e-Power Challenge 2008 update

[mi7d1]

Here's some interesting data of times per lap of the the top 11. Five of them are e-assist. Mitch was running a BionX that stopped providing assist at speeds above 20mph The fastest bike at the event was not a streamliner but a faired and socked Gold Rush Replica. Look how close the times per lap are between second and third .019 per lap


brent 15 laps 50.30 = 3.353 /lap SuperStreet-------> e-assist
todd 16 laps 60.44 = 3.777 /lap StreamLiner
bill b 12 laps 45.10 = 3.758 /lap StreamLiner-------> e-assist
lonnie 16 laps 63.06 = 3.941 /lap StreamLiner
joe 15 laps 62.51 = 4.167 /lap StreamLiner
keith k 14 laps 62.31= 4.450 /lap Men's SuperStreet
cal 20 laps 95.14 = 4.757 /lap Stock-----------------> e-assist
bill s 10 laps 54.12 = 5.412 /lap Stock --------------->e-assist
michael 11 laps 62.54= 5.549 /lap Trike
marilyn 11 laps 63.29 = 5.753 /lap Woman's SuperStreet
mitch 9 laps 53.36 = 5.928 /lap StreamLiner-------> e-assist

 

[calinb]

<snip>
and others have said that I should look for a SLA that is rated at the one hour rate. I'll need to go back and read your post several time and then more pieces of the puzzle will fall into place.

An "18 amp-hour" SLA pack that is rated at a one hour rate can hold more energy than my old "18 amp-hour" SLA pack that is rated at a 24 hour rate. The one hour spec SLA pack will be considerably larger and heavier than the 24 hour SLA pack too.

Actually, battery weight might be a method that could be reasonably used to define the ePower Challenge race energy limits. Different battery chemistries would have different weight limits for any given class. Within any given chemistry, the energy density is fairly constant among manufacturers. There might be some adjustments necessary for the various battery chemistry sub-classes (like AGM vs. SLA) but I think it might work.

I think a bunch of us here are electrical engineers. Although power is not my specialty and never has been my specialty, I think I could explain this stuff much more easily, if we meet for a beer or something. Please PM me, Bill, so we might exchange emails and set something up.

 

[mi7d1]

PM sent

<snip>
and others have said that I should look for a SLA that is rated at the one hour rate. I'll need to go back and read your post several time and then more pieces of the puzzle will fall into place.

An "18 amp-hour" SLA pack that is rated at a one hour rate can hold more energy than my old "18 amp-hour" SLA pack that is rated at a 24 hour rate. The one hour spec SLA pack will be considerably larger and heavier than the 24 hour SLA pack too.

Actually, battery weight might be a method that could be reasonably used to define the ePower Challenge race energy limits. Different battery chemistries would have different weight limits for any given class. Within any given chemistry, the energy density is fairly constant among manufacturers. There might be some adjustments necessary for the various battery chemistry sub-classes (like AGM vs. SLA) but I think it might work.

I think a bunch of us here are electrical engineers. Although power is not my specialty and never has been my specialty, I think I could explain this stuff much more easily, if we meet for a beer or something. Please PM me, Bill, so we might exchange emails and set something up.

 

[mi7d1]

I've just got some additional information from Brent B who was ridding the Gold Rush Replica with a fairing and full body sock. He was 20 seconds a lap faster than me. I was 2 seconds faster than the fastest pedal powered streamliner. Brent and I were the two fastest bikes during the whole weekend but he was much faster than I. Sadly we were the only two to have meters as far as I know.

The stats are:

Brent B GRR faired and full tail sock running 36vLi 20Ah with an EcoSpeed drive system
Distance: 15 laps (29.7 miles),
time: 50 min,
30 sec., Avg.: 35.3 mph,
Max Speed: 42 mph,
energy used: 700 Wh,
Usage per mile: 24 Wh

Bill B WAW velomobile running 48v AGM 18Ah with Crystalyte 406 20Ah controller
Distance: 12 laps (23.76 miles)
time: 45 min,
10 sec., Ave 31.1 mph,
Max Speed 34.2 mph,
energy used 335.7 Wh,
Usage per mile 14.12 Wh/

Here's some addition mind numbing numbers on where the e-assist bikes fit in with the human powered ones. I took the data from the one hour road race for the HPC. The e-assist bikes placed 1,2,11,14,31 There are some photos getting out slowly. Most of the photos in this link to other links are of the HPC although some ebikes can be seen. I was the only one there all three days so I got more photos taken of my velo then the other ebikers did of their rigs.

