Need Suggestions for Modifying EBike SX to Higher MPH

Hi, I'm new here. Yes, I'm female (as you can see from my forum name).

I came here because I got frustrated trying to get a response from author Greg Davey of "How to Build a 50 MPH Electric Bike" before laying down the money to get his book. He's said nothing to me yet. And that's a big red flag to me. (I would never avoid response to customers if I were a technical author trying to make a buck.)

I want to make modifications to my 36volt, 14 year old EBike SX which runs like new.I'm a former scooter rider. I always got frustrated back then that I didn't have someone to help me learn how to service my own scooter, even though I lived in a PA valley FULL of mechanics! I guess I was just supposed to pay them money and let them have all the glory, and "keep my mouth shut", being a woman. Well, eventually my cheap Chinese scooter played out on me, and I wasn't able to ride it anymore.

Fast forward to today: I'm junking my old car, and looking for a way to increase this SX's capabilities to about 50MPH or more. I feel sad about losing my old car, but it's a source of pride for me to come here to want to learn as much as I can on on how to get this EBike more powerful. I'd like to make it my pet project, in fact.

It's harder for me to get my head around the electrical concepts, because I was used to making minor repairs to my car, so would anyone like to jump in and help me out?

Here's a video of an EBike being stripped down (good for viewing the frame, battery pack, control box and brushed hub motor) https://www.youtube.com/watch?v=vzbLFRIppLA

Will my project be a case of just getting different batteries and a different controller, or am I better off with all this plus a Hub Monster or Cro Hub as well to fit onto my vehicle? I am a heavy lady at 215 pounds, and the bike frame without its lead acid batteries inserted into the downtube is 65 pounds. With batteries - 75 pounds.

Note: right now, it's a real struggle for me to lift a bike OVER 65 pounds when traveling but I'm willing to accept any new parts as long as I don't have to lug this thing onto public transit anymore to help me get accross town!

Currently the new lead acid batteries only get me 3 miles down the road, at 15 MPH before they are discharged. And that's with pedal-assist too on this 7 speed bike. How embarassing!
It's not much fun. :|

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Max speed you want?
Range you want at max speed?
Range you want at 20mph?
How much do you want to spend?

People who write books about building ebikes are the worst...

Anyways, Wesnell asked some important questions that we'll need answers to. Also, and just to give you a better frame a reference here from the beginning, what you are asking to do is a pretty serious project, not so much due to the complexity, but more due to to the cost and safety considerations involved here. Those two things sort of work hand in hand. You can build a 50 mph ebike for not huge amounts of money, but it isn't going to be safe. To go those speeds you need parts built for that kind of work. For example, that motor is a no-go at those speeds. Next, that frame is in the 'maybe' category, but still leaning towards dangerously underbuilt. Same with that fork - I can't tell what brand it is and that's not a good thing.

Next, batteries. SLAs simply don't hold enough charge in a small enough package to give you any usable range at 50mph. You need lithium, and you're probably talking about RC lipo batteries at that point to give you the power you need for those speeds. RC lipos are no joke. They're explosive devices that can be used to power electronics. You can't just hook 'em up to charge like your standard SLAs.

I'm not at all trying to discourage you, I think you have an awesome goal and I want you to succeed. But you do need to know that at the power and speed level you are talking about, the safety requirements preclude most of your setup there. Any 50mph ebike that is both safe and reliable simply isn't going to be cheap and isn't going to be something that can be made out parts you mostly already have in your garage. That being said, you came to the right place as many of us can help you achieve your goal in the right way.

wesnewell said:

Max speed you want?
Range you want at max speed?
Range you want at 20mph?
How much do you want to spend?

Click to expand...

I think we should talk about range first, if high speed is so costly. (I am in love with the frame of this bike, by the way, and I do know who can give me more info about it. I'd be THRILLED to be able to keep the frame and fork intact in the beginning.)
I'd like a range of 60 miles at 35-40 mph to manage the feeder roads safely enough in traffic.
Sort of like a 45 cc scooter motor using 2 gallons of gas, with a big lady on it :lol:
Cost for this: "meh" (whatever it takes)

Is there a way to do this so that when the time comes to upgrade to more speed, I won't have to chuck out the parts I will change this year?

mlt34 said:

People who write books about building ebikes are the worst...

Click to expand...

is that why you wrote your own? :lol:

Seraffa, is the "Ebike SX" you're talking about this model: http://endless-sphere.com/forums/viewtopic.php?f=3&t=49081&start=25#p732574

If yes, then it is a piece of ebike history, and the best thing to do is upgrade the 36V SLA battery to lithium, and if you are very ambitious, perhaps swap-in a 48V brushed controller and battery to up the top speed 30% (compared to 36V). Here is your brushed motor (just quickly scan the pics): http://endless-sphere.com/forums/viewtopic.php?f=2&t=4190



A 215-lb rider is common enough, but your desired performance goal is going to be very difficult.

