Battery issues

[occruiser]

I’m hoping you folks could point me in the right direction. I have a stock, 6/72 40 and I’ve been having battery drain issues for the past few weeks. I’m usually able to jump start the battery and run without issues. Anything over 3-4 days and the battery goes completely dead, jump start is not an option. Once running, I had no issues.

Last night I was running and I started to notice my lights dim and hesitation. I pulled over and dead. No power, just a click. Tried to jump start and zero. I jump started and finally charged enough to limp home.

I’ve used the search to find a similar thread but didn’t find anything with similar symptoms. In my experience, (unless I’m completely wrong) once the engine is started, even if the battery was low, the running engine should help recharge and maintain. Any thoughts on where I should start my problem search?

I’ve checked all my engine bay wiring and grounds are good. I have not changed or modified anything. The battery is brand new.

 

[pb4ugo]

Charge the battery and have it load tested to see if its good. Check the charging system while its running and see if it's charging.

 

[charliemeyer007]

Three issues. Battery is bad - they are crap these days - load test it.
Alternator isn't putting out or the voltage regulator is bad - test them with a VOM.
You have a weak short in the system. The battery is draining through some circuit. Some switch has crap built up in side and electricity is leaking - ignition, head light, brake pedal, wiper.... and the voltage regulator. Some wire is rubbing threw. The back of the use box is corroded and conducting. Any plug could be corroded.

Take your battery ground cable off when not running until you find the problem - you drain a lead acid battery flat a few times it will be junk soon.

So a few weeks ago, I backing home. Get to my spot, mash in on the clutch and switch off the key - The engine keeps running - that's new. Never done that before in the 44 years I have owned it. Leave key off, put it in neutral - engine stops. I haven't done anything with lights in years. Mice, corrosion, bad wire switch? I'll fix it in the spring. I don't leave it in reverse and the battery stays charged.

 

[Gotta40]

if it died while driving, the alt might not be working right. a bad diode in the alt can drain the batt.

 

[occruiser]

The battery was tested and came back good. It was under warranty so they gave me a new one anyway.

Thank you all for the responses. I'll start behind the dash and work my way down The rabbit hole. I'll keep you updated.

 

[pb4ugo]

Do you have a Voltmeter or Multimeter? If you don't, buy a multimeter, or take the vehicle to the auto parts store and have them check to see if your alternator is charging. Check to see if the vehicle has a short and is draining the battery, as @charliemeyer007 mentioned.

 

[occruiser]

Do you have a Voltmeter or Multimeter? If you don't, buy a multimeter, or take the vehicle to the auto parts store and have them check to see if your alternator is charging. Check to see if the vehicle has a short and is draining the battery, as @charliemeyer007 mentioned.

Just bought one. I’ll report back with the results tomorrow.

 

[WarDamnEagle]

Check to see if the vehicle has a short and is draining the battery, as @charliemeyer007 mentioned.

How do you do that? Maybe with an amp meter in line with the positive or negative in line with the main battery terminals? Seriously just curious.

Only suggestion I have is to check the battery terminal voltage while running. It should be 14v +/- 3 or 4 volts.

 

[pb4ugo]

1st I disconnect the battery and check and note its voltage. Reconnect the positive lead, connect the red meter lead to the negative cable and the black lead to the negative post of the battery. You've completed the circuit. You probably will see a ever slight voltage from a clock, radio or something. If you get a larger voltage reading, that is the your voltage loss from the short. Start pulling fuses until the voltage drops and ID's the offending circuit.

Edited. For correction.

 

[WarDamnEagle]

1st I disconnect the battery and check and note its voltage. Reconnect the positive lead, connect the red meter lead to the negative cable and the black lead to the negative post of the battery. You've completed the circuit. Check and compare voltages. You probably will see a slight draw from a clock, radio or something. . If there's a noticeable difference in the 2 readings start pulling fuses to ID the offending circuit.

I could be wrong but I am pretty sure a voltmeter will measure zero volts in line with one leg of the battery terminal. You would need an amp meter to see if there is any current draw.

 

[george_tlc]

Measuring current, especially if you think there's high drain, is best done with a DC current clamp meter. With that you can clamp various wire feeds and determine what is drawing higher current.

Something like the UNI-T UT210E has decent low current capability for checking parasitic draw etc. No risk of blowing the fuse of your multimeter (on the amp range).

You do have to be careful in your setup for low current measurements. You need to zero the clamp meter (clamped closed on nothing) and then you need to not move the meter out of the plane you zeroed, since the earth's magnetic field and other stray magnetism can affect the hall sensor reading. Done right you can resolve/measure to a few mA.

cheers,
george.

 

[rlong]

With a meter that measures milliamperes the proper test procedure is described below.

