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16-01-2017, 17:26
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#31
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Registered User
Join Date: Apr 2008
Location: out cruising again, currently in Fiji
Boat: Sailboat
Posts: 1,466
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Re: Turn calories into electricity?
Quote:
Originally Posted by meatservo
If there was a way to harness all of the hot air and bullsh*t coming out of Washington this past 8 years, we would be energy independent...
meatservo
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no worries, the will be so much more hot air the next couple months
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16-01-2017, 17:34
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#32
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Senior Cruiser
Join Date: Sep 2014
Location: puget sound washington
Boat: 1968 Islander bahama 24 hull 182, 1963 columbia 29 defender. hull # 60
Posts: 12,121
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Re: Turn calories into electricity?
Quote:
Originally Posted by meatservo
If there was a way to harness all of the hot air and bullsh*t coming out of Washington this past 8 years, we would be energy independent...
meatservo
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Hopefully you meant Washington DC not Washington state our fubar ended 4 years ago .
__________________
Non illigitamus carborundum
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16-01-2017, 23:27
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#33
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Registered User
Join Date: Apr 2013
Posts: 11,002
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Re: Turn calories into electricity?
Quote:
Originally Posted by adoxograph
I think the Romans, the Greeks and the Vikings were quite successful with human powered boats.
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Perfect, I only need a crew of 200 to generate 50hp for short bursts of speed.
Then again, I think they chained them to their seat 24/7 and they lived on water and gruel...were you volunteering?
One thing to keep in mind, just like with the Diesel vs Hybrid discussions, it will be far more efficient to directly drive the propeller rather than convert the pedaling to electricity, store it and then convert it back to mechanical energy if you are thinking propulsion (same works for a pedal powered blender).
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17-01-2017, 05:58
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#34
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Registered User
Join Date: May 2014
Location: USA
Boat: 41' yawl
Posts: 1,187
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Re: Turn calories into electricity?
Quote:
Originally Posted by newhaul
Here's the math
120 volts DC at 20 watts which is about .16 ah I see lots of pedaling in someone's future to charge a battery to use a microwave off an inverter to heat a cup of coffee better to rub your hands on the cup
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120VDC at 20 watts would be .167 /amps/.
If you pedaled for 1 hour, you'd have generated .167 amp hours.
If you are a 12V system, same wattage, those numbers change to 1.67.
Later in the thread folks state the output you can achieve is significantly higher, but still sounds like we'd be better off with a Mr. Fusion converting our food scraps.
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17-01-2017, 06:05
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#35
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Moderator Emeritus
Join Date: Oct 2013
Location: Jacksonville/ out cruising
Boat: Island Packet 38
Posts: 31,351
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Re: Turn calories into electricity?
It takes 300 to 400 watts to sustain Human powered flight, and there are very few people that can do that. I'm talking kids who are Pro athletes. I know compared to my prime, physically I am a joke. I'd bet few of us could sustain 100 W, its harder than you think. I have pedaled a bike set up as a demonstration running a small portable TV that pulled I think about 60W, and had to pedal my butt off, I could not have sustained it for too long, and that was when I was younger.
It's one of the things that really impressed me at just how much power there is in things that generate heat. You would likely work yourself nearly to death to generate enough heat for a cup of tea.
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17-01-2017, 06:17
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#36
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Senior Cruiser
Join Date: Sep 2014
Location: puget sound washington
Boat: 1968 Islander bahama 24 hull 182, 1963 columbia 29 defender. hull # 60
Posts: 12,121
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Re: Turn calories into electricity?
Quote:
Originally Posted by chris95040
120VDC at 20 watts would be .167 /amps/.
If you pedaled for 1 hour, you'd have generated .167 amp hours.
If you are a 12V system, same wattage, those numbers change to 1.67.
Later in the thread folks state the output you can achieve is significantly higher, but still sounds like we'd be better off with a Mr. Fusion converting our food scraps.
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I only carried out to a hundredth of an ah on that one.
Later in the thread I linked to a much larger bicycle powered unit that would use a multi speed bike making it easier to maintain the needed rpm on the pm motor.
__________________
Non illigitamus carborundum
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17-01-2017, 06:41
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#37
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Registered User
Join Date: May 2011
Location: Sea of Cortez and the U.P. of Michigan
Boat: Celestial 48
Posts: 904
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Re: Turn calories into electricity?
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17-01-2017, 07:03
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#38
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Senior Cruiser
Join Date: Jan 2010
Location: PORTUGAL
Posts: 30,585
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Re: Turn calories into electricity?
Quote:
Originally Posted by Stumble
Ya, the pedal power is for the 15 minutes or so it takes to trim the sails after a tack, electricity comes from the towed generators and solar panels.
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15 minutes to trim sails after a tack.. what are you sailing a brigantine..???
