Last Updated on December 8, 2022
The main functions of an alternator are to generate electricity for the electrical components of the vehicle and to charge its battery. The alternator produces this electrical energy by converting mechanical energy.
If you were to try and start your vehicle without an alternator, the battery alone would not be able to produce enough power to get the engine running.
Even if you had a new car battery and were lucky enough to turn the engine over, it would probably run for about 10 minutes before the power cuts out. The alternator is necessary to keep the battery recharged and to alternate the electrical current throughout the many components of your vehicle to keep them powered.
Read Also: How to Fix an Overcharging Alternator
Causes of Alternator Not Charging the Battery
A lot of people get confused when they begin to have electrical problems with their vehicle. It’s easy to misdiagnose these problems as being a bad battery instead of a bad alternator.
To understand the difference, you must first learn about what causes an alternator to stop charging. Then, you can inspect the vehicle and determine if the problem is your alternator.
Below are the top 5 causes of an alternator not charging:
#1 – Computer Error
Most people are driving cars made within the last 20 years. These newer cars all have a central computer system or engine control unit (ECU) which manages and operates the vehicle’s components and parts.
This computer manages the alternator as well. Therefore, all it would take is a computer error and the result would be a malfunctioning alternator, preventing it from charging.
#2 – Broken Belt or Pulley
The belt and pulley produce the mechanical power which gets converted into electrical energy by the alternator. Your serpentine belt can easily break if it gets stretched out too much, causing it to snap apart.
The pulley can also get damaged after a while. In either case, the alternator will no longer be able to produce a charge for the battery.
#3 – Blown Fuse
There are certain models of car which have alternators dependent on a particular fuse or fusible link to operate. However, these fuses can blow due to a power surge or simply from old age. Once that happens, the alternator will no longer charge the battery.
If you don’t know whether your vehicle has an alternator fuse or fusible link, you’ll have to check your owner’s manual to see which one it has. Checking the fuse is well worth investigating in the event your car battery is not charging properly.
#4 – Wiring Issues
There are numerous wiring components in a vehicle that help produce power for the alternator. All it would take is for one wire to be disconnected or cut for power to stop being generated. As a result, the alternator won’t be able to charge the battery until the wire is repaired or replaced.
#5 – Bad Alternator or Battery
Alternators and batteries do not last forever, and each have their own lifespans. A car battery will last from 2 to 5 years, depending on how often you drive and the climate where you live. Batteries generally last longer in colder environments and shorter in hotter environments.
Alternators will on average last about 7 years or every 80,000 miles but there are always exceptions.
See Also: Code P0562 (low voltage)
How to Fix
The most common reason for an alternator failing to charge a battery is one of them going bad. You can easily test the voltage by connecting a voltmeter to your battery while the engine is off. The voltage reading should be between 12 and 13 volts. You can automatically assume there’s a battery problem when the reading is lower.
In the event your battery’s good, start the vehicle and get the engine up to 2,000 RPM. This will put a lot more demand on the alternator. A decreasing voltage reading on your voltmeter indicates you have an alternator problem.
My vehicle has the problem of battery not charging due to the fuse box what can I do its a corolla vvti
Check under the cover of your fuse box or in the car manual to see where the alternator fuse is and simply replace it with the same fuse type.
All my fuses are good and have new battery in my 1990 corolla but lights,hazards and hooter aren’t working while car is running. Battery isn’t charging. When I disconnect the battery while the car is on…it does immediately. How can I fix this?
I drive a 2000 Ford Taurus the anti-lock system I guess think froze up I don’t even know if it was that but the battery light stayed on and it stays on when I turn the car off which causes the battery to drain and when I’m driving it is like sputters a little bit and wants to stall out the battery I just got less than a year ago I had to change the mega fuse cuz it was sort of doing the same thing a year ago any advice please help
Im having the same issue but lights work
Can a broken gauge stop the alternator from charging the system?
