[jeffp]

I replied to a post about the zx alternator and fusible link problem one person was having. I asked if he had a high power stereo/amp hooked up to the battery and he did. The reason I asked the question was that I found this is a problem with ALL zx cars when you start demanding additional current from the battery/alternator for a high power stereo/amp and additional accessories. The stock zx charging system WILL NOT handle the current and the fusible link(black link) and the wire connectors fail after a few months of use this way. I will start with my car then explain the system.
I have a stereo system that is about 400watts total. The total current draw on the battery is about 70-75 amps above and beyone the current requirement of the rest of the car. My MSD draws 10 amps max (average 7 amps) the turn signals draw in the 15 amp range momentary operation, the head lights and tail lights draw in the 20 amp range (and that is stock lights, not the H4 90watt lights I am going to install) the ECU/fuel injectors draw about 10 amps. The fuel pump 10-15 amps.
So say one night I'm out partying driving around and listening to the radio(it is wide open because it still is not loud enough, I'm going deaf, but it is not loud enough still, I have a theory on that one also) so lets total up the total current draw on the charging system and the battery for my little joy ride that night.
1) 70 amps for the stereo, peak power
2) 10 amps for the ignition
3) 10 amps for the fuel pump
4) 20 amps for the head lights
5) 10 amps for the EFI harness and ECU
6) turn signals 10 amps
total 130 amps total.
Now lets apply some practical electronics principles.
1) the # 10 wire from the alternator, and the fusible links, and main wire to the battery are not any where near the size required to operate and work with that kind of current. The average # 10 will handle 50 amps continueious and about a 70 Amps for short periods (peak current) (like when that bass hit hard)
Now the alternator is a 65 Amp unit stock from Nissan, and the stock battery what a joke, 450 Amp hour battery (and I have some information on batteries also if you want it) so what we have here is a total current draw (continueious draw) that is exceeding the maximum current capabilities of the system designed by Nissan by about 50%-65% total current draw.
Now you have all this stuff and the alternator dies and you wonder why, the fusible links fail and you wonder why. The car wont start and you wonder why. Well when you tax the system that hard, over time the harness and the battery and the alternator ARE GOING TO FAIL.
In order to run the system this way you need to redesign the charging system, replace the alternator, get the biggest battery you can fit in the car, and change out the wire used for the charging and run a # 6 wire minimum, and replace the black fusible link with a link that is rated for at least 100 Amps. You will need to design an additional charging buss to the battery, and still maintain the 40 Amp fusible link to the rest of the car to do it right, so that if there is a problem in the system the link will still blow and not melt down the entire system.
When I go to the junk yards one of the things I do is intertain myself and look at the fusible link area (the small black box) and can tell right away who had a high power stereo in the car at one time. Nissan NEVER intended or designed the wire harness for high current capabilities.

 

[Chromeshadow 71 240Z]

Current readings

Jeff, thats a good explaination...I'm currious how you are measuring DC current of 130 Amps.

Chrome

 

[jeffp]

Re: Current readings

I am taking the accumulated current draw of the various components of the car. Current is additive TC= the total current draw of the entire system. It's basic electronics. I have not put my load on the system to check the current, but as I said you can calculate the current by adding all of the components operating at one time.
There are a few formulas you can use to do the calculation. E=I X R where E= voltage (the denominator of the fraction) I= current R= resistance (both are the numerator of the fraction. P=E X I where P=power(measured in Watts) E=voltage I=current (P is the denominator of the fraction) (Both E and I are the numerator of the fraction.