__________________
It was a dark and stormy night and the captain of the ship said.. "Hey Jim, spin us a yarn." and the yarn began like this.. "It was a dark and stormy night.."
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17-01-2017, 07:33
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#39
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Registered User
Join Date: May 2014
Location: USA
Boat: 41' yawl
Posts: 1,187
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Re: Turn calories into electricity?
Quote:
Originally Posted by newhaul
I only carried out to a hundredth of an ah on that one.
Later in the thread I linked to a much larger bicycle powered unit that would use a multi speed bike making it easier to maintain the needed rpm on the pm motor.
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No, my correction wasn't about the precision and rounding error, it was about the difference between power and energy (well, more specifically, amps vs ah).
You said "120 volts DC at 20 watts which is about .16 ah" but in fact meant "120 volts DC at 20 watts which is about .16 amps". That many amps would need to be accumulated somewhere over the course of exactly 1 hour to achieve .16 ah.
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17-01-2017, 08:35
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#40
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Registered User
Join Date: Sep 2013
Location: San Francisco Bay
Boat: Chung Hwa Boat Builders, Magellan 36
Posts: 446
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Re: Turn calories into electricity?
The link Newhaul offered is close to the numbers I have considered. A fit athlete can do one third hp or 250 watts. That produces close to 20 amps @ 14 V. If two persons could do one hour sessions each the total would come to 40 amp hours. Just about enough for efficient refrigeration. Go for it. It's been a dream of mine too. F
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17-01-2017, 09:06
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#41
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Moderator Emeritus
Join Date: Oct 2013
Location: Jacksonville/ out cruising
Boat: Island Packet 38
Posts: 31,351
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Re: Turn calories into electricity?
Quote:
Originally Posted by Dennis.G
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This is an excellent video, look at this guy and how he works at it, and look at how those bars are flexing etc., and run a timer to see how long he can do it.
Now, even in my prime I never had that kind of physique, and I know that just sitting there and pedaling with your feet you won't harness near the power you do if you have bars and can put your upper body into it.
I think you guys are over estimating your fitness level, but one thing is for sure, if you can do it and do it say for a month or so, I believe you will be some kind of fitness animal.
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17-01-2017, 09:33
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#42
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Registered User
Join Date: Apr 2016
Location: Back on dirt in Florida
Boat: Currently in between
Posts: 1,338
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Re: Turn calories into electricity?
Quote:
Originally Posted by a64pilot
This is an excellent video, look at this guy and how he works at it, and look at how those bars are flexing etc., and run a timer to see how long he can do it.
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Holy Crap! Look at the legs on that guy!!
I'm thinking we are looking at the OP's original inquiry wrong. I don't think he is interested in making toast, simply getting exercise while on his boat.
He THEN wants to do something useful, however slight, with the energy he expends while exercising, i.e. dump some juice into an iPad or cell phone. Will he fully charge the device, nope, never.
I think seeing the charging icon light up would offer positive reinforcement to keep him exercising. I don't think most of us enjoy exercising, at all, even though we've been fed multiple reasons over the years as to why it is a good thing for us.
I know positive reinforcement helps keep me motivated!
Then again, I could be wrong..
__________________
SV Bacchus - Living the good life!
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17-01-2017, 09:35
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#43
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Registered User
Join Date: Sep 2013
Location: San Francisco Bay
Boat: Chung Hwa Boat Builders, Magellan 36
Posts: 446
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Re: Turn calories into electricity?
While many of us are past our prime the possibility of generating a third of a horsepower is far from impossible. When I was younger I once hiked up a mountain side and just based on foot pounds per hour; ie my weight x change in elevation X time, I produced a third of a horsepower. Friends at the time could do likewise. So while our geriatric cruisers might not achieve these numbers it is still a way to get exercise and produce some electrical energy
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17-01-2017, 09:57
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#44
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Registered User
Join Date: Apr 2012
Location: ashore in So Calif.
Boat: No more boat (my medical, not the boat's)
Posts: 1,453
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Re: Turn calories into electricity?
Oh come on all you nay sayers. In WW II stationary bicycle generators were used to power radios in remote locations. They worked, and to the best of my knowledge power requirements for the radios of the day were much hight than for almost all modern electronics to the extent things are comparable. Should I even mention present day battery storage and charging when compared the that era. Bah, it can be done, but it requires work (out).
__________________
"Old California"
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17-01-2017, 09:59
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#45
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Moderator Emeritus
Join Date: Oct 2013
Location: Jacksonville/ out cruising
Boat: Island Packet 38
Posts: 31,351
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Re: Turn calories into electricity?
If you do it for the exercise, by all means go for it.
I'm being skeptical cause I'd hate for someone to spend their Solar panel money on an pedal powered generator with the thought that they could keep their fridge running, cause I'm afraid they couldn't.
But hey if its for the exercise, its a good way to exercise your legs anyway, and I have to assume our legs are one part that don't get much of a work out sailing.
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