I have a 2008 Jeep Liberty. Ive replaced the alternator and battery. Both brand new and the alternator isnt charging the battery. The belt and pulleys are all turning the tensioner is good and belt is on tight. Where else can i look. Theres no fuse for the alternator. Alternator has no power sent to the battery and everything is hooked up correctly. This is my third alternator because i thought i kept buying bad ones. Could it be a bad ground somewhere or the pcm bad? Really need help.
Your story is my story with my 2006 Liberty. Third alternator reads only 11.8 volts charge. I guess it’s time to look at all of the wiring coming from and going to the alternator.
Wow 07 liberty on my 3rd too
I have a 97 Oldsmobile Aurora New battery new alternator but car won’t start I noticed that one of the screw’s (bolts) to mount the alternator is not fully connected can this be the problem??
Can a damaged cable leading from positive terminal to fuse box cause the alternator not to charge? Swapped out battery and alternator and van ran fine for 4 days then just shut off.
Computer bad won’t let alternator charge battery
And Chrysler products that seem to be a problem with the ground system you need to check the grounds especially around the transmission it should be a ground is called Ground 300 this ground will break the connection where you can’t see alternator will not charge because of the no ground system is usually a big wire back in the corner at the bottom of the transmission to the frame real they call it ground 300 to verify that the vehicle has he has or has not lost his ground takes a set of jumper cables and ground the negative posts to the alternator with one one part of the cable the next ground the starter to the ground wire and the second wire hooks it back to negative cables that means you will have four cable into going to the negative post one going to the ground closest to the alternator ground close to the starter
The regulator for these vehicles are located in the computer. That’s a trip to the shop or dealership in my case the latter.thanks tk
Disassemble your alternator and look for the brushes. You may found there are separated from their leads.( broken down)
When you switch your ignition on, then check if the alternator (red) light also comes on.
If it does not come on, then the bulb is blown on the dash. This will prevent charging from the alternator to the battery.
Install any other similar type og dash light, and your problem will be solved.
Years ago I had a Ford Cortina V6, and this was the problem which I experienced after replacing the battery and alternator, when a autolec informed me about this. I could not believe that this will prevent your battery not to charge, but it did. good luck
Did you find out what it was? Mine is doing this as well… I need help!
My vw passat has a new battery and a new alternator but still isn’t charging my battery. What could it be?
Make sure the battery terminals are clean and tight. A weak connection to the battery will present all sorts of electrical issues. These include not starting or charging consistently.
Check if the red battery/alternator light on the dash is not blown, if it is the battery will not charge
The charge current either flows through that bulb, or through a fuse in the fuse box
I have a 2006 chrysler town an country I just replaced my alternator but my battery still keeps dying I’ve been told my battery an alternator are good but my battery still dies I’m not sure why or what’s going on would you have an answer
You may have a parasitic drain on the battery. Perhaps you’ve left a cabin light on or the radio is drawing power even when the vehicle is off. If you search google for “how to do a parasitic draw test” you will likely find some very helpful videos on how to perform the test yourself if you are interested in giving it a shot.
My 2009 Silverado has a new battery and alternator but stops charging after you drive it for awhile ?
Since you have a GM, the first thing I can think of is to check to make sure the battery/ALT/CHARGE warning light bulb in the dash is not out. It doesn’t make much sense but that’s how they’re wired. If the battery “idiot” light in the instrument cluster doesn’t light momentarily when the ignition is turned ON, the bulb is bad and the charging system will not work.
If the bulb IS working, make sure you check the voltage at the battery and at the alternator. The numbers should be similar.
Which bulb are you referring to?
The bulb behind the instrument cluster (similar to low fuel or check engine bulb).
65 gto with new battery
New alternator and
New starter all testing good but sometimes
Still won’t turn over
If the motor won’t even turn over you probably have a mechanical problem that is limiting crankshaft movement. If it cranks but won’t start, I would check the ignition system next, then the fuel system.
Check your coil wires.
