Tuesday, November 22, 2016

Discommodulated Battery

No, it's not a crime under Napoleonic Code, it is what we managed to do last week, and it is much easier than posting rotated photos on Blogger....

One LEAF battery pack has been disassembled into sub-packs.  We identified the components, taking special care to disconnect the busbars that were easiest to remove first, as those mid-pack breaks greatly reduce the voltage present and potential for shock.  We learned to snap back the insulating covers after removing the busbar fasteners, as the busbars can be removed without exposing any bare copper.  We double-checked the disconnection of all small sense leads and made sure there would be no snags or shorts in the wiring harness, and then lifted out each of the sub-packs.

Next step is to measure these sub-packs and confirm they won't be a ready fit into the Ranger Sarcophagus, and then we'll advance to disassembly down to the module level, taking careful note of how the sub-packs were assembled, as we'll need to reuse the end plates and hopefully many of the busbars and the BMS wiring harness as we reconfigure the modules into a series string of 'buddy pairs', and restack them using the original hardware, but with a different number of modules in each subpack.



Disassembly without Destruction

The LEAF battery packs are a wonderfully compact kit, with an interesting mix of fragile and overly beefy componentry.  We've now broken down the subpacks into individual battery modules, without a single broken wiring connector and only one stripped screw, out of dozens apiece.
At 8.2V apiece, the individual modules don't pose a shock hazard to bare skin, but the subpacks did, so extra care was employed when exposing the network of interconnected busbars and removing those bolts.
Arrg, can't get it to stay flipped, but you get the picture!
Now all we need to do is fill the big box with what we pulled out of the little boxes.  Seems simple enough, but so does posting photos to a blog!


48 modules, once again in an antigravity orientation...

Thursday, November 10, 2016

We're Lovin' LEAF

Lovin' Life with LEAF salvage, that is.  The two collision-salvage battery packs arrived this week, as did the prototype Wolftronix LEAF Pack Sniffer.  This amazing little device turns on the BMS and reports back the pack voltage, average cell V, # of bars of remaining capacity, identifies the high and low voltage cells, and then scrolls through all the individual cell voltages.  One of the packs was sitting at 396V with four bars of capacity, the other at 393V and 4 bars of capacity.  Voltage as a state of charge indicator is mainly valid at the upper and lower end, and these packs were built two years apart.  I think they will balance out nicely, as individual cells voltages were tight after months of sleep, with only 6 thousandths of a volt difference between the highest and lowest cell.  Most were within 3 thou..  Here's a video of the sniffer in action!
Leaf Pack Sniffin'

The packs arrived on a rollback wrecker, so without a forklift we very carefully set the back edge of the pallets on the ground and then drove out from under them!

  


It may seem scary to sic a student with an air chisel on a highly charged battery pack, but research revealed the safety of this technique, as the sealed surface to be separated is outside of a one-inch protective lip of steel (and by another air gap and metal module covers on the inside) meaning one would have to overshoot the target by quite a distance and cut through multiple layers of steel after the target of a single layer of sealant! The air chisel made short, but very noisy work of this job, much to the students' delight!  The students quickly learned to distinguish by both sound and feel whether the chisel was hitting sealant or steel!

Wednesday, November 09, 2016

Vindication Monday!

'twas disappointing to see a short in the motor after rebuild, but perhaps that could be explained.  The controller label still wasn't visible, but a document search said that the Sand Star E Plus offered regenerative braking.  That could only mean one thing on a brushed motor with four terminals labeled A1, A2, S1, S2..... SHUNT WINDINGS.  The shunt wound motor is another old workhorse, but rarely seen on golf carts.  It's prime characteristic is that speed is controlled by varying the voltage on the 'shunt' that energizes the electromagnetic fields.  At a certain shunt voltage, the motor will give its all to maintain a particular speed, until the load is too much to bear.  Conversely, if a shunt wound motor is 'overhauled', or forced to turn at a faster RPM than the shunt dictates (rolling down a hill), it will generate current back into the battery.   This revelation comes courtesy of a little consulting and measurement by Dan Bentler, who walked me through the diagnosis.  The motor couldn't go through a full bench test, as the output shaft bearing is integral to the transaxle, but it turned just as expected once bolted back on.  Reconnect the controller, and a dead short appears.  So we have a bad controller, and that's not so hard to replace.  Removal of the controller confirmed that it was an uncommon but affordable shunt motor controller.

