Battery Dying

[BGBronco]

I have a 76 w/ 302 w/ FiTech.

I have a new battery, relatively new alternator and voltage regulator. I'm not able to keep the battery charged for more than a few days.

I'm getting these readings from my FiTech controller ....

- Idle with no lights, flashers, heater - 12.2
- Idle with lights, flashers, heater on - 11.8

Driving at 30MPH with no lights, flashers, heater - 14 =/-.2
Driving at 30MPH with lights, flashers, heater on - 12.5 ish

Battery checked out fine. Alternator checked out fine. Voltage regulator tested bad so I replaced it but still having the same issue.

Any thoughts? Thank you!

 

[tirewater]

Which alternator are you using?

I have a 76 w/ 302 w/ FiTech.

I have a new battery, relatively new alternator and voltage regulator. I'm not able to keep the battery charged for more than a few days.

I'm getting these readings from my FiTech controller ....

- Idle with no lights, flashers, heater - 12.2
- Idle with lights, flashers, heater on - 11.8

Driving at 30MPH with no lights, flashers, heater - 14 =/-.2
Driving at 30MPH with lights, flashers, heater on - 12.5 ish

Battery checked out fine. Alternator checked out fine. Voltage regulator tested bad so I replaced it but still having the same issue.

Any thoughts? Thank you!

 

[B RON CO]

Hi, I would get the charging system checked out by a good elctrical guy.
Maybe you could try a smaller alternator pulley. That would spin the alternator faster at idle.
12.5 volts while driving is not enough.
Good luck

 

[Timmy390]

My money is on voltage regulator or the alternator. Or could be you have a 42amp alt vs the 65amp

FiTech uses some amps as does all EFI. It's powering the fuel pump and the injectors and the ECM. When you start turning on the lights and heater and other stuff, you're pulling max amps....

While not EFI, I had this issue with my Samurai. Turn on the lights, blower and radio....forgetaboutit...I upgraded to a bigger alt and all seems better now.

On my Bronco, everything was dim at idle even with a stock "new" alt and voltage regulator. I upgraded the alt and everything is great now......

Tim

 

[BGBronco]

I need to figure out what alternator I have. Definitely a 1G just not sure of the amps.

 

[DirtDonk]

When you had it tested, did they give you any indication of what it was capable of? Even if you don't know the original "official" rating, the testing I would think could tell you what it's max is. Often the original rating is above or below it's actual capabilities.

But since they said it was good, I would imagine it has to be at least 50a or so. Otherwise they might have tried to sell you a new one. With good reason...

How's your wiring? Got pics we can check out of your under hood, and especially the voltage regulator areas?
You definitely don't have enough output, but it can be a wiring problem as well.

Good luck.

Paul

 

[BGBronco]

it's a 60 AMP alternator.

 

[DirtDonk]

Then it should be enough for most chores.
How is it wired? And how is your voltage regulator wired?

Are they grounded together? Usually just a single small wire between the alternator case and the regulator case.
What is the general condition of the wiring? Maybe the regulator tested good but isn't, or maybe the wiring is suspect.
But like was said, your voltage readings are way off. The only one that's close is the running with no load giving you 14v or so. But obviously something is amiss because it should not drop at all when you turn on the loads. A 60a alternator should be able to immediately keep up with whatever load it's given, up to about 60 amps in fact.

Paul

 

[BGBronco]

I'm going to swap the regulator out again just to make sure but I suspect it's the wiring at this point. I will check wiring and report back. Thank you.

Then it should be enough for most chores.
How is it wired? And how is your voltage regulator wired?

Are they grounded together? Usually just a single small wire between the alternator case and the regulator case.
What is the general condition of the wiring? Maybe the regulator tested good but isn't, or maybe the wiring is suspect.
But like was said, your voltage readings are way off. The only one that's close is the running with no load giving you 14v or so. But obviously something is amiss because it should not drop at all when you turn on the loads. A 60a alternator should be able to immediately keep up with whatever load it's given, up to about 60 amps in fact.

Paul

 

[gnpenning]

Try a regulator bypass test first. Also make sure your regulator has a good ground.

 

[DirtDonk]

gn's idea is a good one BG. It's called "full-fielding" and in your case you would just unplug the regulator (don't have to, but it aids in the test) and jumper between the Yellow "A" wire and the Orange "F" wires.
With the engine running this tells the alternator to put out it's maximum potential. So you only want to do it for a few moments at a time. Don't want to overheat anything.

When it's full-fielded you should immediately see 14+ volts at the battery, likely moving up to 15, 16 and, if left on long enough, perhaps even 17v at the battery. Which is too much for the battery too, if left on too long.
So as said, only do the test for short periods and then disconnect the jumper wires so that everything goes back to normal.

If you do not see those high voltages, and don't hear the engine bog down noticeably when they're connected, then either your alternator is in fact not good after all, or something is wrong with the two wires, or their connectors.

If there's more to it than that, hopefully someone will fill in any details I left out.

Paul

 

[BGBronco]

Thank you both. On this list for the morning!