$10 tailbox

[energyi]

ES:

Tried to post this at bentriders, but couldn't upload the link. Might also belong at recumbent.com, but am posting it here because it has an hub motor too ~smiley~.

What is the etiquette, do I need to cut and paste the text, photos and video or can I just post the blog http://renewableenergyspace.blogspot.com/2012/11/inexpensive-lightweight-recumbent.html? Feel free to move this to another ES forum. Thanks in advance.

http://renewableenergyspace.blogspot.com/2012/11/inexpensive-lightweight-recumbent.html

Hope this helps. Thanks. Best, Joe Mc.

 

[SamTexas]

Did I miss it? I looked at the 2 links you posted but could not find any actual performance numbers. Have you tested the efficiency of your tailbox?

 

[energyi]

Haven't tested the performance of the tailbox, use the theoretical in the SA article and calculator referenced. Hope to do some closed track testing with and without fairing with hub motor tracking electrical energy usage, constant wind. Waiting for Speedict update.

 

[SamTexas]

Looking forward to the actual numbers. Thanks for posting.

BTW, if the tailbox performs as expected, you could use it to enclose the biggest battery ever installed on a tadpole!

 

[spinningmagnets]

 

[energyi]

Looking forward to the actual numbers. Thanks for posting.

BTW, if the tailbox performs as expected, you could use it to enclose the biggest battery ever installed on a tadpole!

Trying to keep the whole thing less than 300 lbs with the heavy rider. Figure I'll bring it down to the local NY Pizza joint and show them the right vehicular for delivery. It is the advertising on the fairing/tailbox that makes the best billboard. Piping smells out the back, handing out coupons at stop lights....

Best, Joe Mc.

 

[salty9]

It is good to see finally see a useful purpose for political advertizing.

 

[energyi]

Did I miss it? I looked at the 2 links you posted but could not find any actual performance numbers. Have you tested the efficiency of your tailbox?

Two tests performed so far, one an oval ~0.5 mile for a total 1.8 miles, the other straight line back and forth 2 miles with and without tailbox. Using a simple amp-hour accumulator between the battery and the controller, on the oval track with the tailbox had 20% less amp-hours. The straight line, slightly faster track with tailbox had 25% less amp hours. Let me know if you want the spreadsheet. Speeds were between 22 and 24 mph, within one mph of each other for each test. Will try to go faster if I can find a flat track in Colorado.

Best, Joe Mc.

 

[SamTexas]

That's very encouraging! Yes, I would love to see the spreadsheet. I assume you also have the Wh numbers in addition to the Ah, right?

 

[www.recumbents.com]

Wow, nice testing, and it's amazing that it does so well. Mother-of-all-tailboxes strikes again! I may have to dig mine out again...

-Warren.

 

[energyi]

Image attached is the spreadsheet for full transparency. (while trying to attach the .xlsx error message "The extension xlsx is not allowed.")

Feel free to correct me if/where I have taken any liberties with assumptions. Yes, watts are calculated by I*V, starting voltages. Amp-hours * Volts = Watt-hours. Also included a watt-hours for charging the battery pack back up, which is about right for an 80% efficient charger.

Best, Joe Mc.

 

[sendler2112]

with tailbox had 25% less amp hours. .

Most excellent! Imagine what the difference would be at 40 mph. I have just bought a (soon to be) dual suspended recumbent.
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bike to start on something like this.
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[SamTexas]

Image attached is the spreadsheet for full transparency.

I can see a definite improvement/advantage between run 3 and 4.

I'm not sure about run 1 and 2 though. Run 2 (without) was with some wind but got a higher average speed. Run 1 (with): No wind but lower avg speed?

I know it's hard to do these tests in the real world. It would help if you make the run longer and in a loop. Also the Whs derived from Ah and starting voltage is not accurate. A true watt meter would do the calculation in real time using the real time current and voltage.

Still it's good to see some numbers. Have fun with your new toy.

 

[chisixer6]

On Warren's www.recumbent.com site there are article to build a cheap coroplast faring, blow your owm front lexan fairing and other items....here is the coroplast link


http://www.recumbents.com/wisil/gin/fairingseminar.htm

 

[energyi]

Just ordered a Speedict ( http://endless-sphere.com/forums/viewtopic.php?f=3&t=22919 ), so hope to be updating these trials this spring with more power analysis.

Joe McSolar

 

[bowlofsalad]

Just ordered a Speedict ( http://endless-sphere.com/forums/viewtopic.php?f=3&t=22919 ), so hope to be updating these trials this spring with more power analysis.

Joe McSolar

Hilarious. I've been doing tons of reading on ebikes for a long time, this is the first time I've heard of the speedict. It seems interesting. I have a cycleanalyst, but using a smartphone for this might have potential advantages. I am sure plenty of ebike users will carry a smartphone, seems like a great combination.

 

[energyi]

Took a while but I have just finished doing two runs with and two runs without the rear fairing using an energy meter. 10.1% reduction in energy with rear fairing on a hilly, curvy road, down and back averaging 22.4 mph all out throttle. More data in the future, but wanted to get this out, hope it helps.

Hope to be testing a flat circuit soon.

Joe Mc.