EXAMPLE: I have a set of 90 Watt head lights. I have a 12 volt DC source (battery)
the formula is this 180Watts divided by the 12 volts (battery) = 15 Amps total current draw for two 90 Watt lights. Then you do the calculation for the tail lights and the side marker lights, lets say 40 Watts total for all of those lights, we use the formula and plug in the values so 40 Watts divided by 12 volts = 3.3 Amps the total system draw off the battery and alternator (when the battery voltage gets below 13.8 volts the alternator regulator turns on the charging of the alternator) is 18.3 Amps total just to turn on the head lights.
Now my stereo is 400 Watts( that is full volume like I listen to it) for the amps and 1.5 Amps for the head unit. So we have 400 Watts divided by 12 = about 33 Amps, then you have to factor in the efficiency of the amps and that figure is generally about 40-50 % so lets take the lower number and say 1.6 and we get a number of = 53 Amps total (the easiest way and best way to figure the current on the amplifiers is look on the specs of the unit. My Kenwood draws 35 Amps wide open, and my Fosgate Punch 300 draws about 30 Amps wide open.
So now with the lights on we have 18.3 Amps, the Stereo blairing out a cool tune 60-70 Amps total that takes the current draw to about 80 Amps
Then I have to add the MSD I am running, the spec is 7 amps nominal and 10 Amps @ 10,000 RPM's Then the fuel pump Draw, then the Turn signal draw, etc etc. Do you see where I am going here? All of this current is coming off the battery, and when the voltage gets low on the battery, the alternator regulator says we have low voltage charge the battery. The battery says I cant give that much current for that length of time, so the alternator stays on and supplies the additional current to the battery. All of this current is going through the black fusible link, through the white wire off the back of the alternator, the connectors, and the spade lug connector tucked behind the EFI relay under the black cover on the passenger side of the car in front of the battery.
I do have a meter (calibrated meter) that I can put in line (series) with the main battery B+ wire and get the exact current draw, but that is not really an issue here because I can do the calculations using Ohms law and determine there is excessive current draw/requirements from the system and it was not designed to handle that much demand.

 

[EagerCrow]

I'd like to see the info you have about the battery

Also what is that little can looking thing bolted on the alternator at the negative side? When I took the alternator out I thought all those wires look very skimpy, might be a good idea to upgrade all those.

Thanks,
Josh 83zxt

 

[zx-ae]

How about those cold rainy nights when your running the wipers and heater is addition to all of those other things you mentioned? I know that isnt good for your charging system. I have problems running my heater stereo(after market 35X4 head unit plus a CD changer nothing else) and lights at the same time.I gotta keep my foot on the gas a little to keep the charge from dropping too far.

I bet it has something to do with the way I have my heater setup. One day it stoped working didnt have the money to fix it right so I took out my haynes manual and ran down the wires. Grouned one wire from the heater motor and wired a toggle switch into wireing harness. When I hit that swtich you can see the needle on the amp gauge drop.



Justin T

 

[Bobs Z Twins]

Thanks Jeff I never really thought about the effect of adding extras. I am a stock kind of guy anyway but I will be giving the car to my teenager and who knows what happens then!

 

[jeffp]

I will explain both of the questions. First let me give you an illustration of the average battery place. You go to the store and you want a monster battery for your, the biggest Amp hour battery you can get and still fit in the car OK
You look at a number of batteries in all shapes and sizes, and post configurations.
One battery is 9" long 6" wide and 8" high and it is rated at 650 Anp hours. You find another battery and it is 12" long 7" wide and 10" high which is the better battery????
Well batteries are built with plates(made from lead) and stacked into cells (six cells generally, six filler caps, each filler cap constitutes a cell, similar to a D cell battery for your flash light just arranged differently and with different materials, but you get the idea right?)Each cell is about 2 volts(6 cells=12 battery) @ a specific current draw (Amp hour) for a specific amount of time and then it starts loosing its charge, it is not quite a linear decrease but for this illustration lets say it is. So this cell will give you say 1/2 Amp for 2 minutes and after that the current drain is to much for the battery so the voltage starts dropping off until the battery is dead.
The Amp hour rating of a battery depends mainly(in the case of a car lead acid battery) on the plate area of the cell(the physical size of the cell plates) so a bigger cell(physical size) will be better able to provide the 2 volts ata 1/2 Amp longer then the cell that is rated @ 2 volts at a 1/2 Amp simply because of its size. Now BOTH battery cells will do the 2 volts @ 1/2 Amp like the sticker says, but the smaller battery will not be able to sustain the 2 volts @ 1/2 Amp as long as the bigger battery. This then becomes a matter of time the battery will stay charged when it is being taxed like cranking a car, also the amount of recovery time(the time it takes for the cell to get back up to 2 volts)will be different, the smaller battery slower, generally, then the bigger Battery.
Now lets go back to the store to get your battery:

You walk in and the guy at the counter says you need a battery, what kind of car do you have? You tell him, he looks in his book(because he knows little about batteries, the manufacturers suggested current rating for your car, or the post configuration) and he says oh, this battery such and such is the one for your car. You look at the battery and it looks good, but next to your battery you see a bigger battery and it will fit your car also. The bigger battery is really heavy, you need a wheel barrow to get it out of the store. Which battery do you buy? Well if you are like me and know you need a really good battery because you have a killer stereo and killer fog lights, and up graded yada yada yada part that all run off the battery, you get the heavy bigger battery.
In a nut shell, a heavier battery has more plate area and will sustain the rating on the battery longer then the battery that has the same rating but weighs less then the monster you got. Plate area is justhat plate area, and when it comes to batteries the more plate area the better the battery, it WILL be heavier. Lead weighs allot.
The can thing you mentioned: that part is called a capacitor. The part is rated @ .05 Mfd thats .05 Micro Farads. This is put on the Alternator B+ and the B+ of the coil on our cars. This part is being utilized as a noise filter in both cases on the car, so you dont have problems with your ECU acting weird and you can listen to that killer stereo without all the noise that drives you crazy when the engine is running. Here is how it works: The capacitor is built similar to a car battery. It has two plates that are seperated by a number of dielectrics(paper,poly urethane, plastic, and finally air to name a few) This part will take a voltage charge and store it until you put a load on the + and - leads of the part and then it will dump ALL of its charge, so its similar to a battery, but a little different.
Now when your alternator is running, the unit is basically a generator but a little better, it is a three phase generator and for a number of reasons, for current capibilities, and for what is called ripple, they are arranged so that they are at peak voltage potiential 120 degrees apart between the three phases. The generator develops an AC voltage that if you picture 0 volts on a horizontal line,and you picture the AC vlotage on a verticle line the portion of the line above the 0 horizontal ine beinf positive, and the verticle line below the horizontal line being negative(remember that a positive voltage and a negative voltage are the same just different polarities). the ac voltage will run plus and negative of 0 volts so what we are really talking about here is a difference of potiential of the voltage. Now to the point: there are 2 Diodes per generator coil, a total of 6 diodes(there are some variation on the total number of diodes from design to design, but a min of 6) the diodes are unidirectional, meaning they let voltage and current flow one way(there is a continueing arguement on flow VS hole filling of electrons, some schools teach positive to negative, and others teach negative to positive flow, it really makes no difference and nobody can really prove one way or the other because it is theory meaning they cant prove it, but it appears to work that way) now the diode one one end of the coil is orientated one way to let only the negative portion of the AC voltage pass and the other diode on the other end of the coil is positioned to only let the positive portion of the signal pass. Both portions of the signal are referanced to 0 volts so what we get is one part of the signal say +6 volts and the second half of the signal-6 volts for a total of 12 volts potiential out of the generator, each winding. Now we have this 12 volts coming out of the coil, but the very top of the = 6 volts and - 6 volts is for a very short time, so the actual operating voltage is about .636 (average voltage) of the total voltage picture it like this two horizontal lines 1" apart(this represents the Average voltage potiental) with little hills on top and bottom of the lines positive and negative respectively. These little hills are called RIPPLE VOLTAGE and this is the voltage that makes the noise, because they come at a specific frequency, that will change with the rotational speed of the windings. That is why you get that weird sound in your speakers and when you give the car some gas the noise changes and gets faster.
The capacitor charges up to the very peak voltage, in this case being 6 volts. Now the capacitor resists a change in voltage potiential in the line voltage, so when the sinewave of the voltage starts on its way back to 0 and then to negative voltage, the capacitor discharges in an attempt to keep the line voltage at it's highest potiential. What this does is to increase the AVERAGE VOLTAGE of .636 to a higher potiential RMS VOLTAGE of .707 of the peek voltage or higher depending on the capacitor rating, and the frequency of the sinewave, thereby having a smoothing effect on the output of the generator on the peaks of the sinewave. Your noise goes away, the effective voltage of the generator goes higher and every body can listen to their killer stereo without noise and the car will not be running rich because the ECU is wigging out on the AC ripple.
Hope you got all that, I just went through more theory here then I have in the last 5 years.
You have now graduated ZCAR charging 101 and Alternator 101 for a total of 4 credits, the generator was a lab so you only get 1 credit for that coarse
P.S ignore the misspelling, I'm to lazy to check it.
REGARDS: Jeffp

