Safe's Electric Bike Project #001

[Toorbough ULL-Zeveigh]

** danger will robinson **
stay away from the red Tenergy 4500 mah NiMH!!

On just about every RC forum you can find several reviews on these particular cells.
No one has been able to get more than 3000 mah out of them.
They run very hot, are incapable of achieving the advertised 10C indicating a hi internal impedance with several instances of the shrink melting off, pix available on request.
All-battery has steadily dropped the price on these for over a year now trying to unload them.

** warning! warning! **

 

[safe]

Should have waited a month or so. 4500mah subC NiMH's with a 40A drain rate with or without tabs are available now on Ebay for $.58/wh

I saw those... they are a bigger investment up front and NiCad's do tend to have a longer cycle life, though the extra amp hours would be nice. It's possible I might try those too. The main thing I wanted to get established was that the Solderless Tubes idea worked out okay. Now that it's proven to my own satisfaction to be a success I'm more open to other possibilities that might involve more money. Having to manually solder so many cells like Dirty_D has done is more work that I was willing to do and all the other negatives about solder coming loose would have dragged the whole idea down a lot.

There might be some NiMh in my future... I had done calculations on both types in advance and chose the NiCad's for their longer life. It was a very narrow decision... I was torn about which type to go with and I think someone choosing the other is doing very well too. As might be expected I went for the lowest startup cost.

 

[safe]

That's it! With all your tubes and sla's you have to conduct a 24 hour marathon and see how many miles you can go. Its a charge and go marathon. The winner gets bragging rights and an online trophy!

That's actually a pretty good idea... however... in order to ensure safety I'd say make it a 12 hour time limit. (I have no ability to do night riding) See how many miles you can rack up in a single 12 hour time period. That's going to favor people with fast chargers... something that is not really the case for my SLA's. My NiCad's can be charged at about double the rate of my SLA's right now, so the SLA's will hold me back. However, with about another $50 for a 25 amp charger (verses my present 10 amp) I'd be able to do it. That would mean about a half hour on the bike and an hour off. What is that?

Equation 1 : RiderHours + ChargeHours = TotalHours

Equation 2 : ChargeHours = RiderHours * 2

Equation 3 : TotalHours = 12

RiderHours + ( RiderHours * 2 ) = 12

RiderHours * 3 = 12

RiderHours = 4

RiderHours * RiderSpeed = TotalMiles

4 * 30 = 120

So at an average speed of 30 mph I'd expect that 120 miles is possible in a day.

(that's going to be a tiring day if you are doing road racer type riding... not so bad in a velodrome type setting if you could find one)

 

[safe]

Rain

Not much to report today... it's been raining since late yesterday. (over an inch, maybe two) I spent most of yesterday afternoon fiddling with the front brakes. However, I have ordered a #25 chain 13 tooth motor sprocket which will increase my gearing so that some new speed records will again be possible. Top gear will place the peak power right around 48.5 mph (no load speed 64.7 mph) which should make being able to pull speeds above 55 mph a reality. Also I found a road that is long, smooth and slightly downhill to help give me enough time to get up to that kind of speed. On the old motor the top speed was geared slightly too high (56 mph peak) and my 1200 watt motor and present gearing is a little too low (41 mph peak), so I'm hoping this will be a "sweet spot" in the middle. When the peak was 56 mph I just couldn't quite get to it (sort of bogged down) and so I'm hoping to strongly pull past it at 48-49 mph and be entering the higher efficiency areas as I go. Plus I've got the NiCad's to eliminate the "sag" so I should be able to hold the full voltage for the run, which makes a big difference on top end speed.

This "should" be what is happening in order to beat 55 mph (on a downhill):

Rpm - 3400
Efficiency - 75%
Power(in) - 1177
Heat Losses - 187
Controller Losses - 108
Power(out) - 882
Horsepower - 1.18

We will see... :wink:

(actually the biggest difference will be fairings, but I haven't done them yet)

 

[vanilla ice]

Throw one more lead brick on there and a few more nicads. You've already proven the chassis can handle more weight, so do it! Forget about 56 downhill, do it on the level with some extra volts.

 

[D-Man]

He doesn't have any flat roads around. Thats why he's posting avg speeds and downhill speeds.