On the Grumman project, we got the motor mated back up to the transaxle, but discovered a different bolt spacing on the end bell that didn't match the other motor, but it will match if we simply remove and 're-index' the adaptor plate (rotating the motor housing 90 degrees).  We need practice installing motors anyway, right?

Friday, November 04, 2016

Setback Friday

Today was hoped to be a milestone, as we were all set to install the replacement motor in the Grumman, and also completed re-soldering of a broken field wire in the Smithco trike.  Alas, it was not to be.

Prior to installation, we did a test spin of the whole assembly (motor with mounted hub, flywheel, clutch and pressure plate).  It wobbled.  A lot.  It wasn't expected to be a perfectly balanced assembly, as the clutch centering tool isn't that accurate and the heavy Rabbit MK1 flywheel with a scallop cut out for clearancing obviously wasn't high-speed balanced at the factory.   Here's the video (With apologies for the authentic mechanic's shop color commentary.)
video

So, as a team we discussed whether to cross our fingers and run with it, or investigate further.   Out came the dial indicator.  We all learned how to use it, and found 20 thousandth's of an inch in runout. A coupla' thou would be okay, but not 20.  So off comes everything except the hub, and we dial it up again.  Still at 20 Grand.  SIGH, ...despair briefly raises its ugly head.  One team member even said "Well what did you expect, bringing the truck to a bunch of dumb high school kids.  If you wanted it fixed, you shoulda gone someplace else!"  

We popped off the hub, which was easy because we hadn't painted the thing with locktite like the Texans did waay back during the Carter Administration when this thing was first assembled...  BUT, there wasn't a setscrew in the keyway either.   Matter of fact, the setscrew hole wasn't even tapped.  WHAT IF?
So, out came the taps, and a bolt was quickly installed.  WELL WHADDA YA KNOW!!
Upon reassembly, the hub spun true, at 1.5 Thousandths of runout.  The threads weren't tapped exactly straight on axis, and our key was fractionally shorter than the slot, so this opportunity to correct both of those situations was seized upon, and we'll reassemble it all and install on Monday.

Similarly, two teamsters had tackled a very challenging soldering job in the Smithco trike motor and managed to get the motor fields intact again.   However, it was still a dead short when we tried to do a test spin.  I now think that the field wire snapped during disassembly, as it wasn't scorched like a short should be, and the heavier-gauge motor leads showed a lot of heat...  Back to the drawing board for this motor, but we eliminated a variable.

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 http://www.better-energy-llc.com/ 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 DontCrush.com 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

Friday, August 26, 2016

Adopting a Unicorn.

One-owner 1983 Mazda RX7 GSL Aztec Gold Electric Vehicle Conversion
Built by an electrical engineer and driven daily for 18 years.  
2 year old flooded lead-acid battery pack
Vehicle Garaged and rain-tight
All systems in good working order.
FREE TO A GOOD HOME

This imagined advertisement describes the situation that came to me via the grapevine this week, and now it is indeed mine.  Having passed muster as a worthy adoptive father to this antique love child, I brought it home to the genuine surprise of my wife, who couldn't believe that someone would give away such a beauty.  But then of course, she's never tried to sell a unique but low value used car on Craigslist, inviting all sorts of unsavory time wasters to your inner sanctum....  My great gratitude goes out to the builder, who did not desire publicity.

Vital stats are a 108V battery pack, Curtis 1231 controller, 9: ADC motor, high quality workmanship.
The top-of-the-line GSL included a limited slip differential, steel sunroof (with good seals and drains that aren't clogged), electric windows and solenoid-actuated hatch and filler door release, along with a leather interior and unique aluminum alloy wheels.

This car includes amazing documentation, from notes on the builder's first ever trip to an EV Assoc. meeting, to a log of all build progress and repairs, to the original window sticker and brochure, sales receipts for EVerything, engineered drawings, and EVen a typewritten RX7 EV Maintenance Manual complete with color photos for each procedure, such as battery pack replacement.  

The jury's still out on how healthy the battery pack is and whether it'll make my round-trip commute, but it'll definitely be a fun errand-runner and show car.  It also fits into my Karmann-Ghia sized car trailer, and most of all, it was ready to roll!  No work needed, it can simply be driven leisurely and gradually upgraded over time.


Thursday, August 04, 2016

The Grumman Gets Going!

After this chump got stumped for weeks trying to wake up the motor controller and diagnose faults, EV Expert Dave Barden came over for a visit from Vashon Island and solved my woes in one quick computer session.  I've gotta get a dedicated old laptop or Palm set up for this purpose, as the Zilla seems to be stuck in an old world of 9600 baud serial port communication, and USB to serial port adaptors are a wily bunch.....