We will tackle range last, but flowing in and out of traffic requires serious power. 30-MPH is easy...40-MPH is very expensive...don't even think about 50-MPH. I am very serious about this. You can take a generous budget and build a 50-MPH motorcycle conversion, but that is a completely different discussion.

Seraffa said:

I think we should talk about range first

Click to expand...

Range is simply a factor of battery capacity. If stock was 10AH, then 20AH would get you twice as far (or slightly under twice, due to inefficiencies). So that means range is simply controlled by how much lithium you can shove in that battery compartment or elsewhere on the bike. This would be a good use for lipo since it is so small, but again, lipo isn't a game. You've got to know what you're doing so you don't burn your house down.

Seraffa said:

Is there a way to do this so that when the time comes to upgrade to more speed, I won't have to chuck out the parts I will change this year?

Click to expand...

speed is simply a factor of battery voltage. twice the voltage equals twice the speed (or again, slightly less than twice, due to inefficiencies). So if you want to later upgrade the speed, you'd just add more batteries in series. Like in your test you had 3 SLA's. Adding a fourth would get you to 48V and another 30%-ish increase in speed, like spinningmagnets said.

I recommend reading thru this wiki article's links:
http://www.endless-sphere.com/w/index.php/I%27m_a_Noob_and_I_Wanna_Go_50MPH
There are a LOT of discussions of "really fast" ebike conversions / upgrades / custom builds here on ES. Most of the ones listed in the wiki article are simply discussions about why some thigns are good ideas, some are bad ideas, and associated costs and risks. Some are build threads, and some are just data.

Welcome from another female member.

I wish I knew more about that bike, I think Dogman had one back in the day, a geared heizman motor, brushed. All my hubs are brushless, but scooter stores cell brushed controllers online, so you can get upgraded parts. Putting together a bike with a new controller and motor is not so difficult to learn, I figured it out and people here will help you. I think you could just upgrade the battery for a start and you may be happy with the increased performance.

If you want to go Lipo you can fill that case with 12 series batteries, maybe 12 series 10 AMPHR so 4 bricks, and get more MPH and range of say 15-20 miles, more if you pedal.
there is a learning curve, but they are modular so when you upgrade to a higher voltage controller you can use your old Lipo batteries to do so.

Please someone correct me if I am wrong but I heard that the controller can handle a small voltage increase, such that 12 series lipo will run it. You can read about lipo and maybe search for heizman and ev global bike for more info. here are the lipo noob links to learn about Lipo. I dont want to discourage you but you have to start somewhere, why not start with overvolting a tad and settling for 20-30 MPH.

when readying about the bike you should try to find out what the voltage max of that controller is on your bike so you do not go over that max voltage and blow the controller.

I heard that the controller can handle a small voltage increase

Click to expand...

I've heard that too. There is an "over voltage" safety switch on the controller, so...slowly raise the voltage of various battery combinations until you reach the approximate voltage that is the highest that the stock controller will allow (This switch also protects the capacitors from being popped, so don't bypass it). Then, you can build up a new battery pack at that slightly higher voltage.

If you are using LiFePO4, I "think" it is common to charge them to 3.60V per cell, and LiPo/LiMn/NCM/NCA are usually charged to a max of 4.10V per cell.

That being said, one of the biggest benefits of brushed systems is that common controllers are so cheap. Going to an off-the-shelf brushed 48V controller allows you to also select common, affordable, and available 48V batteries and chargers.

spinningmagnets said:

Seraffa, is the "Ebike SX" you're talking about this model: http://endless-sphere.com/forums/viewtopic.php?f=3&t=49081&start=25#p732574

Click to expand...

It is indeed.
I'm glad to have so many people responding!

It's not hard to get over 40mph as long as you don't need to go more than a few miles at that speed and can then drop back to under 35mph. If you want to maintain 40+mph, then you will need more than a typical cheap 1000W motor. So if a 35mph cruise speed is ok with occasional burst to 40+mph, then you can do it fairly easily. Range is the problem. You've got limited battery space and it's going to take a lot of battery for 60 miles at 35mph. 40ah of 24s lipo would do it, but just the batteries would cost ~$1200, and it wouldn't fit in the battery compartment, and it would weigh ~50 lbs. If you cut your cruise speed down to 30mph, you could get by with 30ah, but I'm not sure you could fit that in the bike either, so you may have to mount some on a rear rack at that. For the speed and range you're wanting, a small ice scooter would be a better and cheaper option imo.

