Slow drain on electrical system

Good afternoon,

I attached a guide for you to follow for testing.

https://www.2carpros.com/articles/car-battery-dead-overnight

You will need to disconnect the negative cable and put a voltmeter in line. Red lead to the cable and black lead to the battery post.

Set your meter to DC amps and let it sit for 10 minutes.. Then check the reading. It should be 50 to 75 milliamps.

If it is more, then pull the fuses one by one until the draw comes down to normal.

Roy

Roy, thank you for your help. should I also remove relays to check them?

No, just the fuses until the draw drop down to specs.

Let me know which fuse so I can help further.

Roy

Roy, thanks for your help. Do you mean to hook my multimeter from negative post and negative terminal? And then set meter to 200 mili amps. And also do you know how many volts the stop start battery is supposed to have when I charge the main battery to 12.9v? thanks

You are welcome.

12.6 volts is a fully charged battery.

Remove the negative cable. Red lead from the meter to the battery post and the black lead to the cable.

Roy

Thanks Roy. right now I am checking out the ess battery. I have had the main battery on a 4 stage charger since Christmas still in the vehicle. It tests 12.9v. But the stop start battery only tests out 5.8v. could that battery be draining the main battery?

Yes, it could be trying to maintain a steady voltage. I doubt the battery is any good.

Roy

Thanks a lot. I am putting that battery on charge by itself just to see if it will hold a charge on its own.

Sounds like a plan.

Roy