Chains and Sprockets (Dept of Everything You Need To Know)

I’ve been trying to sort out chain sizes and ratings, and found this site:  Notes on Sprockets and Chains.  I am now a Chain Geek. For sure, take a look, and you can be one too.  Great links at the end, too…

This is specifically what I was looking for:

Chain Dimensions

Chain types are identified by number; ie. a number 40 chain. The rightmost digit is 0 for chain of the standard dimensions; 1 for lightweight chain; and 5 for rollerless bushing chain. The digits to the left indicate the pitch of the chain in eighths of an inch. For example, a number 40 chain would have a pitch of four-eighths of an inch, or 1/2″, and would be of the standard dimensions in width, roller diameter, etc.

The roller diameter is “nearest binary fraction” (32nd of an inch) to 5/8ths of the pitch; pin diameter is half of roller diameter. The width of the chain, for “standard” (0 series) chain, is the nearest binary fraction to 5/8ths of the pitch; for narrow chains (1 series) width is 41% of the pitch. Sprocket thickness is approximately 85-90% of the roller width.

Plate thickness is 1/8th of the pitch, except “extra-heavy” chain, which is designated by the suffix H, and is 1/32″ thicker.

 

Dept of Intenets Gossip: Shelina Moreda Rides a Brammo

Yup.  You heard it here first.

What?  You want MORE?  OK.  Here’s my guess.  Brammo has seen how HUGE the traffic on my “Who’s Hotter, Shelina Moreda or the Brammo Babes?” post is, and wants to corner the Hot Bike Chick market from both sides.  OR.  They want a spokesperson who actually RIDES for some cool shots instead of more shots of Brian with his sneakers.  OR, they’re shopping for rider/spokespersons.  OR, they’re shopping for a rider.  OR, they slipped a little crack into my koolaide this morning.

Oh.  Right.  Need photo of Shelina.  Here’s my fave:

Shelina, doin’ what she does.  Which is whatever she wants.  Awesomely doing it.

…it’s from her Facebook page.

moo.

First EVER ELECTROPALOOZA is a GO!

May 5th, Lebanon Speedway.  Be there, bitches! All the deets here.  Want to chime in?  Join the planning committee here, on Facebook.  Hope to see you there!

Nuts & Volts Meets Obama at OSU

Kyle Ginaven, aka Nuts & Volts of ElMoto fame, was chatting me on the FB yesterday and said, OK, gotta go get ready to meet the president.  Little did I know he meant, meet The President.  I couldn’t decide whether this post should be in the Dept of Holy Crap, or the Dept of Awesome Awesomeness and Congrats!

Here are some shots from the OSU Facebook page, I’ll credit them when I find out who took them:

For a full story on Obama’s visit to OSU and his comments on EVs, electric motorcycles and energy policy, try this story from the Columbus Dispatch.

…from Fossils to Flux- New Ad Shots

Git yer New Ad Shots herez:

 

Swappable Batteries: Tell Me Again Why Not?

The Ripperton bike I just posted about with the hot-swap batteries (15sec for a swap-out, bitches), has me all wound up about hot-swap batteries.  Tell me again, why doesn’t this make perfect sense?  Why isn’t this the main focus of every EV design being made?  I’m talking every, here, not just motorcycles.  Is it just too perfect?  Is that it?

Starting with the Ripperton bike and the racing applications, it adds the ability to have recharge pit stops, right?  Halfway through the race you can stop for 30sec, slap in a new pack and beat the crap outta that baby for the rest of the race, when you’re field is working on half-spent capacity and the voltage sag that it gives you.  Seems like game over, to me.  Beyond just the ability to add more distance to the race.

On my personal motorcycle, for a trail bike I can throw a pack into the truck and slap it in at the gravel pit or wherever I ride.  For my commuter I could have a pack with a 40-mile range and make my commute to work (30 miles), swap it out with a pack I have charging there, put it on the charger and I always have a fresh pack.  Same equation on a car.  Smaller pack option, make it a hot-swap.  With a car, you could even carry the thing in the trunk.  Want to double your range?  You got your junk in the trunk.  (Yes, I’m fully aware of the size and weight of a car pack, but still…  even just for emergency use?  How much would a 5-mile lithium pack weigh?  Not all that much…)

I’ve heard the downside of this from an infrastructure standpoint, where people are proposing the idea as a gas-station option.  Drive in, swap out your pack, drive away…  and one that really doesn’t work, at this point, anyway.  There are too many problems- different designs, the cost of the pack, etc.  But on an EV, how hard is it to make a hot-swap pack as opposed to a permanent pack?  I’d argue, not hard at all, since that’s exactly what I’m doing with the R5e2.  Who cares that it’s not universal?  I just want to be able to pull in, drop out my old pack, slap in a new pack and ride away.

