20mph+ from EZIP 24 volt OEM pack!

DrkAngel · #1 (**permalink**) 07-11-2009, 08:45 AM

I've achieved a sustainable 20mph from a 24v battery pack.

The "stock" EZIP Trailz, Mountain Trailz also, has a typical top speed of about 16mph, with some "assist" up to about 18mph. I felt that they must have made some mistake in their concept since the USA legal limit is 20mph. I felt it my duty to try to fix their mistake!

The most reasonable, (simplest), method would be to change the motor's gear ratio.

Two methods are possible: note:T = teeth.
1. Increase the size of the motor drive sprocket, OEM is 9T, 11T would be about right. 22% increase.

2. Decrease the size of freewheel on the rear wheel, OEM is 20T, 16T would be perfect.

After an exhaustive search, I was unable to find, any compatible motor sprocket, anything close required, modification, custom adapters, machining, or all 3.
Took me quite a while but I finally found an acceptable 16T freewheel. The difficulty is that it must have a Left-Hand thread, comparatively rare. After a few "wrong" purchases I finally came across the: ACS (manufacturer), Southpaw (model), 1/2" x 1/8" x 16T freewheel. Perfect, (well almost).

Going from a 20T to a 16T would increase top speed , from 16 MPH up to 20MPH, a 25% increase, "torque" however, would be lessoned by 20%, requiring more pedal assist on, the same, hill climbing.

Instructions:

Parts:
1. ACS Southpaw 1/2" x 1/8" x 16T freewheel.
Note: 14T is also made, but, will not fit!

2. A "single speed" chain repair link.

Special tool:
Small grinder - Dremel tool with small grinding wheel, or similar.

Step 1
Remove motor. I securely taped it to the battery rack.
Loosen motor mount bracket, 2 adjustment & locking bolts.

Step 2
Remove rear wheel.
Place bike, upside down, or on side, and loosen 2 rear nuts. Remove wheel, an extra pair of hands is helpful, managing chain, etc. Careful you don't pinch or mash your friends fingers! - Now comes the hard part.

Step 3
Remove the freewheel.

Method 1

The OEM freewheel is designed as cheaply as possible, which means, no notches for removal, hence the grinder.
The freewheel is loosened by turning in a clockwise direction.
There are 2 indentations, designed for a spanner wrench, but only suitable for the original install. You can try, but wear gloves to protect you fingers, and place something on top of spokes to protect them.
I ground 2 opposite side notches and used a freewheel wrench to remove. Any method that lets you get a grip on the, non-spinning, center, is acceptable. 2 synchronous tapping with hammers & screwdrivers might work. My method let the freewheel survive, just in case.

Method 2

Works on "new" unused, possibly slightly used, freewheels!
Personally have removed 2 new & 1 slightly used.

Was able to replace freewheel with 16T, method explained.

Requires Park tool SPA-1 spanner wrench. $10 - $15 shipped.

Most important is that wrench is securely seated and supported.

Turn clockwise, to loosen!

Note: Stock freewheel comes, smothered in a "gruesome" green grease. Yuck!

Step 4
Install new freewheel.
I mentioned the Southpaw was "almost" perfect...
Being a "quality" freewheel it has removal notches, unfortunately they make it slightly wider.

Two possible solutions:
1. Seal all joints, I used duct tape, to keep grinding residue out of freewheel. Grind notches down, about half way. Remove tape and install.
2. Insert a 3/8" standard washer as a spacer, clearance is very close, 1/16" might be enough, 1/8" thicker than necessary.
Install freewheel, check for clearance, before tightening. Center nut, or washer, must rise slightly above freewheel.

Step 5
Shorten chain, by 1 link, this would be 2 segments. Remove 3 segments and install repair link. I've done similar with hammer & screwdriver, or 2 pair pliers. Chain breaker, works perfect, any bicycle shop should do the job for you very cheaply. Get them interested in the project and they might jump at the chance to help, with the whole project.

Step 6
Reassemble.

Don't worry if you forgot to put the motor chain back on, open the link, install, close link.

Done!

Fresh battery - 65lb tire pressure - full throttle - level road = 20 mph. Tested on slight downgrade and confirmed, some assist through 22mph, slowed down when throttle released.

Added Bonus!
OEM freewheel is very stiff, even after being "broken in".
Southpaw spins easily.
Like stirring a pot of grease, compared to stirring, a pot of water.
Which means ... pedaling, without motor assist, is less work, more work goes to the wheel, less to the crummy freewheel!

Will add pictures and updates.

markc · #2 (**permalink**) 07-11-2009, 09:28 AM

Good job.

DrkAngel · #3 (**permalink**) 07-11-2009, 02:15 PM

1st off. I've been running at 36v for almost 1500 miles. It been so long since I've run at 24v that I'm not sure how accurate my opinions are.

