Question (about 'jump starting')
02-11-2005, 07:21 PM
#31
Rennlist Member
dmk,
oops, sorry I was forgetting US cars were L-jet in 81. So you do have an LH ECU (fuel injection control unit). But they are not delicate like the 87- ones. Take sensible precautions like you are doing, and you'll be OK.
Lauren's advice is good - the more discharged your car battery is, the more careful you need to be.
oops, sorry I was forgetting US cars were L-jet in 81. So you do have an LH ECU (fuel injection control unit). But they are not delicate like the 87- ones. Take sensible precautions like you are doing, and you'll be OK.
Lauren's advice is good - the more discharged your car battery is, the more careful you need to be.
02-12-2005, 03:47 AM
#32
There MUST BE a difference by and large from the 83 and older vs the 83 and newer owners manuals.
Emergency starting procedures from my 82 as well as my son's 81 state -this is for JUMPING-:
1. Both batteries must be 12 volt. The capacity of the battery supplying current should not be significantly below that of the discharged battery.
2. Only battery cables with adequate diameters should be used. Observe Manufacturers specifications.
3. A dicharged battery can freeze at -10 degrees centigrade. A frozen battery must be thawedout before connecying the battery cables.
4. There should be no contact between the two vehicles otherwise current may flow when the positive pole/cable is attached.
5. The discharged battery must be correctly connected to the vehicle electrical system.
6. Run the engine of the vehicle supplying the current.
7. Connect the auxiliary battery leads in the following order:
First fix one end of the positive (+) lead to the (+) clamp on the right at front of the engine compartment (arrowed) -arrow points to the + jumper pole in the picture-. Then connect the other end of the lead to the (+) terminal of the feed battery.
Now clamp one end of the (-) lead to the (-) terminal of the feed battery, then attach the other end to the cylinder block or the transverse strut in the engine compartment.
Care must be takenthat the cables do not make contact with each other and that the positive cable does not come in contact with other electrical terminals -danger of short circuit!
8. Start the engine as described in the section "Starting the engine".
9. When the engine is running disconnect the cables in the reverse order.
Numbers 1, 5, 6 are of interest to me because of some of the other reply's.
This started as a 'Jump Start' post and we branched into charging as, I'm assuming, an alternative.
Consequently, there is an overlap of information between jumping and charging. There is a difference
between the two.
IMO
Bottom line on charging off of another vehicle I'd disconnect the negative lead on the dead battery,
both if you are inclined. Connect the cables for 5 or ten minutes to put a low charge(warm-up) on the dead battery. Then disconnect the cables, hook up the cables on the 'dead' battery, start the engine on the feed car and hook the jumper cables back up. Then start the dead sHARk.
This will help in several areas of concern:
1. The 'dead' battery will have been 'slow charged', if you will, supplying it with several additional volts and any number of amps.
2. With the additional volts and amps in the 'dead battery there will be 'less chance' of frying the low end diode on the feed cars alternator as it supplies both battery charge and start volts/amps to the 'dead car'.
3. The same applies to the dead car's alternator. With additional volts/amps in the dead battery even though it isn't at 12 volts there will be less of a demand for the re-charge and consequently less heat across the low end diode and less heat and possible cell damage/seperation in the battery.
4. There should be less chance of a spike.
Hopefully, while trying this method you won't 'kill' the battery in the donor car, resulting in two dead cars....
Personally, I'd just jump at the front post and go for a long drive...different strokes for different folks.
As for charging, disconnect the ground and feed cables and trickle charge over night or longer.
Emergency starting procedures from my 82 as well as my son's 81 state -this is for JUMPING-:
1. Both batteries must be 12 volt. The capacity of the battery supplying current should not be significantly below that of the discharged battery.
2. Only battery cables with adequate diameters should be used. Observe Manufacturers specifications.
3. A dicharged battery can freeze at -10 degrees centigrade. A frozen battery must be thawedout before connecying the battery cables.
4. There should be no contact between the two vehicles otherwise current may flow when the positive pole/cable is attached.
5. The discharged battery must be correctly connected to the vehicle electrical system.
6. Run the engine of the vehicle supplying the current.
7. Connect the auxiliary battery leads in the following order:
First fix one end of the positive (+) lead to the (+) clamp on the right at front of the engine compartment (arrowed) -arrow points to the + jumper pole in the picture-. Then connect the other end of the lead to the (+) terminal of the feed battery.
Now clamp one end of the (-) lead to the (-) terminal of the feed battery, then attach the other end to the cylinder block or the transverse strut in the engine compartment.
Care must be takenthat the cables do not make contact with each other and that the positive cable does not come in contact with other electrical terminals -danger of short circuit!
8. Start the engine as described in the section "Starting the engine".
9. When the engine is running disconnect the cables in the reverse order.
Numbers 1, 5, 6 are of interest to me because of some of the other reply's.
This started as a 'Jump Start' post and we branched into charging as, I'm assuming, an alternative.
