Go Back   EcoModder Forum > EcoModding > DIY / How-to
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 11-08-2013, 09:29 PM   #11 (permalink)
Master EcoModder
 
Join Date: Jan 2012
Location: United States
Posts: 1,258

spyder2 - '00 Toyota MR2 Spyder
Thanks: 77
Thanked 208 Times in 155 Posts
I don't think alternator load is a problem with this kind of mod. The battery is only there to provide reserve power when the engine is off or when the accessories overwhelm the alternator, which is very rare. At all other times, the alternator pretty much puts out full voltage and powers everything in the car.

I think there may be a benefit to having normal electrolytic capacitors in a car, as the ripple from the alternator is substantial and you could smooth it out with capacitors, possibly improving efficiency? Depends on how the regulator circuit works, but if it doesn't measure RMS voltage correctly then this would be useful.

The way I see it, the primary use of ultracapacitors is to take load off the battery for starts as they have much higher power density than batteries.

  Reply With Quote
The Following User Says Thank You to serialk11r For This Useful Post:
TexasCotton (11-11-2013)
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 11-09-2013, 02:20 AM   #12 (permalink)
EcoModding Newb
 
redpoint5's Avatar
 
Join Date: Aug 2010
Location: Oregon
Posts: 5,781

Acura TSX - '06 Acura TSX
90 day: 28.39 mpg (US)

Lafawnda - '01 Honda CBR600 F4i
90 day: 47.32 mpg (US)

Big Yeller - '98 Dodge Ram 2500 base
90 day: 21.82 mpg (US)

Prius Plug-in - '12 Toyota Prius Plug-in
90 day: 79.06 mpg (US)

Mazda CX-5 - '17 Mazda CX-5 Touring
90 day: 28.88 mpg (US)
Thanks: 1,986
Thanked 2,054 Times in 1,481 Posts
Quote:
Originally Posted by TexasCotton View Post
The price issue makes the 66 dollar 20 farad look promising canadidate componet.....
New Hybrid Planet Audio PC20F 20 Farad Digital Power Car Auido Capacitor | eBay
I wouldn't bother unless I had about 20 times that farad amount.
__________________
Gas and Electric Vehicle Cost of Ownership Calculator







Give me absolute safety, or give me death!

Last edited by redpoint5; 11-09-2013 at 03:20 AM..
  Reply With Quote
Old 11-09-2013, 02:25 AM   #13 (permalink)
Master EcoModder
 
Join Date: Jan 2012
Location: United States
Posts: 1,258

spyder2 - '00 Toyota MR2 Spyder
Thanks: 77
Thanked 208 Times in 155 Posts
Quote:
Originally Posted by redpoint5 View Post
I wouldn't bother unless I had about 50 times that farad amount.
To be fair, this guy:


is using 6 350F caps in series for a capacitance of 58.3F, which is not a whole lot more. A good battery supplement, IMO. I'd shoot for more like 100F though.
  Reply With Quote
Old 11-09-2013, 02:54 PM   #14 (permalink)
Southern Squidbillie
 
Join Date: Aug 2012
Location: Heart of Dixie
Posts: 97
Thanks: 50
Thanked 25 Times in 21 Posts
Not Hardly Worth the Effort is it.

Quote:
Originally Posted by RobertISaar View Post
i don't know what kind of ESR the "Stinger" would have, but let's assume it is something quite usable.... 1,666 watt-seconds could almost entirely replace a battery. if it were all drawn within 1 second, that is almost 120 amps, which is enough to run a starter motor on nearly anything that isn't a semi or larger.
Can't imagine what sort of starter motor/engine could start with only 1 second of 120 amp cranking, especially on a cold morning. The current in the starter motor will be limited in rise time by the inductance and resistance of the motor windings, and the motor speed will be dropping faster than debutante panties on prom night as soon as the voltage sags.

Remember that a capacitor is a passive electrical component primarily used for filtering and can't source energy like a battery, which is an active chemical reaction device.
  Reply With Quote
Old 11-09-2013, 03:58 PM   #15 (permalink)
EcoModding Newb
 
redpoint5's Avatar
 
Join Date: Aug 2010
Location: Oregon
Posts: 5,781

Acura TSX - '06 Acura TSX
90 day: 28.39 mpg (US)

Lafawnda - '01 Honda CBR600 F4i
90 day: 47.32 mpg (US)

Big Yeller - '98 Dodge Ram 2500 base
90 day: 21.82 mpg (US)

Prius Plug-in - '12 Toyota Prius Plug-in
90 day: 79.06 mpg (US)

Mazda CX-5 - '17 Mazda CX-5 Touring
90 day: 28.88 mpg (US)
Thanks: 1,986
Thanked 2,054 Times in 1,481 Posts
Quote:
Originally Posted by serialk11r View Post
To be fair, this guy is using 6 350F caps in series for a capacitance of 58.3F, which is not a whole lot more. A good battery supplement, IMO. I'd shoot for more like 100F though.
I revised my statement since 1000 F is a bit high, but I still wouldn't bother unless I had at least 400 F.

The series capacitance would not be less than the rated 350 F, unless you are accounting for the fact that only a fraction of it is usable due to voltage drop. The series configuration increases the voltage capacity to > 14V so that it's usable in automotive applications.