Pluses:

Speed, 20mph makes a world of differance compared to 16mph!
22 mph is the maximum speed my feet could pedal, 20 mph pedaling is sustainable.

Minuses:

Hills, tougher on hills. But, getting a better run at small hills helps.
Range would be decreased, due to more demand from the motor.

Other:

The new freewheel is much more noticeable, noise wise, twice the volume of a 10 speed freewheel, when not using the motor. But it turns MUCH more easily than the OEM freewheel, which seemed stiff.

This is a new EZIP, my 3rd, got it from ToysRus during the couple days it was available. I had planned on converting to 36v, with the goal of 30mph sustainable, but the newer 24v controller would not support 36v. So, I decided to give my new innovation a proper trial at 24v.
I like it! With my 36v bike I typically cruised at 20mph anyhow. And, over the past few months I've wandered up to 208lbs. So, there will be an extended 24v trial, with the oem EZIP battery, it will require substantial assist to obtain a reasonable range, (I need the exercise).
Each day I'm running a fairly level 10 mile course, same EZIP battery, pedaling constantly, averaging right near the 20 MPH mark. Don't know that I'm helping much, but trying. 50 miles so far, still 20 mph at the end of each 10 mile trip.

Don't worry, my 30mph version will be coming, I already have a 58T, (up from 44T), front pedal sprocket, to help me pedal assist near that speed.

DrkAngel · #4 (**permalink**) 07-16-2009, 07:53 AM

About 100 miles with the 20mph mod. I have been "pedal assisting", with my, bought last year, used-abused, batteries replaced , used-abused some more, original battery pack. Noticeably degraded from new pack, I made a few comparison runs.

So far I've had no trouble maintaining 20mph on a 10 mile, fairly level, blacktop trail. Usually I run it twice a day, morning and evening, when its cool.

I would recommend this modification as, the cheapest & most effective. It helps the EZip reach its "proper" potential. Motor speed now matches pedal assist capability, sustainable at 20mph, and with some assist and vigorous pedaling, above 22mph! Yes, it will run 20mph, motor only, reduced range, of course. And most importantly it still complies with federal definition of "Bicycle". Making it "street legal". Test with speedometer, right near 20mph. If testing-certification required, either, use partially charged battery, or, reduce tire pressure slightly, to guarantee not exceeding 20mph.

Only problem I foresee is that Li-ion batteries can't be constructed into a 24v pack. The closest I can come is 25.9v. (22.2v is not acceptable) Yes, I will give it a try. I will rearrange the cells in one of my 37v 20ah pack into a 25.9v 30ah pack, will require the 80 cells +4 additional. Still smaller, and much lighter than EZip OEM battery pack. The little more speed, provided by extra voltage, couldn't hurt ... me.

First I will test jumper from the 25.9v point, of my 37v pack, to confirm that it doesn't exceed the "over-voltage " protection, of my 24v controller.

Will keep everyone apprised of my progress.

Bike still runs just fine if you want to use partial throttle and idle along at 15-16mph.

PS. I'm working on a much better method of freewheel removal, already successfull with a new wheel. will post details after successfull removal of remaining 500 mile used freewheel.

Work! Work! Work!

WARNING! Don't watch this, too long. It's better than counting sheep.

thcrw739 · #5 (**permalink**) 07-16-2009, 09:01 AM

Sounds pretty cool & a great mod.

I wouldnt be one to try it myself as im not good at this stuff, but if anyone starts a upgrade service or producing the wheel with larger sprocket installed, & pre made chains i'm in line to by one.

SieGunso · #6 (**permalink**) 07-20-2009, 07:36 PM

i was wondering if this would work for the drive sprocket

Motorized Bicycles Detail Page

DrkAngel · #7 (**permalink**) 07-21-2009, 04:18 AM

Would require major adaptation. Designed for 5/8" shaft. EZip appears to use 7/16" shaft. Any bushing must be secured to sprocket, this sprocket is zinc coated, making that, difficult.

EZIP Sprocket.

DrkAngel · #8 (**permalink**) 07-23-2009, 10:48 PM

200+ miles, so far. Runs great, even with my old worn out batteries (stolen from my 36v "toolbox" pack, with over 500 miles on them).

My new batteries are due to arrive tomorrow. Am hoping to have better luck than mikefish. Have had good success with this company, on multiple purchases. Motobatteries. 12V 10AH Scooter Battery Schwinn Mongoose (Set of 2) - eBay (item 400056878206 end time Jul-19-09 05:45:54 PDT)

Note: New EZip rack uses chromed "cone" contacts, old EZip uses "domed" brass contacts. I cleaned old pack contacts and used bungee, to get proper connection.

