How To Check If Alternator Is Draining Battery

Went out tonight and the car was pitch black, AGAIN. Failing alternators can drain batteries, leading to their inevitable death. On the way back popped in to Harbor Freight to pick up a trickle charger for $5. Hi wonder if anyone can help. Kudos too on getting your money back. As far as checking for a drain on the system, I have an ammeter that I put inline between the positive on the battery and the cable. But I don't see any reason to think that's true in your case My experience: Really bad battery, Good alternator = You jumpstart the car and can drive wherever mostly fine, if it dies on you you need another jump start. I'm sure others will have more ideas/advice. The battery should have 12 volts or higher with no load on it (ignition and lights off). If you can't test the battery, try jump-starting. I think once you put the new alternator on everything will be ok. Doing this would allow you to check whether the alternator is putting out enough current to run the vehicle. Tools needed: Multimeter. also check the fusible link on that red lead going to the battery circuit. So, you’ll want to check for the below signs to determine if it’s just the battery or if it’s the. My Onan 5500 gas generator doesn't have an alternator and I trickle charge the batteries in the trailer for the winch and generator with the tow vehicle. Disconnect one lead of the battery and wire it in series. Once a battery is drained, it doesn't hold a charge as well and is easier to drain down. Recon alternator. Doing this would allow you to check whether the alternator is putting out enough current to run the vehicle. Both are worth investigation. We take care of our cars and are diligent with service, but accidentally leaving an interior light on overnight creates a big headache the next morning. If the engine cuts off, it is a sure sign that the alternator has died. Probably what I'd do is take the battery in for a load test. Well then, there is something electrical in your vehicle that is draining your battery and that is what we call a parasitic battery draw. Battery or alternator? Hiya Just trying to leave work this evening, but when trying to start my car there was a tiny amount of charge left in the battery (clock and central locking still worked etc), but as soon as I turned the ignition the clock went off, and there was nothing from the engine. Check the Battery - A fresh battery should produce slightly more than 12 volts -- up to 12. As a rule, a three-phase alternator can operate with only one of the stator windings operational, although it's only one-third as efficient. Once the battery is charged and you have the car running it's time to check your alternator. Few days ago almost same thing happened to me and I know very well that my Battery is okay and rewire said alternator is also okay THEN WHY THIS PROBLEM, it was later we discovered it was ordinary car charger directly plugged at the back seat that is draining the battery. If your battery is drained, it will not run the important electrical systems in your car. Since it is a 1965 model, it should be a 12-volt system with an alternator. The headlight test is quick and easy, and should be performed outdoors to ensure that you don't have a carbon monoxide buildup inside your garage. I have asked a couple of auto sparkies about this question- why doesn't the alternator pump out 55Amps when both or one battery is dead flat. Get a DMM that measures AMPs in DC current. Both should ideally be above 10. Took it to the shop can find nothing wrong with battery alternator and or belts. Jump-start the car, remove the jumper cables, let the car run, and wait. The battery should be kept clean. Likewise check for a voltage between the battery -ve and grounding point on the engine. 8 volt range, depending on the ambient temperature and how recently the battery was used or charged. Check for any leakage if you have older lead acid battery. Then take your voltmeter and attach it across the battery terminals (red to + and black to -). On a car with an alternator and no drains a typical analogue meter will show about 6v, which is the microscopic leakage of the diodes, and unplugging the alternator will drop that to zero. had alt and battery both tested and both were bad. Tools needed: Multimeter. To check an alternator, pop your vehicle's hood and hook up a voltmeter to the car's battery by connecting the red lead to the positive terminal and the black lead to the negative terminal. One day i went to start it up, and nothing. Check to make sure not burnt out. Start the engine and run at around 2000rpm whilst monitoring battery voltage which should have increased slightly if the alternator is charging the battery. Re: Honda Odyssey Battery (draining) question. Battery or alternator? Hiya Just trying to leave work this