Advertise on fullfatrr.com »

Home > In Car Electronics (L322) > Why 12V DC in cars?
Post Reply  Down to end
Page 2 of 2 <12
Print this entire topic · 
KurtVerbose



Member Since: 08 Aug 2010
Location: Les Arses
Posts: 5848

Switzerland 2007 Range Rover Vogue TDV8 Stornoway Grey

oldcro wrote:
northernmonkeyjones wrote:
Im convinced. Very Happy

Though i think the voltage humans can tolerate is much higher, its the amount of current which kills you.... A low voltage shock can do a lot of damage if its accompanied by high current, whereas a hight voltage low current shock can be tolerable.


I think it is the other way round. Tazers shock you with 50,00 volts yet, when I worked in a chlorine plant the cells had 300,000 amps at 4.5 volts running through large exposed copper bus bars. Loads of magnetism in the air but no fear of harmful electric shocks.


That's the same way round - you're both agreeing with each other.

Had a small motorcycle when I was a bigginer years ago and that had a 6v battery. It was terrible.

Post #159747 24th Dec 2012 8:26am
View user's profile Send private message View poster's gallery Reply with quote
stan
Site Moderator


Member Since: 13 Jul 2010
Location: a moderate moderated moderator moderating moderately in moderation
Posts: 35114

United Kingdom 

so every ones agreed to agree then.... Thumbs Up



[must be xmas Mr. Green ] ... - .- -.




click link for ,

FORUM WIKI

HOW TO Ǝꓕ∀ꓕOꓤ PICS

workshop manual downloads are in our wiki

.

Post #159748 24th Dec 2012 8:37am
View user's profile Send private message View poster's gallery Reply with quote
SteveMFr
Site Sponsor


Member Since: 22 Nov 2009
Location: Strasbourg, France
Posts: 1641

To make electricity understandable to people with no background in the subject, I usually use water hoses as an example. Voltage is equivalent to the water pressure and the current or Amperes is equivalent to the amount of water (=a larger diameter hose). Which is exactly what Dom was saying above with the electrons.

Only both together can provide the energy needed to do work and only bot together are dangerous. A spark plug will need 20000+ Volts to jump the gap - yet anyone who has ever worked on engines a bit will have gotten a shock from a plug wire at some point. Unpleasant but not dangerous.Think of this as a tiny hose with enough pressure to squirt over a house. The other extreme would be a fire hose with water slowly flowing out. Not dangerous either. Add pressure to the fire hose and it becomes dangerous. Or is able to achieve work.

Cool 
RRC 2Dr, RRC 4Dr,
P38, and 2 L322s
(wife thinks I'm nuts - prob right, too)

Post #159819 24th Dec 2012 2:23pm
View user's profile Send private message View poster's gallery Reply with quote
northernmonkeyjones



Member Since: 24 Mar 2012
Location: derby
Posts: 8486

United Kingdom 2016 Range Rover Autobiography SDV8 Santorini Black

which I think is what I was saying...... Very Happy

High Voltage low current - uncomfortable
High Voltage high Current - Dead
Low voltage high current -Possibly ok
Low voltage low current - like licking a 9v. There is nothing that can't be fixed with a hammer😜😜
FFRR 4.4 SDV8 Autobiography Santorini Black.
Fiat 500x 1.4 multiair Lounge 2015
2010 LR D4 Commercial 2.7 TDV6

Post #159832 24th Dec 2012 3:07pm
View user's profile Send private message View poster's gallery Reply with quote
47p2



Member Since: 05 Oct 2010
Location: Gone Beyond, Subaru
Posts: 8048

Scotland 

I think in the near future we could see some of the car manufacturers changing to a 24v system to cope with the massive array of accessories now fitted to most cars

Post #159838 24th Dec 2012 3:17pm
View user's profile Send private message View poster's gallery Reply with quote
Ukdave104



Member Since: 26 Apr 2012
Location: Aberdeen
Posts: 116

United Kingdom 2011 Range Rover Vogue 4.4 V8 Rimini Red

It's the current that will kill you not the voltage. The higher the voltage the easier the resistivity of the skin breaks down allowing a current to flow. If you limit the current flow as in a vandergraph generator then the voltage you can safely be in contact with is several thousand volts. 
2011 Range Rover Vogue 4.4 TDV8, Mine........ALL mine.
2012 Freelander 2 HSE SD4 - Mrs UkDave's new toy
2007 Freelander 2 GS TD4 - gone
2010 Discovery 4 XS - gone
2008 Discovery 3 HSE - gone
2007 Freelander 2 GS TD4 - gone

Post #159841 24th Dec 2012 3:21pm
View user's profile Send private message View poster's gallery Reply with quote
stan
Site Moderator


Member Since: 13 Jul 2010
Location: a moderate moderated moderator moderating moderately in moderation
Posts: 35114

United Kingdom 

all i know is if you stick your fingers in that socket on the wall, it hurts... Mr. Green ... - .- -.




click link for ,

FORUM WIKI

HOW TO Ǝꓕ∀ꓕOꓤ PICS

workshop manual downloads are in our wiki

.

Post #159844 24th Dec 2012 3:25pm
View user's profile Send private message View poster's gallery Reply with quote
haveplan



Member Since: 28 Oct 2012
Location: kent
Posts: 7

United Kingdom 2008 Range Rover Vogue SE TDV8 Giverny Green

Couple of things whatever the voltage used is stored energy in a cell, for lead acid that's approx 2 volts, hence 6ceels= 12v. other types of cell have different voltages. As for current, this flows in the opposite direction to the flow of electrons. As for safe voltage, it is considered that the safe touching voltage is 170 volts and this is how, for domestic electrical systems, it is derived that at 240 volts (domestic supply) a current of 30mA does not harm a person, hence the 30mA rating on RCD's and RCBO's. Gravity is a force attracting any solid object to another and this is why my golf balls always head for the trees Twisted Evil Twisted Evil

Post #159914 24th Dec 2012 6:42pm
View user's profile Send private message View poster's gallery Post Reply
Post Reply  Back to top
Page 2 of 2 <12
All times are GMT + 1 Hour

Jump to  
Previous Topic | Next Topic >
Posting Rules
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum



Site Copyright © 2006-2024 Futuranet Ltd & Martin Lewis
fullfatrr.com RSS Feed - All Forums


Switch to Mobile site