Hyde440duster
Well-Known Member
OK so I have a 72 duster with a 440. I used a newer GM alternator, I show 14 volts on the gauge but my battery seems to be discharing. Any ideas? Kinda puzzeled . Any belt would be greatly appreciated.
440 duster Charging problem.
- Thread starter Hyde440duster
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68gtxman
I used to reMember
Measure the voltage at the battery terminals while the engine is running. Less than 13 and you have a further problem to track down. Over 13 volts and it's time for a new battery.
67Dart273
Well-Known Member
Sorry not correct, unless you mis-typed
A warm engine (warm regulator) and "normal" charged battery system voltage should run no less than 13.5 and no more than 14.5. 13.8--14.2 is optimum. Check it with engine running to simulate "medium cruise" RPM, and battery up and normal.
txstang84
Well-Known Member
Check grounds yet?
How is your alternator wired?
Do you have anything in series with the charging circuit that's staying on when the engine isn't running?
How is your alternator wired?
Do you have anything in series with the charging circuit that's staying on when the engine isn't running?
txstang84
Well-Known Member
I thought about asking the exact same thing...
Hyde440duster
Well-Known Member
Thanks for all the help. I charged it 100%. Then drove it probably 10ish miles and when I hot back home I put the charger again , Just for a test and only showed 52% charged. But when I'm driving it ahowed 14 volts. I have added a couple grounds . I'll check them and maybe add a few more.
Beatnik
Well-Known Member
Start by probing it with a multi across all the usual spots with it running. Verify with a buddy against the gauge etc. sure your gauge is accurate? Sounds like your battery may not be taking a charge. If the gauge is accurate and the alt and other components are doing their job supplying/regulating the voltage then maybe the battery dropped a cell or something and isn't accepting a charge. I've had it happen where a trickle charger will charge it then when put in use it just drains similar to you say happened....everything else being fine just a bum battery.
Good luck. Let us know what you find ....
Good luck. Let us know what you find ....
68gtxman
I used to reMember
I used 13 volts to allow for a mis-adjusted voltage regulator. Batteries with a full charge should normally show 12.5 volts with the engine off. Yes, it should normally be 13.5 volts to 14.5 at the battery terminals with the engine running.
BTW, 67Dart273 rocks!
67Dart273
Well-Known Member
This is pretty much normal so the original question remains. Just what exactly is happening that leads you to believe it's
discharging the battery?
not charging enough?
???????????????????
Hyde440duster
Well-Known Member
I drive it 10 miles. Then its 50% charged.
67Dart273
Well-Known Member
one bad 440
Well-Known Member
txstang84
Well-Known Member
Have you metered at the battery when it's running?
What's the voltage with above condition?
Again, how is your alternator wired?
You stated it's a Delco unit, those only have two connections last time I messed around with one-one charge which should be wired straight to the battery terminal on the starter relay, and one switched 12V excite wire...probably the blue wire coming from the ignition switch at the bulkhead connector.
And again, are there any other terminals to/from those connections?
Has anything else [electrical] been modified?
Does the alternator housing have good ground to the chassis?
Have you physically checked your battery to chassis/engine block grounds for voltage loss or continuity? The reason I ask this is my wife's '04 Mustang has sizable ground cables, but the terminal on the negative post of the battery was so damn corroded, it kicked off the battery idiot light, but the alternator would still kick out good volts...just not getting to the battery since the ground was incomplete.
The tester your using is measuring an arbitrary value, and what you need to do is measure the actual voltage at the battery terminals with it running, and measure for continuity between your battery negative and chassis/engine block.
If you're getting good volts (13.5-14.2) at the battery, and it's still kicking out a discharge, have the battery load checked...it may have a dead cell or low electrolyte. If you're not getting good volts to the battery, start chasing it from the alternator charge wire and find where your voltage loss exists.
What's the voltage with above condition?
Again, how is your alternator wired?
You stated it's a Delco unit, those only have two connections last time I messed around with one-one charge which should be wired straight to the battery terminal on the starter relay, and one switched 12V excite wire...probably the blue wire coming from the ignition switch at the bulkhead connector.
And again, are there any other terminals to/from those connections?
Has anything else [electrical] been modified?
Does the alternator housing have good ground to the chassis?
Have you physically checked your battery to chassis/engine block grounds for voltage loss or continuity? The reason I ask this is my wife's '04 Mustang has sizable ground cables, but the terminal on the negative post of the battery was so damn corroded, it kicked off the battery idiot light, but the alternator would still kick out good volts...just not getting to the battery since the ground was incomplete.
The tester your using is measuring an arbitrary value, and what you need to do is measure the actual voltage at the battery terminals with it running, and measure for continuity between your battery negative and chassis/engine block.
