Charging issue

[Rattletrap]

Mustang with battery in trunk show 12.5v while idling, 13.3ish at alternator.
Motor is a 6.0 with EWP and UD Crank pulley with truck accessories.
And I am making the assumption that even when driving around at 3k there is not enough juice getting back there since it wont start if I cut it off.
Battery is grounded to frame @ rear, then ground from chassis up front to block.
Positive wire from battery is huge stereo cable from rear to front where I have a bulkhead and the alt wire is connected to it. and So it all the other stuff that needs power.
Starter wire runs from/to this bulkhead too.

This sounds like what most do with all the mustangs and relocated batteris, well they run it from/to the starter 'noid but the same concept.

I have run a ground wire from the alternator casing to the chassis and no change at battery.

Looking for suggestions. They have ranged from:
-I need a 1/0 wire for ground from battery to the back of head/block
-maybe the UD pulley needs an OD pulley since the battery is moved
-maybe battery needs replacing-wont take charge-its an 09 Red top

I do not like relocated batteries-this is the major reason, would rather run a small LW battery up front...

[LXtasy]

Check all grounds again. Sometimes one loose ground will cause this very same issue

[BigdaddyDupree]

You sure the battery is good?

[Rattletrap]

You sure the battery is good?

no, its an 09 Red Top I bought 'out the back' of Adv Auto some time ago so who knows. I used it in my truck for years and put it in the stang b/c it had the top post.
Might take it in to have them test it, think that would be worth doing?

Will check grounds tomorrow and report too. but got a feeling those are good and tight.

[oldskoolstang]

Try a different battery and see if the results are the same. I've had no luck with red top Optimas...

[Rattletrap]

Try a different battery and see if the results are the same. I've had no luck with red top Optimas...Thought of that but that means I will have to reset the radio in the vehicle I take it from :poke:

probably will do that tomorrow too....:bigthumb:

[BigdaddyDupree]

It's the battery. If you put a charger on it and it cranks then it won't crank by itself again it needs a battery. Also if it's the aluminum kind of thin strand wire throw that shit away. My truck has 2 gauge bulk wire from Oreillys to the starter solenoid and the battery and engine are grounded to frame. And it's flawless.

[ShawnBoyMoody]

Try a different battery and see if the results are the same. I've had no luck with red top Optimas...

I never had any luck with Optimas either.

[Qwik_Sn95]

I had a brand new yellow top that was great. I used zero gauge welding lead on all my hot wires.

[BigdaddyDupree]

i have an optima problem free. might be lucky

[Rattletrap]

Batt from van shows 13.3V in trunk. Is .4-.5V drop from front to back OK? but also would like to thank for checking grounds. Back of head was loose. That was not good. But I did check V before and after that which doidnt help. The different battery shows to be the right way to go.

[ShawnBoyMoody]

Yeah thats okay. I would like to see 14 plus but it is charging. Does it hold 13.3 with the headlights and fan running?

[Rattletrap]

Maybe I need an OD alt pulley since it needs the extra umph.
Lights/etc has not been tested.

[oldskoolstang]

i have an optima problem free. might be lucky

I had a blue top marine battery that was badass. Never gave me a lick of trouble for the almost 2 years that I had it. I've had 4 red tops and 3 have failed in the first year.

[schardbody]

optima isnt what it used to be.... do some research on the company if you want to know why i say that.

[MonteC]

two red tops in my diesel. No problems, I ran them both dead on accident twice, still work great.

[BigdaddyDupree]

so?

[04ctd]

14.4 is what it SHOULD be at the Alt while running.

now...if you have 13.3 with no load, you have a bad Alt.

and ALWAYS move your ground to three different locations to verify you have a good ground.
I have worked on two cars lately for a few hours before I figured out the ground was bad (had multimeter on Batt Ground terminal)
once I put the ground lead for the meter on the frame, i had +7v everywhere :(

so put the ground on the:
-battery
-engine (carries ground for alternator, usually)
-firewall (lots of electronics ground there)
and see how it all measures. that will SAVE alot of time...ask me how i know...


so test Volts at Alt,
-idling (rev it up first, some alternators need to go above a certian RPM to "self excite")
-revved up (say ~2500 RPPM)
-Idling loaded (lights, AC, radio)
-revved up loaded.

then, do all the same tests at your battery.

it sounds like the Alt is weak, because even with an UD pulley, at 2500 RPM it should make the juice.

if your voltage varies greatly (the Alt & battery readings) from the front of the car to the rear, then you have a bad connection somewhere.

all you guys should read this when you are bored next time, lot of info here:
http://www.madelectrical.com/electricaltech/howitworks.shtml


The on board charging system must exceed the 12.6 level for electrical current to flow through the battery during charging. Electrical current must flow through the battery during charging to cause chemical reaction between the liquid acid and the lead plates within the battery. The 14.2volt level causes about the correct amount of current flow through the battery to maintain a fully charged condition.

[Rattletrap]

I have not done anything, waiting on a buddy to get me a battery but he is dragging his feet so I may have to go get it myself.

the OD Alt pulley came in yesterday, have not installed. Yesterday was a crappy day, today seems to be alot better so maybe tonight, LOL but I bet I will have to get a new belt which I will do after I relocated a pulley....

I will do those thing that 04ctd recommends once I have all this in place.

[Rattletrap]

Well....looks like I had too small of a wire gonig from Alt to the lug where the battery is hooked to. Put a much larger wire on there and we have lots of juice now!!