Wednesday, December 29, 2010

Holiday Inn

Time seems to be a rare commodity lately.  I had to cover up El Gixxer for the winter to keep the other garage projects from contaminating the old boy.  A sad state of affairs.  Prior to my Winter break I had the 25 Headway cells installed and did a series of test rides to see how they faired.  To say I'm impressed is a gross understatement.  25 of these 16AH batteries are 50 lbs. lighter than the 17AH lead units they replaced, but put out  way more juice. 


Not wanting to damage the cells, I needed to keep my current draw under 10C (160 Amps).  I borrowed a clamp meter and did some riding to calibrate my wrist.  Turns out 150 Amps accelerates the bike pretty well, and maintaining the top speed of 48mph only takes about 50-60 Amps.  I started out at 5.0 miles, and worked my way up 10.2 miles on the last trip, which happens to be 0.2 miles longer than my round trip commute.  With the average voltage of the cells starting at 3.40 I finished at at average voltage of 3.24.  Plenty of juice to get to work and back.  But having spent all funding on batteries, I was out of cash to finish up the 12V wiring. 


Bummed I couldn't be legally on the road, I turned my attention to charging and monitoring voltages.  My plan was to use the Headway 72V charger (which charges to 86V) on the 25 cells without BMS.  By using 25 cells instead of the usual 24 cells, they are less likely to be overcharged. With 25 cells in the pack, the average charged cell is 3.42V, which is just about right, since there is very little capacity above 3.45V.  Some of the cells were noticeably higher, between 3.50 and 3.8V, and some were lower at 3.32 to 3.34.  I made some attempt to top balance, by draining a few of the highest ones with a small light bulb.  But every time I ran them through a discharge/charge cycle, they were out of balance again.  I kinda see the need for a BMS, but still think the safest route is to under-charge and under-discharge.


The only thing I wanted for Christmas was another set of Headway 40160S cells and Santa sure delivered. 

Next step is to build up my 2P25S pack of 50 cells and turn up the Amps.

Tuesday, September 14, 2010

From the Ashes...

With a bunch of burned out chargers and smoked battery, things were not looking so good.  I contemplated buying replacement chargers or more of the Battery Tenders, but that would mean buying a battery or two.  Unfortunately, I could not justify $2000+ for Thundersky or CALB units, and even if I could, what would I charge them with?

Epiphany:  If I use a cylindrical cells, I can put together a modular pack that will handle my daily commute with a lower initial cost.  I may need to charge at work, and watch my Amps carefully, but at least I will be on the road.  As funds allow, I can add more batteries. Sure, the $/AH will be higher, but if my goal is decent acceleration and a 10.0 mile round trip, this really makes sense.

Big Break #1:  One of the guys on ElMoto.Net was selling a 72V charger made for Headway batteries.  It was a bargain so I jumped at it, thinking it could be used for any LiFePO4, and even temporarily for SLA's, if I stay that route a little longer.

Big Break #2:  Headway comes out with a new bigger cells (40160S).  These 16AH cylindrical cells will do 5C continuously and 10C for 30 seconds.

Big Break #3:  Manzanita Micro starts carrying Headway cells.  A reputable US based supplier is critical.  They are a long time player in the EV industry and have a terrific reputation for service.

So I dropped a small fortune on 25 cells, bus bars and holders.  Only problem now is all the empty space that is left.

Up In Smoke

Last month, after a test run on a fairly hot day, I plugged in my bank of ACI chargers and left them to do their job.  I returned a few hours later and noticed flashing red LEDs.  As I got closer I could see some severe distortion of the charger cases.
Crud!
All of the chargers had blown thier fuses, and three of the six had significant heat damage.  I tried replacing the fuses but the damaged ones still did not function.  A quick disection reveals the transistors smoked themselves - note the burn marks on the heat sink.
I'm no longer a fan of the ACI chargers. In fact I was pretty upset at ACI for building such a crummy product, for a while.  But you get what you pay for and they are cheap. 

The bigger question was what am I supposed to charge my SLA's with?  I proceeded to plug in Ole' Reliable:  my Deltran Battery Tender Plus.  The Battery Tender only charges at 1.25A, so it's slow and I could only charge one battery at a time. 

The other question, is are the batteries still any good?  After two days on the charger, the 17AH batteries seemed to be holdin a charge OK and voltages looked almost normal, but two were slightly lower than the others. Suspect cells were at 12.7V and 12.9V vs. 13.1-13.3V for the others. 

A trip down the street and back, the bike seemed to run fine.  Then I took El Gixxer around the block a few times and the batteries started to feel sluggish - so I gave the throttle a little more wrist. Oops! A high pitched squeal pierced the air - I thought it was a controller alarm, so I let off the throttle and the sound went away.  Then I heard a sound like a pressure cooker belching steam and looked down to see the #5 cell spewing gas only inches from my knee.  The controller went into Limp mode and I barely made it back to the garage.

Double-Crud!!