evening, but when trying to start my car there was a tiny amount of charge left in the battery (clock and central locking still worked etc), but as soon as I turned the ignition the clock went off, and there was nothing from the engine. It can create a. What can be draining my batteries?. Most part stores can test an alternator. If the car starts right away, your problem is most likely a dead battery. I have a Misubishi Canter, it's over 4 years old. Grasshopper lawn mower new battery draining Sounds to me like it's not charging the battery. Without a functioning alternator, the vehicle quickly uses up all of the battery's capacity, leaving it drained. I had a bad diode in my alternator that was draining the battery quickly when the car was off. 12 Volt Electrical Systems. Anything less is just throwing darts at the problem. If you get more than the very smallest of sparks, something is draining the battery. I bought a new alternator, installed it, and had no issues drinving last night or this morning. You can perform battery check using either a multimeter or voltmeter or a battery analyzer. it looks like a wire but it's function is similar to a fuse. Check the Battery - A fresh battery should produce slightly more than 12 volts -- up to 12. I did this test below and found the voltage drop at the battery terminal connections. ) I need to find out where that blk/yellow wire goes too. It was a slow drain because it would take a day or two. Because 3 batteries went to bad I told the dealership I am not going to replace battery with Hyundai brand every year and the delaership better recheck the radio. The alternator's purpose is to replenish the battery. When your battery is not charging, you have to think about the current. If the battery holds a charge when it's not connected to the car - something is draining the battery far faster than the computer memory and digital clock. ALWAYS TEST YOUR MULTIMETER ON A KNOWN LIVE SOURCE AS A TEST SUCH AS THE BATTERY. An alternator problem can quickly drain your battery, so if you see a warning light on your system, take your car in for service as soon as possible. When the alternator does not supply enough current it takes it from the battery and run it down. You said they should be ok, but it's something to not overlook. Please click like and subscribe, click on my name. Tried to jump it and I got lights inside but not enough to start it. The alternator's job is to produce electricity and charge the battery. How does one tell the difference between a bad battery and a bad alternator? My car will not crank, but has some power (the dome lights, panel lights and power locks work). If the test light illuminates, then there is some type of drain present in the system. Read on to learn how to check if your alternator is charging your battery. Took the Hum out today will see what happens. 5VAC, if you get more, your rectifier bridge on your alternator. Check your battery or have it tested at your local auto parts store. One way to minimize the risk of premature failures and unnecessary warranty returns is to always check for resistance (voltage drops) in the charging circuit connections. What could be draining the battery while the car is running that causes it to die? There is an aftermarket stereo in the car so our next guess is that maybe the stereo is hooked up wrong and draining the battery but I don’t know if this makes sense because shouldn’t the alternator be charging the battery as it is driving? Please help!. With the Key off the 2 large Slots (Red Arrows in the pic) should always have Positive Battery Voltage as they are eventually connected directly to the Positive Battery Terminal. That is very easy to do with a voltmeter. If we were to put a resistor in the brown wire (only wire on the alt other than the charging wire to the battery), then the resistor may drop the voltage to the alternator, but would still draw current from the battery & potentially drain it. I think once you put the new alternator on everything will be ok. If nothing is actively draining your battery, then it's likely that your battery isn't getting enough charge from the alternator. Check the Alternator. Troubleshoot continued problems by using a multi-tester to see if your battery drains power while not in use. I am not sure why the battery is draining. It can create a. What I would recommend is idle the car for ten minutes, then turn it off, Try to start it back up and see if the starter motor cranks at the normal speed. A fresh battery and a malfunctioning alternator, however, will quickly leave you stranded again. check the connections to the alternator for corroded terminals, and at the battery as well. In some cases, however, the alternator can actually drain the battery, causing significant problems. You need to consider that the failure of your alternator may