The biggest single question I get is about range.  The second question is about recharge time.  This makes both of those questions go away.

Everybody’s an armchair designer, but Brammo, Zero, all you others?  Tell me again, why aren’t you thinking in terms of a hot-swap pack?  Why wasn’t this the idea from the very beginning?  Zero even offered one…  why isn’t it on all their bikes?  Enquiring minds want to know.  The past aside, though, I think it’s undeniably what we’re going to see in the future, because it truly is a game-changer.

Ripperton R1 Electric Superbike for 2012: 15sec Battery Swap, Liquid Cooling

In a post on ElMoto, Andy Marsh of evmotorcycle.org posted a story about Ripperton’s entry for 2012- an ultra-lightweight build based on an R1 with a liquid-cooled version of the Motoenergy AC ME0913 and a 7.5kwh interchangeable A123 pack.  Yeah.  You read that right.  Before you go all skeptical on it, the change-out time is a whopping 15sec.  This is huge.

One word.  Pit stops.  No wait.  Pitstops.  There, that’s better.

The post on ElMoto is here.  Tony Castley has added some nice shots of his own to the thread.  Ripperton’s build thread on DIY Electric Car here (with index, no less…).

On the Battery Swap system:
Daniel has consistently been designing with the removable battery system in mind. The new pack, which will be the third iteration of his quick swap design, is a completely removable unit, similar to a conventional battery power tool. Having the battery removable in this way means that the racer can swap battery packs in approximately fifteen seconds. ‘This would get the rider half way around the Isle of Man circuit, making a pit stop at Sulby Bridge. Not having to carry the full load would mean that the rider could take advantage of the lighter machine over the course. The bike could be ridden faster to offset any time penalty for the swap.” Daniel said.

On the liquid cooling
One major lesson that was learned in the 2011 racing season was the importance of keeping these motors cool. With an effective cooling system the motor can be run over three times as hard without any problems. A 12kW motor with a good liquid cooling system becomes a 40kW motor with increased reliability. Heat is definitely the enemy of the electric motor. Keeping it cool increases the performance considerably.

Though we all know I’m a fan of cooling, I’m not at all sure of those numbers.  They seem pretty optimistic, but I’ll write it off as pre-season trash talkin’.

Besides anything else, hell.  It’s damn pretty.

Go to 7:00 to see what that looks like, with an older pack design:

Care and Feeding of LiPo

I have been wondering about storing my bike outside in the cold New England winters.  Here’s a great post that talks about that, and other storage, temperature and charging issues with lipo batteries from none other than the RC aviation community.  Who else?

He focuses on getting the most life out of lipo, and the secret is in not abusing them…  knowingly or not.

Lithium lifetime is based on several factors:

1. Temperature while in use
2. Temperature while in storage (for our purposes, “storage” is the same as “maintaining a constant voltage level”)
3. Percentage of “full charge” (4.20v/cell) to which a cell is charged
4. Percentage of “full discharge” (depending on chemistry, somewhere between 2.5v and 3.2v) reached by a cell
5. Rate of charge (depending on chemistry, between 0.3C and 3C may not be excessive)
6. Rate of discharge (depending on chemistry, up to 20C may not be excessive)
7. Charge level while in storage

In particular, there’s the issue of charging when the batteries are cold. And by cold, he means around 32F.  If you top out the battery at that temperature, you’ve overcharged it.  When it gets warmer, your 4.2V charge is going to go well over that, apparently, so you may have taken as much as 10% off the life of the pack.

Here’s another very informative post on lipo use in general: Lipo Usage Best Practices.

