Latest bike

[billvon 2,380]

Stats:

72 volt system, 35A max through controller
Crystalyte X5304 geared brushless DC hub motor
$150 Target bike (i.e. cheezy)
Lead acid battery (Hawker cells) for now, li-ion coming soon
Max speed so far 40mph (too chicken to go faster on this frame)
Max power 2.4 kilowatts measured

[ACMESkydiver 0]

-What does it weigh? Can it be strapped down in the back seat of a Piper Warrior?

~Jaye
Do not believe that possibly you can escape the reward of your action.

[quade 3]

Oh my . . . you've beat the poo out of me and for far less money.

I do think I'll beat you on "style" points however.

What does your range pencil out at? Will this be a commuter?

quade -
The World's Most Boring Skydiver

[MikeForsythe 0]

If you are running the batteries in series why not stick a 175W solar panel/controller over your head to charge batteries? It would be a pretty easy frame to make. It would solve charging availability issues and give you a greater range of use. And then there is the cool factor!

Looks great, congrats

Time and pressure will always show you who a person really is!

[JackC 0]

You don't fancy actually peddling the thing then?

[billvon 2,380]

(answering a few here)

>What does it weigh?

About 60lbs

>What does your range pencil out at? Will this be a commuter?

Will be a commuter; don't know the range yet. I suspect it will make it 5-6 miles (home to work) but I'll have to charge at both ends. The li-ion batteries should solve that problem.

>why not stick a 175W solar panel/controller over your head to charge batteries?

It's the 72 volt system that's the problem. I'd need 6 panels in series to get the voltage I need to charge. (Or a boost converter; I'm working on that.)

> You don't fancy actually peddling the thing then?

I figure it will be apart often enough (like it is now) that I'll still get plenty of exercise on my usual bike. I often use it when I have to get somewhere without being all sweaty (like happy hours on Friday.)

[Mostly_Harmless 0]

That's pretty neat. Please wear a grey suit and red bowtie when you ride it!

_________________________________________
www.myspace.com/termvelocity

[Phillbo 11]

and don't forget the lights

[Mostly_Harmless 0]

I was thinking more of....

_________________________________________
www.myspace.com/termvelocity

[johan420 0]

Quote

You don't fancy actually peddling the thing then?

classic....hahaha

[Shotgun 1]

Quote

I often use it when I have to get somewhere without being all sweaty (like happy hours on Friday.)

But you'll be more popular with the ladies if you're all sweaty at happy hour.

[billvon 2,380]

>But you'll be more popular with the ladies if you're all sweaty at happy hour.

Why do I somehow doubt that? "Sorry about the puddle. Don't worry, it's just sweat."

[johan420 0]

Quote

>But you'll be more popular with the ladies if you're all sweaty at happy hour.

Why do I somehow doubt that? "Sorry about the puddle. Don't worry, it's just sweat."

fresh sweat is sexy.....on girls.

[Remster 24]

Quote

>But you'll be more popular with the ladies if you're all sweaty at happy hour.

Why do I somehow doubt that? "Sorry about the puddle. Don't worry, it's just sweat."

Bill: we are talking about Keely here. Who knows what the little freak likes.

Remster

[cocheese 0]

Pretty sweet. I'm not even going to ask how much a brushless motor that big costs. (just in case your wife reads this.)

[billvon 2,380]

>I'm not even going to ask how much a brushless motor that big costs.

Cheap! (Well, relatively.) $399.

[cocheese 0]

yea sure. "It was on sale".

[cocheese 0]

How much for the new battery? ( Li-ion)

(damn, i killed the thread with that one)

[Shotgun 1]

Quote

Quote

>But you'll be more popular with the ladies if you're all sweaty at happy hour.

Why do I somehow doubt that? "Sorry about the puddle. Don't worry, it's just sweat."

Bill: we are talking about Keely here. Who knows what the little freak likes.

Well actually I said "ladies," which would probably not include me. And I was probably lying to Bill anyway, as usual.

[MikeForsythe 0]

Quote

It's the 72 volt system that's the problem. I'd need 6 panels in series to get the voltage I need to charge. (Or a boost converter; I'm working on that.)

If it is a 72V system and the panels are 36V why would you need six? What is the voltage of each battery? You could use diodes and charge multiple batteries in parallel and still run in series to maintain the 72V.

Time and pressure will always show you who a person really is!

[quade 3]

Mike, uh, dude.

Of all the people on the planet I would not question about solar power and batteries; billvon.

Seriously, you should go to his house sometime.

quade -
The World's Most Boring Skydiver

[MikeForsythe 0]

Paul, uh, dude,

Maybe I am asking the questions because I don't know the answers or have all of the information. Maybe I made a statement of what normally works and I would like to know why it won't in this application.

Maybe I am asking because it IS BILL.

Time and pressure will always show you who a person really is!

[quade 3]

Fair enough.

quade -
The World's Most Boring Skydiver

[billvon 2,380]

>If it is a 72V system and the panels are 36V why would you need six?
>What is the voltage of each battery? You could use diodes and charge
>multiple batteries in parallel and still run in series to maintain the 72V.

The battery I have now is made up of 18 packs, 2 cells each, total of 36 Hawker lead-acid cells. They are connected in series to get 72 volts.

To charge lead-acid batteries, you need 2.35 to 2.5 volts per cell. That means you need 85 to 90 volts total to get the batteries to charge correctly.

Most solar panels out there use 36 silicon cells at about .45 volts each. They are listed as 12 volt, which really means 17 volts or so. Six of them give you 72V nominal (actually about 102 volts.) The extra voltage is important because when the panels get hot their voltage droops, and there is some loss in the system. You could probably get away with 5 panels though.

Lithium-ion is similar, but you have to be MUCH tighter on charge voltage.

An alternative trick is to mess with the battery topology. For example, if I could throw a switch and go from a 72 volt battery to three 24 volt batteries in series, I would need only two panels. Since a few panels contain 72 solar cells instead of 36 (called 24 volt panels) I could get away with one panel there. Unfortunately these panels are the really huge ones, like 3' by 6' and 40 lbs.

A third trick, one I will probably try, is to boost the 12 volts to 72. This gives you better voltage control and you can use almost any panel out there.

[quade 3]

bill --

Been doing a bit of thinking because I also have a similar type of device I'm using for my daily commute and now I have a couple of questions for you;

1) How would one go about figuring out the the energy/carbon break even point of such a device? The device takes a finite amount of energy to manufacture, ship and eventually dispose of. How many miles am I going to have to commute (since recreational use shouldn't count) to break even? I know how much gas I would have used in driving and I know how much I'm saving by using my device, but I can't for the life of me figure out how much of a whole I created for myself by getting the device to begin with.

2) I was thinking of designing a solar powered charging station for mine, but the numbers don't seem to pencil out. It appears as if I'd be making a fairly substantial energy/carbon whole in building it to begin with and the power I get from the utlity company seems like it would be less expensive in the long run to boot.

3) Are you experiencing any "hostility" from random people because you're riding on a "different" device? For instance, when you ride past a spandex clad biker, have they ever made a comment that you're being lazy or cheating? Personally, I find the comments facinating and was wondering if you had any stories.

quade -
The World's Most Boring Skydiver