technology.  Which do you think will find the final solution faster?

Tuesday, October 11, 2016

Speaking of great weights, how about a battery sponsor?

Longtime Karmann Eclectricians will recall that the 2014-15 Grumman KurbWatt project came together thanks to the generous sponsorship of and several local hobbyists who shared spare and/or used parts.

The Ranger EV does not yet have a funding source identified for batteries.  The students and I are running the numbers on different battery options, both new and OEM salvage.  Our goal is a solid 100 miles of range, which means at least 35 usable kWh with a pack voltage that ranges between 300 and 370V.  A pair of crashed i-MiEV, a couple of original LEAF packs that are already down their depreciation curve,  some orphan Think packs, a couple of Volts or a crashed Smart ED or Spark EV- the list of possibilities is very long.  Who out there in the ether cares to step up?  I have truck and will travel!

  Image result for LEAF battery packImage result for volt battery pack
Image result for Spark  battery packImage result for Enerdel  battery pack

A great weight is lifted...

After a quick orientation to the vehicle and the inherent hazards herein, we commenced to removing the pack of dead lead.  All 1950 lbs of it...
What the shop manual declared to be a 40 minute task was accomplished by our crack team in about 20 minutes, and removal of the coffin lid's 22 bolts took under 5 minutes; light work with many hands!

Underside orientation and discussion of the designated lift points.

The sarcophagus will reveal its secrets

The battery lift is certainly earning its keep!

38 custom-sized lead-acid 8 volt batteries.  WHY, Ford, WHY!
The upper stack has heat pads bonded to the sides, rest have them below.  Battery heating was activated in freezing weather only when connected to a charging station.  This would be a useful feature to retain with the lithium pack.

Monday, October 10, 2016

A Lonely Ranger is coaxed out of hiding...

One of the more mythical EVs out there is the factory Ford Ranger EV of the 1990's.  Approximately 1200 of these were made to meet the first California EV Mandate, and about 800 of them were sent to the crusher when the automakers won their hollow victory, ceding the electrified space to Toyota and then TESLA for nearly two decades.  Thanks to and other protests by the RangerEV, S-10 EV and EV-1 leaseholders, one third of the Rangers were spared and went into private hands a decade ago.  Many of those vehicles saw good service in their second life, but a few fell through the cracks.  This is one of them.  A former Georgia Power fleet demonstrator, this lead-acid Ranger EV wound up with a nonprofit in Washington State in 2006.  They drove a victory lap straight off the transport truck, but then later discovered that it would not recharge.  A thorough diagnosis was not performed until so much time had elapsed that the battery pack was hopelessly dead.  The truck passed through two more sets of hands that never actually started on a revival, which brings us to today.   Sumner School District has received the vehicle, and we will be resurrecting it in the High School Auto Shop as this year's advanced class project.  As an extra-special bonus, this vehicle came with the huge hydraulic battery lifting jack, which will be very handy, considering that we have a 1950-lb battery sarcophagus to remove and rebuild.
The battery lift is harder to keep on hand than the truck itself

On a trivial note, the Ranger EV was one of the very few production vehicles ever to use the DeDion tube rear suspension, and another is my daily-driver i-MiEV.  This allows a lightweight but rigid rear end for heavy loading and a close-coupled motor and gearbox that is fully suspended.  The Ranger EV rear suspension is made of Aluminum forgings and aluminum tube.
Notice the dimples in the Ranger EV-only lightweight aluminum hood!

Offloading the Dead Lead Sled