I need a new alternator.

Topic: I need a new alternator. (Read 11775 times) previous topic - next topic

I need a new alternator.

May 11, 2013, 09:50:32 PM

Guy's,
Once again, I need your advice. Now I have the A/C on when I drive, along with the electric fan running while and even a little after (fan) I stop the car. So my Optima battery (only about a year old) is not getting a full charge, it's around 11 volts (while driving) with my little 65 amp. alternator. So, now I need to get either a 100 amp. alternator or maybe just be safe and get a 140 amp. alternator. Seems like they are all one wire, and what I need to ask is would the 100 amp. be enough or should I go with the 140 amp alternator. If I go with a 140 amp. then hopefully I can put a decent stereo in without any problems. Also, I am putting in electric windows, and locks. No use in having all these new accessories if I don't have the juice to use them. Thanks!

I need a new alternator.

Reply #1 – May 11, 2013, 11:41:46 PM

you can get a 130 amp from any parts store or junkyard that basically bolts in. just need yo grind down the alt braket a bit. look at a 90's taurus with the 3.0 v-6 I believe. coolcats.net has a good write up under 3g alt install.

I need a new alternator.

Reply #2 – May 12, 2013, 12:46:21 AM

agreed, and matters only get worse if you run your car a lot at night due to general lighting draws.
im actually surprised my 20th puts up with all the electronics i have as stock items.

however,,,,,,,,,,
in stock form, the alternator was/is sufficient for the load demands to include HVAC.
what you are saying is that all your stock items prevent your cars battery from charging but i dont think your Efan is stock.

arent those optima batteries gell cell or dry cell?
gell/dry cell have different enviromental risks then flooded cells with respect to heat alone, you cant really abuse them as much as flooded or VRLA batteries.

the only way to verify the efan is the cause is to bolt back on your clutch fan and see if things go back to normal.
If your not able to use a clamp on amp meter, find someone who has one and clamp around the alt output wire and let us know how much amps is being demaned from the alternator during the day with no lights, no radio, no extra stuff running.
Next do the same wtih all possible loads on to include the efan running (the inrush on the fan is a battery storage killer and the voltage reg on the alternator takes the first hit for the inrush.

typically when a motor starts up, it can draw 3 times its nameplate rating for as long as it takes to get the motor spining at the design speed.

just getting you thinking and all,

one other test that might be valuable,, and not really endorsed here but the way i do it , i feel is ok to do.
with the car running, remove the pos battery cable then clamp on the the alternator cable to see if its the car that is loading down the alternator or if its the battery.
you could also just use a meter to see if the voltage goes up as well.

if you find out your voltage went up then its likely your battery is the cause... and its the continuous load pulling down the alternator voltage.
if the voltage stays low then..................
~its likely your total load of your car is infact pulling down the alternator (gotta have the EFan running to determin this
~or its likely your voltage reg is going bad or has very short brushes.
~~~to check, set your meter to AC volts and see if you have any AC potential coming out.,, in effect you slightly boil your battery electrolyte if this is the case but barely noticeable if your running a "barely broken" voltage reg.

shut off the car then reconnect the battery.. dont reconnect the battery with the car running.

have a friend read this incase your not the electrical guy, comment back with comments or results. I hate the battery game because when on thing breaks it usually ends up meaning you should replace the alternator and batt as a matched set to prevent other grimlins from poping back up.

I need a new alternator.

Reply #3 – May 12, 2013, 10:19:15 AM

I would suggest that you change out the charging wire from the back of the alternator to the starter solenoid. The factory one was never meant to handle the demands you are currently putting on it. Disconnect the existing wire(s) from the back of the alternator and run a new, temporary 8 gauge wire from the back of the alternator over to the starter solenoid and see what happens. I did this on my buddy's 69 Mustang because we added a Taurus fan and he was having charging issues, this cured the problem. I installed the 8 ga wire permanently with an 80 fuse as close to the starter relay as I could. The reason for the fuse is the same as the fusible links on our cars.

Basically just see if the single 8 ga solves your problem. If not then go the 3G alternator route and use a 4 ga wire from the back of the alternator over to the starter solenoid and fuse it.

Darren

I need a new alternator.

Reply #4 – May 12, 2013, 11:16:34 AM

to be honest, i would have your fuse your mentioning at the alternator end.

I need a new alternator.

Reply #5 – May 12, 2013, 11:22:39 AM

Good morning gents.,
The Optima is a gell cell battery. Being just about every thing I have done to my car this last year was replaced with new parts, I want to do the same with these electrical parts as well. I am pretty sure the problem is the efan drawing so much electricity. The A/C compressor is also original and is most likely pulling a lot of electricity also. I just filled it with freon and it is working well, so when it dies I will put in a new A/C set up. The efan is an upgrade from stock and my responsibility is to give the power it needs to function correctly. So, 100 - 140 amp. alternator, a voltage regulator (being mine it 27 years old) and a 4 ga. wire with fuse should be a good setup. The reason I am doing it this way is for reliability. I will be moving about 130 miles from here, and I will be driving back and forth at least once a month. Great write up guys! Thanks!

I need a new alternator.

Reply #6 – May 12, 2013, 11:58:07 AM

86cougar,
Sounds like you have a plan.

jcassity,
As for the fuse location I disagree. In a crash the engine typically stops running so the alternator no longer has output so moving the fuse as close to the starter solenoid reduces the length of wire that is still energized by the battery which IMO is safer. This is also the stock location of the fusible links. I am open to reasons why it would be better at the alternator but I just don't see it. Then again you could always install two fuses and call it a day.

Darren

I need a new alternator.

Reply #7 – May 12, 2013, 01:15:08 PM

86cougar,
Sounds like you have a plan.

This is where I was used to getting slammed. Yep, a plan...my car....my plan outlined by helpful, knowledgeable guys willing to assist in this plan. No name calling, or demands to be met. Nice! I bet this plan works out very well also! Now, I can go work on my car at my own pace, with my own tools and enjoy my myself......Cool! Thanks guys!!

I need a new alternator.

Reply #8 – May 12, 2013, 01:51:30 PM

good point on the fuse,
my line of thinking is to fuse as close as possible to the item that is generating the amperage, in dc and low voltage, there are many reasons this is a benefit but thats a different topic. The primary benefit is to protect the voltage regulator as close to the regulator as possible , otherwise there is additional length of wire a fault would have to travel down before it finally gets in touch with its inteneded over current protection.

i do see your point though

I need a new alternator.

Reply #9 – May 12, 2013, 01:54:31 PM

Just so you know that 3G alternator is internally regulated so you ditch the external one in the car. This is a pretty good thread on another site dealing with non-EFI cars but it has a link to the one for EFI cars on the Corral:

http://vb.foureyedpride.com/showthread.php?t=76480

I know lots of guys here have done it as well so searching here should turn up some other threads on the topic.

Darren

I need a new alternator.

Reply #10 – May 12, 2013, 03:42:05 PM

Nice article. I see that some vendors have "large case" G3 alternators are they different from the rest? I can get a G3 from the local shops here but I need to find one with over 100 amp.. They also have them with lifetime warranty. Thanks!

I need a new alternator.

Reply #11 – May 12, 2013, 06:31:58 PM

I had to do some homework finding out who locally has what I need. The parts locators on line would not let me look for a G3 alternator, I had to look up different years, and cars and amperage then look at the picture to see if it matched what I have. I finally ended up with exactly the same one that "Corral" used on their article. 130 amperage is the most I could find, but that should be fine. Should be very little modification for installation also. I bought the 130 amp., "new" not re-manufactured, with a lifetime warranty. I "Thank You" gentlemen for your assistance!

I need a new alternator.

Reply #12 – May 12, 2013, 10:29:56 PM

I have a 130 amp 3G in both of my cars with Mark VIII fans, 500+ watts of stereo, MSD ignitions, A/C, and loads of other after market stuff that eats power. No issues what so ever with having enough juice.

Darren

I need a new alternator.

Reply #13 – May 13, 2013, 09:07:30 AM

i wanted to say this earlier and forgot.

i assume you got your AC working,,,,,the other thread said you had no freon as confirmed by post 2 & 3,,,,, but,,,,,,,,,,,,
pls keep in mind that if the system is over charged, you may experience too much load on the engine.,, it may simulate alternator issues.

if you select AC and your compressor runs constantly, there is likely too much
if you smash the gas pedal to WOT, you should feel warm(er) air coming into the vents , this is confirming you WOT switch is shutting off the compressor during these high gas pedal / passing gear situations and engine demands.

just fyi, to be honest if they were not qualified to determine the system had charge in the first place, i would recommend you have them provide you with the procedure they used to charge your system, tell you how much vac and how many lbs of charge they put in.

eventually this could / will / should lead to slightly higher engine running temps due to the additional load.

you have to be careful bringing these cars to shops today, most of the techs working on them are not qualified to work on them or they dont have the tech docs on line or in paper form to reference. A lot has changed in the world of air conditioning with respect to the transition from R12,, and i mean a lot!!!!
the procedure for charging has basically remained relatively the same but there isnt really a standardized LBS of vac to pull or a standardized LBS of charge to add so the tech could have been guessing.

This is my opinion on what appears to be a proper 1980's R12 system.
your car is at idle with ac on
your compressor engages and stays that way for about 8 to 10 seconds then cuts off fo about the same amount of time.

im sure you have noticed if it cuts off and on or not.

if it runs constant with AC selected which isnt a good thing, im sure you would have mentioned that by now,,

I need a new alternator.

Reply #14 – May 13, 2013, 09:40:45 AM

i would also recommend you inspect your large conductors going into your ignition switch as well while you are making your car better.

I personally removed my son's Efan because i didnt really see a mechanical gain in having it, the oem fan clutch is very sufficient and provides no additional alternator load to run it.

I think Efans are over rated, the path of least resistance is to run the oem fan clutch.

do you have the Efan set up to a temp probe to determine its relay driven on of state or is is wired differently?

The placement of the temp prob can also cause it to run too often preventing your battery from replenishing and thus causing your alternator to see the discharged battery as more of a constant load than it use to be.

under nominal conditions, your battery would be constantly fully charged and your alternator would typically only be loaded down with approx 40A of demand with every single thing you can think of turned on to include full heat blower motor and hitting a power trunk switch.

if it were me,, i wouldnt even do an Efan, there really isnt a gain in it.
the smaller fan clutch load you take off the engine is quickly replaced by greater additional "electrical load friction" put on the alternator.
geometrically speaking, since the alternator is wayyyyyyyyyyyyy off to the side of the center line of all the rotating parts, "our" alternators actually load down our engines more with "less" load than the 4.6L with the alternator situation more in the center of the belt arrangement. The 4.6L alternator location allows the engine to have more mechanical leverage than if the alternator were way off to the side thus making best use of the max ampacity capability of the alternator especially at lower speeds.

since your oem fan clutch is close to the centerline of your crank geometrically speaking, its actually more efficient and offers less engine load.

this topic was debated a three or four years ago, became an interesting thread.