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Something draining my battery while running?

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chuck1006

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My 59' BN6 starts up strong after sitting overnight but when driving and stopping a short time it revs slow and finally starts but only after about 4-5 seconds. What could be draining the battery while driving?
Facts:
New wiring harness installed.
Same generator that came with it.
I switched it to positave ground.
I installed an after market Stereo/CD...got to have my Jazz! It is tied to the ignition switch so should be OK when off.
Battery was purchased a while ago but hasn't been used that much plus it harges on itsown after a while.
Have a Petronix ignition.
I think that is all the pertinent info so please advise.

Thanks
 
Just a guess. The battery may not be draining. The starter may have a heat related defect which is causing more than normal starting current to be drawn.
D
 
With the old generator the aftermarket jukebox might be pulling down the battery. If it starts slow even after a drive without the tunes I would suspect the starter also. Just my personel preference but a nicely tuned big Healey with a good exhaust system makes all the music I need. Skip
 
Thanks Dave and Skip,
I will try a test run without the jutebox on but the short hop I made yesterday was only a mile away so, I would guess Dave might be right although it was only 80 degress here. Any instructions on rebuilding a starter?
Thanks Again
 
Chuck,
In all of this I am assuming that the battery really is good & is being properly charged as you say.

I recently changed to a negative ground. I haven't really investigated why?, but I had several problems with electrical contacts failing after the conversion. Maybe something about electrical contacts & polarity. I spent quite a while cleaning & adjusting the turn signal relay before it worked again. Same with a couple of bulbs.

While we are on the subject, I hope you know that some of the newer SU fuel pumps are polarity sensitive. If the pump has an arc suppression diode instead of a capacitor, reversing the polarity will cause the diode to fail. No immediate problem, but the pump contacts will fail in a much shorter than normal time.

A good local rebuilder should be able to handle the starter & testing. Check around for someone familiar with Lucas. One of the common problems is for the starter end bushing to wear to the point where the armature drags on the field poles. This drag causes much higher than normal current to be drawn. I have no idea if the starter problem is related to the polarity reversal or just a coincidence.
Good luck,
D
 
I had a very similar problem. Car starts fine. Drive to restaurant to pick up pizza. Not enough juice in the battery to restart car to take it home.
The mechanic who works on my car diagnosed a defective voltage regulator. Installed a new one and the problem was solved. Always get the pizza home now.
jim
 
Chuck: When you changed the polarity of the generator, did you flash the field windings? If not, sometimes the generator gets confused about what it is supposed to do and may be draining the battery on its own. AL Bradley
 
Thanks for all the input.
I have a new later model fuel pump and it is for negative ground.
When I converted to negative I did the generator flash.
I will check the voltage regulator.
Anyone have test procedures for it? I will check my book but it never hurts to ask.
 
[ QUOTE ]
Thanks for all the input.
I have a new later model fuel pump and it is for negative ground.
When I converted to negative I did the generator flash.
I will check the voltage regulator.
Anyone have test procedures for it? I will check my book but it never hurts to ask.

[/ QUOTE ]

Chuck,

I had a similar problem which I eventually traced to the battery isolator switch - it was fine cold, but would get worse when the car was used for a bit. When I dismantled it the copper studs had worn down so they were no longer just proud of the base moulding - I could just have packed them back up again with washers but I actually fitted a replacement switch and all the 'warm' starter problems vanished.

/ubbthreads/images/graemlins/england.gif
 
Hi Chuck, It is a very common case that the voltaage regulator will act up when the ground system is changed from one polarity to the other, This is particularly problemsome when the voltage regulator has been in use for a significant length of time .Cleaning the points as defined in the shop manual sometimes puts them right,but if it is an old one generally peace of mind requires its replacement.-Fwiw---Keoke /ubbthreads/images/graemlins/patriot.gif
 
I would have to agree with Keoke. I had a 67 Chevy that would every six months or so exibit similar symptoms, even without the polarity change. Replacing the regulator always cleared it up. Right up until I replaced the generator with an alternator and did away with the regulator all together.
 
It sounds like either a mechanical(starter) or electrical(fill in the many possibilities)problem.This might be an easy elimination of the starter without pulling it for a bench check: Take an EXTRA fully charged battery in the trunk. Get the car hot. Start the car/drive more until your problem exists. Quickly change batterys and re-test...if the problem is a dragging starter, the new battery won't make any difference. If the problem is electrical, the (new)battery will "fix" the symptoms for a short period, then they will reappear. Good luck.
 
Hey guys methinks I have the solution, as you know I have just finished the running chassis on my car. I have a new alternator, new battery cutoff switch and new wiring harness. The only thing I have not done yet is to rewire the voltage regulator for the alternator. I went to the shop this evening to run new fuel lines and the battery was dead as a stone. The only thing I can think of is the old voltage regulator and it was a positive ground regulator before I changed everything over. Just my idea. Skip
 
Hello Chuck. There's an old mechanics trick in testing the voltage regulator. With the car in the garage, or outside in the dark, turn on the headlights. Step on the gas slowly and watch the brightness of the headlights. They should get brighter if the voltage regulator is working properly. Let off of the gas and they should be somewhat dimmer. May not be the answer to your problem, but fun to try anyway.
 
/ubbthreads/images/graemlins/shocked.gif Skip, what kind of an alternator do you have that requires an external regulator??-Keoke /ubbthreads/images/graemlins/devilgrin.gif
 
[ QUOTE ]
The only thing I have not done yet is to rewire the voltage regulator for the alternator. I went to the shop this evening to run new fuel lines and the battery was dead as a stone.

[/ QUOTE ]
Hi Skip,
It's not clear to me if you just added the alternator for the first time without rewiring the regulator. All modern alternators that I know of are internally regulated. If so, there are several wiring modifications that you have to make on the old "regulator" before connecting the alternator. There are several methods of modifying the regulator ranging from moving wires around externally to gutting the old regulator box & using it as a wiring connection point. If the old cutout relay in the regulator doesn't open when the engine is shut off, it will keep the red lamp on & discharge the battery. I gave you a couple of references in your other recent post on the subject. I can only speculate on what would happen if you left the regulator wiring the same as original & connected the alternator.
D
 
Sorry guys I gave the wrong impression. I have a Delco single wire alternator. The rewiring I was talking about was to install the gutted regulator and remove the one that was on the car now. I hadn1t had a chance to remove the good regulator and install the gutted one and I can only figure that the regulator drained the battery.
 
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