How to Find Parasitic Battery Drain with a Multimeter | Fluke

Follow this step-by-step guide to find parasitic battery drain with an automotive multimeter. Includes tips and best practices.

www.fluke.com

 

[CloudForestCruise]

Charging a completely dead battery, too many times, with the alternator can burn out the diode and even overheat and burn out the windings. An alternator is designed to maintain a charged battery not to recharge a dead one. If you were driving and the lights dimmed and then the car shut off, this is textbook bad alternator.

There are probably better ways to do it, but here is how I've tracked down a parasitic load with a test light. It works for these old classics best. With the car off and key removed, bridge the fuse panel contacts, one at a time, with the test light. If the bulb lights, you have a draw...the brighter the light, the bigger the draw. This will only test for a draw on the main harness. If you don't find it, look in the engine bay for wires hacked in before the fuse panel. I like this method because, in a 50 years old vehicle, you are likely to have more than one and by testing at the panel, you are where you need to be to trace the wire back to find the damage.

For 2 weeks I've been pulling out old wire hacks and repairing damaged wires.

 

[brian]

For a completely flat or damn near flat battery, it's best to hit it with a charger for a few hours rather than trying to get the alternator to fully charge it.

 

[pb4ugo]

I could be wrong but I am pretty sure a voltmeter will measure zero volts in line with one leg of the battery terminal. You would need an amp meter to see if there is any current draw.

I corrected my previous post and wanted to correct and clarify here to. Your right the voltmeter will be close to zero volts with no short.
It's been years since I've had to track down a short or parasitic draw. I wanted to do some testing b4 i responded. As I mentioned b4. Disconnect the negative battery lead, connect the meters red lead to the -batt cable end and the black lead to the negative batt terminal. If the reading extremely low or nonexistent then there's no short other than a clock, radio, old wiring, etc. You'll likely see some extremely low #'s. A higher volt reading indicates a short or draw or something is on. The # is how much voltage the short is taking.

 

[WarDamnEagle]

I corrected my previous post and wanted to correct and clarify here to. Your right the voltmeter will be close to zero volts with no short.
It's been years since I've had to track down a short or parasitic draw. I wanted to do some testing b4 i responded. As I mentioned b4. Disconnect the negative battery lead, connect the meters red lead to the -batt cable end and the black lead to the negative batt terminal. If the reading extremely low or nonexistent then there's no short other than a clock, radio, old wiring, etc. You'll likely see some extremely low #'s. A higher volt reading indicates a short or draw or something is on. The # is how much voltage the short is taking.

Sincere apologies in advance but I still think you’re confusing volts with amps.

 

[pb4ugo]

Nope, check it out yourself. A draw is putting a load on a circuit like a light bulb or a radio. Hook up a voltmeter as I mentioned. Take a reading with nothing on, then turn something on and see what you get.

 

[fjwagon]

I forgot that you have a 72, not sure if you still have the external voltage regulator. The OEM shows you how to check it. It also shows how to make adjustments to it.

 

[WarDamnEagle]

Nope, check it out yourself. A draw is putting a load on a circuit like a light bulb or a radio. Hook up a voltmeter as I mentioned. Take a reading with nothing on, then turn something on and see what you get.

This discussion is apparently about terminology if nothing else. Please read the Fluke procedure above as posted by @rlong. You have to use an amp meter, not a voltmeter. I have a Fluke 179 which is a multimeter and it has to be set to DC Amps, not Volts. If you have it set to amps then your procedure works. If it's set to Volts you get nothing. A "draw" or "load" on a circuit is measured in Amps, not Volts.

 

[pb4ugo]

This discussion is apparently about terminology if nothing else. Please read the Fluke procedure above as posted by @rlong. You have to use an amp meter, not a voltmeter. I have a Fluke 179 which is a multimeter and it has to be set to DC Amps, not Volts. If you have it set to amps then your procedure works. If it's set to Volts you get nothing. A "draw" or "load" on a circuit is measured in Amps, not Volts.

This is not about terminology or confusion, it's about a different approach. I'm familiar with the testing procedures Fluke describes and have tested that way also. The Fluke instructions say <50 mA is normal, that means Volts are present too. I dont think you can have one without the other. I usually avoid multimeters, they're a pita to use. I prefer a test light, they're quick and easy for electrical issues. Using a test light as @fjwagon mentioned is no different than using a voltmeter the same way. In the pic below you'll notice it is impossible to switch the my meter to Amps. It's set up as i described in an earlier post, the meter is reading 6.32 Volts because the radio is on. I wire my radio to the hot side of the fuse box. If I turn if off and turn the ING on I get 10.5 Volts. With nothing on I get .19 Volts, which could be attributed to the radio and clock. I dont think you would ever get to 0 volts. I think that would indicate an open circuit. I was taught this way decades ago and it stuck with me. Its quick and easy if I have to use a meter.