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18

Cost is the main reason. An alternator that can provide full charging current would be far larger requiring bigger rotor and stator windings. This would make it more expensive and heavier. The manufacturers are using the fact that you only spend a small amount of time idling compared to driving to their advantage. Most cars are designed to cruise at ...


14

Your battery was dead. In many cars, when the battery can't provide enough cranking amps, you will hear a clicking instead of the normal starting sound. The starter battery draws a lot of current. When that happens, the voltage available to the rest of the system drops dramatically, especially if the battery is weak. That's why your clock reset itself. ...


13

Your question is difficult to answer without you knowing the inner workings of an alternator. The basics. If you move a magnetic field near a coil of wire the electrons in the wire get exited and electricity will be made. The amount of electricity made depends on the size of the magnetic field and its speed. The bigger the field and the faster it's moving ...


13

I can't give you numbers or calculations without some work, but I can tell you than energy is never free. Cars have an A/C compressor that is mechanically driven by the engine because this is the easiest way to get the job done in a typical consumer car. An A/C compressor actually takes a huge amount of energy to operate. In fact a central A/C unit for a ...


11

Most of the time a ground loop is the cause of this problem. This problem is common especially if your stereos speakers are amplified, and can be fixed my making sure that your stereo unit and/or amplifier have a good ground connection. This can be done by either finding a more direct ground connection to the cars frame, sanding the area around your ground ...


11

Given all the inefficiencies, is it "free" to plug in, say, a smartphone into a car to charge while I am driving? Short answer: no (but it's so hard to measure the impact that it be hard for you to tell). Remember, the alternator has to power everything connected to the electrical system. Charging the battery is a big load at first but drops off as the ...


10

Well, Teslas (and presumably other all-electric cars) have A/C so it's not impossible, but A/C takes a fair amount of power. On the other hand, Teslas store a lot of energy. The A/C is something like 2.4kW which is about 8,000 BTU/h or about 3HP. So using an electric motor on a conventional car might give you a few more HP briefly, but the alternator has ...


9

Since you have a battery which isn't that old (most batteries have about a five year life span), I'd suggest you put it on a charger and try to recharge it. This will allow the battery to come back to full charge without putting an undue stress on your alternator. You have to decide if the time spent in recharging the battery is worth your time. To me, ...


8

So, bear with me on this and maybe I can help. Mind you, none of what I'm going to say is going to be easy to do, but that is because your issue is not an easy one to solve. The main problems I see here with any solution is alignment and distance from any mounting point I can discern. My main thought here is you need to get the alternator connected back to ...


8

In an alternator there are two major components; the stator and the rotor. The rotor has a coil wound on it. By applying a current to that coil a magnetic field is formed and then spinning the rotor electricity is excited in the stator. Because the rotor needs to spin while mainaining electrical contact for the coil slip rings are used. There are ...


8

A battery that has an internal electrical short, usually one of the plates has come loose and is touching its neighboring plate will cause the alternator to work much harder than normal. This can shorten the life of the alternator. This condition is usually discovered quickly as the battery will not function well in this case. When alternators or motors ...


8

The short answer to your question is no. As @JPhi1618 noted, the compressor is mechanically driven. Without the compressor you don't have any cooling. The AC runs by changing the state and pressure of a liquid, and compressing the liquid is a big part of that cycle. If you bolted an electric compressor onto the car you would have to find a way to switch ...


7

Measuring the state-of-charge of a lead-acid battery is non-trivial. The easiest way is to use a voltmeter. You'll need a digital meter with 3 1/2 digits of precision. Let the battery rest, disconnected, for 24 hours. Then measure the voltage across the terminals. According to http://www.phrannie.org/battery.html, anything over 12.60V is at least 85% ...


7

You should not incur any issues using a secondary battery with a battery isolator. It will not cause any damage to your alternator. For your edification, it won't be using wasted energy, but your engine will probably using a tad more gas to operate the alternator, which will have to do more work. On a side note, you might want to rethink exactly what you ...


7

No. Your 12V socket is designed to deliver 12V, at a current described in your car manual. Most of my 12V sockets in the car can deliver up to 5A apparently (haven't tested this though, but I run a 200W invertor when I go car-camping. It is handy for everything) The worst that can happen is if your invertor tries to draw more than the 12V socket is fused ...