Consequently, there is an overlap of information between jumping and charging. There is a difference
between the two.
IMO
Bottom line on charging off of another vehicle I'd disconnect the negative lead on the dead battery,
both if you are inclined. Connect the cables for 5 or ten minutes to put a low charge(warm-up) on the dead battery. Then disconnect the cables, hook up the cables on the 'dead' battery, start the engine on the feed car and hook the jumper cables back up. Then start the dead sHARk.
This will help in several areas of concern:
1. The 'dead' battery will have been 'slow charged', if you will, supplying it with several additional volts and any number of amps.
2. With the additional volts and amps in the 'dead battery there will be 'less chance' of frying the low end diode on the feed cars alternator as it supplies both battery charge and start volts/amps to the 'dead car'.
3. The same applies to the dead car's alternator. With additional volts/amps in the dead battery even though it isn't at 12 volts there will be less of a demand for the re-charge and consequently less heat across the low end diode and less heat and possible cell damage/seperation in the battery.
4. There should be less chance of a spike.
Hopefully, while trying this method you won't 'kill' the battery in the donor car, resulting in two dead cars....
Personally, I'd just jump at the front post and go for a long drive...different strokes for different folks.
As for charging, disconnect the ground and feed cables and trickle charge over night or longer.
02-12-2005, 04:34 AM
#33
Rennlist Member
John, with all due respect, given the source of that first set of steps.... IMHO it's dangerous to take that approach. The instructions should be amended... at least mentally... to stress that one should never handle jumper leads while either car is running, as an accidental short will blow anywhere from 1 to 3 diodes on the alternator of the car that's running! The safest procedure is:
1) Make sure car with good battery is "Off"
2) Connect jumper cables
3) Start car with "good" battery and let it charge the dead battery.
4) Turn off car when you think you've charged long enough.
5) Now attempt to start car with dead battery
Running a car while jumping another car, while that second car is being cranked, is another way to stress an old diode past its breaking point.
I know we've all broken these rules before... but they are a reasonable and safe starting point.
1) Make sure car with good battery is "Off"
2) Connect jumper cables
3) Start car with "good" battery and let it charge the dead battery.
4) Turn off car when you think you've charged long enough.
5) Now attempt to start car with dead battery
Running a car while jumping another car, while that second car is being cranked, is another way to stress an old diode past its breaking point.
I know we've all broken these rules before... but they are a reasonable and safe starting point.
02-12-2005, 05:45 AM
#34
Dave,
I agree on some points but we end up back at a chance of a bigger spike if we crank the feed engine AFTER cable hook-up. And if you are using a running feed car to charge the disconnected dead battery you are in effect 'HOT CHARGING' with possible heat/cell damage to the dead battery.
I do wonder if we can trust the Porsche owners manual information when it comes to electrics...after all if the same team who overdesigned the electrical system -cause of much grief- also made inputs to the owners manual IMO the manual would be slightly suspect.
I agree on some points but we end up back at a chance of a bigger spike if we crank the feed engine AFTER cable hook-up. And if you are using a running feed car to charge the disconnected dead battery you are in effect 'HOT CHARGING' with possible heat/cell damage to the dead battery.
I do wonder if we can trust the Porsche owners manual information when it comes to electrics...after all if the same team who overdesigned the electrical system -cause of much grief- also made inputs to the owners manual IMO the manual would be slightly suspect.
02-12-2005, 10:52 AM
#35
Rennlist Member
Yeah, true.... Well, there's always a risk. Skipping 3 and 4 in my list would minimize it further. I just think it would suck big time if some guy were helping me out and we blew his alternator due to a 100% avoidable mistake. 
02-12-2005, 01:28 PM
#36
"6. Run the engine of the vehicle supplying the current.
7. Connect the auxiliary battery leads in the following order:
First fix one end of the positive (+) lead to the (+) clamp on the right at front of the engine compartment (arrowed) -arrow points to the + jumper pole in the picture-. Then connect the other end of the lead to the (+) terminal of the feed battery.
Now clamp one end of the (-) lead to the (-) terminal of the feed battery, then attach the other end to the cylinder block or the transverse strut in the engine compartment.
Care must be takenthat the cables do not make contact with each other and that the positive cable does not come in contact with other electrical terminals -danger of short circuit!
9. When the engine is running disconnect the cables in the reverse order."
- John Struthers -
#6. is problematic
Running the source car's engine runs the risk of shorting the running car's
alternator, whether jumping or attempting a "quick" charge of the dead battery.
#7. is "don't care"
It doesn't matter electrically which lead is connected first. It just prevents
"sparks" while hooking-up the postive lead, i.e. postive lead may touch a
ground point.
#9. is problematic
Leave the jumper battery connected a short while to allow the
dead battery car's alternator to "see" a load battery versus
a potential "spike" in alt. voltage because the dead battery
still doesn't have enough charge, i.e. the alt. must "see" a battery
load when the jumper cables are removed.
