Suzuk-E 

1987 Suzuki RM125 Conversion - Part 9 ...

June 2009

I never imagined that this project would drag on for 9 installments... if you too are frustrated that it hasn't resolved on a closing note, count yourself lucky that you haven't had to spend the time or money I have with so little to show for the effort...

Part #8 ended with a custom PWM LED Dimmer and an analog Voltage scaler to accommodate approximately 45V to 55V of deflection on a 1ma 85 ohm meter.

The sensor lines, Aux Battery, AC to the blower, and switch wiring to the small console would have been impossible for me to connect without the schematic for reference. 

This was predictably boring and sucked back at least 3 or 4 days as I was willing to let any diversion hold my attention, realistically a solid day without interruptions and a better attitude would have been enough to do a good job of it.

The application of intuitive colour coding and details like heat-shrinking soldered joints was probably the most time consuming, but hopefully will repay the effort in hours saved should problems arise and require diagnosis.

More Data Acquisition Gear

To the right is one of the distractions that I indulged in while avoiding the dreaded "Console wiring"...

Canadian Tire offered a "Blue Planet - Electronic Energy Meter" on special for under $20 one week and I just couldn't pass-up that sort of value.

As impressive a buy as that may seem, I added the materials to the right to create what I think the Energy Meter should have been from the factory...

Aside - Blue Planet & Canadian Tire, you're welcome... 

and Yes! I'd gladly accept any payment in the form of goods or currency you think is appropriate...

This is what I'm talkin' about!!!

Portable, compact and able to assess multiple loads like a PC, printer and multiple LCD screens as a unit...

The switch kills the Hot AC lead to the main outlet, a handy feature for the variety of Battery Chargers I own that are all absent a Power switch (even though they claim to be "Smart Chargers")

A very clever bit of code in the Blue Planet Energy Meter is the ability to log the Kwh and cumulative cost per Charge of say individual or Banks of batteries...

In our part of Canada we pay a flat 5.6 cents per Kwh up to the first 1000 Kwh's, and the rate jumps to 6.5 cents there after...

By checking our past bills I can generalize that we suck-back roughly 50/50 per billing period ie; 2,000 Kwh at a blended rate of 6.05 cents per Kwh...

6.05 is close enough to 6 cents that I use that value regardless of where we lay within the billing period...

Like the man that has just bought a hammer, and all the world is a "nail"... 

I proceeded to charge various configurations of 12, 36 & 48V strings of batteries and noting approximations of efficiency of the charger itself, since the meter is logging all the energy that is drawn from the wall rather than that Ideal value that actually activated the electrolyte in the cells.

The theoretical components of charger efficiency aside, if the Suzuk-E is drained down to 46 to 47V (noticeable performance loss) a full charge consistently comes in at well under 7 cents (even if the 4 bat's are charged individually with the Smart 12V AGM Charger...

There was a a week or 2 of putzing about with various pulley's to improve the belt-drive slippage under hi-load conditions, though the road run data was trending toward 30Km/hr on flat paved ground in 6th gear... I never was completely satisfied with the drive train for off-road usage.

Of the issues that I had concerns about was no-load power that the motor drew from the batteries with the rear wheel in the air... Typically the current draw was close to 10 Amps, equating to well over a half horse power being used by the internal drag of the gear-box and drive train.

This was the last straw some time in early May... 

After a particularly taxing afternoon of beating the trails testing of the AC-Blower and what may well have been the optimal primary drive ratio, the rubber gasket let loose and pissed the entire contents of the gear-box all over the floor...

Fuck-it!!! that disloyal bastard the "Gear-Box" had found the limit of my patience and was summarily demoted to the status of "Door-Stop".

And even then it's utility was suspect as it became the target of the dog's daily markings that aptly mirrored my opinion of the Gear-Box as well.

To be fair, the Gear-box is still a pretty cool bit of kit, but this application just doesn't have the disposable power available that would be required to keep it with the bike... Ideally an 8 to 10 Kw power plant would just shine with that set-up... 

