View Single Post
Old 05-20-2018, 02:16 PM   #380 (permalink)
redpoint5
Human Environmentalist
 
redpoint5's Avatar
 
Join Date: Aug 2010
Location: Oregon
Posts: 12,470

Acura TSX - '06 Acura TSX
90 day: 24.19 mpg (US)

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

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

Chevy ZR-2 - '03 Chevrolet S10 ZR2
90 day: 17.14 mpg (US)

Model Y - '24 Tesla Y LR AWD
Thanks: 4,214
Thanked 4,391 Times in 3,365 Posts
Quote:
Originally Posted by Crashy View Post
5. Supercapacitors are a good addition
False. They have high self discharge and adding losses to a system cannot possibly improve efficiency
Good stuff Crashy, but this statement is false. Supercaps have low self-discharge, but what little they do bleed is significant given the relatively low energy capacity. The highest self-discharge is near the voltage limits of the supercap, and minuscule as the voltage drops below max.

Quote:
6. Alternators don't waste much horsepower when unplugged
False. Bearing, belt and fan friction are still present and are significant. Self excitement of the rotor is still occurring unless you disconnect the main and rotor wires.
Plenty of people have installed an alt-kill switch with great results. Sure, it's not as good as removing it completely, but the improvement in FE is still significant.


Quote:
Originally Posted by RedDevil View Post
The real reason why alternator deletes are efficient is that the whole chain from gasoline through engine efficiency, belt efficiency and alternator efficiency means that just 21% of the potential energy gets converted to electricity - at best.
The ICE is only 25% efficient itself, so the actual efficiency of converting gasoline energy into electrical must be much less than 21%. I'm assuming the 21% is the efficiency of converting the mechanical energy of the motor into electricity?
__________________
Gas and Electric Vehicle Cost of Ownership Calculator







Give me absolute safety, or give me death!
  Reply With Quote