It arrived, but Holy Caution, Batman... Check your wiring!

[philf]

My rear wheel kit arrived yesterday, making the transit time from BC to Ontario 6 business days.  Not bad for a bulky item at the reduced shipping rate these guys offer.

Usual first impressions...  plenty of slack spokes, cheesy tire, annoying valve...  And they shipped the wrong throttle.  I'd ordered a thumb throttle, but got the twist style instead...  Oh well, will press on until I can get that rectified...

I started to put everything together, and this is where things got REALLY interesting...

The first thing I attacked was wiring up the battery pack and power harness, so I could check out the charger.  We've seen plenty of nightmares about those, and I wanted to top up the batteries I've had kicking around for a few weeks - in a supervised way - to prove that everything was OK.  So, following the less-than-perfect English instructions on the charger, I first connected the charger to the batteries, then...  Uh oh.  SMOKE!  I quickly disconnected...

Nothing for it, I've got a good understanding of electronics and plenty of related tools, to boot.  So I slit the warranty labels and opened the charger's case.  Nothing obviously fried, and I went through as many of the components as one can check easily with a DMM and they all SEEMED OK.  The plastic heat shrink tubing on the large cap on the AC input side of the board was burned of off one side - that's a bit of an enigma.  So I plugged the charger into the wall and checked the output...  38.5v.  I would have been happy to have seen a pot on the board that would allow you to tweak that - there isn't one, it's all fixed components with op-amps providing the control...

Hmmm, I thought.  What was wrong with this picture?

Before trying again, I followed the wiring through from the charger to the connector dongle that hangs off the batteries.  AH HA!  The way this was wired, the yellow/green wire was positive, and the red one with the fuse was negative.  Completely wrong, I thought, but...  I reversed the wires and everything seemed to work fine.

So I went on to mounting the rear wheel.  No issues there, though to get it to fit smoothly, I had to file the paint off the inside of the receiver on one side, but no biggie.  Width-wise, I did need to spread the forks apart a little less than a quarter of an inch (not a lot, I thought).  The bike IS alloy, so this still didn't sit well with me - but it wasn't like asking it to bend an inch or anything, so I pressed on...  Wheel sat perfectly centered, and all looked good (except for that cheesy tire - which is coming off today).

Before getting further carried away, I thought I'd test the electronics and motor at this point.  I set up the batteries, controller, throttle, and battery indicator on the bench and stood the bike in front, wiring the motor to the controller (the cable is long enough).  I just wanted to see this puppy spin before I got into pulling any more of the bike apart.  Hell, let's be honest, I just wanted to see it spin.  Period :-)

That eagerness is what stopped me from realizing and preventing what happened next...

I grabbed the power connector from the controller, plugged it into the dongle on the battery pack, and ZOT!!!  No smoke, but one of the contacts in the connector pretty much vaporized instantly and the fuse flashed VERY brightly as it gave itself up to doing its job.

Doh. The problem was obvious in a millisecond - the charger was wired backwards where the wires leave the PCB to the charger's connector.  My correcting the problem downstream from there meant that I was now carrying forward the error and making the battery pack reverse-polarity with respect to the controller.  What an idiot one can be when one gets too carried away with excitement.

So, A new connector, fuse, and corrected wiring (I have plenty of this stuff lying around, fortunately), and I tried again...  Battery indicator showed two green LEDs (I'm assuming this is to indicate "between half and full"), and twisting the throttle spun up the rear wheel.  A sigh of relief - at least the designers of the controller appear to have had the good sense to put a reverse-wired diode across the power inputs to protect things (by popping the fuse) before damage can occur to the rest of the electronics.  I'd be amazed if that diode can stand another hit like that.  Too bad the designers of the charger didn't include such a safeguard. 

All is well - except that it's obvious that I'm going to be busy with the spokewrench for an hour or so.  Wobbly, or what?  And all those spokes that are so loose, they rattle.  Off to the bike shop today to get a decent tire and tube (I want to leave the old wheel completely intact).  Hopefully I'll get a chance to get this thing together later this afternoon.

[philf]

Carrying on with myself...

After overcoming the slight difficulties I detailed in my last post, I have had the bike out for a quick run...  It took a while to true the wheel, and even after doing the best job I could on it, the thing still really isn't great.  It's slightly out of round (flat) where it's welded, and there is not much you can do about that.  With a new 26 x 1.95" tire mounted on it, though, the small "blip" is only mildly annoying.

Gotta say...  I'm actually more impressed with this thing than I thought I could be.  Very surprised by the torque (I'm 6' 1" at 220lbs, and it got me moving just fine, thanks!).  Didn't get TOO far into testing it - for two reasons.  Firstly, that I'd temporarily mounted the batteries on a seatpost rack, which really isn't strong enough (I wasn't expecting it to be, but the rack was handy), and secondly because I installed the kit on my girlfriend's bike.  She's a short-ass, and I felt like I was riding a pocket bike and sucking on my knees.

I think the thing that stands out, thinking about my after-analysis of my brief test run, is the ridiculous variety of wire gauges that are used throughout the system.  After a run that was about 10 minutes in duration, the controller was as cool as a cucumber.  The SLAs where slightly warmer than room temperature.  The warmest thing in the whole system was the piece of wire that was provided with the kit for the positive connection to the battery.  It's just a 12" chunk of 18 guage wire with a cheap fuse holder in the middle, into which is installed a 30A fuse.  This was a bit of a head scratcher when I first saw it, but after my first run, that red wire and the fuse holder were WARM.  Something I'll rewire for sure, while adding a decent power switch and a proper fuse holder.