7. Connect the auxiliary battery leads in the following order:
First fix one end of the positive (+) lead to the (+) clamp on the right at front of the engine compartment (arrowed) -arrow points to the + jumper pole in the picture-. Then connect the other end of the lead to the (+) terminal of the feed battery.
Now clamp one end of the (-) lead to the (-) terminal of the feed battery, then attach the other end to the cylinder block or the transverse strut in the engine compartment.
Care must be takenthat the cables do not make contact with each other and that the positive cable does not come in contact with other electrical terminals -danger of short circuit!
9. When the engine is running disconnect the cables in the reverse order."
- John Struthers -
#6. is problematic
Running the source car's engine runs the risk of shorting the running car's
alternator, whether jumping or attempting a "quick" charge of the dead battery.
#7. is "don't care"
It doesn't matter electrically which lead is connected first. It just prevents
"sparks" while hooking-up the postive lead, i.e. postive lead may touch a
ground point.
#9. is problematic
Leave the jumper battery connected a short while to allow the
dead battery car's alternator to "see" a load battery versus
a potential "spike" in alt. voltage because the dead battery
still doesn't have enough charge, i.e. the alt. must "see" a battery
load when the jumper cables are removed.
02-12-2005, 02:55 PM
#37
Loren,
On #6,
True, and I indicated in the following IMO section "less chance of frying the diode" because there would be additional amps and voltage in the 'dead battery' after doing a " slow charge " from a source battery with a non-running engine. Which would mean less of a load/demand across the source battery and alternator when you eventually jump start as well as less of a spike -hopefully, thru the dead cars electrical systems. #6 & #9 are related, the difference being a straight forward Jump, or, a 'slow charge' off of the source battery prior to jumping. Either way the source alt doesn't sense/see just a plain draw and supply more current than needed. Nor does a battery, or any electrical system demand more current than it 'needs' unless it is battery initiated, with low battery condition which has to supply current to a high-load,
draw item like a starterand a low charge recieving battery at the same time.
I would, in retrospect, let the donor car re-charge its own battery for a few minutes before 'jumping' after a 'slow charge to the 'dead battery' as to do otherwise would place the load/draw of a low charge recieving battery, a high draw starter and the semi-depleted donor battery across the tender diodes of the donor alternator.
On #7,
Well....
There can and generally will, be sparks/arcing on either (+) or, (-) cable lead
hook-up.
Point of fact, -a demo- if you disconnect the (-) battery ground strap and trickle charge your battery (you should) and then after charging and after dark hook
the ground strap back-up you will see sparks.
Keep in mind that touching any metal object while trying to hook-up an energized (+) cable lead results in a short/arc/grounding which may or may not affect the electrics in the dead car and certainly will result in a surge across
the charging/jumping cars alternator. A much bigger concern than a ground lead touching an unwanted ground point. So while you agree here that the (+)
lead touching a ground point and arcing/sparking is a concern you are saying that it's a "don't care" concern...?
In any case, there will be less demand on the donor alt. when jump starting if you put more more voltage and amps in the recieving battery before jumping. This would also have the benefit of ' reducing the spike/surge ' both to the dead car and across the charging system of the donor car.
On #6,
True, and I indicated in the following IMO section "less chance of frying the diode" because there would be additional amps and voltage in the 'dead battery' after doing a " slow charge " from a source battery with a non-running engine. Which would mean less of a load/demand across the source battery and alternator when you eventually jump start as well as less of a spike -hopefully, thru the dead cars electrical systems. #6 & #9 are related, the difference being a straight forward Jump, or, a 'slow charge' off of the source battery prior to jumping. Either way the source alt doesn't sense/see just a plain draw and supply more current than needed. Nor does a battery, or any electrical system demand more current than it 'needs' unless it is battery initiated, with low battery condition which has to supply current to a high-load,
draw item like a starterand a low charge recieving battery at the same time.
I would, in retrospect, let the donor car re-charge its own battery for a few minutes before 'jumping' after a 'slow charge to the 'dead battery' as to do otherwise would place the load/draw of a low charge recieving battery, a high draw starter and the semi-depleted donor battery across the tender diodes of the donor alternator.
On #7,
Well....
There can and generally will, be sparks/arcing on either (+) or, (-) cable lead
hook-up.
Point of fact, -a demo- if you disconnect the (-) battery ground strap and trickle charge your battery (you should) and then after charging and after dark hook
the ground strap back-up you will see sparks.
Keep in mind that touching any metal object while trying to hook-up an energized (+) cable lead results in a short/arc/grounding which may or may not affect the electrics in the dead car and certainly will result in a surge across
the charging/jumping cars alternator. A much bigger concern than a ground lead touching an unwanted ground point. So while you agree here that the (+)
lead touching a ground point and arcing/sparking is a concern you are saying that it's a "don't care" concern...?
In any case, there will be less demand on the donor alt. when jump starting if you put more more voltage and amps in the recieving battery before jumping. This would also have the benefit of ' reducing the spike/surge ' both to the dead car and across the charging system of the donor car.