Good morning. I have a 2003 Toyota Corolla. I experience some battery or alternator problems which make me to kick-start the car. My car doesn’t have the 100a fuse inserted and where it’s supposed to be the metal clips are bent to touch each other. Can I just open it and insert a new fuse or are there possibly other reasons why it has been bypassed?
1.The car(Chevrolet captiva 2012) made grumpy funny noise when starting and when i poured water it loses them
2.I bought a new battery and the car move for 5 minutes and suddenly stop and unable to move …i jump started the new battery and it works when i remove the jumpers nothing happen what can be the cause
I have a 1980 fiat x19 with a external regulator on my alternator.
Cannot get my battery light to come on when ing is turned on.
I’ve tested the bulb and wiring. What makes up this signal wire. Is there any other connections this wire goes??
Check a wiring diagram for that circuit, then test for continuity with a multimeter.
I have VW Touareg V6 2008. Car is running but battery doesn’t charge immediately when the car is started. If I continue running the car for 15 to 30 minutes and switched off the car then start again, the battery will charge. I am confuse to locate what is the exact error or problem.
Please need some advise.
thank you
Hi, I have the exact same problem. Did you find a solution for this?
I have an 05 tahoe replaced alternator xmas eve now my chargein system failure display showed batteries fine alternators fine the cord that plugs into the alterbator is not giving power any suggestions
Looks like you narrowed it down to a wiring issue. There may be a damaged wire, wiring harness, or short somewhere. I’d look at replacing the wiring harness.
I have had a similar issue with an 03 tahoe, replaced alternator now over a yr ago and battery. Battery not charging light came on. Had both battery and alternator checked both checked out fine. I replaced battery under warranty just in case. Light still comes on regularly its now been 6 months not drop in performance or voltage stands at 14v regularly. Just the indicator light keeps coming on. Fuseable link is fine. Can’t find a alternator fuse if it exists. Someone told me it might be a alternator speed control fuse but I cant find any more info on that. Any suggestions?
I would check all your grounds. Make sure your ground straps are clean, tight, and free of corrosion.
I would like to know when you connect a alternator, if your power wires is short can you use a smaller size wire to connect it to the actual wire that runs to the engin and battery?
The battery light is on while my Toyota auris is running…what’s the problem?
I accidentally swapped the battery terminals but corrected them and the car started, it showed the battery signal which suggest alternator is not charging the battery, i found that there are two fuses died, i replaced them and ON the ignition, the fuses died again. What could be the reason in this case?
Fried voltage regulator in the alternator?
what you mean by (fried voltage regulator) and how to fix it?
The voltage regulator is responsible for making sure the correct voltage is being sent to recharge the car’s battery. In the original commenter’s question, it’s possible reversing the battery terminals caused permanent damage to the regulator (it fried it) and it no longer allows the battery to be charged.
I have a Ford Mondeo 2 l diesel 2011 the battery warning light comes on had battery tested it’s good alternator is putting in 13.9 volts what could the problem be?
This sounds like a smart charge cable very common on the fords easy to replace
I tried to install a car stereo and by pass the factory amplifier and computer but now my battery won’t hold it’s charge it charges and starts the car up but won’t hold the charge the battery indicator the brake indicator and the security light is on on the dash this is on a Cadillac Seville sls 2001 do you have an idea
My car won’t charge new alternator new battery and replaced fuse
Ditto, has to be the wiring somewhere?
Toyota Sahara 1990
I just got a new alternator and battery an now when I turn the key it’s just making the clicking sound and everything in come on the my Nissan Murano but it isn’t starting
Even though you replaced the battery, make sure there’s no corrosion on the battery cables which connect to it and that they are connected tightly to the posts on the battery. If that’s fine, you may have an issue (or loose connection) with the starter.
I have a 2007 Mitsubishi Raider 3.7 L battery light is on battery is good alternator is good cannot find a fuse that is bad any suggestions I switched battery and alternator from another vehicle and still have same results before a short time ago when I took the cable off the battery the car was running now the car dies email me [removed] please.
