minimum gauge required for jumper cables? - BMW M5 Forum and M6 Forums
E39 M5 and E52 Z8 Discussion 1998-2003 Advertiser's Forum

Reply
 
LinkBack Thread Tools Rate Thread Display Modes
post #1 of 11 Old 5th January 2010, 08:32 AM Thread Starter
freakshoww
Member, Sport: On DSC: Off
 
freakshoww's Avatar
 
Join Date: Dec 2009
Location: Vancouver, BC
Posts: 250
Thanks: 64
Thanked 58 Times in 32 Posts
minimum gauge required for jumper cables?

I just picked up some jumper cables and was told by a friend to make sure that they're thick enough to jump my car. I don't wanna find out they're not if my battery actually dies. The cables are 12ft, 6-gauge...
freakshoww is offline  
Sponsored Links
Advertisement
 
post #2 of 11 Old 5th January 2010, 02:20 PM
m3matty
Member, Sport: On DSC: Off
 
m3matty's Avatar
 
Join Date: Feb 2009
Location: Aylesbury, UK
Posts: 257
Thanks: 59
Thanked 49 Times in 32 Posts
12 ft is quite long. The thicker and shorter the better otherwise the volt drop will be significant. Minimise the effect by turning off all unnecessary electrics of the dead car. Depress the clutch to remove the load on the starter motor.

BMW have used 4AWG from the battery to the starter and that must be 15ft or more. Should be OK then

As with all jump starts you should connect the cars together with the donor engine running above idle to get the voltage up to 14 to 14.5V. If the dead car has a really flat battery then you should allow the battery to charge up for a few minutes.

Only jump for a few seconds at a time. Make sure the jump leads don't get too warm and you'll be fine.

I had to start a dead car using nothing but bellwire once. I just left the wire connected for 30 minutes at which point there was enough juice in the battery to start it.

Last edited by m3matty; 5th January 2010 at 02:32 PM.
m3matty is offline  
post #3 of 11 Old 5th January 2010, 08:57 PM
DouglasABaker
M5 Expert (>4000)
 
DouglasABaker's Avatar
 
Join Date: Jan 2007
Location: Franklin, MA
Age: 41
Posts: 6,339
Blog Entries: 6
Thanks: 67
Thanked 2,387 Times in 942 Posts
Quote:
Originally Posted by m3matty View Post
...As with all jump starts you should connect the cars together with the donor engine running above idle to get the voltage up to 14 to 14.5V. ...
I'm assuming this is just poor English, but to be clear, you connect the cars together FIRST (donor + to dead +, donor - to dead ground) and THEN start the donor vehicle. Hold the donor vehicle at about 2K rpm while starting your car. Remove cables in reverse order of attachment.

For the record, that method is called "boosting" a car. Jump starting, which is the preferred method of starting the M5, involves getting the car moving, jumping into it, and releasing the clutch in 5th gear. "Boosting" should be your last resort since it is a good way to fry your nav unit.

d-
DouglasABaker is offline  
post #4 of 11 Old 5th January 2010, 09:43 PM
Mfreakin5
m5board.comoholic (>1000 posts)
 
Mfreakin5's Avatar
 
Join Date: May 2009
Location: Northern VA
Posts: 1,369
Thanks: 5
Thanked 189 Times in 114 Posts
Quote:
Originally Posted by DouglasABaker View Post
Jump starting, which is the preferred method of starting the M5, involves getting the car moving, jumping into it, and releasing the clutch in 5th gear.

d-
pardon my ignorance Douglas but if you depress the clutch in 5th gear going what I can only presume is 5-8 mph how would that start the car? Wouldn't the car just stall immediately or am I missing something?

2003 M5 Le Mans Blue

Quote:
Originally Posted by Greco View Post
...There seems to be less logic and more hot air in this white paper, maybe to sell more of his products...

White paper.... more like toilet paper.
Mfreakin5 is offline  
post #5 of 11 Old 5th January 2010, 09:56 PM
Jan2000_M5
Member, P500, DSC On (>600)
 
Jan2000_M5's Avatar
 
Join Date: Nov 2009
Location: Long Island, NY
Age: 32
Posts: 615
Thanks: 27
Thanked 103 Times in 55 Posts
The AWG of the wire should be sized at least be 6 gauge. (I think the industry wires are sized as such) The gauge is not very important for jump starting since continuous current is not flowing through the cables for longer than 15-20 seconds.
Jan2000_M5 is offline  
post #6 of 11 Old 5th January 2010, 10:14 PM
HarcoM5
Member, Sport: On DSC: Off
 
Join Date: Jun 2009
Location: Harford County, MD
Posts: 245
Thanks: 14
Thanked 15 Times in 15 Posts
Quote:
pardon my ignorance Douglas but if you depress the clutch in 5th gear going what I can only presume is 5-8 mph how would that start the car? Wouldn't the car just stall immediately or am I missing something?
5th might be a little high, but i dont know. I used to jump my beater (98 neon) in highschool because the starter died, but i used 2nd or 3rd gear. I cant remember which one.

