MGB BATTERY DRAIN

[rayjo]

I installed a new Lucas alternator in my 1979 MGB because car died on the road and when tested at auto parts store their tester showed ALTERNATOR FAILED)...also installed a new battery....since that install I have twice fully charged the battery but by the next day it is completely drained of power.

I have again charged it all day today but this time I disconnected the three wires going to the alternator thinking I may have hooked up the wires incorrectly. I will put a meter on the battery again in a few hours to see if it is again draining itself of power.

I am far from being a "mechanic" so am befuddled. Any thoughts?
Ray

 

[Basil]

Ray, you posted your question in our "Forum help" section. That is a forum set aside to ask questions specific to navigating this forum,
I am moving your question to the MG forum. I'll leaver a pointer" in the FORUM Help forum t redirect folks.

If you're reading this you are now in the MG forum.

Welcome aboard.

Basil

 

[NutmegCT]

Hi Ray - welcome to BCF.

First thing I'd do would be drive the MG back to the auto parts store. Explain what's happening, and have them test the new alternator, and the new battery. (They usually do that for free, and give you a printed report.) I'm betting either (1) you may have put the wiring on incorrectly, (2) the alternator is bad, or (3) the battery is bad and won't hold a charge.

Hope this helps.
Tom M.

 

[rayjo]

Hi Ray - welcome to BCF.

First thing I'd do would be drive the MG back to the auto parts store. Explain what's happening, and have them test the new alternator, and the new battery. (They usually do that for free, and give you a printed report.) I'm betting either (1) you may have put the wiring on incorrectly, (2) the alternator is bad, or (3) the battery is bad and won't hold a charge.

Hope this helps.
Tom M.

might it be voltage regulator tom?

 

[YakkoWarner]

I had a 1977 years ago - if I remember correctly the regulator was integral to the alternator in the later models (I had one fail and it sent 28 volts out and popped most of my lightbulbs one night - it required disassembling the alternator to replace).

How I would attack this problem would be to place an amp meter inline with the battery positive cable and directly measure for any current flow. If there is none, then likely the problem is internal leakdown within the battery (confim by leaving with positive cable detached - if its still dead the next day than nothing in the car is causing it). If there is current flow, then I'd start disconnecting components until the measured flow stops, that would give solid evidence to what is leaking down the stored power.

 

[rayjo]

finally figured it out...it was draining because I had the two smaller wires to incorrect terminals...switched them and now just fine. thanks

 

[NutmegCT]

 

[Ian Mckenzie]

finally figured it out...it was draining because I had the two smaller wires to incorrect terminals...switched them and now just fine. thanks

I'm glad that you have managed to find out the culprit to the problem. Good thing it's just the wrong terminal input.