EDIT: The above statement about series capacitance is incorrect. The farad capacity does drop with each capacitor added in series due to a charge plate being effectively canceled out when the series connection is made.
__________________
Gas and Electric Vehicle Cost of Ownership Calculator







Give me absolute safety, or give me death!

Last edited by redpoint5; 12-24-2013 at 03:19 PM..
  Reply With Quote
Old 11-09-2013, 10:28 PM   #16 (permalink)
Master EcoModder
 
Join Date: May 2012
Location: Indiana
Posts: 1,483

Volt, gas only - '12 Chevrolet Volt Premium
90 day: 38.02 mpg (US)

Volt, electric only - '12 Chevrolet Volt Premium
90 day: 132.26 mpg (US)

Yukon Denali Hybrid - '12 GMC Yukon Denali Hybrid
90 day: 21.48 mpg (US)
Thanks: 158
Thanked 324 Times in 224 Posts
Iirc, you have to wire capacitors in parallel to add the capacitance. Otherwise you get effectively half the capacitance.
__________________




  Reply With Quote
Old 11-10-2013, 03:49 PM   #17 (permalink)
Intermediate EcoDriver
 
Mustang Dave's Avatar
 
Join Date: May 2009
Location: Northern Arizona - It's a DRY cold..
Posts: 648

Trigger - '07 Ford Mustang V6 Premium Coupe
Team Mustang
Sports Cars
90 day: 32.15 mpg (US)

Big Red (retired) - '89 Ford F-250 4wd Custom
90 day: 18.13 mpg (US)

Big Red II - '13 Ford F-150 FX4
Pickups
90 day: 18.42 mpg (US)
Thanks: 151
Thanked 114 Times in 89 Posts
Quote:
Originally Posted by ksa8907 View Post
Iirc, you have to wire capacitors in parallel to add the capacitance. Otherwise you get effectively half the capacitance.
You remember correctly.
__________________
Fuel economy is nice, but sometimes I just gotta put the spurs to my pony!



Quote:
Originally Posted by thatguitarguy View Post
Just 'cuz you can't do it, don't mean it can't be done...
Quote:
Originally Posted by elhigh View Post
The presence of traffic is the single most complicating factor of hypermiling. I know what I'm going to do, it's contending with whatever the hell all these other people are going to do that makes things hard.
  Reply With Quote
Old 11-10-2013, 06:11 PM   #18 (permalink)
Master EcoModder
 
Join Date: Jan 2012
Location: United States
Posts: 1,258

spyder2 - '00 Toyota MR2 Spyder
Thanks: 77
Thanked 208 Times in 155 Posts
Yep. To check that it's consistent, just look at conservation of energy: 1/2CV^2. Wiring them in series keeps the total energy constant but raises the voltage, so the capacitance has to be lower to keep the energy the same.

From the charge holding perspective, having greater distance between the plates decreases the capacitance, and that's effectively what you get when you wire caps in series.
  Reply With Quote
Old 11-11-2013, 12:52 PM   #19 (permalink)
EcoModding Apprentice
 
Join Date: Oct 2008
Location: Dallas Fort Worth
Posts: 146

TexasThunder - '08 Toyota Prius Base
Thanks: 119
Thanked 7 Times in 7 Posts
Quote:
Originally Posted by serialk11r View Post
I don't think alternator load is a problem with this kind of mod. The battery is only there to provide reserve power when the engine is off or when the accessories overwhelm the alternator, which is very rare. At all other times, the alternator pretty much puts out full voltage and powers everything in the car.

I think there may be a benefit to having normal electrolytic capacitors in a car, as the ripple from the alternator is substantial and you could smooth it out with capacitors, possibly improving efficiency? Depends on how the regulator circuit works, but if it doesn't measure RMS voltage correctly then this would be useful.

The way I see it, the primary use of ultracapacitors is to take load off the battery for starts as they have much higher power density than batteries.
Thanks
Just for some clarification (4 myself)....The post with the youtube by lasersaber is dated. He used RC lipo battery/maxwell ultracaps. and has made no current posts...
As I have early stated voltage stabilizers are sold on ebay from 40-200 plus dollars.
Can someone further my understanding of series/parallel in relation to a bank of capacitor Example battery in series increase voltage and battery parallel increase the ah/amp hour
  Reply With Quote
Old 11-12-2013, 12:49 AM   #20 (permalink)
Master EcoModder
 
Join Date: Jan 2012
Location: United States
Posts: 1,258

spyder2 - '00 Toyota MR2 Spyder
Thanks: 77
Thanked 208 Times in 155 Posts
The "voltage" you are concerned with is the dielectric breakdown voltage. If you put capacitors in series, the voltage drop is split between the capacitors. So if you put identical capacitors in series, the new peak allowable voltage is the number of capacitors times the breakdown voltage of a single capacitor.

The capacitance is the harmonic mean of them, which in the case of identical capacitors is just 1/(number of capacitors).

It's analogous to resistors in parallel, except instead of adding current you add voltage, and instead of taking the harmonic mean of resistances you take the harmonic mean of capacitances

  Reply With Quote
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com