Henry111's free tech support thread

What is the best style of bike frame for electric conversion. I'm not asking about brands or quality of construction. The basic frame configueration is what I am asking about.

A Downhill style MTB or mountain bike frame. Preferrably steel, with dual suspension, disk brakes, and 26 inch wheels. However, if you are like me, and demand a fatty on the rear, you should get a Giant Stilletto, or a Schwinn OCC, XL. I have a Spoiler, but that has an aluminum frame, so I don't recommend it for conversion. All these bikes offer stability at the higher speeds you will obtain after conversion, as well as the safety options that will keep you out of the Recently Faceplanted, section of the local paper. Welcome to ES.
Brian L.

I would say it depends on where you plan on riding it and how fast you want to go. If you wanna go fast- full suspension & disc brake compatible are best for on and off road...welcome to ES Henry

Any frame could suit someone, somewhere. All that matter, is where and how you ride, and chose accordingly. Many will prefer a large triangle to fit batteries, and steel to have strong dropouts. Disc brake and suspension are a plus if you plan performance, a long wheelbase is good for high speed stability and fine cornering.

Mountain trails are more than half of my mileage, I quitted riding steel frames long ago, for the better stiffness, geometry and balance of modern MTB frames. Steel dropouts and-or torque arms are not a big problem to solve. Also, we add alot of weight to our build, so I find better start with a lighter bike.

Thanks for that folks.
Considering the power-to-weight-ratio factor should one pay extra attention to the bike weight BEFORE converting? Possibly, like an aluminum frame but with steel forks? Years ago when I was racing Go-karts we did everything we could to keep the frame light. But, of course, we were racing and didn't care if the thing fell apart 10 feet beyond the finish line. But I have no plans for racing an eBike. Gettin' too old for that kind of thinking, anyhow.

Rear motor is best for safety, traction, etc.

Thus, you want a bike that has good rear dropouts and the ability to install either torque arms or make a custom torque plate for.

If you are going to exceed 30mph, i would say most definitely get dual suspension to prevent bumps from sending you flying ;D

If you are going to exceed 20mph, front suspension is pretty critical for the sake of your arms!
Disc brakes are pretty much a must..

This is why pretty much all of us are using mountain bikes.

I am new to electric bikes but really excited about the whole concept. I have a background in RC model aircraft, so I am familiar with batteries (smaller of course), ESCs (electronic speed controllers), small brushless outrunner motor and such. Of course, I am wondering how much of this knowledge will be useful as I move into eBikes?
Question:
In RC model aircraft Lithim Polymar batteries have become the only way to go. I am wondering if they are used much to power eBikes? If not, why not?

Many here swear by lipo for ebikes. Me being one of them. I run a 14s pack.

I bet you that 1/3rd of the people on here are using lipo now.

There are some good stickies in the battery technology section about it.

I too come from a RC background and your Lipo knowledge will be usefull in your Ebike quest. I'm using A123's 12s2p, recycled laptop 18650(13s4p) and 18s1p Lipo. Lipo's setup is the fastest and lightest and smallest pack configuration.

Henry111 said:

I am new to electric bikes but really excited about the whole concept. I have a background in RC model aircraft, so I am familiar with batteries (smaller of course), ESCs (electronic speed controllers), small brushless outrunner motor and such. Of course, I am wondering how much of this knowledge will be useful as I move into eBikes?
Question:
In RC model aircraft Lithim Polymar batteries have become the only way to go. I am wondering if they are used much to power eBikes? If not, why not?

Click to expand...

Been there, done that, use them...

everyone is using them. there is decent argument for the ping lifepo4 if you are designing a legal daily commuter due to cycle lifetime, but there is also good evidence that at the low c requirements we are putting on the lipo batteries and with a good charging/discharging regiment of 20% bottom end 10% top they will be good for double, perhaps triple, maybe more, then the 500 life cycles they are rated for.