not have been an all-at-once situation. It could be faulty. New battery alternator is ok surpertine belt and pully system is fine. 5VAC, if you get more, your rectifier bridge on your alternator. If leave the battery cables. It should measure volts in both DC and AC, and resistance in ohms. had alt and battery both tested and both were bad. Self-Exciting Alternator makes no need for Alternator Wiring Diagram The Self-Exciting alternator is an alternator that has a special voltage regulator that doesn't need an ignition wire to activate it. Alternator light in the dash will not turn off even after revving the engine 2. I've said this before but, based on my own battery drain issues with other cars, you can't even start diagnosing the problem until you start with a fresh battery. 3 volts for a six volt battery). If the alternator is bad, the battery will most likely be dead as well. So I'd say go get your battery checked at auto zone and the ford dealer and see if your battery has gone bad already. If this bulb is burned out, chances are the alternator won't work. If you are looking to get an off-grid lifestyle without the off-grid price, an alternator battery connection might be the best option for you. That is very easy to do with a voltmeter. Signs of a dead battery. Take the positive battery cable off your battery, and using a good working 12V test light (like this one) attach one end of the test light to the battery and the other end to the positive battery cable. If the battery holds a charge when it's not connected to the car - something is draining the battery far faster than the computer memory and digital clock. One was from the bulb in the glovebox. A car alternator uses an electromagnet called a field winding to produce a magnetic field which rotates to generate power in the stator windings. This can cause a major electrical system malfunction such as short circuit to the main computer. It is common in the MDX's that if the power liftgate is left open (with NO lights on) it will drain the battery. Tools needed: Multimeter. Just an fyi, a bad diode in the alternator can drain the battery even when the engine is not running. Make sure that all the caps are still on the battery. Knock on wood. The display reads nothing and pressing the power button does nothing either. And whether you're driving a Ford, a Chrysler or a Dodge or a Plymouth, a Nissan, a Mitsubishi, a Volkswagen or whatever, this test will work. Check for a bad alternator voltage regulator and circuit. Step 2 - Check the alternator. Your voltage should go up. If the engine cuts off, it is a sure sign that the alternator has died. Bob further explained that one of the Diodes inside the Alternator could be shorted, causing the drain on the Battery, but the Alternator would still put out 12 Volts, and therefor pass the Voltage Output Test, however it could not put out full Current, and would fail the Current Load Test, IF the Shop actually ran that Test. 5v, at this point rev the engine up to about 2000-2500 rpm and recheck the voltage, it should now be between 13. Parasitic drains when the key is OFF are really rare, so the two most likely causes are: 1) Bad battery 2) Not charging while you are riding If it turns out to be #2, then it probably is also #1 by nowas repeatedly draining them shortens the life a LOT. Also the check gauges light came on and when revving up the jeep, I smelled burnt rubber. the first thing I would do is check the fuse for the charge circuit. Doing this would allow you to check whether the alternator is putting out enough current to run the vehicle. The alternator can drain the battery when parked, or it can cause the battery to drain by not charging the battery intermittently when hot. If your vehicle won’t start, it’s usually caused by a dying or dead battery, loose or corroded connection cables, a bad alternator or an issue with the starter. What are your thoughts?. Reach down and check the belt tension which should be taught. Only when the car engine is running can you check the efficiency of your alternator. Blessings, Austin C. Disconnect the battery, measure the battery voltage and write it down. Check for anything energized while the car is off. Don't test an alternator by disconnecting the negative battery cable. HELP!! 04 CTS draining batteryreplaced, still draining Put new one in thinking that it was the battery as the culprit, but it continues to happen. Years later, had same issue so I had them check out the charging system and it was the battery (they don't make Optima batteries like they used to). When I was driving on the highway my voltage went below 10 volts and the radio turned off, then my transmission stopped working so I pulled over and the car was still running so I turned it off and took the battery to advance to charge it to get my car the rest of the way home. What