Relay SWITCH

[walzy]

Hello,  I am hoping someone can tell me if a relay switch can cause enough of a short to keep the battery from charging. I have a 1970 charger that will not keep a charge. With the car running I can not take the negative cable off the battery and the car continue to run. When I start to put the cable back on I can hear what I am taking to be a relay click. The alternator and voltage regulator is brand new. The previous owner put on after market guages as the cluster needs restoration so I'm not sure where to start. Any help will be most appreciated. Thanks

Kevin

[Rolling_Thunder]

if you can not take the battery cable off while the engine is running - if it stalls at that point the alternator is not charging at all -  make sure the ALT wiring is done correctly -

[70 Charger RT]

You should not have any voltage draw when everything in your car is turned off.  I.e. you should not have any sparks when touching the batt cable to the post.  One way to check also is to put an ammeter in series between the post and the batt cable.  What I would do is attach an ammeter as I've stated and then, one by one pull each fuse in the fuse box.  When your ammeter reads zero, you've found the circuit where the draw is.  You then need to trace that wire back until you find where the problem is.  You could a wire crossed or something not wired correctly.  70 Registry site has a good wiring diagram to follow as well.

A short answer to your question is Yes, a relay that is energized with the key off can drain your battery.

[71 SE3834V]

You shouldn't remove the neg cable w/the engine running as a means for testing. From what I was taught back in school and everything I've heard/read since it will blow out your regulator. Was fine to do back in the generator days but not now w/the use of diodes. Get a voltmeter for testing. They are cheap, sometimes free w/purchase at Harbor Freight. From what I was told from a friend, who used alot of testing meters in the course of his job, he tested one of their cheap ones up against an expensive one and it was just as accurate.

[Hard Charger]

You can also look at as you are not charging the battery. the battery runs down and dies.

the cause can be many things. including a dead relay.