Richie · #9 (**permalink**) 07-24-2009, 06:43 AM

I don't like the idea of chromed contacts. I much prefer the brass. Looks like a cost-cutting measure to me. Thanks for the heads up.

DrkAngel · #10 (**permalink**) 07-24-2009, 03:24 PM

Quote:

Originally Posted by DrkAngel

First I will test jumper from the 25.9v point, of my 37v pack, to confirm that it doesn't exceed the "over-voltage " protection, of my 24v controller.

Will keep everyone apprised of my progress.

Bike still runs just fine if you want to use partial throttle and idle along at 15-16mph.

PS. I'm working on a much better method of freewheel removal, already successful with a new wheel.
Will post details after successful removal of remaining 500 mile used freewheel.

I just tried jumpering from the 7th cell of my 10 cell 37v Li-ion battery pack.
Yeah! _

_

The EZip "new style" 24v controller seems to work fine with a 25.9v Li-ion battery. Am ordering proper charger & PCB.
Will hopefully have prototype operational by next weekend! 25.9V 31.2AH!

I've temporarily given up on taking my EZip Trailz to 30mph.
Just ordered $299, (+ $99 shipping), Mountain Trailz IZip, with Front Disc Brake, to remedy one of my 30mph concerns.
I would like to be able to stop!

Will do my freewheel replacement immediately, I got spares, and have already ordered 36V controller.

But ... I'm tempted to break out my helmet & leathers ... for trials anyhow.

Will keep everyone apprised of my progress.

Richie · #11 (**permalink**) 07-24-2009, 06:25 PM

Quote:

Originally Posted by DrkAngel

Just ordered $299, (+ $99 shipping), Mountain Trailz IZip, with front Disc brake, to remedy one of my 30mph concerns.
I would like to be able to stop!

That is going to be a great bike. I love the front disc brake too.

beachwalker556 · #12 (**permalink**) 07-26-2009, 04:54 PM

these sprockets are available on ebay under $20 shipped!
ACS South Paw LHD BMX freewheel 1/8" X 16T CR-MO BLACK - eBay (item 200362403645 end time Aug-11-09 15:53:46 PDT)

DrkAngel · #13 (**permalink**) 08-05-2009, 02:03 PM

400+ miles with my 24V 20mph mod. New batteries are working nicely, am also using 3 stage charger, charges to 27.2V. Just checked voltage at end of 10mile 20mph run, 25.4V, 23v would be, my empty, others say 21V. I'm trying to stick to the 23V minimum, with the expectation of almost double the recharge cycles.
24v+ = Green LED when throttle released.
24V- = Yellow LED when throttle released.
22.5V- = Red LED when throttle released.

http://www.ecoforumz.com/electric-bi...tery-care.html

http://www.ecoforumz.com/electric-bi...led-e-zip.html

24VDC 2A 3-STAGE BATTERY CHARGER | AllElectronics.com

DrkAngel · #14 (**permalink**) 08-15-2009, 01:18 PM

600 miles, so far, with my 20mph adapted "Trailz".

Forgot to mention, when I swapped the freewheel, I checked the lubrication in the motor, it was properly lubed, with some extra! Motor sounded slightly different, recently, so I pushed bike backwards, spinning motor in reverse, and I believe it redistributed some of the excess onto the gears, sounds better now!...???
Will, of course, visually check, soon.

New batteries are working well. I have a fair bit of power left after my 20mph 10mile jaunts. I will confess, in this hot weather, I've slowed down near the ends of my rides, too cool off. (15 -18 mph for the last couple miles.)

No problems. I adjust brakes and check tire pressure weekly, as well as monitor motor temperature. I don't think there is any problem running the 16T freewheel @ 24V! Getting up to speed is more work, but the extra speed is well worth it!

However, I recommend the upgrade as an electric assist, not as an electric bike. Bike cruises nicely @ 20mph but struggles to get there unless you help, (with pedal power).

PS My "pedal assisting" seems to be working, in the past few weeks, I've gone from 208, to below, 200lbs! My thighs & butt are noticably trimmer, and I can see muscle "definition". I've even thought about shaving my legs.

DrkAngel · #15 (**permalink**) 08-21-2009, 06:24 PM

678 miles on my 20mph+ mod, and it comes down with 2 broken spokes, on the rear wheel. Been running, this bike, for just over a month. I don't think there is any possible way my "mod" could have caused their breakage. I've been running at maximum tire pressure with 200 lb rider, just bad luck?

My 1st EZip suffered broken spokes at the 1745 mile mark, ran it for a full year.

Spoke replacement requires removal of both the "freewheel" and the gear cartridge, both require special tools. Also, if you've ever inspected you'll notice that the spokes are angled differently, one side uses 258mm spokes and the other side uses 260mm. I think I'll buy some spokes, now that I have 2 wheels to rebuild, will be a good idea to have a spare. Plan on replacing all spokes, hopefully with better quality!

