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Alternator Concerns

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  • Alternator Concerns

    I've noted considerable discussion on the board regarding power supply options for carputer projects, but haven't seen any considerations regarding concerns over how the car's alternator can handle the added load of such a system.

    I'm about to buy a brand new car ('07 Accord EX-L 4-cyl 5-spd with Nav), and will be building a complete Mac Mini Intel system to interface with the existing navigation system. Anyone have thoughts regarding the power delivery capabilities of a stock alternator in rendering safe, clean power to the entire car, including the computer/power supply, and all other added accessories? Here's a list of what I'll be adding in addition to all the stock vehicle components:

    1. Mac Mini
    2. P1900 Power Supply
    3. Electrochromatic auto dimming rear view mirror with compass, outside temp, and UV indication (this unit:
    4. OEM Fog Light kit
    5. Occasional cell phone charging

    I'm very concerned about the safety of running all of these additional components, and how it will effect the electrical system of the car. For a fellow of modest financial means such as me, this is a massive expenditure and I'm most keen on learning what I can in protecting my investment (which is a loose word; a car decidedly NOT being an investment!). I want to figure power needs in the worst case scenario, such as simultaneously running:

    1. Windshield wipers
    2. Headlights/tail lights/fog lights
    3. Rear window defogger
    4. Mac Mini/P1900
    5. Nav touch screen
    6. Navigation system CPU and associated components (DVD drive, etc.)
    7. 6-disc CD changer
    8. 6 OEM speakers
    9. Ignition system
    10.Vehicle ECU
    11.Climate control system (fans, LED display, etc.)
    12.Heated seat coils
    13.XM Radio
    14.Cruise control system


    ... basically running everything at once. I want to ensure either the stock alternator or whatever aftermarket solution I need will be able to handle such a load with complete safety and reliability.

    I believe power delivery (i.e. alternator/battery) should be an important topic of discussion in addition to CPU power supply considerations. Especially with the amps people are running these days and all the other power drawing accessories, it's something you have to think about!

    Thanks very much for your input, all--


  • #2
    There is actually a lot of discussion on alternator and batteries but they are usually inside other threads so perhaps that is why you haven't found them. You are quite right to take everything into consideration as it can be a problem specially with older cars. Modern cars tend to have big enough alternators though to take the addition of a computer. You will have to find out the output of your alternator/existing fuse sizes and work from there. Also remember that you are very unlikely to have absolutely everything on at the same time for long periods of time.
    Other than all that to be honest with all the kit your car already has I am wondering why you want to put a computer in there anyway.
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    • #3
      Follow Up

      Thanks for the reply, v8 scimitar!

      I just secured the official Honda service manual for my car, and will check to see if it lists the specifications of the OEM alternator.

      I quite understand it's unlikely that there will be frequent times when nearly all systems are running, but there will be circumstances, such as perhaps in Winter conditions, where the wipers are running, rear window defogger, fog lights, Mac Mini, seat heaters, side mirror heaters, climate control system fans, lights, etc. are all on. Especially when talking about things of a thermal nature (like the heating coils associated with the seats, defogger, etc.), that constitutes a considerable draw! I feel it's critical to account for situations like that-- Such circumstances are when you least want your electrical system (and therebye your entire car) to fail...

      Regarding the reasons for wanting a car CPU-- I love gadgets and the challenges associated with implementing them in a clean, factory appearing form. But aside from that I also want the freedom of instant, clean access to my full music library and wireless internet for such things as checking email while on a road trip, weather reports, news... possibly using the Mini's built-in Bluetooth to acquire hands-free cell phone function, etc.. A computer is the perfect, multi-functioning tool to allow this kind of function. And because it's so flexible, you never know what else you might be able to add down the road-- With a computer you can load new applications at will-- And the Mini can function as a Mac, PC or both simultaneously. It comes complete with a remote control for easy music track navigation... I can use it to monitor OBD-II/CAN data... Basically, an on-board CPU is the ultimate Swiss Army knife type of tool for all of your car entertainment /utility interests. It's just... It's just TOO cool!

      So for me it's not a matter of debate-- I will install my system of choice-- But that said, I also intend to have it thoroughly planned and meticulously implemented. Can't wait!

      Thanks again for your help/comments, all...


      • #4
        I hear you on the fascination about tech gadgets and a clean install. Although a computer does require a substantial amount of energy to function, it likely won't impact your vehicle very much. Just to be sure, I would reccommend you upgrade the "big three" Alternator wire, ground wire, and battery wire. Just add a large gauge to the existing wires in place and you will likely see an improvement in your electrical system (headlights won't dim as much when you hit the power windows, etc.) although its not guaranteed to solve all problems, its probably a safe bet that most newer vehicles will provide enough amperage to keep everything running steady. Use a good power calculator and figure out what you vehicle uses and compare it to what your alternator supplies. Then work from there.
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        • #5
          have you researched how to integrate with the nav? more times than not, it's a lot more trouble than many people deam it to be worth.

          The factory nav screens aren't VGA, and you will have a really difficult time (if you can do it at all) interfacing the factory system with a PC.

          your alternator should be fine just for a CarPC, if you're adding some amps I'd consider an upgrade.
          Jan Bennett
          FS: VW MKIV Bezel for 8" Lilliput - 95% Finished

          Please post on the forums! Chances are, someone else has or will have the same questions as you!


          • #6
            speaking of an upgrade.. im cosidering upgrading my alternator on my civic. I've only been able to fine alternators at around 350$ for about 160 amps. Just wondering if you have any recommendations of places to get alternators.

            oh yeah, my car is a 2001 honda civic lx


            • #7
              perhaps you would be better off starting a new thread for a new question rather than jumping in someone elses thread where few people will see your question.
              Jan Bennett
              FS: VW MKIV Bezel for 8" Lilliput - 95% Finished

              Please post on the forums! Chances are, someone else has or will have the same questions as you!


              • #8
                was mainly asking you, but I suppose thats a good idea


                • #9
                  The Mac Mini is a pretty low power computer. The Accord will most likely be able to handle it.

                  You're right to take it into consideration but just go to the Show Off Your project forum and take a look at what other Accord owners have in their car.

                  You do have a lot of electrical stuff in your car, but as you said, it's really unlikely that you'll be running those all at once.
                  Originally posted by ghettocruzer
                  I was gung ho on building a PC [until] just recently. However, between my new phone having internet and GPS and all...and this kit...Im starting to have trouble justfiying it haha.
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