can be draining my batteries?. draining battery (99 windstar) Windstar Car Forums. The alternator tested good but the battery keeps dying? Test the battery, if it checks out ok, then there is something else draining the battery. Kudos too on getting your money back. Please click like and subscribe, click on my name. Your equipment needs for this are very simple. BOTH THE BATTERY AND ALTERNATOR CHECK OUT GOOD, BUT AFTER A FEW DAYS MY BATTERY DIES? Parasitic battery loss is the technical term for this problem. A6 Not Starting. This voltage test result tells you that the alternator is working (charging the battery). It can create a. When the car is running the alternator produces electricity and the voltage should be above 13. If the starter is good, the last likely culprit is a bad alternator. 1-wire alternator and re-tension the drive belts. Charging and discharging batteries is a chemical reaction, but Li-ion is claimed to be the exception. 2009 LE Blue w/tan Nav Nissan DRLs. Pop the hood and check the battery, and you might think you've found the culprit. In some cases, however, the alternator can actually drain the battery, causing significant problems. ) 5) Increase motor speed to about 1500 RPM. 3L Ford Ranger as BAD. But the one thing it needs is an actual complete circuit. I have asked a couple of auto sparkies about this question- why doesn't the alternator pump out 55Amps when both or one battery is dead flat. I removed one of the battery cables and the car kept on running and My car will stay on when I get a jump but once i turn it off it stays off, so i guess what I want to know is How do I know if the Alternator is going bad and is just Draining my battery The battery is just 11 months old it should still be good. If the engine starts but dies immediately, your alternator probably isn’t keeping your battery charged. A bad battery cell can cause the alternator to over-charge the good battery cells. I'm pretty sure it's not the battery as I replaced it not long after I got the car thinking it was the fault, and it was still doing the same with a brand new battery. As a rule, a three-phase alternator can operate with only one of the stator windings operational, although it's only one-third as efficient. This can be an interior light, radio, etc. to/2ETbrVo No tools needed and find out which one is bad in a couple minutes. Sometimes all it takes is one little light to drain a battery. If the test light illuminates, then there is some type of drain present in the system. Once you have narrowed down the issue with these tests, you can perform electrical tests on the alternator itself to determine for sure whether it is malfunctioning. This will cause an annoying hum but won't drain the battery unless it's getting power at all times. Check for any leakage if you have older lead acid battery. It should measure volts in both DC and AC, and resistance in ohms. An alternator, if your car has one, can put a very light drain on the battery--sufficient to register on a digital volt meter but not sufficient to illuminate a test light. You can try to recharge it with best battery maintainer, maybe it will help your battery keep alive. If you have an auto bilge pump make sure its not stuck on. The Hazard switch. 41 volts — enough to ensure that nothing was draining the battery and that a slight charge was being applied. Mk3 WLA, Alternator, Rectifier, Zeners, battery. If the engine starts but dies immediately, your alternator probably isn't keeping your battery charged. B battery discussion in the Farmall & International Harvester (IHC) forum at Yesterday's Tractors. I just joined on a few minutes ago and I am 100% stumped on my issue over a year ago with factory wiring off the battery I changed my alternator to a single key power with battery leg alternator, part number 7861-7an, it is off of a 94 model chevy 1500 105 amp regular every day alternator (stock) 2 weeks ago I cut the factory wires that had those little white cylinder deals off and extended. I have an '84 300D that I recently(2 weeks ago) put a new battery in. Dead Car Battery… Perhaps the most common sign of a bad alternator, a dead car battery, though inexpensive to replace, it is inconvenient. Dead battery. The Gage on the Graph did go up to near 14 volts when under heavy power so I think the alternator is putting out a charge – I just think the batter was not accepting it well – Got a new battery in there now – I guess we will find out next time out if it works better. I think you can do a similar test without an inverter by starting the motor and then turning on every dc appliance you have - lights, fans, electronics, etc. On older vehicles, the battery light would turn on the alternator light when the alternator output or battery voltage dropped below a preset value. Voltage may dip for a second but should come back at 13 or 14 volts. Test the alternator to make sure that it can start up the battery. In some cases, however, the alternator can actually drain the battery, causing significant problems. it looks like a wire but it's function is similar to a fuse. If there is a bad battery connection at the battery terminals you can check that too. New battery in July of last year. A dead car battery is the first sign that something might be wrong with the alternator. First, check the dashboard battery gauge. Thanks for your help. 79 Used the load test function on my multimeter and it said battery was good. Alternator Draining Battery - Help VW MKIV-A4 TDIs (VE and PD) my 0. When car is running use a voltmeter to check voltage at the battery. except sometimes thr battery light will go off and will charge but. I have four wires going to my battery on the hot side, the wire from the alternator, starter, the sound system and the one that powers all the things in the car. ALWAYS TEST YOUR MULTIMETER ON A KNOWN LIVE SOURCE AS A TEST SUCH AS THE BATTERY. It should read about 12. So they put a new battery in and then find in a couple of weeks that their alternator or voltage regulator has failed and their new battery has been drained because it is not being recharged. Years after that, same issue happened so I had them check again, alternator this time. Check the battery connections and the ground by the oil breather. Here are some ways to test your battery, and determine if it's bad. Jump starting fixes everything. If this voltage isn't present, the problem could be anything from the ground, to the state of the battery connectors, to the alternator, voltage regulator, or computer. The alternator's purpose is to replenish the battery. Wiring an alternator. It could be a bad alternator and as another poster mentioned a leaky (voltage wise) battery charger. Battery or alternator? Hiya Just trying to leave work this evening, but when trying to start my car there was a tiny amount of charge left in the battery (clock and central locking still worked etc), but as soon as I turned the ignition the clock went off, and there was nothing from the engine. If the voltage is low, the battery is flat, which means it may just need a charge, or it might be dead and won't take a charge. Hopefully, after reading this article you will get a deep knowledge about most of reasons that make your car battery keeps draining and do know how to handle with them. 2 volts, it means trouble. And BTW, Dodge we expect you to reimburse us for our incompetence. To do a quick check on an alternator, I was told that you could start the car and then remove the negative battery cable. The symptoms are after driving the car letting all the electronics chill out for a minute the battery will drain 0. the draining didn't stop. I have changed the alternator and computer, but did not fix the prob. Note: Other issues like stuck seat buttons can also cause a battery drain, but it seems that a bad alternator is one of the first things to check. These accessories drain your battery when the car is not running, and your alternator cannot replenish the charge. Are you sure that you have a problem with something draining the battery, or do you have a problem with the alternator not charging the battery? I would have the alternator tested to make sure of that before spending hours and hours troubleshooting electrical problems. Charge the battery and clean the terminals and cable connectors to ensure good contact. The battery should be able to handle 30 mins of standby. You need a "floating ball" battery tester to check the specific gravity of your battery's fluid (assuming you do not have a sealed battery), and an inexpensive multimeter. Hey guys I have a 1997 F-150 XLT and I have an issue with the battery draining when sitting for more than 8 hours. How does one tell the difference between a bad battery and a bad alternator? My car will not crank, but has some power (the dome lights, panel lights and power locks work). If the fault codes are pulled from the vehicle now, you may find overvoltage or under voltage faults. To check using a meter: set the meter to DC volts and turn on the car. If it is, consider the charge cables are not large enough and are dropping when they get hot. When you attempt to start the vehicle, the cranking of the engine is sluggish and takes longer than normal to start. If nothing is actively draining your battery, then it's likely that your battery isn't getting enough charge from the alternator. Check for a bad alternator voltage regulator and circuit. 