If you're getting good volts (13.5-14.2) at the battery, and it's still kicking out a discharge, have the battery load checked...it may have a dead cell or low electrolyte. If you're not getting good volts to the battery, start chasing it from the alternator charge wire and find where your voltage loss exists.
txstang84
Well-Known Member
I'm operating on a simple assumption here too...that your delco alternator has the VR built in. If it is, you can ditch the one on your firewall...
Hyde440duster
Well-Known Member
i have checked charging system and gauge is accurate. Im getting 13.9 to battery while running. You guys are correct it is internal regulated. I tested the battery and load tests fine. Im going to change the battery cable ( since its in the trunk ) and maybe that will help. And yes ALOT has been modified the previous owner did a number on the wiring ( changes color 5 times to still go to same component ). And since I put in the 440 its been interesting trying figure out all the wires.
Hyde440duster
Well-Known Member
67dart273 50 % charge is based off battery tester and slow starts after driving.
txstang84
Well-Known Member
13.9V at the battery with it running is about right, if not a little lower than optimal...you might be losing a little down the line. I'd personally check any and all connections to ground from the battery, ground to engine, and the charge wires for voltage loss on each side of junctions.
What size cables are you running?
If you're mounting it in the trunk, you probably ought to have at least a 1ga ground from battery to chassis, and the same for the positive cable up to your starter relay or power distribution block.
What size cables are you running?
If you're mounting it in the trunk, you probably ought to have at least a 1ga ground from battery to chassis, and the same for the positive cable up to your starter relay or power distribution block.
Dcuda69
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Earlier you said battery charger. Is your 50% charge based on a charger or a tester?...my guess is a charger...which means nothing. If you're showing 13.9 at the batt (in the trunk)running, then what does the alt output show? Bet it will be 14+ volts. If that's the case, coupled with your slow starts after driving, indicates voltage drop in the system...most likely caused by cables/connections. You're covering a lot of footage..you need big cables/good connections to minimize voltage drops....especially when things get warm.
67Dart273
Well-Known Member
This is the kind of info we need.
Here's the general premise:
1--CHARGE the battery keep it disconnected to remove the possibility of a vehicle leak and load test the battery
WHAT did it load test at, what amperage? What cranking amps is it rated at?
2--I'm assuming from your comments which need to be MUCH more specific that it sounds as if the starter is slow. AFTER (1) above is done, and you KNOW the battery is OK, then............
Check for starter CURRENT draw as well as excessive voltage DROP on the cables. Since it is now apparrent this is trunk mounted, this is even more important.
So beg borrow or steal the same type carbon pile load tester that was used to load test your battery:
3--Determine if the starter is drawing excessive current. You do that by cranking the engine, while monitoring battery voltage. The starter will sag the battery to some level after 3-5 seconds. What you then do is you put the load tester across the battery and crank in load until you again sag the battery voltage to the same level as when cranking. Then you immediately read the starter amperage right off the load tester. You'll have to get ahold of a rebuilder to find out starter draw if using a mini starter, I don't have that info.
4--A---At the same time, check voltage drop on the system cables and connections. To do this with a trunk mount battery, you'll need to "rig" a long wire, can by no 16 or 14 to reach from front to rear, with a way to attach to an alligator clamp. You will need two people
Clamp your long wire to the ground clamp at the battery. Run the wire up front, hook one probe of your meter to the end of the wire, and set your meter to "low DC" volts. Stab the remaining probe onto the engine block and crank the engine, ignition off, and read the meter while cranking.
You should read a very low reading, the lower the better. Post this reading.
4--B--Check the "hot" side next. Clamp your long wire to the POS battery clamp, up front hook the wire to one meter probe, and "rig" a clip to the starter terminal to which you hook the remaining probe. Crank the engine and take a reading while cranking As with the ground, you should read a very low reading, the lower the better.
5-- If it's easier to understand the two above tests can be done so: Clip your meter to the battery in the rear, take a reading while cranking. Move the meter probes to the starter terminal and engine ground and crank again. Subtract the two readings, and the result will be the total voltage drop from the battery up to front.
Don't 'assume' anything. I've seen deteriorated cables where they were soldered/ crimped into cable connectors. Speaking of which, anything which gets hot while cranking is a BIG clue. Crank the engine in the above tests, then run around and feel the battery clamps, the ground at the battery, the end terminals of any cables.
How is the battery grounded? To the body? How is the engine then grounded to the body? Or is the battery NEG cable run all the way up front
To repeat earlier, and what others have said, "about" 13.5--14V charging voltage means there is probably nothing wrong with the charging system.
If the battery was PROPERLY load tested by a good tester, this is the starter, cables, grounds, connections. If you have an extra (Ford style) solenoid and or disconnect switch, suspect them as well Once again, if any switches and relays are getting warm, ---trouble inside.
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