That bike looks the same as the Lee Cacocca. There were a couple of threads about modifying them for more power. There's one here:
https://endless-sphere.com/forums/viewtopic.php?f=3&t=14417

Perhaps somebody else could link to others; however, I think that they're a long way short of your target. I think 30 miles at 30mph will be a more realistic target.

d8veh said:

That bike looks the same as the Lee Cacocca. There were a couple of threads about modifying them for more power. There's one here:
https://endless-sphere.com/forums/viewtopic.php?f=3&t=14417

Perhaps somebody else could link to others; however, I think that they're a long way short of your target. I think 30 miles at 30mph will be a more realistic target.

Click to expand...

Of course it's a Lee Iacocca. not sure why you said that, since all of his bikes look the same - except for body color.

Thanks for the older thread. This confirms topping up the speed by way of the older thread:
"guy says it's been upgraded with a 48V 'lithium ion' battery. not sure the capacity. said he never rode it long enough - thought it would go for two hours. he said it went very fast too. like over 25mph. said it's 'street legal' since it's over the speed for an ebike, which i found interesting"

Cool. 8) Here in Texas.....as long as things are started with a pedal and not an ignition key ....you don't need registration or license.
Are lipos lighter in weight than my current batteries? Are they the same shape? I was told I have 4 batteries in the current box that plugs into the downtube. My bike has a luggage rack with max. capacity 10 pounds.

Approximate charging time for lipos?
Cheapest place to get them?
And is there a "cheat sheet" somewhere on this site that connects the dots between power of controlers, power of batteries and types of motors that would work well with one another? I wish I had a Haynes manual with pictures, to this effect.

Old thread featuring an EVG bike with lipo pack pictures. Location near you too.

41MPH EVG SX bike with Magic Pie motor by snellemin
http://endless-sphere.com/forums/viewtopic.php?t=37480

Charging time depends on the size of the battery pack, and what you use to charge it with. Add up the WH of the pack and then divide it be the watt value of the charger to get the approximate time required to fully charge the pack. For instance, a 20ah 12s pack is 888wh, so if you use a 500W charger it will take a little under 2 hours to charge it. The best place to order rc lipo is probably the USA warehouse of hobbyking.com. But if you need some knowledge before ordering rc lipo. Here's a few places to start.
http://batteryuniversity.com/learn/article/types_of_lithium_ion
http://www.rchelicopterfun.com/rc-lipo-batteries.html
http://scriptasylum.com/rc_speed/lipo.html

Seraffa said:

And is there a "cheat sheet" somewhere on this site that connects the dots between power of controlers, power of batteries and types of motors that would work well with one another? I wish I had a Haynes manual with pictures, to this effect.

Click to expand...

Dont you all have a sticky note to this effect on the site or am I winding up buying someone's book for this? I'm moving house and training for a third job So i havent even had the time to peruse and dont have time to look up all a brevations and definitions on google (my bike is not my main hobby because I have several already)

There's no Haynes Manual yet, the technology changes every 6 months to a year, along with our collective knowledge of what does and doesn't work.

A 50mph Ebike is certainly possible. But it's not advisable on a stock frame. From an engineering standpoint, it's a good way to qualify for the Darwin awards. To do it right you'll need to start with a bike that can take the speed.

Before you get too far into the project, you should read this from our Wiki: I'm_a_Noob_and_I_Wanna_Go_50MPH

Speaking from experience, 50mph takes around 4000 watts continuous. So a bike that can sustain 50 mph needs a motor rated to handle 4000 watts nominal, not peak. Otherwise, it will overheat and melt after a few miles. And be able to run for 1 hour, you would need a battery capable of at least 4000 watt hours of output. Since it's ill advised to run a battery all the way down, you'd need around 5000watt hours of battery capacity to keep out of the last 20%.

To put that in perspective, A 5000 watt hour battery is bigger than some electric motorcycles use. If you used LiNM cells, the battery would weigh around 75 pounds. And that's is minimum size. If you add in headwinds, or hills, or stop-and-go driving, your power needs would be greatly increased.

If you cut the speed to 40mph, the power use drops off to around 2250 watts. If you drop back to 30mph, the power use drops to 800-1000 watts. Finally at 20mph, you can cruise along sipping just 300 watts or so.