Hi so I have a Mitsubishi 2009 Galant and I’ve had my alternator replace led twice over the last couple months but recently again my battery has stopped holding charge, is there anything that really might be buggin instead of the alternator itself ?
You didn’t mention how old the battery is but I assume you’ve had it tested before replacing the alternator. Other things to look at: check all cables attached to alternator and battery (make sure they’re tight with no corrosion), check for blown fuses, and check belt condition and tension.
I have a 2003 Ford expedition my battery light came on after I replaced the fuse box I thought it was the alternator I put a new one in then thought it was the battery put a new one in and the battery light is still on how do I fix it
Make sure all your cables have a good connection with no corrosion and your belt is in good condition with proper tension. Not sure if the Expedition has one, but some vehicles have a remote voltage regulator (instead of being part of the alternator) which may cause problems. All related fuses look good?
I have a 2011 Honda CRV. Initially the AC stopped blowing cold air, followed by battery light coming on, after a longer drive all the lights started coming in: abs, awd, hand brake… Barely made it to partssource they changed the battery it was two years old) , it still didn’t charge… Soni went to a mechanic, changed the alternator, still didn’t work… Replaced the ac compressor Clutch switch, no change..
Not sure what to do anymore, worried Honda will rip me off
My alternator was repaired , they changed the regulator amd the other part, it is for Mercedes Benz V230 , it only charged for 3 to 4 days and now its undercharging again and I have a new battery , what. Could be the problem
Hi I have A170 Benz it show altenator problem and the steer wheel does not move it’s 2005 model please help me out
If you alternator (or battery) fails, it will not allow the power steering pump to work. This means your steering wheel will be extremely hard (or impossible) to turn without power assistance.
I have a toyota hiace truck. Its not charging the battery but the day i was cleaning the engine after putting engine cleaner and somw water that spilled on to the alternator. It started charging. But this didnt last for long. What might be the problem.
2003 dodge dakota has new alternator and battery it starts easy but after a few minutes gauge shows no charge and check gauges light comes on
Turn off ignition and wait about 5 minutes and start it will show 12 -13 on gauge in dash what might be wrong
My car is Toyota Corolla Quest 2015 on the clock it is 245000km and it’s not charging will that means a car of that old the alternator is already damaged?
If the battery of my car is 3 and half years can cause car not to charge?
Hi I have a 2003 Lincoln Navigator I bought a new battery a month ago since I took it to autozone to get it tested and they said the battery wasn’t working that in 3 months it was going to go bad so I bought a new one and had someone put it but since I didn’t use the car for 3 weeks after they put the new battery it wouldn’t start so I have to jumpstart it every time and I go into autozone and they check everything and told me that the problem is the alternator but I just bought it a year ago also . Is the alternator the problem? Or what else could it be ?
Sounds like a poor connection somewhere especially since you can jump start the car. Check to make sure the cables are attached to the battery posts tightly and make sure there is no corrosion on the ends of the cables. A bad alternator won’t prevent you from starting your car if the battery is charged.
I have had 3 alternators and 2 batteries replaced in 6 months, the check engine light came on yesterday after I jumped the battery, they checked the system and no errors came up; suggested something in the computer
If your check engine light is on but no code is picked up by the scanner, I can almost guarantee you the wrong scan tool is being used or it’s one of those cheap $15 code readers. Either go to a different mechanic or take it to Autozone. They as well as some other auto parts stores will perform a diagnostic scan for free.
I HAVE A SUBARU IMPREZA GG2 whenever i i start the car it sounds as if it has no power, like has a miss the the idling becomes normal while driving i turn on the lights the this is all the lights plus fog the car looses power and im forced to turn off the fog , if put on full lights the car stalls and looses power. the alternator i had it checked and the guy told me it was charging , help a brother
I can honestly say from recent experience, The best scenario to check the fuse, is when you have a brand new alternator and a brand new battery(or good battery). And you find yourself getting jump-offs, and the car stalling after so many minutes or seconds. That was happening to me after I brought a used car 2 weeks ago. I checked the fuse box and the battery fuse in particular was the wrong fuse. So not only can it be a blown fuse, it can be the wrong one. I got the right fuse in my car is running A1.
