Battery slowly draining despite new alternator

[Jacobvarnum]

So for a while now I’ve been having this issue with the charging system. The car died on me at work one day along with the tach going out, so I replaced the alternator and battery and drove it home, but the tach still wasn’t working. on the way to work the next day, the lights started flickering, battery light slowly came on and then it died on me. Only clicking when I tried to start it. I can charge the battery to 100% and it’ll drive fine for a few days but then the lights will start flickering and then the battery light will come on and then it’ll shut off.
I’ve replaced the alternator 2 times now thinking maybe I got a dud on a rebuilt one, and ive tried putting new battery ends on the cables, But nothing seems to help. The only “recent” work I’ve had done was a starter I got done at a shop.
Any advice or suggestions are greatly appreciated, thank you in advance

 

[Texas Marauder]

What is the charging volts at idle with the lights, A/C blower on high and rear defrost on? Same at 2000 rpm.

It sounds like you got another bad alternator or a wiring problem. Did they bench test the old one and the new one? Rebuild quality has really gone down in the last few years.

 

[luigisho]

Obviously start with the recent work for correct voltage, operation etc. Then start looking for a short somewhere. There are strategies on how to methodically do this online and probably on this forum. I hate chasing electrical bugs. Made me get rid of my last low mile SHO.

 

[ScotSHO]

Most likely:
Like Texas asked, what is the voltage at idle? Should be close to 14 volts. If you have a slow drain it will pull the battery down, but if you can start the car a ~30 minute drive should recharge it. Maybe 5 min short drives are not recharging it, and you do have a slow drain when off.

Separate train of thought:
What is the resistance measurement between the alternator heavy wire and the positive terminal wire, when disconnected from the battery and alternator? Should be <=0.3 ohms. If higher than that, I start suspecting corroded large conductors. Both positive & negative large wires running from the battery, to the solenoid, and to the starter should be replaced.

 

[Texas Marauder]

ive tried putting new battery ends on the cables

This may also be a problem. Did you use proper crimped terminals or temporary repair terminals, example below? If it's not a problem now, it will be in the future.

 

[Jacobvarnum]

thank you everybody for the replies!

The voltage the first time I got it checked (at Les Schwab) was around 12.5 which prompted me to install another rebuilt alternator. I drove it across town, maybe 2 miles back to Les Schwab and it was around 14, so I thought it was fixed. Then I drove it to work the next day, which is a 30-40 minute drive each way, and on my way home, same thing happened again with the lights dimming and battery light etc.

 

[Jacobvarnum]

This may also be a problem. Did you use proper crimped terminals or temporary repair terminals, example below? If it's not a problem now, it will be in the future.

View attachment 97689

I used this exact terminal pictured here