BRENT B 15 LAPS 3030 SECONDS 202.000 SEC/LAP E-ASSIST SUPER STREET 1

BILL B 12 LAPS 2710 SECONDS 225.833 SEC/LAP E-ASSIST STREAMLINER (VELOMOBILE) 2

tod m 16 laps 3644 seconds 227.750 sec/lap streamliner

lonnie m 16 laps 3786 seconds 236.625 sec/lap streamliner

phillip p 13 laps 3419 seconds 263.000 sec/lap men's stock

michael w 13 laps 3438 seconds 264.461 sec/lap men's stock

keith k 14 laps 3751 seconds 267.928 sec/lap super street

joe k 15 laps 3771 seconds 269.357 sec/lap streamliner

keith k 13 laps 3511 seconds 270.076 sec/lap men's stock

alex k 13 laps 3512 seconds 270.153 sec/lap men's stock

CAL 20 LAPS 5714 SECONDS 285.700 SEC/LAP E-ASSIST STOCK 11

daniel e 12 laps 3471 seconds 289.250 sec/lap men's stock

jane m 13 laps 3823 seconds 294.076 sec/lap women's super stock

BILL S 10 LAPS 3252 SECONDS 325.200 SEC/LAP E-ASSIST STOCK 14

brian v 11 laps 3635 seconds 330.454 sec/lap men's stock

joe k 11 laps 3649 seconds 331.727 sec/lap men's stock

lonnie 11 laps 3656 seconds 332.363 sec/lap super stock

jason e 11 laps 3671 seconds 333.727 sec/lap men's stock

jeff w 10 laps 3430 seconds 343.000 sec/lap super stock

michael h 11 laps 3774 seconds 343.090 sec/lap trike

bruce p 11 laps 3774 seconds 343.090 sec/lap men's super street

marilyn 11 laps 3809 seconds 346.272 sec/lap women's super street

barclay h 11 laps 3823 seconds 347.545 sec/lap mens stock

david p 10 laps 3490 seconds 349.000 sec/lap men's sock

marilyn h 10 laps 3656 seconds 365.600 sec/lap women's stock

WSU (brock) 10 laps 3660 seconds 366.00 sec/lap trike

chris & mandy a 10 laps 3697 seconds 369.700 sec/lap tandem

dian w 10 laps 3792 seconds 379.200 sec/lap women's super stock

dave v 9 laps 3676 seconds 408.444 sec/lap men's super street

edna v 9 laps 3778 seconds 419.777 sec/lap women's super street

MITCH S 9 LAPS 3816 SECONDS 424.000 SEC/LAP E-ASSIST STREAMLINER (VELOMOBILE) 31

 

[calinb]

Interesting, Bill!

My mountain bike sucks the power (aerodynamic drag). My battery puts me in eCat 2 - Div 3 but, just for kicks, I calculated that, with the same energy, I could've completed 15 laps in only 3214 seconds or 214.3 seconds per lap. My "seconds per lap" would be even better at distances less than 15 laps too, of course.

What's interesting is the difference in Yesa LiFePO4 battery weight between Div 2 and Div 3 limits is about 6.25 lbs., or much less than the weight disadvantage of even a naked recumbent vs. an upright. In other words, in terms of performance for weight, putting the extra weight of a recumbent into a larger capacity battery on an upright is quite an effective strategy at these race distance lengths. Comfort is a different matter, of course. But then again, my bike may ride on Tri-Met trains occasionally.

 

[safe]

mi7d1

I've got a racers trick for you...

Pre-cool your motor!

Before the race place ice packs onto your motor and get it down to near freezing. That will lower the resistance of your motor and give better efficiency. If the thermal mass is sufficient it might be 10-15 minutes into the race before the motor heats up completely.

That's 10-15 minutes of an advantage.

 

[mi7d1]

Hey safe, I like the way you think! I've often wondered about my motor "cooking" while tucked inside that tail fairing. I could just see Tom, the club president, asking me why my wheel is packed in 25lbs of dry ice. With the race being on a fairly flat track and weight not being as important, perhaps I can insulate, seal off the back end even better and run a little cryo unit. Cheaper yet, I could use a fire extinguisher. Cooling on demand! I can see in my mind while rolling down the track pulling the pin and clouds of carbon dioxide escaping from my velo.

mi7d1

I've got a racers trick for you...

Pre-cool your motor!

Before the race place ice packs onto your motor and get it down to near freezing. That will lower the resistance of your motor and give better efficiency. If the thermal mass is sufficient it might be 10-15 minutes into the race before the motor heats up completely.

That's 10-15 minutes of an advantage.

 

[safe]

I could just see Tom, the club president, asking me why my wheel is packed in 25lbs of dry ice.

The trick would be to not tell anyone. Use the dry ice in the pit area before the race. Then remove it and go out for your ride. That way you get the advantage and no one will know. (except people that read this over the internet... )

I tried it on my bike and it definitely kept the temperature down relative to normal. The power and efficiency increase is very small... like 1% or 2%... but if you are looking for an edge this cheat could do it. :wink:

You know the racers motto:

"Never get behind on your cheating." :lol:

 

[mi7d1]

Thought the motto was something along the lines of: "Don't let your a$$ get frosted" :lol:

I could just see Tom, the club president, asking me why my wheel is packed in 25lbs of dry ice.

The trick would be to not tell anyone. Use the dry ice in the pit area before the race. Then remove it and go out for your ride. That way you get the advantage and no one will know. (except people that read this over the internet... )

I tried it on my bike and it definitely kept the temperature down relative to normal. The power and efficiency increase is very small... like 1% or 2%... but if you are looking for an edge this cheat could do it. :wink:

You know the racers motto:

"Never get behind on your cheating." :lol: