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Figuring out how much wattage I have?

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  • Figuring out how much wattage I have?

    I'm trying to see if I'm going to need to upgrade my alternator, so I am figuring out how much extra wattage I have for a system...

    currently I have a 105 amp alternator.

    105a*14v=1470w

    I'm guessing my climate control takes up about 200watts.

    my component amp takes up 460wrms

    my carputer has a 150watt PSU

    So, 1470w-200w-460w-150w,
    leaves me with 660w to work with. Is this how you can see how many watts you have to work with? I'm wanting to run a 1000watt amp, so I'm guessing I'll need an upgrade?

  • #2
    =\

    HAHAHAHAHAHHAAHAHHAHA!!!

    what was the question? =\

    did you add your headlights? your rail lights... your horn?

    I think this question is pointless...

    Comment


    • #3
      You need a lot more data. For instance, your car uses a big ol' chunk of power to provide spark for the sparkplugs. Electric fuel pump, electric windows, stereo (your stereo probably pulls 50-100 watts alone), ECU...

      The question isn't pointless, it's just a lot more complicated to answer. Also, you need to account for inefficiencies. Your 460 watt RMS output amp doesn't put out 460 watts at 12 volts, for example. So you need more calculation.
      Chrysler 300 - Fabricating
      http://hallert.net/

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      • #4
        is he ever running everything at full power? doubt it...

        the only way you'll know, is to try it, and see if your battery is being charged, or discharged with everything running....

        Comment


        • #5
          Better yet, get everything running, the go to the local Autozone or car parts place of choice that offers free alternator checks. They'll hook up to your system and figure out what type of load your alternator has and whether it's charging, etc, then try and sell you a bigger one. The important part is, you won't have your car die in the middle of the freeway like if you try Never_stock's method.

          I kid, I know N_S was suggesting to gauge the charge with equipment, but I can't resist poking fun. You see, I actually HAVE had a car die in the middle of driving because of electrical exhaustion. What many people don't realize is that an alternator uses electromagnets to control the charge rate, which means that for it to generate power, it needs to have a enough power to charge up the coils in the first place. This is why you can't push-start a totally dead car, the armature can spin as much as it wants, but if there isn't a charged field, it won't make power.

          Consequently, my 1973 Toyota Celica that ran itself dry of power (the alternator lost effectiveness, then the engine ran off the battery until it was dead dead dead (like marley)) and then couldn't be push started, even thought I had turned off all the fans, stereo, lights, etc.
          Chrysler 300 - Fabricating
          http://hallert.net/

          Comment


          • #6
            Originally posted by never_stock
            =\

            HAHAHAHAHAHHAAHAHHAHA!!!

            what was the question? =\

            did you add your headlights? your rail lights... your horn?

            I think this question is pointless...
            If you think it's pointless then don't reply. Actually, there is nothing pointless about the question. I purposely did not add my headlights because I just won't use all the power at night when my head lights are on. My horn? If I'm honking my horn, usually I don't have my system up all the way, or care about a minor dimming in my lights.

            Comment


            • #7
              Originally posted by XxAndyxX
              If you think it's pointless then don't reply. Actually, there is nothing pointless about the question. I purposely did not add my headlights because I just won't use all the power at night when my head lights are on. My horn? If I'm honking my horn, usually I don't have my system up all the way, or care about a minor dimming in my lights.
              well, your amplifiers will never draw full power, unless you're driving around playing sinewaves...

              you're computer won't draw 150watts, unless you're completely hammering the harddrive, and CPU...

              and you're climate control won't draw... whats climate control? =\ and why does it need 200watts? =\=\

              Comment


              • #8
                I didn't pull the pumps into account because I thought it used mechanical energy from the engine. I didn't pull sparkplugs in accounts because I figured it took virtually no amount of watts to make a small spark. I didn't even know the alternator was involved with the spark plugs because on my motorcycle I don't have an alternator or a battery. I thought the only time the alternator was used on the engine was when it starts it pulls a massive amount of wattage (about 300+ watts) from the alternator to crank the pistons.

                Comment


                • #9
                  Originally posted by never_stock
                  well, your amplifiers will never draw full power, unless you're driving around playing sinewaves...

                  you're computer won't draw 150watts, unless you're completely hammering the harddrive, and CPU...

                  and you're climate control won't draw... whats climate control? =\ and why does it need 200watts? =\=\
                  A/C

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                  • #10
                    Originally posted by XxAndyxX
                    A/C
                    not going to take 200watts... 100 maybe.. the AC compressor is driven by the engine... some cars have an extra fan in the engine bay that comes on with the AC I believe... apart from that, there's a fan in the car, and thats about it.

                    Comment


                    • #11
                      I just want to dammage anything by trying to draw more amps than there are available.

                      Comment


                      • #12
                        Originally posted by never_stock
                        not going to take 200watts... 100 maybe.. the AC compressor is driven by the engine... some cars have an extra fan in the engine bay that comes on with the AC I believe... apart from that, there's a fan in the car, and thats about it.
                        Is that the same with the heater? I wonder how much it takes to heat up the coil?

                        Comment


                        • #13
                          Originally posted by XxAndyxX
                          I just want to dammage anything by trying to draw more amps than there are available.
                          you won't damage anything. you'll just discharge your battery, but I don't think you'll have the problem anyway.

                          heaters generally use the radiator coolant, and route it through a seperate small radiator in the dash and then the air is blown across that.... I could be wrong though....

                          Comment


                          • #14
                            Originally posted by XxAndyxX
                            I didn't pull the pumps into account because I thought it used mechanical energy from the engine.
                            Some of the pumps, like water/oil/AC are mechanical. Some are electrical, typically fuel pumps. Some cars have electrical water pumps, some cars have mechanical fuel pumps, you gotta figure out what your car has.

                            Originally posted by XxAndyxX
                            I didn't pull sparkplugs in accounts because I figured it took virtually no amount of watts to make a small spark. I didn't even know the alternator was involved with the spark plugs because on my motorcycle I don't have an alternator or a battery.
                            Your motorcycle has a magneto, which is different from an alternator (but performs a similar function). A magneto has rare earth magnets that, when spun together, generate power. The amount of power generated increases as the RPMs do, regardless of what the system needs. An alternator is a slightly more refined system, in that it replaced one of the magnets with an electromagnet. The amount of electricity generated is dependant on how charged the magnetic field of the electromagnet is. Thus, the voltage regulator system in the alternator uses the power demand to determine how hard to charge the field, and consequently, how much power to create. It's a beautiful thing, and results in less power loss/more stable power, etc. The downside, of course, is a slight reduction in reliability. An alternator that doesn't have any power (because the battery is removed before the car is started, for instance) cannot energize that electromagnetic field, hence my post above about a totally dead battery == no push start. Magnetos are simpler and more reliable, and the piston airplanes I fly use them because of the higher safety factor. If you lose your power system in a car, the vehicle stalls and comes to a halt. In a plane, it's a little more complicated if your engine stalls, so my planes can fly even after a total electrical failure because the engine stays running. You might want to land soon though, since those 'radios' and 'lights' can come in handy.

                            Originally posted by XxAndyxX
                            I thought the only time the alternator was used on the engine was when it starts it pulls a massive amount of wattage (about 300+ watts) from the alternator to crank the pistons.
                            Negative! The power produced for starting is provided by the battery, and the battery alone (for all intents and purposes). This is why batteries have such thick wires. If the car was already running, the battery would have an 'advisory role' at best and could get away with much smaller wires. When the engine is running, the alternator produces all power for your car. It's first task is to get the battery up to charge, then afterwards it just powers your spark plugs (which require a lot of power btw), electrical systems, etc.

                            Think about this logically: If your battery was used all the time, wouldn't it run down? The answer: Yes, but the alternator keeps it charged. In many cars, you can actually take the battery out after the engine is started. The battery provides an electrical 'capacitor' role to help the engine run a tiny bit smoother maybe, but it's mainly just along for the ride after the car is running.

                            EDIT: Added quick note about magnetos and airplanes
                            Chrysler 300 - Fabricating
                            http://hallert.net/

                            Comment


                            • #15
                              Is that the same with the heater? I wonder how much it takes to heat up the coil?
                              Car heaters use a heater CORE. Basically a mini radiator with small fins through which hot water from the engine passes through. Air goes over these fins heating up, and then into your car. That's why your heater is useless until your car gets to OT. So 0 watts are needed for this.

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