The motor is basically an after thought to an ebike. I know that is counter intuitive, but with an ebike, the battery is more important. The next most important part is the bike it's self. As you can see from the battery example, the amount of power greatly increases with speed. This is also true of the amount of energy being transferred to the bike. every bump in the road hits the bike harder. Higher RPMs are harder on the bearings. Tires have to work harder to hold the road and shed their heat. and brakes have to work much harder to stop you. A bicycle was designed to handle 1 human power, around 150 watts. Luckily, most bikes are way over built for being powered by humans, and that's why ebikes are even possible. But there is a limit to how much they can take. As long as they are built to operate in the human range of bicycle performance, things are generally OK. But the human range is pretty low.

Consider a motorcycle built for 50mph, like a classic triumph 125cc. The bike weighs over 200lbs. The tires weigh 10lbs each, the brakes are huge the frame is made out of steel thick enough to stop a small bullet, and of course, it has a suspension. It's not an accident that the bike is built so heavy. In fact, it's built light weight for the job it's expected to do. a 125cc gas motor weighs 30-40 pounds, so the rest of the bike's weight is just to keep it's self from tearing apart at sustained road speeds.
While you can build an Ebike with lighter weight parts, going much lighter comes with risks. Lower rider safety, lower handling performance, lower bike lifespan, and high maintenance cycles. The more bicycle you go in your build, the worse the trade offs get. How much of a trade off you're willing to accept is up to you.

As for the motor, there really is only one choice available in a hub motor. The Cromotor. Anything else available would melt at 50mph for sustained speeds. As you slow down, more motor choices open up.

For controllers, there are several choices, but the best for your needs is likely a 18 FET Infineon built with 4115 FETS for solid 100 volt operation. It's programmable, and should handle the power levels you'll need well. At 50mph you'll be pulling ~4000 watts, but to accelerate up to 50, you may be puling 7-8000 watts.

How much money do you want to put in this project.

Thee are lot of choices for 50+ mph motors. But for a 10mm by135mm dropouts only a few. And cromotor isn't one of them. AFAIK it requires 145mm or wider dropouts. Some may require a 12mm dropouts, which can be fitted by shaving the axle, the dropout or both. These can be purchased on ebay or elsewhere.
http://www.ebay.com/itm/Electric-motorcycle-Conversion-Kit-3000W-Brushless-Motor-w-gear-disc-brake-/161399533826
http://cnebikes.en.made-in-china.com/product/AKfEcqkCgUVz/China-Hot-100km-H-3kw-Hub-Motor-for-Electric-Bike-3000W-Hub-Motor-Wheel-for-Electric-Bicycle.html
http://cnebikes.en.made-in-china.com/product/rXHQUdKYngkZ/China-5000W-Electric-Bike-Motor-Wheel.html

Look long enough and you can find anything you want.

Drunkskunk said:

As for the motor, there really is only one choice available in a hub motor. The Cromotor. Anything else available would melt at 50mph for sustained speeds. As you slow down, more motor choices open up.

Click to expand...

That's a ridiculous statement. I've only used hubmotors, and I've built 6 ebikes that will cruise at over 50 using 5 different hubmotors. 4 of those would top out at about 60mph. That was using 74V nominal batteries. My latest tops out above 100mph on 111V. I've never owned a Cromotor or even seen one in person.

That said, I wouldn't want to go 50 with a wheelbase as short as the EBike SX, especially a hardtail. About 30 is my limit with a typical bicycle wheelbase and typical bicycle saddle height, because my weight puts the CG so high. Since it's a steel frame the wheelbase is easily extended, say 4". Then lower the saddle and push it rearward a bit so pedals are the same reach, and a Thudbuster instead of the pogo for the saddle. The last thing I'd do is upgrade the front fork with a stronger more adjustable modern one. Another goal in the rear extension and fork change would be to add a bit of trail to the steering geometry to ensure that it's stable at top speed. The rear extension also enables fitting any motor to the bike. Upgrading tires and rims to moped stuff would be part of that process.

Have you seen the extensive 4130 steel tubing in that frame. It's stronger than a lot of motorcycles, so the frame is fine. My only issue is the hardtail, but if she's been living with it for this long, then the roads must be quite good.

Serrafa, Lee Iacocca came up with an ebike for you that remains a great looking vehicle. Too bad he didn't go more monocoque, so all those tubing members are in the way of otherwise prime battery space. Even so, you'll be able to fit a lot more capacity in lithium and still be much lighter than the lead batteries they replace. Before going for high speed I'd suggest bumping the voltage up by about 12V with a lithium pack. In addition to more speed from the higher voltage, even moderate power lithium batteries will sag in voltage under load much less than the lead they replace. They'll be significantly lighter too, even with more capacity, so the result will be a very noticeable improvement in performance. Ride that for a while and then decide if you want more, and whether you really want to modify that classic or keep it as a second ebike and go for more extreme performance with a new project. I think a lighter much better performing EBike SX-modified is going to put a big EV grin back on your face quickly, and then you don't have to suffer without your ebike while building a high performance ebike that your friends say is insane, and makes all the kids in the neighborhood green with envy.

