What in the ....?????? Low voltage reading, yet full battery and alternator working.

Topic: What in the ....?????? Low voltage reading, yet full battery and alternator working. (Read 19664 times) previous topic - next topic

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #60 – June 24, 2014, 10:06:45 PM

I have 00 on the 3G install in the convertible. It is definitely not overkill. Clean transfer of power is never a bad thing.

Also, I have a 175-amp car stereo circuit breaker installed inline. What's cool is that, if it trips, it's just an arm that pops out. No changing fuses--just push the bar back in. Nice, simple, efficient. 10+ years on this install and no problems whatsoever.

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #61 – June 24, 2014, 10:53:40 PM

X2 on the breaker, but its expensive.

you can get post extensions off of the box crownvics at the junkyard for the solinoids.

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #62 – June 25, 2014, 12:17:47 AM

I started the car after adding the second ground..... No real change in temp. Still warmer than it should be, but not ridiculous like before....
Took the car to the local car meet I go to on Tuesdays as a friend wanted to see what was going on and it's hard to explain it over the phone, you know. It's only a 5 minute drive so I figured why not? This was the first time ever I actually went and took a fire extinguisher in ANY car for a road trip that wasn't to the track. Made it there and back with no issue.

I did take note of TWO things......

1. My voltage reads FIVE bars at idle with a few items on. I can't ever remember it EVER reading 5 bars before. EVER.
2. A while back I posted about on odd issue the car has had since I purchased it in 1998. When I would turn on the rear window defrost, the oil pressure gauge would read one bar higher and upon shutting it off it would return to it's previous position. After reading 5 bars on the volt gauge in the car, I decided to give that a whirl. On went the rear window defrost. NO CHANGE. I tried it about 5 or 6 times. Nothing. Before tonight it would do this without fail regardless of engine temperature or weather condition. It was an absolute. The speed of light is 186282 miles per second, standard acceleration due to free fall is defined as 9.80665 m/s2, when I turn on the rear defrost my oil pressure will read one bar higher.

I'm going back to the parts store I bought those ground straps from. I'm buying more and installing them in the rest of my cars...

A pic for reference. The red wire is 2 gauge for size comparison.

Tom and Haystack. Thanks for the advice/ideas on the extra post for the solenoid terminal. Another thing I noticed concerning the solenoids in Mustangs. They all seem to use the terminal toward the rear of the vehicle for positive. Every Catbird I've seen in person has had the forward as positive.....
I've also notice that some solenoids have TWO of the smaller posts as opposed to the ONE I've had on my cars....

Pics.....

This is opposite of my setup. I wonder why the difference?

And the one small post as opposed to the double small post.

Quote

http://contentinfo.autozone.com/znetcs/additional-prod-images/en/US/wls/F492G/2/image/4/

Is the double small post for the factory PMGR starter setup?

Quote from: EricCoolCats;435136

I have 00 on the 3G install in the convertible. It is definitely not overkill. Clean transfer of power is never a bad thing.

Also, I have a 175-amp car stereo circuit breaker installed inline. What's cool is that, if it trips, it's just an arm that pops out. No changing fuses--just push the bar back in. Nice, simple, efficient. 10+ years on this install and no problems whatsoever.

Like this?

I see they range from 15-25 dollars. Pretty nifty.

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #63 – June 25, 2014, 01:28:10 AM

The double posts all do the same thing.

one side of the post is always powered by the battery, the otherside is only hot with igniton if i remebr right. been a couple years though.

I'm pretty sure the double post is just a generic part. my autohole solinoid that only lasted a year had both and i think both triggered the starter.

the solinoid is just a the two posts with a ball bearing in the center. when you trigger it a magnet pulls the ball bearing into the posts.

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #64 – June 25, 2014, 07:25:24 AM

NO the single post crank lead is used when the ignition system does not need a resistor bypass circuit. Any ignition system that is void of a resistor does not need bypass so ford eliminated the lug. Also there are some 4 post solenoids that isolate the primary coil to faciliate a NSS switch. As far as which wire goes where on the heavy lug it makes no difference on some. But some relays have a buffer diode and proper phasing is critical. It depends on the year and application. As far as having these numerous grounds i am going out on a limb here and saying grounds are good but i have seen people adding so many it it ridiculous. Grounds should be short and sweet and tight and cross-ion free. Other than that i only use one or two max depending on the setup. Another thing people think having a huge battery feed to the alt lug is better. Not true. Once you pass a certain point i am going to say like 6 Gauge on a 250 Amp alternator the battery lug on the alternator can not handle the extra copper or gauge size. Another words the lug is to small to handle the current a o/o wire can handle and is basically a waste. Also A wire capacity rating depends on how many strands it has and how it is designed. Another words like a welding cable of lets say #2 can handle more current than lets say an automotive cable. The welding cable is the same size but has many many more strands to make it more efficient. Remember the alternator never puts out max current and normally runs at 1/4-1/3 of its ratings if that. have a good Wednesday

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #65 – June 25, 2014, 08:13:13 AM

Quote from: V8Demon;435150

Like this?

I see they range from 15-25 dollars. Pretty nifty.

Yes, exactly like that. I paid something like $20 back in the day. This way you never have to worry about carrying spare fuses or being stranded somewhere. I thought it was a terrific idea.

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #66 – June 25, 2014, 09:02:41 AM

Thanks everyone. I'm in a holding pattern waiting for my power wire now. After I put the car back together yesterday I washed it. Today it is drizzling just enough to make dust stick and cause water spots........yay...

Stay tuned.

Also, found this BURIED in a thread....

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #67 – June 25, 2014, 09:00:03 PM

With all these companies that make these huge alternators and claim hundreds of idle amps. Why then does Ford and chevy trucks come with dual alternators?? I wonder if there claims are a little sketchy. Have a good evening guys.

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #68 – June 26, 2014, 02:30:39 PM

I have the 3G's on both of my cars and they have been on there for 10+ years. When installing the fuse the amperage rating should be the limitation of the wire between the alt and battery or the alternator's output, whichever is less. I run 4ga wire on both the cars and it is the high strand cable. Since both cars have the starter solenoid on the driver side inner fender the length of the wire is almost identical. I found a chart which shows the load carrying capability for 4ga wire over given distances which was less than what the alt could put out. I ended up installing 125A wafer fuses and have never replaced one.

I posted up how both of my cars are wired so I'll see if I can dig that up and post the link.

Darren

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #69 – June 26, 2014, 08:16:14 PM

A number 4 AWG is a very good choice for an alternator battery feed. And protecting it with a 125 is smart. Not to big not to small just right for your application. Perfect setup in my opinion. Running a bigger wire with a 175 Amp fuse is a little overkill. And if that blows you have some serious issues at hand. I KNOW some fords come from the factory with a 175 fuse. I think for an alternator feed it is to big if something goes wrong. Just me. Have a good evening guys.

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #70 – June 27, 2014, 12:15:32 PM

Fuses are cheap enough. The car should never need to draw 125 amps..... I'll order one and give it a whirl.

On a side note, I am now $217 poorer in assorted hardware and miscellaneous stuff I've been meaning to replace on the car. All new, most of it Ford OEM.
Battery trays for these cars are expensive.....

The wife & kids are officially all on summer vacation which means I'll actually have free time.

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #71 – June 27, 2014, 12:56:43 PM

Quote from: EricCoolCats;435155

Yes, exactly like that. I paid something like $20 back in the day. This way you never have to worry about carrying spare fuses or being stranded somewhere. I thought it was a terrific idea.

yeah, except for the allen set screw which distroys the copper when you tighten.

should be made with an elevator plate to "mechanically" bond the connection,, not "cut into".

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #72 – June 27, 2014, 01:50:06 PM

Quote from: jcassity;435234

yeah, except for the allen set screw which distroys the copper when you tighten.

should be made with an elevator plate to "mechanically" bond the connection,, not "cut into".

If they made one with connections for ring terminal ends I'd order it and enough 2 or 4 gauge wire. I feel that would be the optimal setup. Would cost me around $80 to do the way I want by piecing it this way though.

Scott, check this out.
http://www.aliexpress.com/item/200-AMP-12V-DC-CIRCUIT-BREAKER-REPLACE-FUSE-200A-12VDC/744155233.html

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #73 – June 27, 2014, 08:08:30 PM

They do make them with terminals i think i sent Jay a couple of them. By the way you can install a fuse link that is in my view better and neater. Once again if you blow a 125 or 175 or 200 amp or any size fuse circuit breaker or whatever you are not going to be able to reset it. So resetting it and driving in to the sunset is in my view not happening.

You can fuse link a 4 AWG with a number 12 AWG and that is what i would do. Using a 200 Amp breaker is something i would not do. Doing that would allow the alternator to heat up like crazy before it blows. The idea behind fusing is to make sure you do not have a FIRE. Example would you wire your outlets in your house with a 50 amp fuse and number 4 wire. I think not. Sometimes more is not better and with alternator feed wires it definitely holds true. Use a wire size and fuse to satisfy you alternators output and leave the giant wire and fuses for electricians. I think Aerocoupe has a good balance with a 4 AWG and 125 amp fusing. Just me that sounds reasonable in my view for safety and reliability.

The owner of this gorgeous car we restored found out the hard way with big wiring and big fuses. It burned the wiring all the way back to the dash. Notice the bare wires fried to a crisp. He was lucky he did not loose the car and his house also.

I rewired it and saved the car by providing proper wiring. Notice there is very little visible wiring in the engine compartment. I hid most of it . Have a great weekend guys

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #74 – June 27, 2014, 10:04:53 PM

It really is simple math and they have a standard chart to look up.

his alt puts out 158 amps at 13.8's if i remeber right. on a dead battery it is likely the alt when stressed will only put ut a bit over 12v's. that's what i suggested what i did. voltage x amps = watts. 2180 watts. divide that by 12.5 and you get 174 amps. that is the minimum id put in there if it was me.

the 4 guage wire is rated for 150-200 amps assuming the wiring length is 47ft.