Riding, Instruments, & Batteries

School is occupying most of my time, but I've worked in plenty of motorcycling and a lot has occurred in the last month.

The thing is a joy to ride. I know I already tried to describe the sound, but it's such a cool whirring noise. "Idling" at stop lights is completely silent and really makes it stand out when somebody knows better. It's a real attention-getter in general too, because even though people may not recognize it as being electric, they know something is missing, or changed, or totally different about it. Makes for an easy conversation starter, really. As you can see below, I've put 120 km on it so far, which is 74 miles.

Hardware:
I had a few mechanical issues early on. The rear hub is attached to the rear sprocket with four bolts. The nuts are captured in the hub. When I originally tore the rear hob down, I had to fight two bolt-head-locking washers. Each washers secures a pair of adjacent bolts by going on before the sprocket (acting as a washer of sorts) and then being force-formed around the head of the bolts (acting as a bolt-head-lock) to keep them from turning. Long story short, I completely forgot about them in re-assembly and they most definitely serve a purpose. I lost several bolts out of the hub (banging up the swing-arm, the hub, and the sprocket in the process) and unknowingly, barely made it home once or twice. What a mess - I felt stupid.

Gearing:
Meanwhile, I was also finding out that my gear ratio was not going to suffice. The rear sprocket was kind of a random find, so we just went with it because it was easy to make it work. A little measuring, welding, and painting and suddenly, it was ready. We either forgot to adjust the desired number of teeth for the front sprocket, or again went with what was readily available locally. At the time the bike was licensed for use, the rear was a 68-tooth and the front, a 12-tooth. That's a ratio of 5.667:1. That's pretty steep. Having very little experience on any kind of motorcycle, I was still impressed with it's power and ability, but as I tested the top speed, it became obvious this ratio wouldn't meet my long-term requirements. The top speed was 43 mph. The way to work is 45 mph, which means traffic goes 50 mph, so my first ride to work was a bit scary. The trip was a success, but it sealed the deal. I did some calculations and asked a few experts online. We didn't look for a new rear sprocket - I kind of assumed it be hard to find and make work but perhaps not. We went local again and got a 17-tooth front sprocket instead. What a jump! Now the ratio would be 4:1. That's exactly the ratio Juiced from ElMoto suggested for street bikes - as opposed to 3.5:1 for his drag bikes. This new sprocket's arrival coincided with that of the replacement hub, so I changed out both at once, lengthened the chain by four links and I feel great about it. The new hub not only had nuts which fit better, but it came with a new bearing already installed and it was so much smoother than the original. I bought some removable Loctite for the hub bolts and I installed the bolt-head-locking washers with the proper tools for a super snug rear-end. The result was just what both I and my dad calculated. The top speed is now 56 mph. This is perfect for my current and future work commute (we're moving, eventually).

PakTrakr
The PakTrakr has been really useful for gathering all kinds of information: amperage, battery voltages, kW usage, etc. Unfortunately, it's not working quite as smoothly as I had hoped. It could be user error, but I've had problems with the following:

• Battery voltage gauge indicates almost empty while batteries are nearly full.
• The LCD screen has blanked out while under medium to heavy acceleration.
• The entire module has reset while under heavy acceleration.

In the PakTrakr manual, it does state the batteries must be fully charged before plugging in the PakTrakr. The battery gauge showing empty instead of full could therefore be my fault, as I'm not totally sure what "fully charged" is for my system. A 12-volt AGM battery can apparently hold around 12.8 volts under normal conditions, so six of those make for 76.8 volts. However, since it reset on me mid-ride the other day, it now thinks my whole system is overcharged. =/ I do and have had the module set to AGM batteries, so I know it's not the case that it thinks the batteries are flooded or some other chemistry. I guess I'll have to email the manufacturer or post on the forums to figure out what is going on.