The thing that most people screw up with lipo is the changing wires around for charging. We recommend a charging/discharging harness that is as simple as possible with as few connections to be changed as possible; if you leave you balance wires paralleled and then plug the batt in series-ed there is a major short. Many people have done this accidentally after hundreds of perfect charges. A lot of people are bulk charging with various balancing solutions, others reconfigure every charge for 14s and use the excellent hyperion chargers to fast charge anyway.

The hotrods run 24s for 100v. Maybe a couple people running 30s for 120, but only as racers as far as i know; past 100v controller choice is quite limited and they are very large. The RC crowd who use rc engines and reduction drives use 48v and high amperage, the best stuff is the castle creations controllers modified with extra caps, and the astro motors, matt schumaker (member recumpence) has all that stuff as well as his excellently engineered reduction drives. The max speeds on the RC motors is at least 60mph and was mostly limited by gearing; member rodagh (i think thats the spelling). The hub motor speeds are also 60-70mph +ish, but that's about the limit of what people are doing.

Many here run them. there are dedicated E-bike Lipo packs available, but most people on this forum are running Multiple R/C packs in large format size. I've been running my current set since 2008. but was using no R/C lipo before that, and had used Lipo in R/C planes since 2004 or so. I have around 10,000 miles on my current set.

As you are probably aware, Lipo is dangerous by comparison to other batteries. So its a performance option. Not something we normaly recomend to newcomers to the E-bike world. But in the hands of those with the skills and knowledge to use Lipo safely, its an Ideal performance solution.

The best current source for e-bike capable R/C Lipo is Hobbyking.com. I prefer the 5s1p 5000ma packs, and run 8 of them for a 72V 10Ah battery.

your knowledge of Motors and controllers will come in handy, but only to a point. If you build an R/C drive, then it's invaluable information. But for hub motors, they share only the most basic of principles with the R/C world.

So what did you fly?

Spellcheck? Who needs em....

Dual suspension for high speed, 30mph+ sustained. But for lower sustained speeds, a hardtail or ridgid is fine.
Open Triangle is best, regardless, as the best place for batteries in most every case is inside the triangle.
Steel is good, but Aluminum can be fine too. basicly, you want a mountian bike or a hybrid with good solid dropouts and plenty of sopace to mount the battery as close to the center of the bike as possable.

An example of a good basic ridgid bike would be a Trek 800. A Trek 820 for an example of a front suspension bike, for use with a rear motor. And a trek Fuel as an example of a full suspension bike using an open triangle.
I'm Not recomending any of these. They're just some basic examples of the style.

Avoid racing bikes and carbonfiber. Bikes built to be light weight were designed to handle the extream stress of what one man under human power would be likely to do. any striength past that would be extra weight. An Ebike may be able to put out 2 times human power, at it's smallest and weakest level, and 10 times human power in normal opperation. Light weight bikes simply will not survive.
Oddly enough, Department store bikes are great, simply because they get so overbuilt to survive the unknown abuse they might take without breaking at the hans of teenagers and novice riders who don't know better than to ride off curbs or avoid potholes.

grindz145 said:

Spellcheck? Who needs em....

Click to expand...

Folks, I think I am missing a couple of things here:
One:
Someone referred to "...the RC guy...." Does the term "RC" in reference to eBikes somehow different from it's use in R/C model aircraft?
Two:
I don't understand how some of your voltages are being arrived at:
Someone said they are running (8) 5S1Ps (I assume wired in series). That is, as I have always understood it: 5X3.7=18.5V. 8 of these wired in series would equal 148V. Much more than he said he was realizing.
Sorry I don't have everybody's names.
What do I fly? Everything. I publish an online magazine entitled Electric Flyer Magazine.
Henry

Drunkskunk, regarding your use of 8 5SPs 5000mAh batteries. After some thought I think I see what you are doing.
You are wiring 4 in series for 74 volts (you said 72). Then you wired these two sets in parallel to arrive at 10,000mAh.
Have I got that right?
Yes?
No?