2 volts, the Alternator probably has one or more Bad Diodes. That is very easy to do with a voltmeter. Connect the meter leads to the battery terminals and look for 13. having small knowledge of vehicles, jumped it, got it to auto parts store had them test alternator battery and whole charging system. Now I have it disconnected on a tender overnight. Get a DMM that measures AMPs in DC current. Typically you get BATTERY/ALTERNATOR VISIT WORKSHOP warning when the electrical system voltage in the car is below 12. Small engine battery keeps draining. Hyundai Sonata Battery Drain Mystery Or have someone small enough to get into the trunk while you close it to see if the light stays on. 4) check the battery Voltage. Yes my car battery has been drained 3 times. Laptop batteries can fail, or over time can lose their ability to hold a charge. If the battery tests ok and you still get clicks, then I'd measure the voltages at both terminals of the starter motor (compared to the case ground). 02- (I'm an EE) reading through the above, it seems that the correct conclusion has been reached- the alternator is "back feeding" and presenting what's referred to as "parasitic draw" when the engine is off. To do a quick alternator drain power check using your digital multimeter, go to the section Bad Alternator Diode Test below. Check your battery voltage. The battery drains while the car is running. If the decoupler pulley fails, the alternator won’t charge because it is ­“free-wheeling. 41 volts — enough to ensure that nothing was draining the battery and that a slight charge was being applied. To test for this condition begin with a fully charged battery. I took it to a mechanic the first time and he put in a rebuild alternator, since then it has broken 5 times for the same reason, the car drive fine for a couple of days with the new replaced alternator and then start to lose electricity as I drive until it dies, My old battery looked ok but I bought a brand new battery to be 100% sure it wasn. If you have a multimeter like this one, you can connect it to the battery terminals to get a voltage reading. Proper belt tension is important. If the battery holds a charge when it's not connected to the car - something is draining the battery far faster than the computer memory and digital clock. To check an alternator, pop your vehicle's hood and hook up a voltmeter to the car's battery by connecting the red lead to the positive terminal and the black lead to the negative terminal. If you see higher readings, chances are the alternator is good (more sophisticated testing equipment is needed to detect an open or shorted alternator diode). For more specific information, please resubmit your question, with additional details and please include a complete model number. If your vehicle is drawing power from the battery and all of the lights and other electrical components are off, you might have a parasitic battery drain (or draw). Put a DMM in-series between the disconnected negative battery cable and negative battery post. Obviously, batteries sometimes fail on their own--but a bad alternator can actually cause the battery to drain because it's failing to recharge it. Thought it was a bad alternator so replaced it, still getting super hot when off and alt is plugged in, checked all the wiring to starter relay and replaced relay, fuseable link on it is getting hot to the touch but not burnt out, alt is drawing very small amounts of voltage from the battery just enough to drain it if I leave the battery hooked up for a couple of hours, I a m totally stumped. Make sure the connection is clean and tight with no signs of overheating. Check your alternator output first - it should be a nominal 13 volts. If you test it again in about 30 minutes and it already falls below 12 or 11. Dead Car Battery… Perhaps the most common sign of a bad alternator, a dead car battery, though inexpensive to replace, it is inconvenient. Mine only jumped up to 12. According to Nationwide, there are a few different ways to find out if you've got a dead battery or an alternator gone bad. Re: New battery, new alternator: Not charging Quote ">>then the car should run with the battery cable disconnected to see if it is charging. Check Car Battery Charging Voltage. the first thing you need to check for is that you have a healthy strong battery. 79 Used the load test function on my multimeter and it said battery was good. If it's not the battery, be prepared, intermittent battery issues can be a pain to diagnose (and to live with). The alternator can drain a battery over time and shorten its lifespan, and you don’t want to unnecessarily run through batteries on account of a bad alternator. I think you can do a similar test without an inverter by starting the motor and then turning on every dc appliance you have - lights, fans, electronics, etc. While testing with a voltmeter I discovered the source of the drainage was the alternator. 