Bridge car, confused...
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I miss manual transmissions: 1) Get in the car, turn the key to On. 2) Push in the clutch, put the car in gear. 2) Have friends push your car. 3) Let clutch out to engage transmission, engine turns over and starts.
My first car was fitted with a crank. Never used it though, pushing easier.
>64 Some days the dragon wins. Suck it up.
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That only works if the car DOES HAVE a clutch... nowadays is not granted anymore
M.D.V. ;) If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about? Help me to understand what I'm saying, and I'll explain it better to you Rating helpful answers is nice, but saying thanks can be even nicer.
On manual transmission cars? Well, I can easily see that you could replace the mechanical speed stick with, say, a pushbutton panel giving input to some microprocessor managed clutch and gearbox movements. I just haven't seen it yet. I wouldn't want it, though! I've been driving so much on (very) slippery ice that I demand a mechanism that sets the wheels free rolling so I can regain control over the car when it has lost the grip. (If your automatically controlled shift has an option for that, then you do have a clutch, perfectly usable for the purpose discussed here. It just has a user interface different from a pedal.)
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My first car was fitted with a crank. Never used it though, pushing easier.
>64 Some days the dragon wins. Suck it up.
If the car is located on a flat, clean road: Maybe. If the reason why the battery is dead is that you have just dug your car out of a meter of snow, where it has been sitting since September and the battery didn't take the cold well, then pushing the car up on the road may be quite a task!
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No, quite the opposite. When you try to start a second car from the donor's battery it will draw maximum current. And you can drain the battery within just a few seconds if not careful. So always start the engine of the donor car first, so the alternator helps to keep the battery protected. You really do not want two cars with flat batteries at the same time.
Richard MacCutchan wrote:
And you can drain the battery within just a few seconds if not careful.
Eeeeh ... My battery has a capacity of 65 Ah. To drain it in one hour, you would have to draw 65A. To drain it in 3 seconds, 1/1200 hour, you would have to draw 78,000A. At 12V, that is 936 kW - almost a megawatt. Of course that wouldn't be possible. Long ago, I worked with a company making minicomputers. They bought 5A/150A power supplies from a subcontractor claiming that they were shortcut safe. So they tested if it was true: Held a large screwdriver across the poles. The power supply survived, but not the screwdriver: It melted, and they had to cut it away from the poles with an angle grinder. I can't imagine what 78,000A would do, and I wouldn't want to stand close when it is tested. (Actually, the thought of 78,000A scares me a lot more than the thought of 78,000 V!)
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Richard MacCutchan wrote:
And you can drain the battery within just a few seconds if not careful.
Eeeeh ... My battery has a capacity of 65 Ah. To drain it in one hour, you would have to draw 65A. To drain it in 3 seconds, 1/1200 hour, you would have to draw 78,000A. At 12V, that is 936 kW - almost a megawatt. Of course that wouldn't be possible. Long ago, I worked with a company making minicomputers. They bought 5A/150A power supplies from a subcontractor claiming that they were shortcut safe. So they tested if it was true: Held a large screwdriver across the poles. The power supply survived, but not the screwdriver: It melted, and they had to cut it away from the poles with an angle grinder. I can't imagine what 78,000A would do, and I wouldn't want to stand close when it is tested. (Actually, the thought of 78,000A scares me a lot more than the thought of 78,000 V!)
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... it is generally recommended not to leave the engine of the donor car running before 'briding' the two cars. I don't see the reason for this and I don't do it like that in practice. I feel safer when the donor car's engine is running so that I don't have to shut down two cars. Is there a technical reason why the engine of the donor car should not run? Thank you very much in advance.
Yes, if the donors engine has just been started the regulator of the alternator will run at max power to recharge the battery. If you at that moment connect another drained battery the there will be a power surge before the regulator adjusts that might fuse the diodes on the alternator.
Wrong is evil and must be defeated. - Jeff Ello
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On manual transmission cars? Well, I can easily see that you could replace the mechanical speed stick with, say, a pushbutton panel giving input to some microprocessor managed clutch and gearbox movements. I just haven't seen it yet. I wouldn't want it, though! I've been driving so much on (very) slippery ice that I demand a mechanism that sets the wheels free rolling so I can regain control over the car when it has lost the grip. (If your automatically controlled shift has an option for that, then you do have a clutch, perfectly usable for the purpose discussed here. It just has a user interface different from a pedal.)
Automatic has "N" (Neutral), but it still is not the same. In most (if not all) automatic shift, you have to press the brake in order to be able to change to "R" (reverse) or "D" (forwards). And in the moment you press the brake, then most of the effords of your pals pushing the car get wiped.
