Going to look at a good friend's car this week to help him out, but electrical systems are not my forte He has a mid 60's car that is "based on the Falcon platform" that is constantly losing power- I'm guessing either a bad alternator or voltage regulator, but what else should I look for?
Mac,my old flathead powered deuce sedan was giving me fit's and acting like that, it would quit running every now and then,no rhyme or reason,I finally found a bad wire connection from the coil was the culprit. Make sure you that your ohm meter and check wires for continuity.HRP
If it sparks you have a draw(hooking the battery up in the dark). A draw will deaden the battery. Hook a test light in between the negative battery terminal and the negative battery cable. If the test light illuminates, something is draining the battery. Disconnect fuses until the light goes out. When the light goes out there is the problem circuit. Also do this with the alternator(disconnect) as there is a possibility that the diodes in the alternator are shorting.
I suppose I didn't comprehend the question,does your friend have a radio or any accessories that are wired with a memory? they can drain a older battery pretty quick,it could also be the alternator not charging at it maximum output. HRP
Far as I know it's bone stock, so no aftermarket radio, etc. 41hemi, that helps ALOT! Running high on the ignorance meter, but can I just wire a 12 volt bulb, or do I need something more?
Mac, that is a good method, you're looking for 'stray' current loss. The basic auto electric theory (~12 Volts DC) is good to read thru. A test light is a first tool, later you'll find a Volt-Ohm-Current meter worth its weight in gold.
Yes sir a regular bulb will work for you. I've found many short circuits this way. This method is only good for our older cars that don't have all the computer stuff in them.
....also check all of your ground wires...make sure they are clean and tight (you will have to take them apart to check). batt to engine, engine to body, regulator to body
If you suspect the battery, alt, regulator, you should check those first to eliminate them from the equation. A simple volt meter on a fully charged battery should read 12.3 volts. If not replace the battery. Start the engine, the volt meter should now read 14 volts. If not the alt or regulator is bad. I'm an old Chevy guy & I haven't had to mess with regulators in a long time, so your going to have to do a search to learn how to troubleshoot the reg. Once the front end of the system is operating properly you can continue checking the circuits.
My daily does the same goddam thing, and what is REALLY driving me nuts, I checked for key-off parasitic draw with a multi-meter, it showed .12 milliamps, which is virtually nil! It had a large diameter alternator pulley, and with the od, I noticed it wasn't spinning fast enough to charge unless I was on the freeway, so I swapped alternators, didn't make a hill of beans of difference. One day, I got really pissed and pulled and re-did all the under-hood grounds. prior to that it had killed two batteries just sitting, a red-top and a Costco, and I am talking days here, not months. I actually thought I had fixed it, had the red-top back in it, started a few times no problem, then the other day, I went to move it, dead battery AGAIN!! this time, after about 5 days.
Fwiw I just went through 2 new redtops before I got one that would live. .Sudden and complete death on both with no warning. 3rd one was the charm.
Well my first reaction after swapping alternators was to blame the redtop, went out and bought a new Costco battery, it did exactly the same thing.
Batteries can and will sometimes get a bad cell.this happens when particles of lead in that cell,fall to the bottom of the case.finally building up enough to short the cell..6 V battieris= three cells...12V= 6 cells....only take one cell to go bad to drain a battery,,,and NO test will reveal it.Can drain a battery over night,,,but seldom when the gen or alt is running. Back in older days,there were battery rebuilders that could change out a bad cell. and sometimes just emptying the electrolite,washing out the cells,along with the lead deposits, with clean water,drain again and refill with new electrolite...
Just another reason why I love the HAMB! Thanks for all the help- will pick up a test light this week.
Mac If you've got a Harbor Freight near you, go buy an Ohm meter. Less than 10 bucks. It'll serve you well for a lot of other things too
Alternator is supposed to put out dc. Check it for ac output also. Should have no ac output or the regulator is shot. Charge the battery and let it sit overnight not hooked to anything. If voltage drops overnight there is a internal battery problem.
Mac; I've bought from Newark, and they have a good variety of tools to choose from. Fluke meters are pro-level, there are lower cost Volt-Ohm-Meters out there as well. http://www.newark.com/fluke
electrical gremlins can be tough to find - good ideas above. charge battery, disconnect alternator primary wire and let set overnite. see if any change next day. my mid 60's OT ride just needed a new voltage regulator.
We fought one of my student's trucks that would kill the battery in about 3 hours in the auto shop class I taught about 30 years ago and it ended up being a damp and dirty battery top that was letting the power drain right across the top of the battery. Take the volt meter and hook the + cable to the + post and take the neg cable/wire and touch around on top of the battery to see if you get a reading. We were reading over 9 volts on that one in some spots on the top of the battery. We cleaned it off and no more problem and I've seen several since that had milder draws on them. I thought I had a bad battery in an ot truck that I bought a while back and instead it had a bad connection in the charging system that would sometimes make connection and sometimes not and got to more often not than working. I had to bypass a previous owner's not so stellar rewire job to get that to work and still have to go back and repair the harness or replace part of it. Still eliminating possible causes from the equation is probably the best thing, A clean fully charged battery that tests good, an alternator or generator that tests good and good battery and ground cables for a start and then go from there with the troubleshooting. The craziest one was in a Lincoln that I worked on in a dealership that I worked in one summer while teaching. It would run the battery dead sitting on the lot and they would charge it and it went dead again. While working on it in the shop I was on my back on the floor under the dash and a bright light hit me in the face. one of the reading spot lights next to the dome light had been turned on by someone getting in the car on the lot and it was running the battery down.
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