Amps
The amperage on the battery side of the controller has, of course, changed along with the gearing changes. At 5.667:1, I could slowly accelerate up to 25 or 30 mph without breaking 15 amps. At 4:1, I'm immediately at 30 amps or so and it's difficult to cruise at any speed while drawing less than 25 amps. Under hard acceleration, I used to pull maybe 110 amps at the most. With the new ratio, I got a reading of 150 amps. Keep in mind, that this is on the battery side. The motor is rated for a continuous 125 amps with bursts of up to 300 amps for no more than 30 seconds or so. The reduction in leverage is very apparent, both in these values and in the physical feel and pull of the bike. For my use though, it's worth having the top speed where it is now, instead of all that acceleration. I plan on trying to take care of this batch of batteries as much as possible, anyway.

Watts
I finally got a chance to gather a couple readings of kW usage as well. I never checked this with the original gearing, but the new setup resulted in 3.5 kW at around 25 or 30 mph and 5.4 kW at a steady 50 mph on level road.

3.5 kW / 30 mph = 3.5 kWh / 30 miles = .11667 kWh/mile = 116 Wh/mile = 72.5 Wh/km
Similarly, 5.4 kW at 50 mph is 108 Wh/mile = 67.5 Wh/km
I am not positive whether or not these calculations are correct, but they do seem reasonably close to that of other bikes of similar design.

Battery charging and discharging:
Below is the log that I've kept on battery charging discharging. This may or may not be terribly useful just yet, but in case any of the batteries don't last like the others, I'll be able to see if it was destined to or if I did something wrong.

SC = Start of Charge
EC = End of Charge
SR = Start of Ride
ER = End of Ride
BC = Battery Check

Act.	Y	M	D	h	m	B1	B2	B3	B4	B5	B6		Pack		State	Odom	Ratio
SC	10	8	19	22	17	11.5	11.7	11.6	11.7	11.8	11.8		70.1			39.2	5.7:1
EC													76.7			39.2
SR													76.8		resting	39.5
ER	10	8	22	19	00	11.7	12.0	11.9	11.8	11.9	11.9		71.3			68.5
SC	10	8	23	21	00											68.5
EC	10	8	23	23	30	12.4	12.6	12.5	12.4	12.5	12.5		74.9		resting	68.5
SC	10	8	24	20	40	12.2	12.5	12.4	12.3	12.4	12.4		74.2		resting	68.6
EC	10	8	24	21	40	13.0	13.3	13.2	13.0	13.1	13.2		78.8		charging	68.6
EC	10	8	24	22	25	12.5	12.8	12.6	12.5	12.6	12.7		75.6		resting	68.6
SR	10	8	25	19	45	12.4	12.6	12.5	12.4	12.5	12.6		75.0		resting	68.7
ER	10	8	26	01	00	12.0	12.3	12.2	12.1	12.2	12.2		72.9		resting	80.6
SC	10	8	26	18	35	12.0	12.3	12.2	12.1	12.2	12.2		72.9		resting	80.6
EC	10	8	26	21	15								84.4		charging	80.6
EC	10	8	26	23	05	12.6	12.9	12.8	12.7	12.7	12.8		76.5		resting	80.6
SR	10	8	27	07	40										resting	80.6
ER	10	8	28	00	05	12.1	12.4	12.3	12.2	12.3	12.3		73.6		resting	91.1
SC	10	8	29	20	13											91.1
EC	10	8	29	22	00	13.1	15.7	15.2	13.2	13.4	13.5		84.1		charging	91.1
EC	10	8	29	22	50	12.5	12.9	12.7	12.6	12.7	12.8		76.2		resting	91.1
SR	10	9	18	00	28	11.8	12.5	12.4	12.3	12.4	12.4		73.7		resting	91.2	4.0:1
ER	10	9	18	01	25	11.5	12.2	12.1	12.0	12.1	12.2		72.1		resting	100.5
SC	10	9	18	13	55	11.5	12.2	12.1	12.0	12.1	12.2		72.1		resting	100.5
EC	10	9	18	16	10	12.3	12.2	12.1	12.0	12.1	12.2		72.9		chrg B1	100.5
EC	10	9	18	16	50	12.0	12.2	12.1	12.0	12.1	12.2		72.6		resting	100.5
SC	10	9	18	17	00	12.0	12.2	12.1	12.0	12.1	12.2		72.2		resting	100.5
EC	10	9	18	19	00	13.0	13.3	13.2	13.0	13.1	13.3		78.9		charging	100.5
SR	10	9	18	19	15	12.5	12.7	12.6	12.5	12.7	12.7		75.6		resting	100.5
ER	10	9	18	19	47	12.2	12.5	12.4	12.3	12.3	12.4		74.0		resting	105.2
SR	10	9	20	17	50	12.1	12.4	12.3	12.2	12.3	12.4		73.7		resting	105.2
ER	10	9	20	19	00	11.9	12.3	12.2	12.0	12.2	12.2		72.7		resting	110.1
SC	10	9	20	20	00											110.1
EC	10	9	20	22	00	13.0	14.6	13.6	13.1	13.6	13.6		81.2		charging	110.1
EC	10	9	20	23	00	12.4	12.7	12.6	12.5	12.7	12.7		75.5		resting	110.1
SC	10	9	22	17	40	12.2	12.6	12.5	12.4	12.6	12.6		74.9		resting	110.1
EC	10	9	22	18	40	12.9	12.6	12.5	12.4	12.6	12.6		75.6		chrg B1	110.1
SR	10	9	22	19	05	12.5	12.6	12.5	12.4	12.6	12.6		75.0		resting	110.1
ER	10	9	22	20	47	11.9	12.2	12.1	12.0	12.2	12.2		72.5		resting	121.4
ER	10	9	22	23	10	11.9	12.2	12.1	12.0	12.2	12.2		72.6		resting	121.4
BC	10	9	23	17	45	11.9	12.2	12.1	12.0	12.2	12.2		72.6		resting	121.4
SC	10	9	23	17	50	11.9	12.2	12.1	12.0	12.2	12.2		72.6		resting	121.4
EC	10	9	23	23	00	12.8	12.2	12.1	12.0	12.2	12.2		73.5		chrg B1	121.4
EC	10	9	24	00	05	12.3	12.2	12.1	12.0	12.1	12.2		72.9		resting	121.4

