Need a jump, bunkie?

Turbo Tim · **Posted:** Sat Jan 10, 2009 7:16 pm

The “Shock” of connecting the battery cables is nothing compared to what the starter in the dead vehicle is going to do to the good car alternator (if it is running).

Both cars OFF. Connect cables correctly the first time. Start good car and let run for a few minutes to help charge up dead battery. Again, BOTH CARS OFF!!! Now try and start dead car with good car NOT RUNNING!!!
If your lucky and the dead car starts, you can then disconnect, and ONLY then start the good car.

By the way, our CRD alternators do not have an internal regulator. DC has for years put it inside the engine computer. Just another way of forcing you to “Have To Buy” something from the dealer. Other vehicle brands you can get at your local parts store fairly cheep.

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

Quote:

By the way, our CRD alternators do not have an internal regulator. DC has for years put it inside the engine computer. Just another way of forcing you to “Have To Buy” something from the dealer. Other vehicle brands you can get at your local parts store fairly cheep.

Yep,

FSM claims the PCM pwm's ground to that small wire field lead on the alternator. Guess a little added software in the PCM was less expensive than a built-in regulator on the alternator. Maybe Bosch is looking to increase revenue at the other vendors expense. They add a lift pump to the CP3, the EVR software to the PCM, I'm surprised they don't go for the whole shebang and add the BCM, climate controls and wireless TPM monitors while they're at it. More revenue for Bosch, a nightmare in maintenance costs if a minor feature fails.

mackruss · **Posted:** Sun Jan 11, 2009 2:42 am

Another question for the fundis regarding my recent jump start episode and for future reference - the CRD is grounded to earth and i connected the cables to the pos and neg of the battery hence the fuel pump blowing amongst a few yet undetected problems and possible ECU.

Please go ahead and hurl explicits and then explain why you should not connect the neg to the battery on a vehicle that is negatively earthed.

nursecosmo · **Posted:** Sun Jan 11, 2009 7:28 am

mackruss wrote:

Another question for the fundis regarding my recent jump start episode and for future reference - the CRD is grounded to earth and i connected the cables to the pos and neg of the battery hence the fuel pump blowing amongst a few yet undetected problems and possible ECU.

Please go ahead and hurl explicits and then explain why you should not connect the neg to the battery on a vehicle that is negatively earthed.

Huh?

mackruss · **Posted:** Sun Jan 11, 2009 8:22 am

nursecosmo wrote:

mackruss wrote:

Another question for the fundis regarding my recent jump start episode and for future reference - the CRD is grounded to earth and i connected the cables to the pos and neg of the battery hence the fuel pump blowing amongst a few yet undetected problems and possible ECU.

Please go ahead and hurl explicits and then explain why you should not connect the neg to the battery on a vehicle that is negatively earthed.

Huh?

Which part don't you understand..

gmctd · **Posted:** Sun Jan 11, 2009 12:12 pm

Altho we, here in the colonies, term power and signal return as ground, and the sovereign country(s) refers to grounding as earthing, almost all passenger vehicles have some form of rubber tires - knowing that rubber is insulative, and few passenger vehicles have the prerequisite grounding\earthing strap attached thereunto, grounding and earthing should be viewed as common-point termination in the system, rather than actual connection to Mother Ground\Earth - the terms, on either side of the Atlantic, originated in early days of electricity and radio, where the negative buss (and chassis) required physical termination to a rod driven into the ground\earth in order for the antenna to function

I always connect the jumper cables directly to the terminals on the battery - main point is not to connect the negative(-) cable first, as any accidental contact with the initially-grounded\earthed chassis\engine\accessories will result in welding-level currents at the point of positive(+) cable contact

Whether you earth it, or ground it : positive(+) first, negative(-) last on connection - negative(-) first, positive(+) last on disconnection

FYI: our common-return terminations are indicated by a two or three horizontal-bar symbol or upside-down delta, similar to antenna symbols - sometimes both are used, indicating return for separate circuits, such as analog and digital - our terminations to actual earth-ground are designated by a rake symbol with 3 or more tines, which is like an upside-down antenna-array

nursecosmo · **Posted:** Mon Jan 12, 2009 1:58 am

mackruss wrote:

nursecosmo wrote:

mackruss wrote:

Another question for the fundis regarding my recent jump start episode and for future reference - the CRD is grounded to earth and i connected the cables to the pos and neg of the battery hence the fuel pump blowing amongst a few yet undetected problems and possible ECU.

Please go ahead and hurl explicits and then explain why you should not connect the neg to the battery on a vehicle that is negatively earthed.

Huh?

Which part don't you understand..

The whole thing. I know what earth means. All vehicles that have been manufactured in the past 60 years have negative ground as far as I know. Are you saying that you conected the + terminal first and then the - ? That is the correct way to connect the cables except that the negative cable should be connected to somewhere on the chassis so that sparks don't ignite any hydrogen from the discharged battery. The order of connection should not have anything to do with whether or not the fuel pump fuse or ECU is damaged. What is a fundis?

UFO · **Posted:** Mon Jan 12, 2009 2:18 am

Turbo Tim wrote:

The “Shock” of connecting the battery cables is nothing compared to what the starter in the dead vehicle is going to do to the good car alternator (if it is running).

Both cars OFF. Connect cables correctly the first time. Start good car and let run for a few minutes to help charge up dead battery. Again, BOTH CARS OFF!!! Now try and start dead car with good car NOT RUNNING!!!
If your lucky and the dead car starts, you can then disconnect, and ONLY then start the good car.

By the way, our CRD alternators do not have an internal regulator. DC has for years put it inside the engine computer. Just another way of forcing you to “Have To Buy” something from the dealer. Other vehicle brands you can get at your local parts store fairly cheep.

I did not know this, and it comes as a bit of a shock. You CANNOT be serious. The ECM regulates the alternator through which wires? The regulator is going to have to be able to regulate 60A minimum, are you saying there is an unregulated DC going into the ECM and the ECM is the source of the DC powering the rest of the vehicle?

oh my. I guess another part I don't understand now is how anyone ever jumped using the CRD (like me) and had an ECM that survived.

gmctd · **Posted:** Mon Jan 12, 2009 5:47 pm

Alternator regulators don't regulate alternator output - they regulate alternator input, the voltage which is applied to the rotor field coil thru the brushes - otherwise, the 140a regulator would be almost as big as the alternator, itself - at one time, long ago and far away, in another century, you could remove the diodes and regulator from a Chrysler-products alternator, drive it at 3600rpm with a lawnmower motor, and voila!!!!: a gasoline-powered portable 115v 60c AC power generator

UFO · **Posted:** Mon Jan 12, 2009 6:56 pm

gmctd wrote:

Alternator regulators don't regulate alternator output - they regulate alternator input, the voltage which is applied to the rotor field coil thru the brushes - otherwise, the 140a regulator would be almost as big as the alternator, itself - at one time, long ago and far away, in another century, you could remove the diodes and regulator from a Chrysler-products alternator, drive it at 3600rpm with a lawnmower motor, and voila!!!!: a gasoline-powered portable 115v 60c power generator

There is a voltage regulator that float-charges the battery. That's the regulator I'm talking about. I guess the part I was unaware of was the ECM has any part in regulating the field windings -- that makes no sense to me. I don't know how that plays into the jump start, but if the alternator output is protected, there shouldn't be any issues with using the vehicle to jump start another, right? Maybe I'm missing something....

gmctd · **Posted:** Mon Jan 12, 2009 7:51 pm

DCJ has been using ECM to control battery charging since back in the '90's, also using an input from a thermister under the battery to further regulate charge according to battery temperature - gives better handle on actual requirements - plus, alternator replacement is much cheaper

Turbo Tim · **Posted:** Mon Jan 12, 2009 11:51 pm

Think of the alternator as a mechanical/electrical amplifier. It takes a teeny voltage, and the rotational energy from the engine and it will put out about 23 times more power than what went in. (6 amps field current = 140 amps output). The ECU watches the output very carefully and controls the input so the output is just right.
Short-circuiting the output of the alternator, like when requesting 300 amps to start a dead vehicle, will definitely cause an extreme amount of strain (if not damage) to the output diodes. (Remember batteries don’t make lots of current instantly, it is a chemical reaction and takes a little bit of time). This strain is done in micro seconds before the battery can react. I highly suggest not to test the ability of your alternator foolishly.

“All vehicles that have been manufactured in the past 60 years have negative ground as far as I know.”

Not true. Most older vehicles of the late 30’s to early 50’s had positive ground systems. My 48 Ford F1 pickup has a 6 volt-positive ground setup.
It came about in the mid 50’s or so that corrosion control techniques came about that negative grounded systems faired better, including marine applications.

UFO · **Posted:** Tue Jan 13, 2009 12:23 am

Turbo Tim wrote:

Think of the alternator as a mechanical/electrical amplifier. It takes a teeny voltage, and the rotational energy from the engine and it will put out about 23 times more power than what went in. (6 amps field current = 140 amps output). The ECU watches the output very carefully and controls the input so the output is just right.
Short-circuiting the output of the alternator, like when requesting 300 amps to start a dead vehicle, will definitely cause an extreme amount of strain (if not damage) to the output diodes. (Remember batteries don’t make lots of current instantly, it is a chemical reaction and takes a little bit of time). This strain is done in micro seconds before the battery can react. I highly suggest not to test the ability of your alternator foolishly.

“All vehicles that have been manufactured in the past 60 years have negative ground as far as I know.”

Not true. Most older vehicles of the late 30’s to early 50’s had positive ground systems. My 48 Ford F1 pickup has a 6 volt-positive ground setup.
It came about in the mid 50’s or so that corrosion control techniques came about that negative grounded systems faired better, including marine applications.

