Juicer III, thirty mile range?

[Juicerman]

Juicer Electric Motorbicycles LLC is a go! Some of you may have seen my "Etek Build" which got a bit of attention here and there. And though I was happy with the overall design, I knew I'd have to change a few things on the 48v model before inflicting it on a customer. The BMS was too weak, the controller was too strong, the fork was too heavy, and the handlebars uncomfortably close to the seat. I would go about remedying these things for the "production model".

The frame design was sound though, so I bought some new frames directly from the manufacturer and modded one the same as before.

For awhile the Manta motors were getting scarce and the prices went up, so I obtained an authentic, used, Briggs and Stratton Etek for not much more moolah.

I opened it up to check the brushes and decided they were good. Hmm?

 

[Juicerman]

On this board I had only heard good things about the Yesa BMS, and I found that the 16s board was affordable and had two sense-wire plugs which perfectly compliments the EV-Twin design. On the down side, it is BIG. The board itself is big and comes mounted on a huge heat-sink. But after some correspondence with the manufacturer I decided that I could trim it and make it fit in a slightly wider "tank." However that didn't leave enough room for a large controller, so I opted for a Kelly mini-controller. The extra space also afforded a recess-mounted voltmeter a-la Juicer I and more clearance for the keyswitch.

The much lighter springer fork has been modified for more rigidity where it needs it. I have a separate thread about it on the motorbicycling board; http://motorbicycling.com/showthread.php?t=42838

All wired up, throw the switch, SHAZAM! Everything works. These BMS lights go on every once and awhile. What do they mean?

 

[Juicerman]

Riiiight, where was I. Well, long story short, I built the sun bitch in the usual way except using stainless for the tank. Then it was time for a test ride.

Everything worked great. The front chain looks a little slack, but actually all three chains stay on great under load without any tensioners. Right to left, I'm running 41, 415, and 410 chains. Next it was time for the endurance run. I wanted to see how far she'd go, how gracefully the Yesa BMS cut off the juice, and maybe even calibrate the voltmeter (there is access to the adjuster-screw below the window).

Me and three went to our usual proving grounds, the LA river bike trail. We grabbed a surface charge at the tennis courts and sped off with 54.3 volts. Well, we tried not to speed, keeping it around 20 mph for longevity's sake. Last year when I was making Juicer 2, I used Headway 16 ah cells which you can no longer get. Juicer 3 has a single string of 40152s 15 ah cells, yet with the lighter fork, tires, bigger rear sprocket, and better BMS I still hoped to exceed the 13 mi. range of Juicer 2.

Nearly an hour into the ride to my great delight I had clocked 18 miles. My onboard analog gauge had dropped 8%, but I knew, at best, this was a relative measure. I wondered if the LVC failed to kick in and I was draining the batts below the safe level. So I got off and read the volts with a digital device which showed 52.5 volts. Still some juice left, so up and down the path I went, not pedaling at all, and staying near 20 mph. Astonishingly, I passed the 20 and 25 mile marks without tripping the LVC. This bike is far more comfortable than Juicer 2, mostly owing to the forward positioned handlebars, yet it has the same style seat which, after nearly two hours on it, was revealing its limitations. I was getting impatient. It was over 90º and I was feeling sunburned, so I got off the bike path and started zipping up and down the city streets. Now I abandoned the 20 mph limit and started going and up hills, just trying to deplete the battery. I think the BMS was starting to pulse under the higher demand, and finally it cut me off just past the 28 mile mark.

I took this pic and then a reading of the pack, which was 51.1 volts. Too late to calibrate the onboard analog gauge as the BMS cut it off too. It was a little ways uphill to get back to the El Camino, but not a bad experience pedaling this 90 lb. beauty back.

 

[Drunkskunk]

That is an Impressive ride. I'm a big fan of your Juicers. Its a back to Motorcycling's root approach with a cutting edge twist. Really Impressive.

 

[dogman dan]

Definitely love the boardtracker/ curtis/ motorbike look. Not quite pure steampunk but still with plenty of style. Good luck with it!

 

[The fingers]

That would draw a crowd at any event. 8)

 

[mikebikerad]

Looks awesome. good work.

 

[Juicerman]

Hey, thanks for the comments guys. The board always has been a huge source of support.

Now I have two of these 48v beasts with seemingly minor differences between them. To what then can we attribute the major difference in range? Roughly in order of significance I'm guessing these are the factors separating the 2 and 3's 13 and 28 mile ranges;

Gearing; 5:1 vs 6.6:1
Motors; Manta with new brushes vs B&S Etek with broken in brushes
Rolling resistance; 3" Felt tires at 30 psi vs lighter slicks at 40 psi
BMS robustness, if the YESA is doing a better job of balancing the cells I'll have more amp-hours when full and the LVC is less likely to be tripped by a crazy outlier.
Battery QC improvement
Weight; 110 lbs vs 90 lbs
Controller efficiency; KDZ48401 vs KDS48100e

The "e" is for efficiency...when I roll off the throttle I can literally hear the controller go to sleep, "eeeoowwp". I wonder how much energy that saves. Drive-train inefficiencies probably belongs in there somewhere, but I'll have to take Juicer 2 apart to discover where they might be. I'd like you boardies to speculate what might have caused the great leap forward in range, and whether I can stretch it further without adding another string of cells.

 

[Drunkskunk]

I'm going to take a wild guess, but I'm willing to bet your efficiency difference is the controller. KDZ48401 vs KDS48100e. One lets you draw 400 amps, the other just 100. Most of your losses are going to be when accelerating and climbing hills. If Bike 2 can use more power, then it would take Iron will and an aversion to adrenaline to not use the extra power.
The other factor may be the gearing. 2's taller gearing will need more energy to accelerate and climb hills. It may have a higher top speed, but it will burn extra power just to accelerate as fast as 3, or climb a hill as well as 3.

Swap the gearing, and swap the controllers and I'd bet a beer the efficiency of 2 gets much closer to 3

A Cycle Analyst would help diagnose the difference.

As for the tires, I have both Hookworms and Felts on various bikes. Both roll real well for me on a couple of bikes that can cruse efficiently. I can't imagine they would cause any significant difference in range.

 

[Juicerman]

Drunkskunk, you may be right. Even though I programmed each for 100a, the 400a controller may be able to ramp-up the amps faster than a controller that can only peak at 100a. My thinking on the tires was that the Felts were wider, softer and heavier than the slicks, so they would have more rolling resistance and would take more "Juice" to accelerate.

Won't take your bet, but you can still buy me a beer.

Getting a Cycle Analyst would be too predictable besides, I spent all my dead presidents on a clamp-on ammeter. Now the bike is in the window of Hollywood Electrics, but before I turned it over to Harlan, I set 3's throttle to 20mph (with the cat-eye odo on the rear wheel) and wrote down some current measurements which I will compare to equivalent readings from 2 when I get a chance.

 

[Stevil_Knevil]

Well Done!

I nominate Juicer III as the 2012 E-S Best eBike of the Year in both the 'Modern Retro' & 'Most Likely to be Confused as Infernal Combustion' classes.

http://endless-sphere.com/forums/viewtopic.php?f=6&t=45498

 

[Juicerman]

Stevil, what can I say? It's just nice to be nominated.

At least I still have my "Wheel of Change" trophy.

 

[pendragon8000]

Totally read bike. Any videos?
EDIT:read=rad

 

[Juicerman]

Thanks Pen. I didn't make any vids, but there are a couple of short clips on the Hollywood Electrics youtube channel.
http://www.youtube.com/user/HollywoodElectrics

 

[farmkid4]

Very nice and clean I love the looks