Can An Alternator Cause A Parasitic Draw

Y'all walk out to your machine/truck, turn the primal, and you hear the glorious click-click noise. Overnight, y'all've had a battery drain, just you didn't leave the lights on. Who knows where the battery cables are, and you lot oasis't recharged your jump-box since the last camping ground trip. Yep, nosotros've all been there. Nosotros'll show y'all the unproblematic manner to find a parasitic battery drain; in other words, nosotros will find what has caused your dead battery.

Southwire Multimeter - 14090T

Ready to Amps DC – Pay Attention to Wire Leads

Tools Needed:

Multimeter – must have an Amp (DC) reading – at least 10 Amps (We used the Southwire 14090T)
8mm, 10mm, vii/16, or ane/2″ Wrench/Socket – to remove your battery terminal
Needle-nose pliers or Fuse-puller – for removing fuses from the fuse console/south
Goose egg-ties or small clamps

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What is a Parasitic Battery Drain?

It doesn't involve parasites in your battery, and so that'southward a proficient thing. No need for HazMat suits, still! A parasitic bombardment bleed is simply something that consistently and continually drains your bombardment. This could be a faulty relay, a headlight/dome-lite switch, alternator, or any other electrical gremlins. Taking your car to a mechanic with an "unknown" culprit tin can cost you big bucks also. Most mechanics don't enjoy diagnosing electrical problems.

How To Diagnose the Battery Drain

You should be able to diagnose your bombardment drain issue within a few minutes. An actress helper may assistance with this projection, only information technology'due south non needed. Continue in mind, depending upon your vehicle, yous probably have more than than one fuse panel. Most vehicles have at least one fuse panel under the hood, and some other inside the rider area. Some foreign cars accept multiple fuse panels inside, in different areas. You may want to check your owner'due south manual or check one of the forums.

Parasitic Battery Drain

Remove Negative Cable

Step 1: Remove Negative Battery Cable

Parasitic Battery Drain Neg Cable

Negative Cable Removed

Using the correct wrench or socket, remove the negative battery cable from the battery post. In our case, we were working on a 2000 Ford Explorer, then the battery terminal used an 8mm bolt. You can perform this exam/diagnostic by using the positive or negative cablevision, but using the negative is much safer. Grounding a negative wire to basis is not a problem; notwithstanding, grounding the positive could destroy electronics, including your multimeter.

Pace ii: Bank check the Draw Across the Negative Cable and Battery Post

Turn on your multimeter and select the Amps (A) and brand sure it's set for DC (Direct Current). Y'all should run across a symbol like a solid line, with dashes underneath. You Don't desire AC (~), this is for your abode's electrical. Yous will probably take the option for Amps or mA (milliamps), and then cull the Amps to get-go with, preferably 10A or 20A. Make sure your wire leads are in the correct location, on the multimeter. There should exist a diagram on the multimeter, showing you lot where to put the test atomic number 82 wires.

Southwire Multimeter Test Leads

You're going to exist putting your multimeter in series of the battery drain or electric current draw. This means the current draw will be passing through the multimeter. In our example, we had a 4.4 Amp draw, so that ability was flowing through the multimeter. Exist sure your leads and dial are in their correct locations.

Parasitic Drain Zip Tie Leads

Identify one of the wire leads from the multimeter (information technology doesn't affair which i) on the negative battery post and the other on the asunder battery cable. You lot should see the multimeter display the number of Amps that are actively causing your battery drain. Utilize zip ties or pocket-sized clamps to keep the multimeter leads connected to the bombardment final and battery wire.

Tip: A normal operating vehicle will have about 50 milliamps of Amp describe on the battery.

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Step three: Remove and Supercede Fuses

Start with your underhood fuse console. Make sure that y'all can see your multimeter while you lot pull fuses. Use your needle-olfactory organ pliers or a fuse puller to remove and replace fuses, until you meet the Amps on the multimeter drop. Be careful that each fuse goes back into the correct location.

Parasitic Drain - Remove Fuses

Remove Fuses

If you get through all your underhood fuses, then move into the inside fuse panels. This is where an actress person tin help, they can monitor the multimeter while yous pull fuses. If you lot don't take help, the leads on the multimeter should be long enough for you to place the multimeter face up-down on the windshield.

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Stride four: Isolate and Fix the Consequence

Once yous pull the fuse that is the culprit, so you can fix the issue. In our case, it was the Alternator/Voltage Regulator that was pulling more than 4 Amps continually, which turned out to be a faulty alternator. In one case nosotros removed this 30A fuse, the Amp draw dropped to 0.ii Amps, which is still more than typical. We besides found a secondary draw with the Interior lamps relay/switch. Removing both fuses dropped our Amp depict downwards to most nothing.

We replaced our alternator, and we'll supercede the interior switch some other time.

Fix Battery Drain - Issue Found

Step five: Replace Negative Bombardment Cablevision

At present that you have the issue/s fixed, you lot can remove the zip-ties/clamps from the multimeter leads and supersede your negative battery cable. You should be good to get, and your parasitic battery drain has at present been fixed.