How do you test (catch ) an intermittent parasitic load o...

How do you test (catch ) an intermittent parasitic load on a car battery?Battery is fully charged and is 3 days old. Battery passes the load test . Momentary steady state parasitic load, current drain, reverse leakage is 12.5 ma, ...

How do you test (catch ) an intermittent parasitic load on a car battery?Battery is fully charged and is 3 days old. Battery passes the load test . Momentary steady state parasitic load, current drain, reverse leakage is 12.5 ma, yet the battery goes down to 50% overnight. Mechanic's Assistant: Have you tested the battery with a voltmeter? And can you see if it's leaking or not? Yes, and it is not leaking Mechanic's Assistant: What is the make/model/year of your car? Agent Mechanic's Assistant: Are you fixing your vehicle yourself? What have you tried so far? 2002 Cadillac Deville DHS

Automotive Expert
Hello and welcome! My name is \*\*\*\*\* \*\*\*\*\* I can assist you with your question. I am a former master tech and I have worked in this field for 20 years. I specialize this type of problem you are experiencing so I am confident I can assist with this issue. I am sorry you are having this issue and I understand this can be frustrating so I will try my best to help. While we are working on this issue together, please allow up to 30 minutes (or more) between replies as I might be online helping other customers or offline spending time with family. Please understand I can only see what is on this page and what you have already shared with me. Please keep in mind, I don’t know the history of the vehicle and I don’t know your mechanical ability, however, I will try my best to help. The phone call prompts are automatic and are coming from the web site, not from me. If you would like to speak on the phone, please request a phone call on your end and I will call you right away. I am going to start by asking some basic questions to get up to caught up to where you are at with this situation so I can assist you in a timely manner. I appreciate your time and patience while we are working together on this issue. My goal is to provide you with a pleasant experience and ensure all of your questions are answered. Please reply back at anytime so I can fully answer or address any questions or concerns you may have. _Please download or save any documents or images I may send you as they will automatically expire after 7 days._ Can I start by getting your first name? Thank you

Automotive Expert
Thank you Dean. You are going to have to pinpoint what is drawing the battery down. There can be a few different ways to do this depending on the set up you have. The first way is simple. Disconnect the negative battery cable from the battery. Put a test light between the negative cable and the negative battery terminal or post on the battery. With the key out of the ignition switch and the vehicle just sitting there (make sure the doors are closed) the test light should not light up bright. If it does, there is a draw. Then you remove one fuse at a time until the test light goes out. When it does, you have found the circuit that the draw is on. From there we can pull a wiring diagram of that exact or specific circuit and check each component on that circuit one by one to determine the root cause. Sometimes the [alternator](/topics-alternator-cadillac/) can go bad as well causing this condition. Yes even if it is charging when the [engine](/topics-engine-cadillac/) is running it still can go bad draining the battery when the engine is turned off. You would need to disconnect the BIG wire from the back of the alternator to see if the draw goes away. If so, the alternator is the root cause of the battery draw and will need to be replaced. On newer vehicles one of the computers or modules may stay awake or powered up for some reason. They can do this for a number of reasons. Faulty/sticking relay, wiring issue, faulty or insufficient input (like a door switch) or the module itself may just be faulty and need to be replaced. You can also use a multi-meter to check current draw from the battery. Anything over 100 milliamps is too much draw. The way you locate this is to start removing fuses one at a time until the meter drops to normal level. This will be the circuit with something staying on. Determine what components are part of that circuit and check them individually until the problem is isolated. Here is a YouTube video explaining how to check for a battery draw. []( Glad I can help. Please let me know if you have any further questions. Thanks and have a great day!

intermittent parasitic load on a car batteryBattery is fully charged and is 3 days old. Battery passes the load test . Momentary steady state parasitic load, current drain, reverse leakage is 12.5 ma, yet the battery goes down to 50% overnight.Are you still there?
Automotive Expert
YES, I understand. You need to monitor the current draw on the battery at different times to determine when/if there is a draw

Ahhhh... were talking 48 hours here
Automotive Expert
Or you can use a meter that has the recording capability to do this for you so you don't have to stand by the vehicle the entire night to watch for this draw.

Now your talkingWho sells this kind of meter?
Automotive Expert
:). You are most welcome. Please let me know if you have any further questions. I recommend Fluke meters.

Fluke data logger is $3500.00 Can you recommend another lower cost solution?
Automotive Expert
The fluke meter I have was about $300, not $3,500. I do not know if any other company that makes a meter that has this feature but I am sure they are out there. You just need the record feature on the meter. You don't have to get a new one. You can even buy used. Here is one with the min/max record feature for much less. [\_BRCxARIsANMx4S5Vq231fR59o\_NmSVC\_QZUAtpxb-90M8zrKDDsRnbjnlDPHAQcAFyMaAkwHEALw\_wcB](

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