 

[safe]

Throw one more lead brick on there and a few more nicads. You've already proven the chassis can handle more weight, so do it! Forget about 56 downhill, do it on the level with some extra volts.

I was pulling 44 mph on the flat today. (flat roads do exist, but coming from my house they aren't easy to get to right away or are not flat for very long) Hmmmm, I'm sure that with a 48 mph peak in top gear that if I can pull it on the flat that would be great. Right around 44, 45, 46, 47... in that area the wind resistance starts to become a problem for going any faster on the flat at 48 volts. I need a long time to get up to speed, so if there is a turn or a hill in the way I lose my speed.

Jump up to 60 volts?

Well, so far I've gotten away with using a 36 volt controller while running at 48 volts, I have a feeling that if I went to 60 volts I'd burn up the controller. I'm just not sure if it's worth it to take that kind of chance. You can't go backwards from that decision very easily.

 

[safe]

203mm Front / 180mm Rear

I added 203mm disc brakes on the front end a couple of days ago and today I upgraded the rear disc from 160mm to 180mm. Given all the custom stuff going on with my bike I needed to do some grinding and welding to make it happen. Along the way I corrected some other issues so that now everything is how it should be.

Now I actually have some decent braking and am able to get the rear wheel to skid during heavy braking without wanting to do it on purpose. Given the traction on these 3" tires I can easily use a lot more braking for the front, even at 203mm with my small brake pad area the brakes are not enough to get the front end to skid without a bump. But overall things are better and the weight to braking ratio is still very good. (it still stops fast... it's just that the limit is so high because of the tires that there's room for a lot more)

 

[recumpence]

I have the same braking concern. My bike is alot lighter, though. My 203mm brake is plenty strong. But, the pad pressure is too high, which makes the disc glaze over quickly. I have a monoblade fork. So, one disc is the limit. So, I picked up two new calipers. They will both be gripping the single 203mm disc.

Matt

 

[safe]

I have a monoblade fork. So, one disc is the limit. So, I picked up two new calipers. They will both be gripping the single 203mm disc.

On the Project #002 I'm going to go with dual 203mm discs (one on each side like the motorcycles do) and a 180mm in the rear. For that bike it should be plenty. Project #003 is going to use a single 203mm disc and I'll just live with it.

I've got massive tires that grip like a motorcycle tire... I even had to grind little ridges into the rims on the inside so that the tires would grip strongly enough and not slowly drift due to braking forces. I can see that as the speeds and braking forces go up these tires and rims and just generally everything needs to be improved upon. From my perspective I just want to get the general outline of what an Electric Bicycle Road Racer would behave like and worry about perfecting it later. High quality suspension is one of those things that you could spend a few years to get right... it can wait until later.

203mm is better than 180mm... so in my book that's "progress".

Getting hydraulic double or quad piston brakes would be the way to go because you can get massive brake pads which would give more surface area.

...the prices seem to be in the hundreds of dollars.

 

[recumpence]

I do not like hydraulic systems anyway. I hang my bike upsidedown. Hydraulics do not like that.

Besides, it only cost me $100 for my two brand new calipers.

Matt

 

[safe]

...Besides, it only cost me $100 for my two brand new calipers.

No argument about pricing... I bought three Toy's R Us bikes at the beginning for $100 each and got a total of six disc brakes out of it. So I paid next to nothing for mine. :lol:

I've tried really hard from the beginning to keep prices way down... however... I suspect that by now I've spent at least $1500 if not even more on all the parts and stuff.

At some point I plan to elevate the quality level and that will mean higher prices. Switching to an RC motor is a step up in quality and price, so you are in a slightly higher price plateau already compared to me.

 

[johnrobholmes]

Hydraulics are fine upside down unless you have an open bath resi that allows free flow into the master cylinder. I have some open bath maguras and shimanos that can sit upside down for months without getting air in the lines. The trick is to only pump the levers when it is right side up.

Hayes makes some no reservoir systems, but you have to be GOOD at bleeding them to get the air out.

 

[safe]

Still 55 mph

My 13 tooth motor sprocket arrived today and so I slipped it onto the bike and went for a speed run. On the flat I was able to pull more like 46-48 mph, which is good. On the hill that I had high hopes about as a new good place to set a new fastest speed it only delivered 53 mph because while it was long enough it was probably only about a 5% slope. Going back to my steeper downhill near my house I managed to equal my old best of 55 mph. It just seems that I either need to "indulge" in more power or improve on the aerodynamics because the wind is just too much to push through at that speed.