Friday, July 2, 2010

Back in Black

I've been risking life and limb with every test ride, due the fact that my rear tire is beyond bald. There was  significant amount of cord showing (check out the cross section).  So for Father's day my lovely wife gave me a new rear skin (OK I did the shopping).  In addition to the useless rubber, the rear rim is blessed with fluouresent green and purple showing through the two layers of poorly applied flat black   Might as well pull the tire and clean up the rim.  Check out the edge of the rim for the previous color samples. 

It was a total pain to clean and sand, thanks to massive amounts of chain lube and globs of paint.  I think the last coat of black was rolled on.  I also had to clean up the gouged edges of the rim where somebody had ridden the bike on it's side.  Honestly it's still not that great, but is a whole lot better.
Here it is with the new tire, a sport-touring dual compound that will last a little longer with my mild riding habits.  Nice to have some tread to use.

Tuesday, June 22, 2010

DIY tail

I really would like to put an AirTech fiberglass tailsection on the bike, but the budget continues to be tight, so we continue with the "use what ya got" theme.  I dug up some acrylic sheet, and glued a paper version of the sheetmetal pattern I've been working on for the tailsection. I used a 3/4" bar and a small torch to form the bends on the rough blank.  I then took the dremel tool to finish cutting the pattern.


A quick shot of  primer, wentsand, a layer of Rustoleum. Viola, a tail is born.  Just don't look too close.


Monday, June 7, 2010

No longer Flying Blind (sort of...)

For some reason, after putting a guard on the left side of the Upper Battery Tray, I felt the compelled to make an identical piece for the right sided of the bike, even though it serves no functional purpose.  Still looks better, and more importantly is more symmetrical (OCD issues).

Up until this point, a test ride was an excercise in guesswork.  My speedo didn't work and I had no way to measure anything except with my multimeter.  The speedo cable I got with the bike was the wrong one, so I reluctantly ordered one from an eBay retailer. 13.95+shipping and now I can see my speed tops out at 43mph (very close to what I geared for).

I also wanted to know Voltage at any given instant, so I can see how much the batteries are sagging under load.  One of my ELMOTO.NET brothers was selling a cheap voltage panel menter, so I went for it.  Unfortunately, I may have it hooked up wrong, because as soon as I use any juice, the voltage display varies wildly, and shows negative values often.  Seems to work fine at static readings.  I will hold off making a permanent bracket until I figure it out.



I'm still shopping eBay for an analog current gage that will fit in my Tach location. The hard part is finding one that looks right with a black face and white graphics.

Sunday, April 25, 2010

Earth Day

I spent Earth Day at the local Community College displaying El Gixxer along with some other EV's.  Although I'm not a terribly social person, it was cool to hang out with the other local EVer's. When we weren't answering questions from the casual observer, we were busy comparing notes on our projects.
This video doesn't have much of the EV's in it, but I neglected to take any pictures (doh!), so I can only blame myself.
Earth Day Video

The Earth Day experience has inspired met get this thing road-worthy.  I need to start securing the batteries in the racks so they don't shift around. First on the list is a Guard for the left side of the Upper Battery Tray - to keep the batteries from falling out. 

The removable Guard is necessary for battery maintenance.  A simple piece made from 3/16 sheet aluminum, and of course cut with the plasma cutter.  The Guard mimics the geometry of the tray, but extends the left side of the tray high enough to prevent shifting of the power pack.

Sunday, April 4, 2010

Performance Corrections & Wiring Cleanup

I was so enamored by the fact that my creation actually worked, it completely escaped me that it wasn't working as planned.  The acceleration and range were on par with a toy.  I initially suspected the batteries weren't capable of generating the amps needed.  A quick visit to the B-B Battery site shows these 17AH units can do 299A for up to 5 seconds.  Pack voltage seemed plenty high after charging:  78.2V

I knew that any one of the components with temporary connections could be suspect.  First on the list to correct was the main battery disconnect.  Gone is the 30A breaker zip-tied to the wiring panel.  In its place is a real battery disconnect switch, mounted in a new aluminum bracket behind the battery tray.  Since I don't need access to the wiring panel to flip the power on, I could now ride with the tank on.
I also needed to mount the 400A  fuse, rather than suspend it off the contactor terminal.  I know there are mounting blocks for these fuses, but why not take advantage of the acrylic wiring panel, and save myself $20.  Looks cooler too.
Subsequent test rides still showed something not quite right.  Three trips down the street and back later, the bike would barely limp up the driveway, but the pack voltage was still 74V.  The best thing I could think of was to pull some data from the controller while riding.  This would also give me a chance to tweak the controller settings.  Upon connecting the controller to the software, my neglect was evident.  The "Under Voltage" slider was was maxxed out, essentially cripling the controller immediately.  By hitting the "Defaults" button, reasonable starting values were inserted, but I upped the top speed and Max Output Curent a little just to be safe.
Acceleration is much better and the controller logs show almost 180A.  I will need to get some lights wired up ASAP so I can test the range.

Starting to feel like a real motorycyle.