Its a bit of a balancing act as you need to push the clutch back in when the engine turns over.
HarcoM5 is offline  
post #7 of 11 Old 5th January 2010, 10:54 PM
DouglasABaker
M5 Expert (>4000)
 
DouglasABaker's Avatar
 
Join Date: Jan 2007
Location: Franklin, MA
Age: 41
Posts: 6,339
Blog Entries: 6
Thanks: 67
Thanked 2,387 Times in 942 Posts
Quote:
Originally Posted by Mfreakin5 View Post
pardon my ignorance Douglas but if you depress the clutch in 5th gear going what I can only presume is 5-8 mph how would that start the car? Wouldn't the car just stall immediately or am I missing something?
5-8 miles per hour is more than enough to turn over the engine in 5th gear when the clutch is released. You use a higher gear because it is easier on the transmission. Remember, all you need to do is cause enough a spark to start the engine. You release the clutch, the car starts, and you depress the clutch again to let it idle.

d-
DouglasABaker is offline  
post #8 of 11 Old 5th January 2010, 10:59 PM
m3matty
Member, Sport: On DSC: Off
 
m3matty's Avatar
 
Join Date: Feb 2009
Location: Aylesbury, UK
Posts: 257
Thanks: 59
Thanked 49 Times in 32 Posts
Quote:
Originally Posted by DouglasABaker View Post
I'm assuming this is just poor English, but to be clear, you connect the cars together FIRST (donor + to dead +, donor - to dead ground) and THEN start the donor vehicle. Hold the donor vehicle at about 2K rpm while starting your car. Remove cables in reverse order of attachment.

For the record, that method is called "boosting" a car. Jump starting, which is the preferred method of starting the M5, involves getting the car moving, jumping into it, and releasing the clutch in 5th gear. "Boosting" should be your last resort since it is a good way to fry your nav unit.

d-
Yeah, poor english although I did make an assumption that it was commonly accepted knowledge that you connect the cars together first and then run the engine as I described. I should have been clearer.
m3matty is offline  
post #9 of 11 Old 5th January 2010, 11:03 PM
m3matty
Member, Sport: On DSC: Off
 
m3matty's Avatar
 
Join Date: Feb 2009
Location: Aylesbury, UK
Posts: 257
Thanks: 59
Thanked 49 Times in 32 Posts
Quote:
Originally Posted by Jan2000_M5 View Post
The AWG of the wire should be sized at least be 6 gauge. (I think the industry wires are sized as such) The gauge is not very important for jump starting since continuous current is not flowing through the cables for longer than 15-20 seconds.

The gauge is important. If the cable is too thin then the voltage drop across it will be high. Several hundred cranking amps will cause 3-4 volts drop along a 12 ft jump lead.
m3matty is offline  
post #10 of 11 Old 5th January 2010, 11:05 PM
m3matty
Member, Sport: On DSC: Off
 
m3matty's Avatar
 
Join Date: Feb 2009
Location: Aylesbury, UK
Posts: 257
Thanks: 59
Thanked 49 Times in 32 Posts
Quote:
Originally Posted by DouglasABaker View Post
I'm assuming this is just poor English, but to be clear, you connect the cars together FIRST (donor + to dead +, donor - to dead ground) and THEN start the donor vehicle. Hold the donor vehicle at about 2K rpm while starting your car. Remove cables in reverse order of attachment.

For the record, that method is called "boosting" a car. Jump starting, which is the preferred method of starting the M5, involves getting the car moving, jumping into it, and releasing the clutch in 5th gear. "Boosting" should be your last resort since it is a good way to fry your nav unit.

d-
In the uk this method is called jump starting hence the name jump leads. Boosting is a term used in the US. Bump starting is the term given for pushing the car and lifting the clutch to get it started.
m3matty is offline  
Reply

Bookmarks

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the BMW M5 Forum and M6 Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes Rate This Thread
Linear Mode Linear Mode
Rate This Thread:



Similar Threads
Thread Thread Starter Forum Replies Last Post
Bare minimum bluetooth Rhino E39 M5 and E52 Z8 Discussion 7 27th May 2009 04:26 PM
Want to buy Gauge Cluster - Or just the black gauge graphics - from 2000 M5 Diny Parts / Other For Sale or Wanted 4 28th January 2009 06:06 PM
Winter tyres: Minimum tread? rassi E39 M5 and E52 Z8 Discussion 8 20th November 2006 11:51 AM
Minimum Octane Rating 95 M5#3 E60 M5 and E61 M5 Touring Discussion 10 16th May 2006 04:51 PM
SES Jumper Plug 4 Sale bayareabeast E39 M5 and E52 Z8 Discussion 0 10th January 2005 10:36 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome