Battery issue/ Help!!

[joelozano]

Hello Im running a 302/5.0 EFI but battery gets drained after driving a while, has a new alternator and battery. Any ideas on what could be the problem?

 

[Mark]

It only drains while it's running?

 

[bknbronco]

Alternator is shot or ant hooked up right. Probably battery is shot as well if you killed it a few times.

 

[TN1776]

Put a voltmeter on your battery while the engine is running. If you are not registering 14 or so volts, look at the alternator wiring. Maybe as simple as something not hooked up, may be a toasted alternator/voltage regulator. You state its a new alternator... I had two brand new (not reman) alternators test bad off the shelf from Autozone. Got my money back and bought a powermaster.

 

[joelozano]

Will do, thanks guys!

 

[Jerseydevil]

If the regulator is bad, I don't think you will see the proper voltage from your alternator.

 

[robs68]

Do you have a a small light as a resistor in the line if not the alt will not charge the battery. I put a small dash light right after the alternator because I was having the same problem. Normally the light is in the dash on the mustangs. If the light is on then the battery is not charging.

 

[gr8scott]

Do you have a a small light as a resistor in the line if not the alt will not charge the battery. I put a small dash light right after the alternator because I was having the same problem. Normally the light is in the dash on the mustangs. If the light is on then the battery is not charging.

Uh, what?%) I have no such light and my alternator charges just fine...

 

[69red]

i've had this problem before: these were the causes:
1 corrosion on the wire harness that plugs into the voltage regulator
2 poor contact between the big wire from the alt and the batt cable at the starter soleniod lug.
3 bad voltage regulator
4 bad alt.

good luck!

 

[C_Forte_75]

I have had after market stereo system amps draw down batteries when sitting

 

[Arikilen]

Uh, what?%) I have no such light and my alternator charges just fine...

I have the light on my set up as well. It wouldn't charge without it. 86 t-bird 5.0 EFI set up.

 

[DirtDonk]

I've heard of this ever since we've been doing 3G swaps, but have never run across the need myself. At least not yet.
Have installed quite a few 3G and 4G alts without a light and have not had an issue. However, I want to install lights on all the setups anyway, just as an additional warning.
In the case of a lamp, as opposed to a resistor by itself, it was my understanding that it's not to put resistance into the wire, but to keep the alternator working in case the bulb blows out.
So if you do have a dash light, always use a resistor loop to fend off that problem. If you don't have a lamp, I guess it's hit-or-miss?

What alternator did that t-bird setup come with Arikilen? Is it a 2G or 3G? Standard or something exotic? Just curious. I don't want to forget about this the next time I hook one up and it doesn't work!

Paul