Saturday, March 13, 2010

Frankenstein Rides Again

Technically, I've got dozens of things to finish up before El Gixxer is road worthy, but I just can't wait. In EV Motorcycle lingo the first ride has been coined "Frankenstein Mode". Components are are jury rigged and zip tied just good enough to get you down the block. It's not pretty but it works.

video

Acceleration with my 17AH battery pack is pathetic, and top speed seems to be about 20MPH. Nevertheless, it was just as thrilling as hitting triple digits on any other bike.

After four trips down my street and back (probably 1.5 miles total) the batteries were definately done, but it was enough to put that mile-wide EV grin on my face.

Friday, March 12, 2010

It's Alive

An early morning wiring session got me to the point where I need to fire it up. I connected the negative side of the battery pack for the first time, and cautiously flipped the breaker: No smoke.

The Alltrax had the the LED indicating green, but when I twisted the throttle gently nothing happened. Fully opening the throttle turned the LED red. Panic!

I then realized I hadn't engaged the contactor. A flip of the switch and the contactor clicked closed. Now the rear wheel spins happily in response to my twisting wrist.

Cue Oingo Boingo's song "Weird Science"

video

Thursday, March 4, 2010

Burn Notice

Seems like every EV project has one of these episodes.  I thought I was being real careful with my connections.  But my grip on a connecting cable slipped and the end of it managed to contact the wrong spot.  It immidiately lit up a bright-white arc and proceeded to burn anything close for a fraction of a second.

The damage to the terminal and the nearby finger were minor.  But I think another helping of caution pie will do me some good.

Monday, March 1, 2010

Vanity and Power

As is often the case with a well used bike, many pieces are not quite original or altogether missing.  Such was the case for my mirrors:  missing in action.  Truth be told, I never liked the the Gixxer stock mirrors from the 80's and early 90's.  I went searching for something a little more fashionable.  I found this "blingin" set for a reasonable price at RoaringToyz.com.  The chrome is a little over the top, but matches the fasteners I've been putting on the body work. I'm fairly sure my kids are horrified by my sense (or lack) of style.

I started playing with the battery layout.  The six 17AH units fit with room to spare in the upper battery tray.   The maze of wires is starting to hit home.

The "dedicated charger for each battery" scheme has one serious drawback - cable management.  Where am I supposed to stuff these things?

Sunday, February 28, 2010

A Place To Call Home

My AllTrax controller got booted from its home when I mounted the upper battery tray.  So it was high time to re-locate the controller, and a provide some mounting surfaces for the other electrical components. 

I really liked the previous location under the tank. Because it was toward the rear of the steel tank, it shielded the rider from a meltdown.  So my plan is basically put it in the same place, but a little higher to clear the battery tray fasteners.

I found a cool piece of 3/8" thick acrylic in a salvage pile.  It had several holes cut into it, probably to hold or display something.  Perfect for mounting the electrical components, however, not strong enough to hold the controller. But it was so cool looking, so I had to use it.

 I trimmed the Acrylic to fit the front 3/4 of the frame opening. Conveniently a couple of threaded inserts were already located  on the front edge (formerly for some rubber pads to support the tank). I drilled and tapped a few more spots on the frame rail to finish securing the piece.

I trimmed a scrap of 3/8" aluminum plate(leftover from my motor mounts) to span the frame rails and support the controller. Some creative filing and grinding was required to work around the welds. A few drilled and tapped holes later, the controller is mounted.

I even had a little time to mount the Contactor and do a little wiring.  The precharge resistor and main fuse are mounted directly to the contactor.  Color coding the high-current wires (#2 gauge welding cable), keeps me from getting my wires crossed. 

NOTE: much of this wiring layout is only temporary to shakedown the powertrain.


Thursday, February 18, 2010

Lost in the Electric Forest

I've been stalled for a while, primarily because I'm not sure of my direction to take with the batteries and chargers.  I follow the Yahoo Thundersky group, and it seems the more I read, the dumber I become.  I know that Lithum Batteries are a must, but the lack of reliable chargers and management systems make me very nervous.  It's bad enough the only way to get lithium batteries is from china, so I hate to source a charger the same way.  I placed inquiries with Schumacher and Deltran and neither has a product for charging Lithium chemistry.

The old saying goes: "hard to see the forest for the trees" (or something like that).  It's now clear to me that I'm getting bogged down in details but not making any progress.  So, I'm going to focus on getting things running without wasting too much money. (wait have I said that before?) 

I have these B&B 17AH SLA batteries sitting in my garage, salvaged from a  Data Center UPS.  From the start, I've wanted to use them to get educated and test things out, but hadn't figured out the charging method that would worlk for them and Lithum. Occasionally I hook them up to my Battery Tender Plus, to keep them in shape, but there is no way I'm putting six of those on the bike, just for short term use.  Fortunately, one of my brethren on El Moto was selling six of the ACI SuperChargers at a reasonable price.

After getting the chargers, I plugged them all in to make sure they are charging properly.  Now I'm taking turns connecting one of the Gixxer's headlamps to each battery for about 30 minutes, then connecting the charger and a volt meter to observe the charging cycle.