79 Used the load test function on my multimeter and it said battery was good. The alternator's purpose is to replenish the battery. Pop the hood and check the battery, and you might think you've found the culprit. Lastly, check to see if the glovebox light is on, or some odd light in the back of the car or in the trunk or what not. You can perform battery check using either a multimeter or voltmeter or a battery analyzer. If your battery is drained, it will not run the important electrical systems in your car. Through electromagnetic induction,. There are some sure ways you can tell if your battery is bad by simply taking a good look. If you need to replace your alternator, this is going to be a bit more expensive. Make sure that all the caps are still on the battery. So, in theory, a bad R/R would cause the bike's electrical system to draw DC power directly from the battery instead, again causing the battery to drain. com 1-5-2011 EDIT: Started with testing the battery & then added a section on testing the alternator. The Alternator should now produce a battery voltage between 14. On the way back popped in to Harbor Freight to pick up a trickle charger for $5. 5 volts so I put a charger on the batteries overnight. The alternator can drain the battery when parked, or it can cause the battery to drain by not charging the battery intermittently when hot. Typically you get BATTERY/ALTERNATOR VISIT WORKSHOP warning when the electrical system voltage in the car is below 12. Connect the meter leads to the battery terminals and look for 13. The test involves checking the battery voltage with the engine off and with the engine running. Both are worth investigation. The field winding is attached to the rotating shaft of the alternator, and receives power through a p. How Do You Recharge a Dead Car Battery With a Bad Alternator? There are two ways to recharge a battery with a bad alternator: jump starting it with another car or using a portable battery charger. He checked battery, alternator and said he noticed. Took a while to get it started. In particular, pay attention to the battery’s trouble spots, shown here. My Alternator is draining my battery after 1. 9 with car on, and around 13. A few months back my FJ would be dead after a couple of days and had to be jumped off. Refurbished batteries run anywhere from $30 to $60. If your car dies right then and there…. In my case it was the alternator lead! Even though the alternator was charging fine, it was also draining the battery. This is called a parasitic draw( as in a parasite) now start pulling fuses and if the meter drops to zero or changes you will have found the circuit that is draining the battery. It sends power to the starter to turn over the engine and receives generated electricity from the alternator to maintain power. if battery is draining while truck is off something is shorted out (like the dirty wires or module under the bed) that might be the noise you hear!. In the paragraphs below, you will be presented with a number of common car battery problems and their solutions. A likely trouble-spot will be the blue fusible link located closer to the battery. Laptop batteries can fail, or over time can lose their ability to hold a charge. This diagram shows how to wire a Delco (GM) internally regulated 3-wire alternator. You should connect the voltmeter to the battery as before but not the charging voltage and this should be done after charging the battery or jump starting the car. If the belt is loose check the serpentine belt tensioner which may have a broken spring that needs to be replaced. If you dont see the voltage increase or actually see it go below 12 then your whole operation is feeding off battery and you will drain it and eventually get stranded or have to use a trolling battery to get home. I had the new battery tested just incase and theres no issues and the alternator was tested as well no issues. I heard the wire powers the alternator and makes the battery get charge. Thought it was a bad alternator so replaced it, still getting super hot when off and alt is plugged in, checked all the wiring to starter relay and replaced relay, fuseable link on it is getting hot to the touch but not burnt out, alt is drawing very small amounts of voltage from the battery just enough to drain it if I leave the battery hooked up for a couple of hours, I a m totally stumped. Probably what I'd do is take the battery in for a load test. If the alternator is not working, the battery won't re-charge. It's at around 650 and should be at 670. I have four wires going to my battery on the hot side, the wire from the alternator, starter, the sound system and the one that powers all the things in the car. My dad has an 02 wagon that had a battery issue, your story sounds just like his as he drove it only once or twice a week. My buddies 08 began dropping the voltage down also on his gauge and his battery would be dead the next day. A simple test for the alternator is to disconnect the negitive battery cable with the engine running.