Thread: new battery, no juice

Tweet

HELP!!! I have a 1966 Ford F-100, I've been adjusting the fuel-air mixture on the carburetor. Ran the battery down, Tested it found out it is bad, replaced the battery and still not getting enough juice to start it. The battery cables are getting hot when I try to start it. Do I have bad cables? Is this a possibility with the no power to start? Any suggestions is greatly appreciated and accepted. Thank-you all very much.

Originally Posted by Jas

HELP!!! I have a 1966 Ford F-100, I've been adjusting the fuel-air mixture on the carburetor. Ran the battery down, Tested it found out it is bad, replaced the battery and still not getting enough juice to start it. The battery cables are getting hot when I try to start it. Do I have bad cables? Is this a possibility with the no power to start? Any suggestions is greatly appreciated and accepted. Thank-you all very much.

Hot cables mean too much resistance. So the cables are too small, the connections are bad or what my best guess is that you fried the starter. I have found fords to be less forgiving to abuse and continuing to attempt starting with a weak battery will often kill a Ford starter.
How did you test the battery? As far as I know the only accurate tests have to be done to a fully charged battery, which means several hours on a slow charge to do it right.
My guess is that the people who sold you the new battery tested the old one for you.
Also if you have those battery cable repair ends, get rid of the cables and buy new ones, those ends are for temporary repairs only and cause a lot of problems later on. 4 gauge at the smallest, 2 is better. ( smaller gauge size is larger cable)

Sorry, but hot cables means you are CONDUCTING amps. It means LOW resistance.

The cables ( OR ANY WIRE ) will heat because they are carrying an amp load greater than its own resistance will allow.

Now, if you mean the cables have high resistance, then you have something. You see, the volts drop across the load, and the load is supposed to have all the resistance. So, if the load is the starter, then that is where the volts drop. However, if the load is the cable due to bad connection, or degraded conductors, then the volts drop on the cable ( and turn to heat ). Energy is never lost, it is merely converted to another form. Oh, and it takes energy to convert energy. Kind of a law of diminishing returns.

High resistance = low amps, and not hot cables.

Put a voltage meter on it and see what is happening. If the battery does not have 12V to begin with, then therin lies your problem. If the battery is dropping past ( I'd say 10 ) during crank, then it has a weak charge, else a bad cell. OR your starter is pulling too much current. You can also put the meter across the cable itself. If the cable is dropping more than about a half volt, then you have either excessive resistance in the cable, else excessive amp load.

I?E= bad Starter
No calculation required

Originally Posted by firebird77clone

Sorry, but hot cables means you are CONDUCTING amps. It means LOW resistance.

The cables ( OR ANY WIRE ) will heat because they are carrying an amp load greater than its own resistance will allow.

Now, if you mean the cables have high resistance, then you have something. You see, the volts drop across the load, and the load is supposed to have all the resistance. So, if the load is the starter, then that is where the volts drop. However, if the load is the cable due to bad connection, or degraded conductors, then the volts drop on the cable ( and turn to heat ). Energy is never lost, it is merely converted to another form. Oh, and it takes energy to convert energy. Kind of a law of diminishing returns.

High resistance = low amps, and not hot cables.

Put a voltage meter on it and see what is happening. If the battery does not have 12V to begin with, then therin lies your problem. If the battery is dropping past ( I'd say 10 ) during crank, then it has a weak charge, else a bad cell. OR your starter is pulling too much current. You can also put the meter across the cable itself. If the cable is dropping more than about a half volt, then you have either excessive resistance in the cable, else excessive amp load.

Too small of cables or poor connections make high resistance which causes heat. Low or no resistance is good conductivity and that is what you want. Your toaster makes toast because there is resistance in the heating element, not because there is a lack of resistance.

One thing I do believe in is giving someone with a basic question, basic information and not go off into all the technical razoo stuff until I am sure they understand the basics.

While you guys disagree about the resistance, my bet is, the battery wasn't fully charged to 100% before use, it's very important to fully charge a battery before putting it in the car especially if you are going to be starting the engine over and over again making adjustments.

Mike

"High resistance = low amps, and not hot cables." WEll...this is kinda correct...but not quite... High resistence thru a cable or connection will mean LOW voltage and there will be LOW amp flow...A Hot cable means whatever you are trying energize something it is drawing to many amps and the Voltage to this unit will be low.[starter] If the battery cables are too small they cannot carry to load and get warm.

So...make sure the cables are the correct size for your application. Insure that you have good connectiosn at the battery,starter relay and starter, Make sure your ground is clean and tight, Disconnect the coil wire andcrank the engine....if it cranks ok, the timing is set too high.

Originally Posted by Mike52

While you guys disagree about the resistance, my bet is, the battery wasn't fully charged to 100% before use, it's very important to fully charge a battery before putting it in the car especially if you are going to be starting the engine over and over again making adjustments.

Mike

I agree - my old '90 got a new battery, new solenoid and considered new cables before we changed the starter in the AutoZone lot one morning. Started fine at home, would not turn when I went back out. Starter "tested" good on their machine, but would not spin the engine.

Most of those machines only do a free running test on starters, not a loaded test, so many weak starters will check out good.
Once I rebuilt the engine in my Ford pickup. The starter worked fine on the tired engine but couldn't spin the fresh rebuild.

[QUOTE=moter;341414]"High resistance = low amps, and not hot cables." WEll...this is kinda correct...but not quite... High resistence thru a cable or connection will mean LOW voltage and there will be LOW amp flow...A Hot cable means whatever you are trying energize something it is drawing to many amps and the Voltage to this unit will be low.[starter] If the battery cables are too small they cannot carry to load and get warm.

Ok, I think I see what you are saying... high resistance cables will heat with low amps. Ok, that makes sense. And of course, since the voltage drop is across the cables then the voltage to the starter is low. AND since the circuit resistance is higher, then you have low amps.

If it started with old battery and old cables before, chances are problem is a ground or something in the starter(considering you do have a fully charged new battery). It could be cables, but my bet is one of the other two.

[QUOTE=firebird77clone;341440]

Originally Posted by moter

"High resistance = low amps, and not hot cables." WEll...this is kinda correct...but not quite... High resistence thru a cable or connection will mean LOW voltage and there will be LOW amp flow...A Hot cable means whatever you are trying energize something it is drawing to many amps and the Voltage to this unit will be low.[starter] If the battery cables are too small they cannot carry to load and get warm.

Ok, I think I see what you are saying... high resistance cables will heat with low amps. Ok, that makes sense. And of course, since the voltage drop is across the cables then the voltage to the starter is low. AND since the circuit resistance is higher, then you have low amps.

Think of it this way...If you have a confirmed good battery, and the starter cranks slow, it will be slow because of several things: Battery cables not correct for the application and CANNOT carry the load,Starter itself is defective and draws more amps than it is suppsed to. Poor connection on either cable. Anyways, as Amp draw goes UP the voltage will decrease...if there is too high of a load for the battery cables to handle they will get warm... Connect a volt/amp meter to your battery and start the car..when it first starts the volatge wil be lower than 14 volts and the amp reading will be higher than zero because the alternator is trying to bring the battery to full charge. As the battery becomes fully charged the AMP reading will go down and voltage up.

Bad starter will drain a good battery in a few minutes