John

Seraffa...first off you didn't mention your budget. Based on your goals, plan on spending around $1,200 +, and it's not even realistic with this short wheelbase hardtail light frame to go 50mph. Ok, for 30mph.

Here is an upgrade that may be of interest with your same model ebike:

https://www.youtube.com/watch?v=cjwQOuSI5-w

Understand that everyone here making their suggestions are well meaning, though I'm assuming none have actually owned or have even modified this early model EVG SX ebike.

I have this same exact model bike, as well as the other two 36v model versions (LE & PE), and three mini ebikes, with a total of 17 of these ebikes.

These are great $200 range starter used ebikes. They come stock with front disc brakes, both front and rear LED lights, brake lights, horn, and cruise control. But you really want to upgrade to a better chemistry battery source. Plan on spending $400 for a lithium upgrade that will fit in the side case, or even in the original battery box/charger.

The downside of these ebikes, besides being 14 years old, is these bikes came with brushed geared rear hubs, and are very noisy.

My suggestion, to keep your costs down, is to upgrade the battery ($400'ish), new quality tires/hd tubes ($70), increase the front chainring to 46t (max-little case trimming-$25), replace the rear freewheel to a 28t-11t ($30), install a cateye enduro 8 spd computer, and a mirrcycle mirror. This too is still keeping your original stock factory 36v controller that power the lights, which work great. No current stock factory ebikes available today can even compare with these "ahead of their day" EVG ebikes.

Understand your only going to increase your stock factory speed from 16.5mph to around 20mph (195lbs) with the increase voltage from SLA 42v to a 46v (charged) battery source using the stock controller. I've tried 50v (charged) and got 23+mph, but the stock controller gets warm and starts beeping bloody murder!

I've been using, these last four years, the Hobby King Nano Tech 22.2v/8ah & 18.5v/8ah lithium poly batteries. Hooked in series (+ to -) you get a 46.2v/8ah battery pack (10mi). You can parallel another pack for a 46.2v/16ah battery pack (20 mi) that still will fit in the side compartment. You too could find a source that would setup a lithium 18650 cell battery pack that fits in the original battery box/charger, though you will be limited to a 42v charge. Not sure the cost.

Yes, you could also replace the stock 36v controller with a 48v brushed unit, though you will need to also purchase a matched throttle, brake cutoffs, and 48v battery, BUT you will eliminate the use of your great stock front head/rear lights, the brake light function and cruise control. And your speeds will only be around 25mph with a 48v battery source. BUT, you will also be leaning on the poorly designed one-way bearing in the rear hub. It's pressed on, and doesn't have a keyway to secure it, so it's common for this bearing to spin even with the stock 36v battery source. It's very common for the over-weight donut eating police officer PE version ebikes to have spun bearings!

I'm assuming that your riding, and depending on an ebike, for economic reasons and spending around $1,200+ to upgrade this 14 year old ebike would be a burden? Which is why I recommend the above upgrades.

Have you given any thought to purchasing a used ebike, that is complete and a factory setup bike for reliability and takes no mechanical skills/tools to setup? I'd highly recommend an Ultra Motors Velociti or Metro for very reliable service, besides being HD built. I've got 1,800 miles on my '10 Velocity and have had NO problems the last 3 years! Though you are limited to 20mph.

If the need for speed is still required, then spent the money and get a Stealth Bomber....you will get your 50mph, but the cost will be much higher than an upgrade.

I briefly owned an Ultra Motor Europa about 4 years ago which was a direct descendant of the original Lee Iacocca bikes.

http://endless-sphere.com/forums/viewtopic.php?f=4&t=18731&hilit=+heinzmann

The frame was heavy and sturdy and the battery compartment was cool but the Heinzmann motor made a helluva racket. The bike came with a 36V lithium battery giving it top speed just over 20 mph. Unfortunately the motor overheated in just a few miles at that speed. Efficiency of the brushed motor is awful too. Therefore any upgrade has to include replacing the motor.

I would echo what a number of folks have said here; forget 50 mph (have you ever ridden a bicycle at 50 mph ) and simply upgrade the motor (DD motor or perhaps MAC geared), 12 FET 30-40A controller and as big of a lithium battery as will fit in the battery compartment (look at "high C-rate" lithium at BMSBattery) and you can have yourself a nice near 30 mph top speed E-bike for less than $1,000.

-R