Today I sanded the front fairing mold and primed it, then I started with a few wax coatings to get ready for the fiberglass mold making. So I guess you can figure which choice I've made. While for Missouri I still have room to increase power and still be legal (up to three horsepower) I'm not interested in going in that direction... I want the bike to be faster without resorting to "brute force". Aerodynamics defines the top speed, so I'm hoping the fairings will deliver a new top speed one day. Future bikes will be more "750 watt" oriented because I really want to make this "toy" be a lot of fun as an electric bicycle without getting too deep into the "real" electric motorcycle category. At some point you need clarity about what you are building... 750 watts is the true destination. :wink:

Also:

I just passed 4,500 miles today...

 

[johnrobholmes]

Safe, you don't even have pedals on your bike. Will you on future builds, or do you just want to stick with 750w for sake of argument? No matter how you slice it, this isn't an electric bike. It tis a motorcycle.


30mph is the limit in Missouri too, so while you may be under the HP limit you are still outside of non-licensed vehicle spec.


Looking forward to the fairing, I bet you can slip a few more MPH on there with it.

 

[safe]

No matter how you slice it, this isn't an electric bike. It tis a motorcycle.

Before building my bike I checked the Missouri laws and quite frankly they are rather abnormal. First, they group everything into something called the "Missouri Moped Law" and allow up to three horsepower and pedals are not required since many mopeds don't have pedals and are more or less scooters of some sort. One rule that exists that is strange, but makes sense when you understand what was on the lawmakers minds is that "no clutches" are allowed. A clutch? Huh? Well, they wanted to prevent little kids from having to learn on a bike while needing to learn about clutches, so they don't allow that. They allow motors up to 50cc to be on the mopeds.

It wasn't until months later after the first bike was built that I even discovered the Federal Electric Bike Law that was fairly recently passed limiting the motor to 750 watts and making such a bike fully legal in all 50 states.

So I'm just migrating towards legality... my third bike will be fully legal in all 50 states, though my second bike will be another "Missouri Moped" like the one I have now. I might even decide to simply build a new frame for the second bike and just transfer all the components across. The second bikes frame is a little heavy anyway... and I'd like to have more pedal bikes to play with. In some ways most of last summers work is not all that usable... (however it's last years bikes geometry that is the basis for all the fiberglass work and is still the geometry I'm happy with) I should have spent more time refining my ideas and less fabricating, but that's always how it feels in retrospect on these projects.

It always seems like these developments move in a sort of organic manner where you adapt as you go forward. The RC motor concept is something that I also want to integrate in later on as well.

 

[johnrobholmes]

I can certainly help you out in the RC world when the time comes. Your bike does classify as a Missouri Moped, as does mine. I wish we could have clutches though, that would make sensorless motors work like a charm on startup, and be very fun to drive and bang through gears.

 

[recumpence]

The clutches they are talking about are manual clutches. Don't mopeds have centrifugal clutches? Just use a centrifugal clutch.

Matt

 

[johnrobholmes]

Centrifugal is allowed, but that still doesn't give me the fun of a manual clutch and multiple speeds.


One day I will have an electric motorcycle with gears.

 

[Link]

One day I will have an electric motorcycle with gears.

I see your gears, and raise you a sepex motor. 8)

Also about 100kW if I can get away with it.

 

[safe]

The basic outline that the Optibike has laid down is where I think things "should" go and where I'm going with my designs. 750 watts, as many gears as is practical, good aerodynamics, great traction, and (one day) full suspension is the general outline of all my future ebikes.

If you want to focus on power then skip ebikes and go to emotorcycles... being in Missouri just allows me more time to get the pedals to work since they aren't required here.

Two Rides Before The Heat

Managed to get two near 20 mile rides in this morning. The NiCad's seem to be doing well, but one set of tubes has been slow to "wake up" but seems to be getting better with each cycle. Also, the deeper the cycle the better. (as many have suggested for NiCads) The Solderless Tubes themselves are flawless, so if I ever hear anyone say:

"Oh, no you can't do Solderless Tubes on ebikes."