It may not have been obvious from the informal tone of the preceding paragraphs, but we're talking a "Radical Paradigm Shift" here...

These are brand new, 36V 600Watt gear reduced motors procured from TNCScooters.com in Tennesse...

The reduction unit is identical to that posted on the Dirt-E build in 2007/08...

This phase is just to get accurate chain alignment and a secure motor fixture. 

The section below is cut from the spread-sheet that I use to find some basic operating parameters and use as a reference when "real-world" data is available to guide future changes or projects...

The area high-lighted in light blue is the "Target Zone" that I hope that the dual motor arrangement can achieve, based on the Stock 51 tooth rear wheel sprocket and a 13 tooth drive sprocket, driven by 6.77:1 reduction unit on each motor...

The factory MY1020 #35 sprocket is sacrificed for the higher purpose of securing the #40 13 tooth drive sprocket to the output shaft...

It may not be pretty but it works like a charm!

This assortment of 1/16th" mild plate steel and 1/8th" walled round tube were used to fabricate the basic Dual Motor mount.

As always I fall back on my standard excuses for hideous fabrication outcomes...

#1 - It's just a "Proof-of-Concept"

#2 - The next one will be better !!! (which really is just a different way of stating Excuse #1)

As pictured to the right, this mount is just passable for the torsional load of the dual motors in their stock winding.

A 3rd laminate of 1/16th" plate will eventually be added beneath the 2-plys that are on the top, and will extend downward along the length of the 2 upright's that meet the tubular frame mounts.

A few misc details about the mounting of the MY1020's includes the fact that the gear-reduction units on the ends of the motor were rotated 180 degrees to place them closer together for better chain alignment...

The brush-plates were similarly rotated 90 degrees so that the Red Wires would still go to Red and the Black to Black, as the motors need to be run counter clockwise on a left hand drive to achieve forward movement.

The cast end-bells that the brush-plate mounts to had to be drilled out as there are only 2 threaded holes in the gear- reduction castings. 

Since the motors were so thoroughly fiddled about, the timing between the armature and the brush-plates had to be reset... With the factory armature wire still intact The re-assembled motors read 1.45Amps and 2.09Amps current draw when tested with a single 12V battery.

The 1/2 Amp of variance between the motors was both audible and visually evident, in that the higher current draw spun slightly slower. Setting aside non-linear components and dealing just with the linear like RPM, Voltage and Current draw it would seem that one motor would load more heavily than the other and result in poorer performance than if both were timed to run identical current draws...

The end Bells were re-drilled again with 1/4" and I think ultimately a 3/8th" drill-bit to achieve the lowest possible draw from both motors (but identical values)... The matched No-load 12V current was set at 1.20 Amps, and the sprockets turn in unison with such precision (even up to 48V) that they look like there is an invisible loop of chain is tying them together.

Since the armature was accessible I thought I'd measure and record the diameter of the factory windings...

Some where between 0.030" and 0.028" there is a healthy margin of error to point towards AWG#21 or even AWG#22, the image to the right is with the jaws just closed, so 0.031" is not accurate...

It took a bit of head-scratching and trial & error, but the video at the bottom of the page illustrates what I've found to be the quickest and most reliable way to assemble the motors to the mount...

The sprocket alignment is such that I'm waiting for the Suzuki Engineering team to offer me a full-time position with the firm any day now... 

At this point the new revised drive train  (Dual MY1020 config) has had close to 40KM run on it and it is holding up well enough that it will remain like this for the balance of the summer...

As the season winds down towards the end of November, the motors will be re-wound for slightly more top-end as the current low-end grunt is like a 2-wheeled tractor, slow but steady...

Or if a single 7 to 10Kw motor presents itself, the gear-box will be returned and offered the opportunity to redeem itself.

For more details on this page refer to the video posted below... 

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