7

Lead sulfate crystals form on the battery plates as the battery discharges. As the battery becomes more discharged the crystals go from being soft and fluffy to much harder. Recharged in time, the lead sulfate is converted back into sulfuric acid and lead. A month is entirely too long for a battery to remain discharged. Reversing a serious sulfation ...


7

An insufficiently-charged battery would explain what you're seeing: the unresponsive throttle is because the throttle is electronically-actuated (at least that's what eBay reckons) Not sure about the Sentra, but airbag and engine oil lights can turn on due to insufficient voltage the engine will stall because the fuel injectors need electricity to ...


7

The voltage being a little low (13.75 is not low enough to be considered a problem in any case) is not going to affect their RPM reading - as it's the frequency of voltage variations that is measured to get your RPMs. I'd be tempted to say your tach is out slightly. You could ask them about that. There is a smartphone app that you can use to gauge RPMs - ...


7

The one tool you will need to purchase / borrow is a Volt Ohm Meter (sometimes called a Multimeter). Then you need to use it to read voltage AT THE BATTERY, before the car is started and after the car is started. My guess is you won't see any voltage difference. Before the car is started, I would guess you'd see voltages like 12.6v or so. After the car ...


6

First off, you may want a 2nd opinon on the alternator. If both battery and alternator are good, then its either a wiring or ECU problem. Check the contacts on the battery terminals/connectors to make sure they're not loose, dirty, or corroded. Then follow the ground wire (the black one) back to the chassis of the car to make sure it has a solid ground..


6

For anyone who has similar issues I had a similar issue however I don't think it was exactly same. I tried the steps in the accepted answer with no success. Research on my own I tried different phones and noticed that some would have the static at low volumes and other would not. I looked online and sometimes the phone can cause this to happen. How I ...


6

This is actually much simpler than that chart implies. Don't worry about ohms per thousand feet - for a four foot length this will be very very low. What is more important is the maximum current a wire is rated to. So here the question is whether you will want the OO gauge as it is rated to 190A in the power transmission column, or the 2 gauge as it is ...


6

I would think the alternator is the culprit, You can take your car down to an Advance Auto Parts, O'Reilly, Autozone (or the like) where they will test it for free. They can also check your battery, which may be the culprit, but I doubt it. It sounds like the internal regulator is going out (or you might have lost one or more diodes) on the alternator. ...


6

Yes for the most part an AGM is a drop in replacement for your standard Lead Acid Battery. The charging voltages are almost identical. You are correct that they have a lower internal resistance and can be charged at a much faster rate. This shouldn't cause a problem on the majority of vehicles as the wiring in the car is designed to handle the maximum rated ...


6

I don't think you are likely to "put undue stress on the alternator." It is a myth in my opinion that alternators can't handle charging a battery, Alternators are literally motors run in reverse and are designed to handle a lot of current. The only issue with charging a batter is it will get a bit warmer than usual and that shouldn't effect it as long as it ...


6

Yes, this is possible. Several companies (VAG, BMW) have switched to AC units that are driven by electric motors. For BMW, this is part of their Efficient Dynamics strategy, where they'll switch the compressor on/off depending on engine load to optimize fuel consumption. When the weather's not too hot, you can run the compressor intermittently without the ...


6

If an alternator could provide its full output capacity at idle, what would it output at red line? Output amperage is proportional to rotational speed of the alternator. Via gearing, an alternator could be made to spin faster at idle and produce its full amperage. However, at high RPM it would then be exceeding the speed at which it's designed to ...


5

Probably not, but maybe in some circumstances. I've had 4 alternator failures in my life. 1) Toyota MR2 - Alternator diode blew up (big bang and smoke) while driving on the expressway. No prior warning. Just BANG! and was suddenly on battery. 2) Toyota MR2 - Alternator casing broke causing the alternator to bind up and jam (with loud scraping and ...


5

Generally, the alternator provides enough power to run the car, even without a battery present. If your car stops as soon as the battery is disconnected, then you have a problem in the charging circuit. If you're 100% certain that the alternator is good, then something else is preventing the power from getting to the electrical system. If the charging ...


5

It will have to be fixed before you drive it very far. If the battery light is on the alternator is not charging, your not going to make it very far before the battery goes dead. Your local parts store will be able to test the alternator on the car, most if not all will do it for free. Based on the battery light I am confident it's the alternator, but ...



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