Henry111 said:

Drunkskunk, regarding your use of 8 5SPs 5000mAh batteries. After some thought I think I see what you are doing.
You are wiring 4 in series for 74 volts (you said 72). Then you wired these two sets in parallel to arrive at 10,000mAh.
Have I got that right?
Yes?
No?

Click to expand...

Yep, you got it.

And my bad, I should have explained that better.

Typically, not so expensive frames. Because they are steel, or have steel swingarms if FS.

But it then becomes a can of worms if you really ride, because you soon want to upgrade EVERYTHING on the dang bike. A more expensive cheap category bike like the mongoose blackcomb can be a decent choice. Far from perfect, but nice enough that I bought two of em.

Once into good bikes, like a quality FS MTB, then you better have experience. Because now you have to deal with aluminum dropouts and torque arm fabrication.

I have on hand a 150A OPTO ESC from Hobby King.
Is this kind of controller suitable for eBikes?
Or do I need something entirely different?

Naturally I have loads of questions but I will start out just asking about bike selection. I have concluded from many posts that the best bike for conversion would be (assuming that I will be building with a rear hub:Your comments will sincerely appreciated.

One: A mountain bike (both front and rear shocks?
Two: One with disk brakes?
Three: Steel or Cromoly frame?
Four: With gearing of 6 or seven if possible to find? (Something about fewer gears which confuses me?)

So, neither of my two bikes will do because neither has disk brakes. So I am now shopping for a USED bike most suitable for electrc conversion. Your thoughts would sure be appreciated

Welcome to ES. Good luck on your project.

Disk brakes are most important on the front. If your fork has the fittings they can be added. Good rear V brakes are okay. That's what I'm doing (see the build thread in my sig).

The problem with too many gears is pretty minor. The hubmotors don't leave enough room for more than about 6-7, so if the shifters match great, not really a big problem either way.

Dual suspension is good for going fast. Lots of hard tails out there, too. More room for batteries on a hard-tail.

Henry111 said:

I have on hand a 150A OPTO ESC from Hobby King.
Is this kind of controller suitable for eBikes?
Or do I need something entirely different?

Click to expand...

! Not enough information to answer your question...

Answer 1: NO, assuming your talking about turning an ebike hub motor with a hobbyking brush less controller. No because of two main reasons 1. No current limiting built in to the ESC. You pull to much amps and set your ESC on fire.. 2. Designed for high RPM motors, hub motors are slow, kills the ESC...

Answer 2: YES, assuming your will be using a regular brushless motor and running it thru a reduction system.

Answer 3: Kind of, asumming you want to spend lots of money and go in to something like a castle creations ESC... very expensive... advanced configuration required.. is possible to turn a hub motor

VoKuS said:

Henry111 said:

I have on hand a 150A OPTO ESC from Hobby King.
Is this kind of controller suitable for eBikes?
Or do I need something entirely different?

Click to expand...

! Not enough information to answer your question...

Answer 1: NO, assuming your talking about turning an ebike hub motor with a hobbyking brush less controller. No because of two main reasons 1. No current limiting built in to the ESC. You pull to much amps and set your ESC on fire.. 2. Designed for high RPM motors, hub motors are slow, kills the ESC...

Answer 2: YES, assuming your will be using a regular brushless motor and running it thru a reduction system.

Answer 3: Kind of, asumming you want to spend lots of money and go in to something like a castle creations ESC... very expensive... advanced configuration required.. is possible to turn a hub motor

Click to expand...

I don't quite understand your term "...brush less controller..." I've never heard of a controller with brushes.
I will be using a DD brushless motor.

Hi Henry.

I agree with Alan,

There are really no hard and fast rules. It is a question of what will suit you most.

Do you want something for casual commuting or something for draining your adrenals?

Whether or not disc breaks are necessary is a function of how fast you are planing to go??

And suspension, well, what terrain are you planing on covering, how fast and how frequently?

Can you give us some more specifics on you riding requirements?

D