12V draw drops MPG by 10%

Old Jan 24, 2006 | 02:03 PM
  #1  
Casper49's Avatar
Thread Starter
|
Active Enthusiast
Joined: Oct 2005
Posts: 57
Default 12V draw drops MPG by 10%

I am an Angelino...so I find Silicon Valley very cold (what the heck is an ice scraper they keep giving me in Denver when I rent the car!!)

So, I bought a Massager/Heat pad for my HCH-II and immediately noticed my MPG from about 10% - from 50 or so to 45.

It draws 1A at 12V = 120W, so this seems very high to me. Has anyone else notice anything similar?

John
 
Old Jan 24, 2006 | 03:04 PM
  #2  
Duc's Avatar
Duc
Stock Sucks
Joined: May 2005
Posts: 236
From: Kingsland, TX
Default Re: 12V draw drops MPG by 10%

Interesting so based on this finding you should get worse mileage at night than the day, do you notice this to?
Clif
 

Last edited by Duc; Jan 24, 2006 at 05:34 PM.
Old Jan 24, 2006 | 03:34 PM
  #3  
lakedude's Avatar
Super Moderator & Contributor ($)
Joined: Jul 2004
Posts: 1,672
Default Re: 12V draw drops MPG by 10%

Your pad draws about 16% of one horsepower. I doubt this would cause a 5 mpg drop. It is likely that the cold itself is more responsible for the mpg drop. The pad will cause a drop but I suspect that would be on the order of at most a couple mpg.
 
Old Jan 24, 2006 | 03:36 PM
  #4  
zimbop's Avatar
Ridiculously Active Enthusiast
Joined: Aug 2005
Posts: 609
From: New Mexico
Default Re: 12V draw drops MPG by 10%

Originally Posted by Casper49
I am an Angelino...so I find Silicon Valley very cold (what the heck is an ice scraper they keep giving me in Denver when I rent the car!!)

So, I bought a Massager/Heat pad for my HCH-II and immediately noticed my MPG from about 10% - from 50 or so to 45.

It draws 1A at 12V = 120W, so this seems very high to me. Has anyone else notice anything similar?

John
You have moved closer to the pedal by the thickness of the seat pad, thus aplying more gas.
 
Old Jan 24, 2006 | 04:33 PM
  #5  
sactoroy's Avatar
Enthusiast
Joined: Nov 2005
Posts: 41
Default Re: 12V draw drops MPG by 10%

Originally Posted by zimbop
You have moved closer to the pedal by the thickness of the seat pad, thus aplying more gas.
ROTFLMAO
 
Old Jan 24, 2006 | 05:00 PM
  #6  
phoebeisis's Avatar
MPG FANATIC WITH GUZZLERS
Joined: Sep 2005
Posts: 521
From: New Orleans
Default 1A 12V= 12 WATTS- 12/750= less than 1/60 hp

I think it actually uses 12 watts or 12watt hrs used every hour.I don't think you could measure the tiny effect this would have on your mpg.This is only about 1/60 of a hp-.Thanks.Charlie
 
Old Jan 24, 2006 | 05:21 PM
  #7  
Casper49's Avatar
Thread Starter
|
Active Enthusiast
Joined: Oct 2005
Posts: 57
Default Re: 12V draw drops MPG by 10%

Originally Posted by Duc
Interesting so based on this finding you should get worse mileage at night than the day, do you notice this to?
Clif
My driving is 90% during daylight hours so I have not tested specifically for this.

Several tests during the week, with and without pad yields consitant ~5mpg difference.
 
Old Jan 24, 2006 | 05:21 PM
  #8  
Casper49's Avatar
Thread Starter
|
Active Enthusiast
Joined: Oct 2005
Posts: 57
Default Re: 1A 12V= 12 WATTS- 12/750= less than 1/60 hp

Originally Posted by phoebeisis
I think it actually uses 12 watts or 12watt hrs used every hour.I don't think you could measure the tiny effect this would have on your mpg.This is only about 1/60 of a hp-.Thanks.Charlie
My typo... ...it is 1A at 120V. I would have thought this too, but there definately is a difference.

I'll check the battery, but maybe it's forcing ICE to ON for charge... or does 12V charge from Hybrid battery?
 

Last edited by Casper49; Jan 24, 2006 at 05:24 PM.
Old Jan 24, 2006 | 05:22 PM
  #9  
lakedude's Avatar
Super Moderator & Contributor ($)
Joined: Jul 2004
Posts: 1,672
Default Re: 1A 12V= 12 WATTS- 12/750= less than 1/60 hp

Originally Posted by phoebeisis
I think it actually uses 12 watts or 12watt hrs used every hour.I don't think you could measure the tiny effect this would have on your mpg.This is only about 1/60 of a hp-.Thanks.Charlie
You are correct, sorry I didn't catch the mistake in the original math. I took the 120W figure and ran with it.

A one amp heating pad at 12v isn't much of a heating pad. Maybe it is a 10 amp pad?
 
Old Jan 24, 2006 | 05:24 PM
  #10  
Casper49's Avatar
Thread Starter
|
Active Enthusiast
Joined: Oct 2005
Posts: 57
Default Re: 1A 12V= 12 WATTS- 12/750= less than 1/60 hp

Originally Posted by lakedude
You are correct, sorry I didn't catch the mistake in the original math. I took the 120W figure and ran with it.

A one amp heating pad at 12v isn't much of a heating pad. Maybe it is a 10 amp pad?
Actually rechecked the pad, it is 1A at 120V. So, 10A at 12.
 

Thread Tools
Search this Thread

Contact Us -

  • Your Privacy Choices
  • Manage Preferences
  • Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

    When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

    © 2026 MH Sub I, LLC dba Internet Brands


    All times are GMT -7. The time now is 04:00 AM.