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Old 07-26-2003, 01:43 PM
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power=voltsXresistence

I was thinking about how alternators work i mean a average 12 volt alternator has to power, gages, sparkplugs, fans, etc...etc.... so i was thinking 12 volts isnt enough is there a company out there that makes a 42 volt alternator i know about semiconductor and i know how to work with them. ok if you dont know why i want to do that think about it it takes 8.33 amps to make 100watts with 12 volts but with 42 volts it will only take 2.38amps

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Old 07-26-2003, 02:00 PM
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I understand the idea the aircraft industry has used that principle for years. Here is the problem, you may start out with 42 volts but in order to get any 12 volt items to work that means a voltage divider or regulator circuit. Thus you not only loose the advantage of the higher voltage but now you have put more demand on the system for regulators etc. There is also a heat issue, dropping 36 volts across a device is a huge amount.

Finding 42 volt car stereos, fuel pumps, ignition devices, headlights etc. is going to be a bit of trouble too. Remember there is no free ride when it comes to ohms law, your going to pay for it somewhere in the system.

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Mark
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Old 07-26-2003, 02:02 PM
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yea i know but i mean you could adapt it by swapping out ressistors in the system themselves i dont know this is only a theory i'm trying to figure everthing out
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Old 07-27-2003, 12:29 AM
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go for it

DMN,

You can do it yourself. There is a voltage regulator built into your alternator, just replace it with a 42 volt regulator. Then, you can install another regulator outside the alternator to 12 volts. It sounds like an awful amount of work to have the same output that you started with. Electric generators are available up to 18,000 volts, or something like that. A 42 volt generator with 90 amp output is going to be much larger than your stock alternator. It will take special mounting steps and custom work. Then, a large voltage regulator will need to be installed to cut the output to 12 volts. Your problem is going to be in containing the additional amps. The additional amps cannot be absorbed by a single battery. It will overheat and explode. You will have to add up to 5 more 12 volt batteries to absorb the additional output. Even then, if there is not a whol lot of draw on them it will greatly reduce their life if they are constantly being charged with little draw. This type of setup would be feasible for a custom stereo installation with 1,000 - 2,000 amp draw that was always on. It might also be feasible for a motorhome (with refrigerator) in keeping appliances running. If this is something that you really want to follow through with, you may want to contact a couple of motorhome manufacturers to see if they have researched such a device. Good Luck!
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Old 07-27-2003, 08:44 AM
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i know about the batteries i just need 4 and run them parellel this is only a theory i havent worked everything out yet

HEY TOYOTA HAS A 42Volt alt in there royal crown royal saloon so its not imposible

Last edited by D M N; 07-27-2003 at 08:44 AM.
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Old 07-27-2003, 06:22 PM
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Quote:
i know about the batteries i just need 4 and run them parellel this is only a theory i havent worked everything out yet
Wrong! Parellel batteries will only give you 12 volts but a huge amount of current, Series Batteries will give you 42 volts but only as much current as the weakest battery can produce.

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Mark
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Old 07-27-2003, 06:23 PM
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???? i have to check that
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Old 08-04-2003, 08:55 PM
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DMN, Dude, I suggest you give this some more thought. It isn't voltage that is the problem it is usually a lack of current. I am not a Electrical Engineer but I have worked it the electronics industry for 30+ years as a technician. By the way, the alternator does not power the spark plugs. Jag is correct about the batteries. A high output Alternator and two good batteries hooked in parallel should do most anything your basic hotrodder would want.
Good luck,
Vern
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Old 08-05-2003, 06:15 PM
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Voltage is a function of V=IR, v = voltage, i = current . r = resistance. Ohms law.

Most heavy duty stuffs run 24vdc, but that's because a harness can wrap around the vehicle twice, as there is no spliced harnesses like in a car.

Yes you can get more "power" ie watts through higher voltage and lower current. Same principal as running AC in our power lines versus DC, low line loss. 4160v coming off a 6 generators at 350 - 450 Mw apiece. is 4.1kv is almost infinite current. Seeings how I work at a power plant I can vouch for this. In theory this sounds pretty good so far. BUT, (you knew it was coming) industry don't work that way.

For example cars started out at 6 volt systems, now 12, but look at the changeover involved in that, regulators, wires, lights, etc.

Now throw in computer controls and chipsets rated for 12vdc with a maximum tolerance of up to 15.5 / 16 volts. How do you change a modern industry that drastically? similar to the principal of running alternative fuels, the big oil producers don't like it, well the chip makers (motorola, intel) are in the same boat.

And more step down transformers means more material plus power lost to resistance / heat.

it's a conspiracy

Not really just cost driven
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Old 08-06-2003, 09:31 PM
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HEY DMN: We do work for Delphi who manufacture alternators for General Motors. They are test a 48 volt system that will be in all new GM cars and trucks very shortly.....DAVE
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Old 08-06-2003, 09:37 PM
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really??? that is awsome but that will be a biatch to retro fit into an older car owell i'll just attach one and what ever catches on fire i will replace it
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Old 08-06-2003, 10:13 PM
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Dude?

You can't be serious, WTF, now Im all gibbled.

are you actually serious or not.?

Hollywooding
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Old 08-07-2003, 10:22 AM
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yea its not worth it i was just kidding 48 volt alternator man does cars are going to be crazy man
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Old 08-07-2003, 06:17 PM
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By the way just noticing the title of this thread is incorrect.

POWER=VOLTAGE x CURRENT is the correct mathmatical formula also known as PIE (P=IxE).
P=Power
I=Current
E=Voltage
Ohms Law is Voltage=Current x Resistance or E=IxR


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Old 08-07-2003, 06:19 PM
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wait power=watts
volts= ohh man i didnt notice that thanks man
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