Finally, none other than Battery University:

Many battery users are unaware that consumer-grade lithium-ion batteries cannot be charged below 0°C (32°F). Although the pack appears to be charging normally, plating of metallic lithium can occur on the anode during a subfreezing charge. The plating is permanent and cannot be removed with cycling. Batteries with lithium plating are known to be more vulnerable to failure if exposed to vibration or other stressful conditions. Advanced chargers, such as those made by Cadex, prevent charging Li-ion below freezing.

Shelina Burnin’ Dinosaurs (Dept of AWESOME Video)

I gotta get me a GoPro.  Yeah, OK this is just me taking some notes on killer camera angle and placement on a motorcycle, since it’s the most AWEsome motorcycle racing video I’ve seen.  (Are you listening, butt-shot-video-boys?)  Looking forward to kind of work on an electric bike…

Here it is:

No, now stop it, it has NOTHING to do with the fact we can gaze into Shelina Moreda’s eyes as she slams that bitch through the turns (or watch her butt…  wait, WHAT??)

It’s all about the camera.

Yeah, that’s right.

.

Understanding Battery Current and the Balanced System

This is really a very simple concept to get your head around.  The problem is that you have to have the basic concepts down before it all makes sense.  Ah, Watts, current, C rates, all that stuff…   I want to start by thanking Noah Podolefsky for his help distilling this down to a “eureka!” moment.  This is about understanding how your total battery pack capacity determines the current delivered to the motor, and how to balance your battery type, it’s discharge rate, and the total capacity of the pack.

This starts with the fact that battery discharge ability, measured in amps, is cumulative when you wire batteries or cells in parallel.  So, you have a cell that can discharge a continuous 1amp, and parallel it with 99 others like it, you get 100amps.  Here’s why that’s important.

When you’re planning your build, you need to make sure you have adequate current delivery from your batteries to match (balance) the rest of your system, in particular, your motor.  If you have a motor that can handle 150amps continuous, but your pack can only feed it 50amps, then you’re underpowering the motor.  When you’re making the decisions about the size and type of your battery pack, you have to consider the discharge rate.  When you put your packs together in a parallel/series configuration, usually you’re thinking about voltage and Ah – amp-hours -  which will give you an idea of what your range will be.  You have to keep in mind the total discharge rate, or amps, you’re putting together too.  To do that, it’s better to think in terms of Watt-hours rather than Ah.

Here’s the reasoning behind that.  A typical motorcycle uses, say, 100Wh/mile, regardless of the voltage.  Now…  let’s decide our range.  We want a range of say, 50 miles, you need 4.3 kWh.  4.3kWh figures out to 60Ah at 72V.  If you want that range, with a 72V system, you’re going to need 60Ah…  simple enough.  When you change the voltage around, you’re going to change the Ah around too…  that’s why it’s better to talk about the “work” done – or Watts – than the capacity (or Ah).

How ‘m I doin?

Here’s where it gets interesting, from a current standpoint.  When you start putting your batteries together, you’re adding the voltage together when you put them in series.  One cell that can do 3.2V at 10 amps with 9 others can now do 32V at ten amps. Now parallel them with nine other modules.  You now get 32V at 100amps.

Secret of the Universe: You can only get a grip on the current the pack can deliver once you decide how you want to configure them.

Let’s break it down and throw out some configurations, based on a 72V system and a target of a 50 mile range.  We can do it a few ways.

GBS 60Ah batteries will give me 3.2V and 60Ah, so I need 24 of them to get 4.3 kWh.  This will give me a total current of 180amps continuous.

Headway 8Ah cells will give me (at 24s 8p) my 4.3 kWh, and because they have a higher discharge rate they will deliver, what, 600amps?  Crazy talk.

Running my RC lipo that are rated at 20C, 60Ah of this stuff will give you 1200amps continuous.

These rates are far more than my motor can handle. There are, of course, other decisions that go into picking a battery, like, for instance, my lipo packs are half the size and weight of those Headways and GBS.  Then, you have to consider cycle life- if you’re hitting the pack for all it’s worth, all the time, it’s going to wear out faster.  If you’re tapping it for a fraction of what it can do, it will last longer.

So, to sum up – the procedure would be, pick your desired range.  This would determine your kwh for your pack.  Once you have that number, compare your battery choices at that kwh for current, cost, size and weight.