Thanks for that info, I'm an electrical engineer who designs power systems (not automotive), but I still learn more about them all the time.

I think a lot of the British cars used positive grounds well into the 70's. :oops:

Wobbly · **Posted:** Tue Jan 13, 2009 1:04 am

UFO wrote:

Turbo Tim wrote:

Think of the alternator as a mechanical/electrical amplifier. It takes a teeny voltage, and the rotational energy from the engine and it will put out about 23 times more power than what went in. (6 amps field current = 140 amps output). The ECU watches the output very carefully and controls the input so the output is just right.
Short-circuiting the output of the alternator, like when requesting 300 amps to start a dead vehicle, will definitely cause an extreme amount of strain (if not damage) to the output diodes. (Remember batteries don’t make lots of current instantly, it is a chemical reaction and takes a little bit of time). This strain is done in micro seconds before the battery can react. I highly suggest not to test the ability of your alternator foolishly.

“All vehicles that have been manufactured in the past 60 years have negative ground as far as I know.”

Not true. Most older vehicles of the late 30’s to early 50’s had positive ground systems. My 48 Ford F1 pickup has a 6 volt-positive ground setup.
It came about in the mid 50’s or so that corrosion control techniques came about that negative grounded systems faired better, including marine applications.

Thanks for that info, I'm an electrical engineer who designs power systems (not automotive), but I still learn more about them all the time.

I think a lot of the British cars used positive grounds well into the 70's. :oops:

My Norton Commando and Triumphs all have positive "earth".

Uffe · **Posted:** Tue Jan 13, 2009 3:35 am

Ranger1 wrote:

If you believe a DC powered automotive system is nearly immune to induced voltage spikes, think about the military electromagnetic pulse shock weapons. They can disable everything electronic in a modern automobile. How do you suppose that works? Why doesn't the battery filter it out? Where is the inductive load in the vehicle coming from?

With all due respect, bullet-proof glass doesn't stop a nuclear blast either.

Uffe · **Posted:** Tue Jan 13, 2009 3:42 am

Turbo Tim wrote:

The “Shock” of connecting the battery cables is nothing compared to what the starter in the dead vehicle is going to do to the good car alternator (if it is running).

Both cars OFF. Connect cables correctly the first time. Start good car and let run for a few minutes to help charge up dead battery. Again, BOTH CARS OFF!!! Now try and start dead car with good car NOT RUNNING!!!
If your lucky and the dead car starts, you can then disconnect, and ONLY then start the good car.

By the way, our CRD alternators do not have an internal regulator. DC has for years put it inside the engine computer. Just another way of forcing you to “Have To Buy” something from the dealer. Other vehicle brands you can get at your local parts store fairly cheep.

When the voltage drops across the alternator, the battery in the good vehicle begins to take the load. Then the alternator will be controlled to give more juice, and a short while after the dead vehicle will be powered up and running.

These short loads shouldn't hurt your alternator, the overload will warm everything up, but because the load is in such a brief time, everything should be fine.

I suggest you take a little look at the electrical winches power draws and compare with how many dead alternators these people have had.

On the topic, the only alternator I've ever had to replace was in my Nissan Patrol after having a bit too much fun in a mud-sand filled gravelpit

nursecosmo · **Posted:** Tue Jan 13, 2009 11:14 am

Turbo Tim wrote:

“All vehicles that have been manufactured in the past 60 years have negative ground as far as I know.”

Not true. Most older vehicles of the late 30’s to early 50’s had positive ground systems. My 48 Ford F1 pickup has a 6 volt-positive ground setup.
It came about in the mid 50’s or so that corrosion control techniques came about that negative grounded systems faired better, including marine applications.

OK, within the past 50 years then.

British cars which were wired by the Prince of Darkness do not count

mackruss · **Posted:** Tue Jan 13, 2009 11:52 am

nursecosmo wrote:

mackruss wrote:

nursecosmo wrote:

mackruss wrote:

Another question for the fundis regarding my recent jump start episode and for future reference - the CRD is grounded to earth and i connected the cables to the pos and neg of the battery hence the fuel pump blowing amongst a few yet undetected problems and possible ECU.

Please go ahead and hurl explicits and then explain why you should not connect the neg to the battery on a vehicle that is negatively earthed.

Huh?

Which part don't you understand..

The whole thing. I know what earth means. All vehicles that have been manufactured in the past 60 years have negative ground as far as I know. Are you saying that you conected the + terminal first and then the - ? That is the correct way to connect the cables except that the negative cable should be connected to somewhere on the chassis so that sparks don't ignite any hydrogen from the discharged battery. The order of connection should not have anything to do with whether or not the fuel pump fuse or ECU is damaged. What is a fundis?

I connected the pos to the pos on my battery and the neg to the neg on my battery but i'm not sure in what order. Now the fundis ( experts ) told me that i must connect the neg to the grounding like the engine block.

Need a jump, bunkie?

Who is online