...all I'll be able to do it roll my eyes. (they have performed perfectly from the start)

I will add however... that when you unscrew the caps the wires tend to want to rotate with the screw. I might add a washer in between the copper contact area and the spring to allow for smoother usage. That's a refinement, not an absolute necessity.

 

[Toorbough ULL-Zeveigh]

no one said it wouldn't work, just that a side-by-side layout with battery bars works a whole lot better.
Configuring an ebike battery to be like a flashlight is definitely a step backwards.

I don't know where is this mythical 'smart-crowd' you keep referring to in the RC world, cuz everything I've been reading on every RC forum out there is that they have completely abandoned what they call the 'shotgun' configuration several years ago in favour of SxS.
They even go to the extreme of ripping apart a brand new pack to reconfigure & resolder just to give you some idea how much they detest end-to-end cells.
I could bury you with links if I had nothing better to do instead of enjoying the summer sun on my e-ride.
I may anyways at some point, if you can provide me with a single link from the 'smart'-(lol)-crowd of one, or even if you don't, just to dispel your poo-poo kakka bs disinformation you're laying down.

You have to count Scotty Pollacheck & the Killa-cycle boyz as not one of the smart crowd.
Hell, even the flashlight guys on the CPF have seen the light that a welded/soldered pack can pump out a lot more current with far fewer voltage drops by avoiding numerous marginal interconnects.
It's still a tube tho, no getting around that in a torch, but I'm sure they would change that if they could.
That covers a wide spectrum of real-world, hard-won direct experience that has determined thru multiple, multiple trial & error which is the better way to go.

I believe in their thousands of tests to your one opinion.


Also:

I just passed 5,500 miles today...

TURBO ALL THE waaayyyyy....

 

[recumpence]

The issue seems to be the amount of current being drawn.

RC applications typically draw huge current in bursts. That is really bad for touch connections. But, drawing a relatively small amount of current will allow pressure connections to work.

That being said, there are a few ways to make stick packs without pressure connections (soldered stick packs). But, I won't get into that at this point. (Soldering is far better for high current applications.)

I agree that the best replaceable cell setup is a framework with cells mounted side-by-side, held in place with screw tabs at each end. That is a more solid friction connection.

Anyway, if it works, it works.

There are benefits and drawbacks to everything.

Matt

Oh, 300 miles for me, Woo-Hoo! :wink:

 

[safe]

...I agree that the best replaceable cell setup is a framework with cells mounted side-by-side, held in place with screw tabs at each end. That is a more solid friction connection.

Wait a second... that's the technique that fails!

No, the secret is the spring loading.

By allowing the cells to "breathe" as they heat and cool they are able to maintain a constant firm connection. Tests done by the RC Solderless Tube people have shown that direct metal to metal contact works equally well to soldering and if you are willing to buy some expensive silver conductive paste it's actually better than solder. (plus it can never break)

After all this don't direct people down the road that we already know is the wrong way. If you plan to create Solderless Tubes use the spring approach, do NOT try to use a screw alone.

But my design takes it a step further because it uses both a spring and a screw so that you can adjust the tension of the spring. Since all springs "sag" over time and are a little different from each other it's this coupling of the best of both that made it work so well.

I'm getting very good range and power from these Solderless Tubes on the bike so in actual riding they work flawlessly. They seem to get better as I cycle them and as the cells "zap" themselves together by rubbing next to each other.

This kind of reminds me of how long I spent simply arguing that gears provide a benefit to electric motors when they are built to comply with a set power limit. It's so intuitively obvious to be true (and the Optibike has done an excellent job of showcasing it) but there was so much of a "fog" of misinformation about it (people would confuse peak efficiency with overall efficiency) that it's only been recently that the forum has mostly given in to the argument.

Solderless Tubes may not work in extreme situations where you desire 1000 amps for an electric motorcycle, but for the real world needs of an ebike that only needs to draw 40 amps the Solderless Tubes work great. And you can inspect and repair the cells when needed... something that you cannot do with a rigid pack.

 

[TPA]

I see your gears, and raise you a sepex motor. 8)

Also about 100kW if I can get away with it.

If you haven't already, start a thread for this project you keep hinting at. Is it in the motorcycle area?