Calling all experts...

[dewbers]

Ok guys, I need help. My mechanic has been trying to find the source of the power "drainer" in my car. Battery is brand new. Alternator has been check and it's functioning properly. My guy is going to check the regulator today. I'm just thinking I'd ask you all to see if anyone has any thoughts...

Background - 72 Centurion ragtop. Stock with the exception of the tires and we added a radio/cd player to the glove box. Oh yea, added dual exhaust as well. So the car is basically as she was 38 years ago. Ran like a champ when she entered the garage in November. Started it a few times over the winter, but it would never hold a charge. Still won't. My mechanic says it's producing too many amps. I think he said it was tossing out 17 to 18 and it should only be producing 13 or 14? Do I have the numbers right? Anyway, a bunch of you have way more experience than I do... Any help is appreciated.

[73 Centurion]

Hi Dewbers,

There are 2 most likely possibilities.
1) If the alternator is charging the battery too quickly (too many amps) the plates in the battery will buckle and short out. Draining a battery too quickly can do the same thing. If this is the problem the battery will not hold a charge even if it's out of the car. If you disconnect the battery, put it on a charger you can see if it holds a charge. If it does the battery is OK and the problem is elsewhere.

2) If the battery is OK something is draining it. One way to check for power drainers is to put an amp gauge between the positive cable and the battery. With the key off it will show you if the battery is being discharded. A little bit of discharge is to be expected for the memory in your radio but that's so small it probably won't show. If you see a drain you know there's a problem. You can then begin removing fuses 1 at a time and see when the drain stops. That's the circuit to investigate.

I use a motorcycle trickle charger on my batteries. They are good at maintaining a battery but will take a long time to charge a flat battery. I like them because they come with leads you can permanently attach to the battery with a weatherproof connector. I leave the connector behind the grill so I can reach it (from under the bumper) without opening the hood. This makes it simple to connect or disconnect the charger. Just be sure it is diconnected before you try to start the engine.

Let us know what you find.

John
John

[centurion 455 ragtop]

John seems to have a good starting point I would start there first. With my 70 GS and 73 Centurion I switched a while back to a one wire alternator with an internal regulator eliminating the external one. But start with the above post. It may very well be the external regulator.

[Centurion717273]

I simple thing to check for is to make sure the trunk light is going off when closed, and the glove box light is going off when closed - these all to often end up being the problem with draining batteries

[Robroy]

Stewe,
What John suggests as part 2 in post #2 is a very effective way of troubleshooting for your kind of problem; I’ve used it myself on a BMW that ate batteries.

If you use the car rather seldom, you could also install a battery disconnector.
That would not solve the rot cause to your problem though.
With that you can very easily disconnect the battery when the car is not used and that way prevent draining the battery.
It will also prevent any short-circuiting when the car is in the garage, or if it happens when driving you can very quickly cut the power. After all our cars is almost 40 years old.
They have the kind that is very easy to install directly on the battery + connector
Backside would be that the radio will loose its memory and the clock (if it works) will be wrong every time the power been off

[dewbers]

Ok, so here's where we are... The car is up and running and purring like a kitten!
1. replaced master cylinder - all ok with brakes.
2. voltage regulator was burned up - replaced - all reading are perfect
3. points burned up b/c of voltage regulator - replaced
4. tuned her up, changed fluids, etc...
5. fluffed and buffed her to a mirrored shine!

Really surprised all this went south as she sat for the winter. Just proves these lovely ladies don't like to be "away" for any length of time. Seems the more I drive her and give her attention, the better she responds!

Bottom line.. she is really running great!! :laugh: She is looking great!! :p
I was looking like this all weekend! :cool:

[Smartin]

Isn't it weird how all the problems present themselves when the car isn't driven? I think most of us experience that same issue...

Great to hear the BBB (Big Black Buick) is running well!