Starter Update

[cannondale27]

Maybe we should also use a ground strap to body right at the battery. Is what most vehicles do. We have a 6ftneg cable to motor and then the motor is grounded to chassis. That is different. Most vehicles ground is within a foot of battery usually it's a Seperate strap.

 

[Curtis Chambers]

If all the electrons went neg to pos you would short everything out to frame. I run 12v
Dc systems all the time hundreds of feet but not the same draw as a starter. Power would go from relay to starter not through frame ground. Just unused power. Yes I am an electrician. Otherwise your fuses would be at the negative side, the source to protect the wire.

 

[cannondale27]

If all the electrons went neg to pos you would short everything out to frame. I run 12v
Dc systems all the time hundreds of feet but not the same draw as a starter. Power would go from relay to starter not through frame ground. Just unused power. Yes I am an electrician.

I am talking the negative cable which goes to the engine. Normally in a vehicle negative cable goes to engine and in addition is immediately grounded to the chassis right at battery. Our sleds are not like normal. You lost me with your last comment. Can you explain?

 

[Curtis Chambers]

Sure , if power ( electrons) went neg to pos the fuse I would think should always be at the source. The fuses are at the pos side , the source or the start. Battery post are T- tapped on pos side. Do you know the draw (amps) of a typical starter I have formulas for voltage drop. Hope that helps I am not an electronics expert but fuses protect wires and (special characteristics of certain fuses) and overloads protect equipment. I do know some vehicles are switched on neg side. Number one wire is good for ( depending on type) is good for roughly 110-140 amps
1/0 is 125-150 prob even more in vehicles due to cold temps. Hope that helps.
US ratings may vary. A diagram showing a short may be easier.

 

[yamahaguy]

The only reason I pointed out electron movement is to show the importance of both cables so lets not get to deep here. Ben Franklin got it wrong in the beginning so don't feel bad. ha ha
Both cables have a equally important roll in current delivery to the starter.

If you want to get deep here's a link :

http://www.science-campus.com/engineering/electrical/dc_theory/chapter2/dctheory_2_1.html

 

[Curtis Chambers]

Sorry buddy I've read enough of that crap lol.

 

[cannondale27]

Sure , if power ( electrons) went neg to pos the fuse I would think should always be at the source. The fuses are at the pos side , the source or the start. Battery post are T- tapped on pos side. Do you know the draw (amps) of a typical starter I have formulas for voltage drop. Hope that helps I am not an electronics expert but fuses protect wires and (special characteristics of certain fuses) and overloads protect equipment. I do know some vehicles are switched on neg side. Number one wire is good for ( depending on type) is good for roughly 110-140 amps
1/0 is 125-150 prob even more in vehicles due to cold temps. Hope that helps.
US ratings may vary. A diagram showing a short may be easier.

Nobody has a problem with shorts or the fuses I am just talking grounds. I am not finding specs for the starter in Service Manual but remember if the engine doesnt fire the Amp draw will change drastically. If you have ever tried bench cranking even a single cylinder motor to do a compression test even with a car battery you wont get many cranks and wires get very hot. So its not cut and dry. If the engine doesnt help the starter which it normally would draw changes big time.

 

[Curtis Chambers]

I see what your saying and totally agree . It's called LRC locked rotor current and there is formulaes for everything. My option is just that changing wire from number 4 (80amps) to whatever, unless motor actually draws close to that under load. It's not going to make difference. Voltage drop from 15 feet at 12 volts with wire that size is going to near zero but yes will change when heats up.

 

[stingray719]

The only reason I pointed out electron movement is to show the importance of both cables so lets not get to deep here. Ben Franklin got it wrong in the beginning so don't feel bad. ha ha
Both cables have a equally important roll in current delivery to the starter.

If you want to get deep here's a link :

http://www.science-campus.com/engineering/electrical/dc_theory/chapter2/dctheory_2_1.html

Awww cmon was just getting ready to enter the fray and add the "hole flow" of electrons and really confuse people. (went to College eons ago for electronics)

 

[Curtis Chambers]

Lol, yep that's some very boring reading material there.

 

[cannondale27]

There is proven formulas for everything and many times can save the day. Thats why I like having you Engineering guys around even though you can confuse the heck out of me many times. I wont argue with the formulas. The math works!

 

[cannondale27]

Now to actually get in there and measure voltage is another thing! Wish I would have thought of it when header was off!

 

[Curtis Chambers]

Stingray do you happen to know the draw of the motor I could go to garage and put my meter on it but it's very warm here so the motor won't have to work that hard I guess it would give me an indication or even how big the fuse is for the starter.

 

[cannondale27]

How long of leads on a Fluke 77 are allowed for accurate volt drop reading? Stock isnt long enough to reach batt and starter!

 

[bbquadrider]

No fuse on a starter circuit ever

via big bad phone