Driving 17 miles home, the battery pack didn't sag much when kept under 400 amps, and I've resolved to take it easy while working out the bugs.  For example, there's a nagging noise coming from the right front corner that I erroneously diagnosed as a bad constant velocity joint, so the students and I put on two new axles, complete with stub axles and four CV joints.  However, that didn't include the wheel bearings, which are part of the front hubs that the stub axles are inserted through.  Off it all came again today and we pressed new bearings into that olde hub, still bearing the May 1982 inspection sticker!

The old bearing seemed good, but the first test drive seemed to prove us out.  Then we noticed a missing circlip that serves as the bearing retainer, so out came the hub again and during this reassembly, we noticed that a brake pad had delaminated during the test drive and the backing plate was bent.  SO, after that one short test drive, the Grumman went back on jack stands, awaiting new front pads and the retainer bolts that the pads slide on...

Saturday, June 11, 2016

Sylvester chomps at the bit...

Our Grumman Kurbwatt rebuild at Sumner High school is nearly complete, and just in time for the end of school.  There's an annoying no-start error light flashing on the Zilla controller's hairball (brain), caused by critical low voltage on the 12V circuit, according to the error code extracted.  However, after wiping the error code and doing a couple of disconnections of both 12V and the traction pack, the hairball just lights up red with an error again upon attempted restart.  No fuses blew, big or small, but research reveals that early hairball firmware could be corrupted by this very condition. I spent this week rounding up equipment to talk to the 9600 baud serial port on the hairball, which has become a challenge in the modern era.  (I've dredged up a serial terminal that just spit out code that I couldn't comprehend, and now a Palm Pilot with a serial cord, as well as a USB-serial adaptor for my laptop, and a couple of programs to try.  To further complicate matters, the hairball is no longer flashing codes or resetting using the simple 'shorting plug' signals of last resort.  Oh well, if all else fails it's good to be close to Manzanita Micro here in WA for repair.

The main activity of the past couple of weeks was to go ahead and install the second battery pack: ten more modules in parallel with the ten installed in the slide-out battery tray.  These are tucked away in body cavities below and behind the seats, and though permanently paralleled, one can run one or both packs with selective use of the Anderson SB350 connectors.  Replacing the terminal posts with contactors would enable series/parallel switching of the packs, for 240V 'strip' or 120V 'street' operation, but from the initial road tests, it may be that 120V will be plenteous power, given a doubled-up pack rated for 1000 amp discharges!




We also replaced the rusty sideview mirrors and both of the driveline half-shafts complete with four CV joints, but that turned out to not be the source of an annoying clicking sound when making left turns.  More diagnosis to come once it's running again next week.  Lastly, I finally found replacement gaskets for the round stop/turn/reverse lights and sealed in some really bright LEDs that should be a snazzy safety enhancement.

Speaking of safety, one student demonstrated the value of safety glasses after carefully removing a window, cleaning and lubricating the chain-drive regulator, and reinstalling it, only to have the window shatter when he turned the crank.  No good turn goes unrewarded, but that window was luckily a match to all of the big brother Grummans, and replaceable for only $30 from Mill Supply!

Friday, June 10, 2016

Solar Washington, Part Trois.

Part Trois?

Well, more of a patois really, because this array is completely nonstandard and much less conventional than the first two!  Via Craigslist, I happened upon a remarkable creation on the back lot of a local farmer.  His son built a large solar concentrator quite a few years ago by laboriously glueing hundreds of hand-cut mirrors to a ten-foot diameter C-band satellite dish (state flower of West Virginia, common 1980's yard art).  This aluminum mesh dish took the liquid nails perfectly, and very few little mirrors had been knocked off during its years of neglect.  The dish mounting pole was welded to a very beefy base of heavy steel tube and channel, which was mounted on casters (which could even still roll after being encased in a turkey manure slurry for the past decade!  The young man's creation can still set fire to green wood in seconds and melt aluminum.  Though it has a focal length of about five feet (meaning that at ten feet away the un-focused sunlight is no stronger than what's already pouring down from heaven), the local high school's science fair administrators refused to allow the device on campus, fearing it would burn the place down.  Such small-mindedness is no doubt a contributing factor to that lad now being a grown engineer working far from home...

Anyway, good neighbor Tom loaned a wide-decked trailer and good buddy Tim helped me haul the device home, which we did under cover of darkness to avoid undue attention to our oversize load, but it sure got the attention of stopped motorists at the crossroads, when their headlights were reflected back at them by the passing monstrosity.  To stimulate discussion with the neighbors, I left it parked out front for a few days, declaring that we'd all have free TV very soon.....
After arousing sufficient curiosity, I managed to unload it without flipping the dish, thanks in no small part to its sturdy foundation.  
The dish was dubbed "Archimedes' Death Ray", and served to entertain and roast food during Jason's 8th birthday party on a partly cloudy Saturday in March.  Word to the wise- sunshine doesn't really roast marshmallows, it just turns them into an iris-searing white blob of incandescence before they melt and slide down the skewer...  Hot dogs, on the other hand, blister in seconds.  Patience was required to warm the core without burning the skin!  
After our fun with the sun it was time to get serious about making greater use of said solar energy, so removed the dish (again, without flipping it even though the thing weighed a ton!).  It awaits reincarnation as a padoga roof over our hot tub, complete with a disco ball hanging from the center!

The antenna base was refitted with a uni-strut frame and grid of aluminum solar rail leftover from my salvaged Kaneka array, and topped with the 18 BP modules that were originally mounted on the WattSun dual-axis tracker (sidelined in favor of more productive and powerful made-in Washington Itek Energy PV panels).  The original 36" linear actuator is plenty powerful to move this new array, even after hibernating in a barn for a decade after being removed from the salvaged satellite dish during it's first afterlife. My current plan is to just manually adjust the elevation on a seasonal basis with the original elevation screw, and  use the actuator for daily east-west action, which does the most to maximize production.  I'm using the Axe-Tracka controller from Australia again on this array after a good experience with this hand-built unit on my first array and excellent customer service from the actual man who designs and builds 'em at home, rather than some nameless corporation or Ali-Baban. You'll also notice that I added wheels and a removeable tongue (which also serves a the removeable hitch for the Karmann Eclectric!).  That allows repositioning of the array and trailer loading with minimal effort.  The frame was cleverly welded so as to allow pass-through outriggers for stabilization.  I haven't found the ultimate solution yet, but will start with some timbers inserted through the steel for safety and added stability.  The tip-tilt motion of a satellite dish is not as refined as the WattSun tracker, which keeps modules parallel to the ground as the array is rotated about the pole, but the mechanisms are much simpler and robust this way.  

After this assembly and testing, the frame was painted (green, of course) and the new-old-stock Outback Power PS-1 installed on the base.  Next comes 48 Volts of EV-salvaged batteries, which will ballast the array against wind loading while also providing backup power for critical circuits in the home.  It doesn't get much better than this!!


Thursday, March 31, 2016

Gotta big new Green Box, but where should I stick it?

Ten years after getting my first Zilla (John Wayland's old Godzilla 1800, S/N 003), and then a Z1k, I've finally graduated to a Z2k for the Karmann Eclectric!  

Mounting this 2000 amp monster poses a quandary.  Do we saddle it directly to the 9" motor case?  My first controller endured some fairly violent clutch chatter before I got that all sorted out, and it died mysteriously while the car was tied down in a trailer, but with the telltale smell of popped capacitors.  Otmar had warned that extra vibration is something to avoid.   So- I seek consensus.  Is the eye candy of a color-matched controller riding atop its motor-mate with very short input cables worthwhile, or should the controller sit a foot away mounted vertically on the firewall, possibly even on rubber isolators for maximum vibration dampening?  In the past decade, many other motors have been ridden by their controllers- any regrets out there?  The other option is to mount it to the firewall, where there's plenty of space and probably enough structure to support that 24 lb chunk of copper.  


Thursday, March 17, 2016

Sylvester Lives!

On this sunniest and warmest day yet of 2016, we made the final wiring connections, and after a couple of minor hiccups, Sylvester took his first drive on Lithium with Zilla Power!
Only for a few blocks, as the pack needs to be recharged and there remains a lot of wiring clean-up and adjustments to be done, but we DIDN'T BLOW ANYTHING UP.

Must be just a little luck o' the Irish in there, if I don't say so myself.

And it just so happened that I found a couple other ice cream trucks to park next to too!
(Yes, generic white trucklets in front of generic white houselets, Sumner really is more interesting that it looks!)



Thursday, March 10, 2016

A month is a long time

So, we have much progress to report on the Grumman Kurbwatt!
Installation of the following components has been accomplished.