 

[jeffp]

The thing to remember guys is that Nissan did design the system with some headway, but not to the extent most of us need or want for the car, so we really need to look at the wiring as much as the engine and rest of the mods we do to our cars. It's really a new designed car for what we are doing with them. and all systems need upgrading to complete the ultimate zcar.

 

[Madeline Michele]

Without a doubt if you pump an amp with 0db or higher during PEP you may find this to be the straw that breaks the camels back.
Some figures you are dealing with are PEP.
If you were to look at this amplifier more closely you will see that the number 400 is PEP. The truth is that the elusive "Watt" is not as definitive as the average enthusiast would like it to be. Technically it would require a perfect current reading and a voltage sample, and then one with a degree in electronic engineering would sit down in front of a computer and work out the math. When a manufacturer or dealer refers to power, they are usually referring to Peak-to-Peak power.
You can pretty much add up some unvarying wattage as in lighting but that’s about it.
Your amplifier and other systems is not doing X number of watts, it's just not that simple.
Indeed you can come up with a number and you are truly starving for power but for anyone to slap a number on it is ludicrous. You would need to introduce a 1 k tone and tune the preamplifiers signal to 100%vu or 0 db whatever floats your boat.
If you have a system that walks the line drop in half a farad (500,000 microfarads) or even a farad.
Make sure it is not rated at 12 volts; look for the magic number 16 vdc if anyone of you has seen one of these babies blow you would understand.
One-farad explosion would take out a big chunk of interior.
SO FOR GODS SAKE don’t under rate the voltage to 12vdc or mistake the polarity!!!!!!!
I have made jokes in some of my postings about a Big Kaboom and now that I look back at this it’s not funny at all because when I speak about an actual Kaboom I may be taken for someone crying wolf.
This is not a joke! They can blow up big time!!!!!!!
The cap will clip the PEP and draw current more like you would find in RMS.
Also the cap will try to establish a slightly higher voltage but the battery will compensate for much of this.
Yes, it’s true our zx electrical system was not designed with high power audio systems in mind. Understandably we can opt to add PIP to form a base number in wattage but this is not the Golden Fleece. The cap on line with a system that integrates a large alternator and battery is indeed what you need.
So all this in mind I must go along with Jeff, somewhat.

God I wish I could stop thinking for just a week or so.

Madeline

 

[Madeline Michele]

****, Jeff you need the same vacation I'm looking for.
Looks like we went to the same school as well.


"Help me, Spo-o-ock!"
"Help me, Spo-o-ooock!"

Madeline and Kristine
33021

 

[jeffp]

Good reply about the Amp, and the CAP on the B+ line for a filter. In regards to my Amplifiers, Yes they do 70 Amps total with a 1 volt PEP line input @ 1k ferequencyinto the front end of the amp. I also agree with you that most manufacturers advertise their equipment with the PEP= (peak envelope power rating) to make their equipment look better then it really is. Fosgate is not one of those manufacturers, as well Kenwood in the early 80's for the most part on their higher end equipment.