I'm still learning plenty about the batteries and my chargers. The chargers are supposed to be intelligent enough to do a 3-stage charge and turn their LEDs green when in the float-stage. This has never happened and makes me worry about A) the chargers being wired and used in a manner for which they were not engineered or B) the two large sparks upon finally assembly having screwed them up. I guess option C would be that I've never absolutely fully charged the battery pack halves. This would actually be good news I think. What's strange is that the PakTrakr shows some batteries slowly being charged up to 12.9 volts, while others batteries show to be charging up to 14 volts and higher, and accelerating upward in charge voltage. For example, look at August 29th, during charging (EC.10.08.29.22.00). Here, batteries 2 and 3 were very far above 13 volts, which was scary and I have no idea if this is dangerous or normal. Maybe they would eventually get float-charged by their charger, once B1 matched them.

Balancing:
Balancing the pack is also a new adventure. I purchased a 12 volt battery charger from Walmart which stated it was compatible with AGM type batteries. So far, batteries 1 and 4 have turned out to rest just a bit lower than the others. Attempts to bring B1 up with the likes of B5 and B6 haven't exactly been successful just yet. However, I haven't let this charger, like the other on-board chargers, reach what it considers fully-charged. I still need to learn how sensitive the batteries really are and whether I'm hurting them in any way. Once again, this will take research and assistance from the forums probably.

Other Notes:
I accidentally got caught in the rain the other evening - No failures of any kind, but how much water can the ME709 really take in those vents?

Inspecting the bike has been more critical than I expected. Had I inspected it closer from day one before each ride, I would have avoided several headaches and delays. Far too many close calls in this area.

Also, for the record, I would like to say how much I enjoy the correctness of the term "motor-cycle". Naturally, I never thought of it as inaccurate before stumbling into the EV scene, but how cool is it that my bike really is a motor cycle, not an engine cycle.

-Colby