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snafu

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Posts posted by snafu

  6. Help with electrical plan - 94 F350

    in Electrical-battery- Alternators- Wiring

    Posted

    Okay, here is what I would do.

    First, I would hold off on the dual alt setup. Plan to attempt that later, after all the other build stuff is done.

    Then, I'd get a good quality HO alt, either a Mechman or a Singer, or whatever you decide, and do your wiring properly, and you should be good to go for the time being.

    Then, I'd get back to work on all the other stuff you got to do :)

    Here is my thinking:

    If you have one good alt, and three good batteries, and the proper wiring, than that should be fine for what your using.

    Then later, when you have time, you can further explore the possibility of adding the second alt. Then you would have 2 high quality alts.

    I'd probably steer clear from the OEM upgrades, you would probably be disappointed.

    Although I'm sure it's tempting at those prices, I'd still probably just call Mike!

    Hope that helped in some way...

    Oh and Snafu, I'll be contacting you soon to make me a relay/ fuse box.

    Just let me know how I can help.

  9. Help with electrical plan - 94 F350

    in Electrical-battery- Alternators- Wiring

    Posted

    That's a pretty cool location for those batteries, but I agree that it would be better to have them better protected. Looks like you'll need about 235 amps or so to supply those amps at 14.4 Volts DC on music. So, you may consider a larger alternator than what you are considering. Call Mechman or click on their banner . . .

    As for the electrical side of things, I can certainly help you there. I offer pre-made Big 3 kits and they are designed to make connecting additional batteries a snap. I can build any / all cables for you to your specifications if need be. Click on my banner to visit my web site or visit my forum here at SMD if you like.

  16. 3875 watts... what upgrades?

    in Electrical-battery- Alternators- Wiring

    Posted

    Math.

    3,875 / 75% amplifier efficiency = 5,166.67 Watts Input

    5,166.67 Watts / 14.4 Volts DC = 358.8 Amps Required to reproduce sine waves at full output

    358.8 x 50% = 179.4 Amps Required to reproduce music at clipping

    If you'll be listening to music with this amp, then . . .

    Alternator size = 179.4 Amps + Stock Requirements + 10 Amps for each additional battery (3 Amps for each XS Power Battery) + 20% buffer

    Otherwise, use the BIG number . . .

    Methinks it's time to make a calculator and stick it on my web site . . .

  19. Can you trick an inductive ground pickup?

    in Electrical-battery- Alternators- Wiring

    Posted

    FYI, 1/0 AWG has a resistance of .0001 ohms per foot. At 1,000 Amps, voltage drop across a 3 foot cable would be calculated as follows:

    E = R X I

    E = (.0001 ohms X 3 foot) x 1,000 Amps

    E = .0003 x 1,000

    E = .3 Volts

    .3 Volts / 14.4 volts = 2% - just under the 3% guideline that I typically go by. Of course, this assumes your terminations on either end of the 1/0 AWG cable are rock solid, as well as the connections holding the lugs to the distribution block and vehicle chassis.

    Obviously, you will not be passing any where near 1,000 amps through this cable as your alternator would have to be large enough to supply that. So, I'm thinking that'll be a non-issue.

  20. Can you trick an inductive ground pickup?

    in Electrical-battery- Alternators- Wiring

    Posted

    A single 1/0 AWG ground of a short length won't be the kind of limiting factor you may think. The dealer will tell you that your electrical modifications are the reason why it is not working correctly currently. They will be correct.

    Look at it like this. The water meter on your house is on the main feed - all water that is used in the house must pass through it. Therefore it's reading is exact. If you want this circuit to work correctly in your vehicle, you will have to adopt a similar philosophy.

  21. Can you trick an inductive ground pickup?

    in Electrical-battery- Alternators- Wiring

    Posted

    Well, you have numerous connection points between the charging system and ground now. Stock, the inductive ring around the ground cable was able to monitor the state of the charging system via the battery's ground cable. This is no longer possible.

    I have not worked on one of these vehicles yet, so I do not have first hand familiarity with this arrangement. However, it would make the most sense that you isolate the ground distribution block from the vehicle where you currently have it mounted. Then, I would reference ALL grounds to this block except the alternator grounds - stock battery (if it is still there), aftermarket batteries, amplifiers, etc. You would then connect a single 1/0 AWG cable from the distribution block to the chassis of the vehicle, passing this cable through the ring. As for your alternator grounds, you may be able to connect them to the same point at which you have this main cable connected but you won't be able to tie them to the distribution block.

    Look at it this way, the only way the PCM can monitor the state of the charging system is to have a similar arrangement as what the factory laid out. As far as your alternator is concerned, everything you have added is simply a load.

    Best of all, this would be fairly easy to do. I make no promises as again I have not worked on a vehicle with this arrangement. But, I believe what I've laid out will get you in the ball park.

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