The thing to remember and I thought I was clear, for the most part, is that you need to design a system based on the total maximum current load.
I also mentioned to look at the current specs the manufacturer listed on the spec sheet of their equipment. You will still get current peaks when the amp goes into saturation on the bass bumps.
When it comes to the Fliter cap, you are very accurate and correct. I have been in Electronics for a long time and I have had a couple of caps detonate on me while testing power supplies. These things will leave a very pronounced dent in any body part of the car when they blow. They do have the potiential of killing a person with the right circumstances.
Electrolitic capacitors CAN NOT compensate for a supply voltage that is higher then their rated voltage value. You can install a capacitor the is rated well over the operating voltage of the system you have, but not lower.
You sound like you are informed on Audio, so you will understand when I tell you my system hits volume peaks in the 125dB range measured on a Db meter. My system is no slouch. That thing pounds. Audio has always been my favorite electronics. I have spent so much money on my car equipment, and about twice that on my home stereo and it pounds out 860 watts through 4 Infinity SM150 speakers, that thing literally shakes the whole appartment building LOL, but everybody complains, they just have no appreciation for music LOL
Have a good one.

 

[jeffp]

Yea, I'm a spaz, poping the aleve top downing with a shot of JD. LOL

 

[Madeline Michele]

What a co inkie dink I am sitting down looking at 4 Infinity Reference Speakers as well.
I have 5 of these babies, one is used as a spare when I send one out to be repaired.
I also can place on line 2 McIntosh theater speakers vintage 1974.
My system is redundantly backed up by using a Pioneer and a 24-bit Sony.
I also am running 4 subwoofers but never need to place them on line.
When I kick in the totality of my system integrating all subwoofers, towers and MaCs to my Plinius SA 250 MK3 Class A Amplifier you can actually feel your heart skip a beat.
The magnitude temblor originating around my place can be measured in California on a Seismograph hehehe. My sound system will cause intense pain if I pull it to full power.
I don’t think I could handle full power without ear protection.
The best thing of all is knowing you have a system online that can be listened too with clarity several miles away. When I run a 1 K tone it’s comical how you can move to the sweet spot as the speakers are slamming each other in and out of phase. You can find spots of anti-sound then turn your head an inch and the sound falls in and out of phase.
Running class A is like having a direct short in your electrical meter, the thing takes off spinning. I have the system tuned to face my exact position in the room. If I run a tone and move inches from the sweet spot (My Chair) you hear the system fall away.
Now that’s some crazy sh;t.
Try it sometime.

 

[jeffp]

I setup my system so it sounds good the best in the center of the room. I have also had to repair all of the cross overs in my system, seems the 125 Mfd caps for the woofer cant handle the peaks to long before they detonate. To funny, now I know why you are on zcar forum LOL your a spaz to ROFL. I keep it down to stay out of trouble. I think I am one of the only people here that got a 270.00 dollar ticket for disturbing the peace with noise. Yea that was me, down to the police station and everything. My girl friend at the time said you are a bad boy Jeff, what can I say. So I cooled it down since then. But, I just had to hear jimmy play the national anthem last year on the 4th LOL
My friend and I have played some with the phasing just for fun, have you ever put two speakers so that the phase was 180 degrees out at 1K reeealy weird man LLL.
You know I have always wanted to try a wall and pound its ressonance frequency at it to see it start shaking apart that would be cool. ok dont want to get into trouble here so I will not say any more LOL
Have a good one. Jeffp

 

[Chromeshadow 71 240Z]

Re: Current readings

Whew, remind me not to ask you what time it is...Let me know if you ever want to borrow a DC current clamp. These are great to double check your calculations.

Chrome

 

[jeffp]

Re: Current readings

I have a similar unit, but not an inductive unit. Sorry about the long posts, but everybody keeps asking about all this stuff and I answer and they have another question, so I thought a fairly good explination was in order. It's hard to stuff 6 months of school into a short post and have everybody understand it.

 

[Madeline Michele]

How can you associate audio too an uncontrolled neurological tic?
I’m an Audio Engineer not a spaz.

Madeline Michele
Hollywood, FLA

 

[jeffp]

LOL obviously, to run that kind of power and not smoke something doing it requires an understanding of the electronics, and speakers behind it (reproducers LOL) I know next year, we can both play jimmy on the forth and see if we can hear each others system LLLLLLL to funny, but it would be fun trying.