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noz |
Posted: March 30, 2004 07:30 pm
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Andre's Mate Group: Members Posts: 1673 Member No.: 12 Joined: November 22, 2003 |
Jim,
To answer your queries in the order asked: There should be no problem jump starting either way. The electronics are pretty robust. I have never believed previous stories which abound about this. Obviously if you have a dead short, say, in the car which won't start and you connect the good car to the other with jump leads then you may cause damage to the battery or alternator of the good car. But then this is common sense. Don't know about autoboxes to answer your question fully. I would suspect towing in neutral would be fine since no work is being done by the box. If the fluid inside churns during this process I'm not sure if the heat produced would be dissipated by the oil cooler. Maybe the oil wouldn't be pumped in the right direction? Someone who knows auto boxes would be more qualified to answer. cheers noz -------------------- '10 '59' C5 2.0 HDi Exclusive Tourer Metallic Grey
'97 'P' XM 2.5 TD VSX Saloon RP 6610 Blue '97 'R' XM 2.5 TD Exclusive Saloon RP 7158 Silver '88 CX 22TRS Croisette Location: Avonbridge - Stirlingshire - Central Scotland |
noz |
Posted: April 02, 2004 07:25 pm
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Andre's Mate Group: Members Posts: 1673 Member No.: 12 Joined: November 22, 2003 |
Jim,
Ther are another couple of screws hidden behind the grille where the chevrons are. Get a torch and you'll be able to see them. Hope the CD helps you to solve the problem. Cheers noz -------------------- '10 '59' C5 2.0 HDi Exclusive Tourer Metallic Grey
'97 'P' XM 2.5 TD VSX Saloon RP 6610 Blue '97 'R' XM 2.5 TD Exclusive Saloon RP 7158 Silver '88 CX 22TRS Croisette Location: Avonbridge - Stirlingshire - Central Scotland |
mach11 |
Posted: April 13, 2004 08:49 am
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New Member Group: Members Posts: 7 Member No.: 46 Joined: March 22, 2004 |
the reason that you can get problem with jumpstarting is that when you initialy start, you have got 24v instead of 12v.this can sometimes blow your alternator or cause a problem with other electrics. thankfully this is rare as most items are fairly robust, however it has happened to me on 4 occasions.
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noz |
Posted: April 14, 2004 05:28 pm
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Andre's Mate Group: Members Posts: 1673 Member No.: 12 Joined: November 22, 2003 |
sorry to disagree mach11 but you're reasoning is wrong. You could only get 24v if you connect the batteries in series. This would mean disconnecting one of the battery terminals, linking + to - from one battery to another and finally the spare terminal linked back to the one you disconnected. All in all not an easy job.
If you connect the batteries in parallel ie +ve to +ve and -ve to -ve then you'll still have 12v, maybe a lot of additional power but still only 12v. If you connect an infinite number of batteries in parallel you'd have infinite power but still only 12v. This is not what causes electrical failure when jump starting cars. It's usually connecting the jump leads the wrong way round or earthing a stray +ve lead against the engine or body. cheers noz 8) -------------------- '10 '59' C5 2.0 HDi Exclusive Tourer Metallic Grey
'97 'P' XM 2.5 TD VSX Saloon RP 6610 Blue '97 'R' XM 2.5 TD Exclusive Saloon RP 7158 Silver '88 CX 22TRS Croisette Location: Avonbridge - Stirlingshire - Central Scotland |
AndersDK |
Posted: April 15, 2004 02:34 pm
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New Member Group: Members Posts: 6 Member No.: 45 Joined: March 14, 2004 |
Hi Jim -
For voltage spikes (overvoltage surges) to occur when making/breaking live connections, you must have some inductance (i.e. coiled circuit) in the circuits. The lenght of the jump wires does in fact cause a minor inductance, but this is so small compared to the very low (ohmic) resistance of the battery cells. In the event the dead car's battery is defective, and hence would have a high internal resistance, you won't get a current surge which would cause a voltage spike anyway. I think the worst you can do is to directly connect jump start cables on to the startermotor terminals, as the startermotor is a huge inductance in itself. Another cause of voltage spikes, is the sudden load seen by the helping car's alternator, which will be exposed to a sudden minute voltage drop by the load connecting a dead car's battery. The effect is then the alternator will kick back with a minute overvoltage, trying to immediately compensate the sudden voltage drop. It's all marginals, since the alternator have a finite reaction time to alter it's charge voltage, and I believe that most fatal events is caused by rescue car drivers connecting directly to startermotor on dead cars. These modern "electronic" jump start cables contains a lump where a couple of surge arrestors are fitted, exactly to shortcircuit (or limit) voltage spikes. Some cheaper variants simply have coils and a small capacitor, which are not that efficient. I have never heard of or experienced any events with broken down electronics by jumpstarting a dead car. Only read of it all over. |