So yes if you know your alternator is good and your battery is good, and your battery is continuously drained, it is definitely worth investigating. I’m a living Witness.
I have a 2017 hyundai santa fe..was driving down the road and every warning light possible started flashing and car died ..battery was dead and alternator not charging..had alt and battery both tested and both were bad .put new alt on new battery still no charge coming from alt.except sometimes thr battery light will go off and will charge but as soon as the car is turned off and you restart it the battery light and discharge warning come back on and drains battery ..im lost cant seem to find an alt fuse cause no info is available to me online or manuels to be bought..
2010 Kia Forte Ex
The battery light came on one day and slowly the instruments are cutting out. E.g, the rear defroster and heated mirrors don’t work, running daylight don’t work, and the AC doesn’t work.
I took the car into a mechanic shop thinking that my alternator is bad, but the location of the alternator in the car is tough to get to (located underneath the power steering pump). The alternator and battery were replaced a few months ago in late February and there were no problem with anything until 2 weeks ago.
I took the car to a mechanic shop nearby but they were unable to reach the alternators location to do proper testing. Could it be a fuse or wiring because the alternator doesn’t make any wining or grinding noises at 2000 rpms. And the belt doesn’t look like there is any tears or wearing. I believe that was replaced as well.
Any suggestions??
I have a 2008 Ford Focus 1.6 tdci. The battery voltage (battery only 12 months old) is 12.6 volts, when I start the engine it goes up to 13 then to 14 but after 30 seconds or so the battery light on the dash comes on and the voltage drops to 13.6 and fluctuated between 13.6 and 13.7. What is going on?
regulator knows battery is charged. shop told me this is normal. its been 3 yrs and I haven’t had trouble. my car does just what u described.
I have a 2011 Chevy equinox changed alternator and starter but don’t know what wires to get
Your local Chevy dealer or auto parts store can tell you the correct cable/wires to get.
I have a 2006 Hyundai Tuscan and I have put in two new alternators and battery but they keep blowing. Even the little fuse on the battery. There is no wires that are damaged but I don’t know what else to try. Any clues on what it could be?
Electrical problems are always the worst to diagnose. I’d recommend taking it to an auto electrical repair shop for advanced diagnostics. Some people may enjoy trying to troubleshoot but to me, it’s not worth the headache most of the time.
I have a 2003 Ford Taurus and it’s not charging at all
I have a brand new Alternator , Brand new Battery and a Brand new Starter.
My Alternator Light came on and I went to the auto part store where I had bought the alternator and it was tested on the car and wasn’t charging so we thought the voltage regulator had gone bad within 24 hours so I took it off right there i the parking lot and they took it in and did a bench test on the Alternator and it passed the bench test 4 times in a row. Put it back on and it wasn’t charging again. What else could be the problem ??
I have had 6 different people say that there is a ground off , Broken off or just Missing all together. I’m lost so could someone please help me out or point me in the right direction. PLEASE !
I’ve been without my car for 3 weeks now
Im having the exact same issue. Im on my 5th alternator because its not charging on the car but passes on a bench test everytime. If you find a solution please let me know too. Been 2 months now borrowing a buddys truck.
I have a 2005 Honda civic dx. Replaced the alternator but the battery tries to start but never turns over. When you try to jump it still wont start. Is it possible that when the alternator went out it screwed the battery up and now wont charge enough to start
Testing a battery with a voltage meter is fine, but each cell needs to be tested separately with a hydrometer, (old school). There are six cells in a 12 volt battery. One cell could be floating three balls. Another two and another one none. No ball floating indicated a dead cell. This battery could check OK on a voltage meter, but it would not hold a charge for an extended time. ALL cars, new or old, has a slight parasitic draw to keep memory of components alive and will drain an already weak battery over time. A car runs off the battery. The alternator is there to keep the battery charged. That is its sole purpose. An alternator goes dead and the car will run on the battery alone until the battery goes dead, then the car quits running.
Am a technician and one Hyundai Santa Fe is having alternator problem I changed it and it’s not working I have checked the fuses and all the same what can I do?
I have Toyota Yaris 1.5 2010 the alternator is not charging the battery or slow charging and all the fuse are replaced but still acting up , what can i do to sort the issue or diagnose the fault on the alternator .
I have a 2006 jeep liberty and the engine light goes on just put a new alternator and battery and it start to lower the battery little what could it be
I have a Honda crossroad 2007 model. One time it stopped charging and the mechanic didn’t find fault with fuses and Alternator. The only fault found was one of the cables was not supplying power to the Alternator, then he had to cut the Black and White wire and connect to another black and white wire connected to the plugs and the alternator started working. Now the check engine, VSA and another warning light are on the dash board always. After taking it for scan, The following codes appeared P0141, P1298, P0102 and 83-1 ECM/PCM relation failure. What could be the problem?
2007 Toyota Camry se 2.4 engine. I replace battery and alternator in March 2019. also replace alternator in June 2019 both rebuilt alternators. replace alternator in Sept 2019 with new not rebuilt alternator. The first 30 days or so the car start right. Now the car start slow like before. Have any ideas?
Run a voltage test on your battery and alternator. There might be a drain somewhere. Also, could be your starter going out.
I have a 2006 Scion TC. Recently, my car just died as I was driving. My dashboard lights go dim, but when I press on my brakes, all of the dashboard lights fully light up without the key in the ignition. My car won’t turn over and the lights slowly dim if I’m not pressing the brakes. My battery tested good, but my alternator was bad. I replaced my alternator, but I still have the same issue. I’m assuming it’s electrical wiring and not fuses at this point right?
Sounds like a vacuum leak (brake booster or hoses) to me since the car stalls when releasing the brake pedal.
My car Toyota Camry 2006 model when I use AC the battery drain , I don’t know what is wrong ?
The car’s AC should not put any additional load on the battery as long as the engine is running. Why do you suspect it’s the air conditioner?
i have a 2010 transit van which had a new alternator put on but the plug that goes on the alternator is loose because the clip that holds it on snapped and im not sure what this part is called so i can get another one please help im in the uk
I have a 2007 Dodge pickup diesel, i put 2 new batteries and a new alternator it drives around for a little bit then dies down, the batteries die..what could be the problem?
My Iveco omnibus is idling at high revs about 1500revs I go to an iveco dealer and he said it is under charging, so my question is what might be the problem on the alternator. Can it be a regulator but the brushes are okay
Hi guys my battery is being over charged and sometimes doesn’t wanna start as there is to many volts then amps. Got battery tested and battery life is 89% and battery charge is 30%. Do I have to change alternator or do diagnostic cause engine light is on? It’s a Chrysler Neon 1.6 SE 2002 model. Oh and does my alternator have a regulator or is my ECU (Computer box) suppose to regulate my battery charge? Please I need help
I had a similar problem to you after the alternator was replaced by myself I connected it exactly how the last one was. It turns out that some are to be connected opposite to the original. If that’s the case then it would cause you a problem like yours
I have a Benz E 250 1996 model. Using new battery. While starting voltage is increasing up to12.90 volts only. While idle for 5 hours voltage reaches 12. 04 volts. Meantime alternator generating current. Do you know any fuse using for charger of e 250.
The bolt to Nissan Altima won’t come off to take alternator off my uncle is trying to fix his car it won’t turn on
Is the bolt rusted? Try soaking the bolt with some penetrating lubricant such as PB Blaster or Liquid Wrench to loosen it up a bit. Letting the product sit for a few hours will maximize its effectiveness.