M.D.V. ;) If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about? Help me to understand what I'm saying, and I'll explain it better to you Rating helpful answers is nice, but saying thanks can be even nicer.
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Automatic has "N" (Neutral), but it still is not the same. In most (if not all) automatic shift, you have to press the brake in order to be able to change to "R" (reverse) or "D" (forwards). And in the moment you press the brake, then most of the effords of your pals pushing the car get wiped.
M.D.V. ;) If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about? Help me to understand what I'm saying, and I'll explain it better to you Rating helpful answers is nice, but saying thanks can be even nicer.
Sure, cars with automatic transmission don't have a clutch. They never had! Ed Kautz, who I responded to, started his post saying "I miss manual transmissions:". It is certainly true that far more cars have automatic transmission nowadays - that is exactly what he is bemoaning. I did own an automatic transmission car for a few years, a rather strange one, a DAF66 with "variomatic" continuous variable transmission. Nice in summer, terrible in winter with slippery roads (even with studded tires). I decided never more to buy a car without a clutch (or another mechanism for setting the wheels free-running when skidding).
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Richard MacCutchan wrote:
And you can drain the battery within just a few seconds if not careful.
Eeeeh ... My battery has a capacity of 65 Ah. To drain it in one hour, you would have to draw 65A. To drain it in 3 seconds, 1/1200 hour, you would have to draw 78,000A. At 12V, that is 936 kW - almost a megawatt. Of course that wouldn't be possible. Long ago, I worked with a company making minicomputers. They bought 5A/150A power supplies from a subcontractor claiming that they were shortcut safe. So they tested if it was true: Held a large screwdriver across the poles. The power supply survived, but not the screwdriver: It melted, and they had to cut it away from the poles with an angle grinder. I can't imagine what 78,000A would do, and I wouldn't want to stand close when it is tested. (Actually, the thought of 78,000A scares me a lot more than the thought of 78,000 V!)
Just a thought...perhaps just problem with historical problems and exactly what problems might occur? Certainly at one point in time with a gas engine in a car when attempting to jump it from another gas engine car if you did it incorrectly you could at a minimum damage at least the electrical system of one car. That did include destroying a battery which of course would seem like it had 'drained' in seconds. So perhaps that is what was seen? I would suppose that it is possible that, at least with older EV batteries, that it might have been possible to destroy them also.
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On manual transmission cars? Well, I can easily see that you could replace the mechanical speed stick with, say, a pushbutton panel giving input to some microprocessor managed clutch and gearbox movements. I just haven't seen it yet. I wouldn't want it, though! I've been driving so much on (very) slippery ice that I demand a mechanism that sets the wheels free rolling so I can regain control over the car when it has lost the grip. (If your automatically controlled shift has an option for that, then you do have a clutch, perfectly usable for the purpose discussed here. It just has a user interface different from a pedal.)
trønderen wrote:
I wouldn't want it, though!
I know some construction workers and for years they would agree with that but more recently... "Things to Consider When Purchasing New Dump Trucks[^] "The automatic transmission eliminates the wear and tear of the clutch of the manual and automated transmission, and it is the easiest to drive, making it less fatiguing for the driver or operator. It also allows the driver to keep their eyes on the road and hands on the steering wheel, increasing safety. Additionally, the automatic transmission actually increases the engine torque in first gear to make the truck perform better when operating off-road and in soft soil conditions. Finally, these transmissions are more often the driver’s personal preference, making recruiting and retaining good drivers easier." If I looked it up right it costs $10,000+ to replace the transmission on one of those. And as a work truck that is something that end up getting replaced. Perhaps several times. So extending the life time might be a good idea. Also as a thought a standard dump truck has between 10-18 gears. Probably with that many getting it right all the time is unlikely.
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trønderen wrote:
I wouldn't want it, though!
I know some construction workers and for years they would agree with that but more recently... "Things to Consider When Purchasing New Dump Trucks[^] "The automatic transmission eliminates the wear and tear of the clutch of the manual and automated transmission, and it is the easiest to drive, making it less fatiguing for the driver or operator. It also allows the driver to keep their eyes on the road and hands on the steering wheel, increasing safety. Additionally, the automatic transmission actually increases the engine torque in first gear to make the truck perform better when operating off-road and in soft soil conditions. Finally, these transmissions are more often the driver’s personal preference, making recruiting and retaining good drivers easier." If I looked it up right it costs $10,000+ to replace the transmission on one of those. And as a work truck that is something that end up getting replaced. Perhaps several times. So extending the life time might be a good idea. Also as a thought a standard dump truck has between 10-18 gears. Probably with that many getting it right all the time is unlikely.