I've corrected the rear rack issue today (I got a rack that securely mounts to the bike in 4 places, as to replace the aforementioned seatpost job) and changed a bunch of other hardware.  MUCH more secure. I also caved and bought a decent 36 hole rim.  If this thing stands up for a few good rides, I'm DEFINITELY going to re-lace that wheel.  I used to build wheels back in the 70's, so this'll be a refresher :-)  Thanks to the late Sheldon Brown for helping to get the cobwebs out.

The other thing that's pretty obvious, once you've put everything together, is that you really can't use a center kickstand.  With a trio of SLA batteries on the carrier (even small ones, which I tried first), there is just too much weight at the back of the bike.  On the center stand, the whole thing just wants to twist around and go wheels-up.  I've replaced the center stand with one that mounts just ahead of the rear axle, and it's MUCH steadier with the battery pack mounted.

More as it happens

[ahend]

Sounds like you are on your way!

I had a similar experience with my wheel. Not being too knowledgeable about how best to true it up, I took it in to a shop. They did what they could but the welded seam, as you pointed out, created a flat spot that could not be worked out. I should spring for a wheel here soon as well. The spoke-rim interface is scary too. A lot of undue side pressure is put on the nipples because they cannot seat in the rim completely parallel to the spoke axis. If you lace up the new wheel, I’d like to hear how it goes.

Sheldon Brown, can you remember the man without smiling?

[philf]

Well...

The intended victim of this project got to ride her bike for the first time today.  Big smiles :-)

I haven't re-laced the wheel (yet), but do have the rim of choice waiting in the wings.  I've also ordered another rear wheel kit for my own bike - because this has just been too much fun.  Well, actually, I'm sure that some readers of my earlier account would think it's been a NIGHTMARE - but I don't see it that way.  I feel I got what I paid for - hence the second purchase.

I mentioned the puff of smoke that came out of the charger, due to reverse wiring at the PCB, and once we ran the batteries down to where the needed a charge, I got a chance to see if the thing actually worked.  It didn't.

I went through the whole thing again, this time paying attention to how it was made.  There >IS< a protection diode in the charger that is intended to pop the fuse in the event that someone accidentally plugs the battery in backwards, but whoever they farmed out the PCB manufacture to has used the cheapest single-sided board stock that they could find.  The copper traces are REALLY thin.  So thin, in fact, that a trace had actually bubbled away without breaking the green solder mask.  There were no burns on the board, and I only caught it because I was looking at the thing in highly directional light.  When I poked at what I thought looked like a bubble, a piece of the mask - along with a quarter inch long piece of rippled copper - just fell off.

I bridged the melt point, and went to test the charger again.  THIS time, it was delivering charge.  I left it for about an hour, but when I came out to check on things, I was alarmed to find that the voltage across the battery had risen to nearly 45V and all three units were audibly boiling.  I disconnected the charger, and the whole pack rapidly dropped down and quiesced at about 39.2V.  I'm not way up on SLAs - I've only used them in the context of completed circuits (like UPSes or alarm systems).  I'm thinking this charger might've popped the relief caps out of the batteries if left unattended.  The batteries were not warm, however.  Just noisy.

I've ordered a 36V BatteryMinder charger/condititioner (which includes a thermal probe to include pack temperature in the charging equation) to regain some comfort.

Other'n that...

Other than making some elective wiring changes (swapping some of the connectors for ones that don't bug me, for example) all looks good....

[Grunchy]

Thanks for keeping us (other) newbs informed about your progress....
I keep thinking about the G.M. claim, "up and running in 20 minutes!"

Do you think humidity from the rain played any part in causing the shuddering problem?

[philf]

Of particular note...

Forgive any "pleklunks" in my typing.  I managed to seriously slice the ring finger on my left hand while (figures) unpacking my second GM rear wheel kit - which DHL delivered today.  No noodling on the guitar for me, at least for a bit :-(

In the context of this thread, though, I thought I would share...  Other than a quick once-over of the stuff in the kit (all was well), I was curious to check the charger.  Guess what?  Just like the charger I got with the first kit I got my mitts on, this one was reverse polarity as well.

So.

Without making the mistake of plugging the charger into the battery (before plugging the charger into the wall, as the instructions clearly dictate), I fixed the wiring and THEN plugged the thing in.  No crackling noises this time, and certainly no smoke.  And the damned thing WORKED!  Charged the batteries and actually quit when it was supposed to.  The tri-colour LED even switched from red to green when it was done.

How many of these things have gone out this way?  I can't believe I'm the only person batting a thousand on this.  Is it possible that such a simple thing is behind all of the complaints against the GM-supplied charger?

Wow...

[PaintingLoft.com]

..."to prove that everything was OK.  So, following the less-than-perfect English instructions on the charger"...

you got instructions?  I might be having the same problem.  I am clueless about electricity and don't even know how to check that problem.

http://goldenmotor.com/SMF/index.php?topic=328.0

i've had a little spark action on my latest pics on this post.  I'm trying to find a friend that knows anything about this.  I hope I didn't blast my controller when that happened.