  • Manzanita Micro PFC-20 battery charger with J1772 compatibility upgrade, along with an external dc-rated input circuit breaker and output fusing that bypasses the 'Run' contactor.  
  • Zilla 1k motor controller, coolant pump, radiator, reservoir, and fan.
  • 53 amp 13.8 Volt output DC-DC converter and 'house battery' using a spare Valence XP-27
  • Two Kilovac contactors, one for "Run" and one for safety.
  • A Gigavac manual disconnect, essentially a rotary version of their vacuum-sealed contactors
  • An LED dome light with red "night vision" auxiliary function.
We re-energized the 12V system yesterday to re-verify function of all original components and begin the commissioning of the 12V control and instrumentation wiring.  

After that comes the first high-voltage tests; first of the charging system and then propulsion.  Having a rear-mounted pack with a rear disconnect has been a blessing, in that we can work freely without any high voltage present in the motor bay.  



Thursday, February 11, 2016

Batteries Are In and Baby Got Bling (just some new shoes).

We kept it simple and put a single string of ten modules in the tray for, 120 V nominal and 15.6 kWh of capacity.

There's a couple of awkward-looking long jumpers in there, but it was the only layout that placed most positive and most negative at the back of the pack without placing any modules on edge.  
The rearmost compartment has one battery in it in this photo as a counterweight, but that cavity will remain empty for Phase 1.  It may be used when a second string of modules is added.  This shot was taken while filling the gaps with foam insulation board.  

After cabling up the battery pack, freshening up the Anderson disconnects and re-mounting them with stainless hardware (yes, the corrosion risk is tiny compared to the old flooded pack, but I don't like rust!), we turned our attention to the outside.  

Through creative dealmaking, I wound up with a couple of parts cars: a 1985 Nissan Pulsar converted by Dave Cloud in 1996, which the last owner had never gotten around to modernizing, so we're reusing the Valence battery pack that never got installed, along with the battery charger and a few other components to reuse on this project, and the motor, etc. for others.  

That car also came with some very shiny aluminum wheels that were good as new and period-appropriate for the Grumman.  Besides- everybody knows that little Japanese cars use a 4x100 lug bolt pattern, right?  Confident in that fact, I mounted new LRR tires and brought my prize to the student mechanics.    
Time for another lesson.  The Pulsar had 4x4.5" lug spacing, aka 4x113.4mm.  So no fit.  There's room in the solid centers to re-drill the 4x100 pattern, but machine shops willing to take on that work are rare, and I found a set of billet adaptors for less than redrilling should cost.  
The adaptors add 1" of track to each side, but the front tires still fit within the wheelwells and there's no chance of rubbing, even at full suspension travel.  In the rear, the sidewall bulge is barely wider than the body, but there won't be any rubbing either, due to the generous wheel openings.  All the tread is inside the wheelwell, but some fender flares might be in order down the line.  I'm not worried about extra stress on the spindles from a wider stance, as this battery pack is 484 pounds lighter than the original one, and even adding a second string will be 40 lbs less than original, and more evenly distributed.  Lastly this van was designed to carry a full load of mail in addition to the lead-acid batteries, so there will be durability to spare.  


Lastly these new wheels brought our attention to a bit of camber, probably because the suspension is riding higher to the tune of 484 lbs.  It's not bad, so I'll wait for the weight of a second string before adjusting the ride height.  And of course, if this project wraps up well, the kids would love to airbag Sylvester!  



Thursday, January 28, 2016

Stuffing is the hardest part

After rebuilding the Grumman battery tray rollers with technical help from the capable countermen at Motion Industries, we discovered that though the tray could hold 14 batteries with a few rows set on end, two of those rows would just barely interfere with a floor beam, and the cabling gets difficult any time you set batteries on end.  Also, the manufacturer may allow it, but they're never quite as comfortable with any installation where the batteries don't sit on their base as designed.
That and other factors is pushing us towards a simpler pack layout with ten in the main tray, and ten in the forward body cavities.  Those two parallel strings at 120V nominal will still provide over 30 kWh of capacity, yet be a very safe voltage for student mechanics to work with.

BUT, when adult entertainment is desired, a simple switch could unite the two strings in a series circuit of 240V for higher performance.

Also in the interest of speed and simplicity, I'm leaning towards getting the van rolling with a single 10-battery pack to start off with, and then add more once the bugs are worked out of EVerything else.  placing batteries is tough work, especially when safety is job one!

The charging inlet has been changed from a jury-rigged industrial plug that was placing 12 VDC on two pins and 144 VDC on the other two, all in close-proximity exposed blades, to the modern J1772 standard.  The original inlet mounting plate was reused, so of course a billet aluminum inlet from Modular EV Power was used to match!