I have a 1992 Lincoln town car that began (what appeared to me to begin misfiring and bogging/hesitating before finally cutting out completely.
After having it towed back to my home the tow truck driver put a portable jumper and it started. He said the alternator was bad and not charging the battery thus not creating spark to fire the plugs.
Long Story Short…
I replaced both the Alternator and battery. But after doing so a handheld voltmeter pulled the same result…
No recharging to the battery.
Then had the New alternator tested at the auto parts store. It passed. But they gave me a second new replacement alternator just the same.
Fuses all appear good. Nothing obvious (broken wires ect.)
I do have some minor electrical issues, Like a short or grounding somewhere, Radio static, (more so when wipers and heat/ac is on) door locks buzz occasionally when pressed,
No funds to have it brought to a garage and I have no clue or idea how to trouble shoot this problem.
Please advise, any feedback/assistance is much appreciated and warmly welcomed.
Thank you.
This sounds like a grounding issue. Make sure the battery terminals and posts are really clean. Get a battery terminal cleaner if you don’t have one and clean off any corrosion. Corrosion around the battery often appears white, but could also look like rust. Make sure you disconnect both ends of the battery when you do this (disconnect the negative terminal first).
Check all your ground straps to make sure they look clean. A loose or dirty ground strap could cause a plethora of seemingly unrelated electrical issues.
Additionally, I would look at the wiring harness in the engine bay (particularly around the connectors) to make sure no wires are severed or have exposed insulation. Sometimes these wires get brittle with age, especially in hot areas.
Sometimes the simplest failures cause the largest issues. Good luck on your search.
My AC technician replaced my Toyota Sienna 2000 Condenser and Compressor. After the replacement the battery won’t charge when the AC is on, until I switched it off. Now I drove for about 30 minutes with the headlight on, I packed to pick up some items then return to switch the car on then discovered the battery is totally flat. All these happen the same day, after I picked the car from the technicians shop.
Please what could be wrong?
Have your technician recheck the belt tension. The A/C and alternator share a belt on your vehicle.
I have a classic old school corvette with factory stock amp meter with needle that will go to. Charge or discharge only problem I have is I have never seen the ammeter needle go to charge? Even at higher engine rpm however the needle will jump to discharge when I turn on my headlights I do have a new high amp alternator but shouldn’t it go to charge when engine is going down the freeway or turning a higher rpm? Thanks for your input
Hi
can be this the reason why I can not start my car if the smart charge alternator is faulty?
Ford Focus mk2 1.6 TDCI 2005
Yes, a bad alternator could cause the battery to run too low to start the car.
Alternators use the mechanical power of a belt and pulley to generate the electrical energy for the vehicle. The problem is that the alternator belt and pulleys are not too durable, which means they can easily break.
My car battery only charge when I give my car gas, when the engine is high or 60mph
I would have both the battery and the alternator tested at a local auto parts store.
My alternator is OK but it’s not charging the car is isuzu bighorn
How old is the battery, and have you had it tested recently? A bad battery may not hold a charge.
Good afternoon, my car is 1999 Toyota sienna, I bought my battery 2yrs ago but recently if I want to ignite my car it’s struggled to answer and later it was showing battery on the dash board. I recharge my battery and yet the battery got low within some minutes. I call on technician he said i should change the alternator capacitor and cut-out. Please can I go ahead.
That sounds like an accurate diagnosis. I would see if I could test the alternator before replacing it, just to be sure.
2000 Jeep Cherokee
Meter on dash board shows a slight discharge, adding a load (lights, A/C, radio, turn signals) the discharge gets greater. At first I just thought it was a bad battery so I replaced it. Took about 2 months and the battery started to loose charge. Replaced the alternator and the symptoms are still the same. Slight discharge without any load. Any ideas?
It sounds like you may have a parasitic draw. Do a quick google search on how to test for a parasitic draw and see if that helps you find the problem. You will need a multimeter for this test.