Got on the phone with Currie and they are sending me a new wheel. The bad news .... I have to pay $25 shipping and, "out of stock", "be a month before shipment".

Looks like I'll be stuck back on my 36V Mountain Trailz, for a while, as I savor my IZip development.

DrkAngel · #16 (**permalink**) 09-04-2009, 01:43 PM

EZip got me a replacement rear wheel, well ahead of schedule!

Wheel came safely packed & complete with tire! Was able to replace freewheel with 16T, method explained.

Requires Park tool SPA-1 spanner wrench. $10 - $15 shipped.

Most important is that wrench is securely seated and supported.

Turn clockwise, to loosen!

Note: Stock freewheel comes, smothered in a "gruesome" green grease. Yuck!

OOOOHH! The wheel they sent me has a gigantic "low end" gear!

Not sure how well it will work with my derailler!???

Will keep every one informed.

DrkAngel · #17 (**permalink**) 09-23-2009, 05:24 AM

Just passed the 1000 mile mark with my 20mph modified Trailz.

I never installed the new wheel that EZip shipped me. I re-spoked my original wheel and have been running that. Also, just received, (better quality?), spokes, 36 of each: 260mm & 258mm, enough to completely re-spoke 2 rear wheels.

Only problem-complaint, is that @ 20mph, even with pedal assist, the OEM battery doesn't last worth crap. Soooooo .... Am finally building 25.9v - 31.2ah Li-ion battery.

The "OEM" battery is a 10ah SLA type.
http://www.ecoforumz.com/electric-bi...tery-care.html.
Unfortunately, the 10ah rating is based on a 20 hour discharge cycle. When discharged in 1 hour, the actual output is barely 6ah!

My 25.9v Li-ion, discharging at the same rate, will last 3 hours+, with an actual output of 30ah! ... 5 times the usable power!!! ... 60% of the weight! ... same size pack!

Range @ 20mph should exceed 25 miles, 15mph should exceed 35 miles without pedal assist! With assist: 40 miles @ 20mph, 70 miles @ 15mph???

At 20mph, and higher, wind resistance becomes the major, power robbing, factor.

May plan fall tour of Letchworth State (NY) Park.

Just got tracking info: 25.9v charger & PCB won't get here till next Tuesday, CA to NY. I expect to have battery pack built & tested by next weekend.

For more info on "Homemade Li-ion Batteries"

http://www.ecoforumz.com/electric-bi...tery-ezip.html

Got all excited about this project then got delayed shipping notice and decided to expend some energy telling people about my plans.

Hope you enjoy.

Stay tuned!

DrkAngel · #18 (**permalink**) 10-08-2009, 04:00 AM

I just got my 25.9v Li-ion battery pack built & installed. Yes, it works with the EZip-IZip "newer" 24v controllers. Decided to go with the 31.2ah size, that is equal to 5 times the usable output of the EZip's OEM SLA battery pack. I anticipate, near to, 40 mile range @ 15 mph, without pedal assist, towards 30 miles @ 20 mph!

Fresh charge produces 22+ mph, with a 200lb-er on board. A lighter, or more aerodynamic figure, would go even faster! Motor "assists" past 25 mph!

Link to more specifics, and future info: http://www.ecoforumz.com/electric-bi...tery-ezip.html

Fantom · #19 (**permalink**) 10-08-2009, 12:12 PM

Folks,
Changed the freewheel to the new ACS, Southpaw, 1/2" x 1/8" x 16T freewheel, and still using my lead batteries, no pedaling, got 22mph with the wind on my back and 20 mph against the wind (wind est. 10 mph). Before the change, it was 18 with the wind and 17 against the wind.
This mod is great for flat Florida. In hilly country, I don't know.

It is a "must" mod.

The most difficult part of the project, was taking off the original freewheel. I used the Parker Tool spanner SPA-1 as shown by DrkAngel, but my particular freewheel had the center part (the one that actually screws to the hub) formed over the freewheel cone, so I had to chisel it out towards the center until I was able to get the cone out as well as the guts of the freewheel and the teeth ring. After that, it was just a matter of clamping what was left of the freewheel (the center part) on a vise and unscrewing it (clockwise) off the hub.

Fantom · #20 (**permalink**) 10-13-2009, 04:58 AM

Hi again!,

Went for the distance today.
On assisted pedaling mode, and keeping the speed at about 20 mph, my batteries lasted for 11 miles. I could have squeezed a couple more miles out of them, but by then, the top speed, no pedaling, was only 18 mph, against the 22 mph I get from them when freshly topped off.

Equipment:
Old Mongoose/Currie bicycle
2 12v, 12ah batteries
16 teeth freewheel (for the motor)