When to replace alternator

Hey guys. Just asking before I'm left stranded on the side of the road. When should I replace my alternator? As far as I know it's the original tow package one, have about a year old battery. Accessories are led lights, light bar, led fog lights, and a decent sound system more recently.

 

I just had the charging system light come on this past weekend and had to replace the alternator. That was at over 300k miles on an ‘05.

 

I rebuilt mine a while back after I started hearing a noise, still going strong. If it ain't broke don't fix it until you do break it.

https://www.tacomaworld.com/threads/2nd-gen-1grfe-alternator-rebuild-mud-cleanout.453757/

 

At first I thought your post was asking when the alternator needed to be replaced due to wear and age. After reading your post again, I believe you're asking "at what point have I exceeded the capacity of the alternator and need to UPGRADE it". If that's correct, here are my thoughts...

The towing package alternator makes 130A if memory serves me correctly. You need to check the amperage draw for all of your additional components. As an educated guess, I'm thinking you're not even close to overloading the stock alternator but let's do a little math and find out. List all of your lights and your amplifiers. Bonus points if you can find the amperage draw for each of them so I don't have to find (or calculate) it.

 

Unless his "decent sound system" is a crazy high end sound system then the stock towing 130amp alternator should be more than plenty. A simple amp clamp around the positive alternator to battery cable will tell all that's needed.

 

Yep, that's why I stated that in my post too. The LED lights will draw almost nothing at all and the stereo isn't likely to draw more than 50 at most. Even if you have a 1000w amplifier and you listen to it at peak volume/power all the time (assuming your speakers can handle that) that's 83A. Realistically, most people don't even use more than about 25 watts of power during normal listening (and that's listening quite loud).

And I agree with @Sandman614 if you have an amp clamp it will tell you what your draw is quick and easy. That being said, anyone asking questions like this likely doesn't own an amp clamp. Hell, I don't even have one.

 

keep a spare engine, diff, drive shaft, battery, tires, tool chest in the bed

or wait till it dies, 196k and original alt here

 

If you do replace your alternator make sure it is a Denso Unit.

 

and why do you say this?

 

Factory is best dang, who taught you automotive, they spent all that time and research looking for the best unit at the cheapest cost..

 

We bought my son's 2006 a year and a half ago, on the test drive the charge light came on and the dealer bought an AutoZone grade rebuild unit which I installed. Last week the truck crapped out on the road with wife and son in it due to a bad alternator, I had my friend who runs a local garage collect them and put a new alternator in it since I was out of town for work. The truck sat in his lot for 3 days waiting on the Denso unit since there were not any local, he strongly advised on not going with another brand. I've been dealing with him for 20 years and he's never steered me wrong in the past.

 

I have not changed a Toyota Alt yet and owned 4 since 88. Ill stick with OEM for this part.

 

I have a spare Denso I got from LKQ for $55 shipped. 2015 V6 4x4 TRD donor with 50k miles on it. For now she waits...

Anyways, you can get a used Denso that will be better and cheaper (from what I've read here) than a new or rebuilt AutoZone alt.

 

If I had an issue I couldn't fix on the side of the road (mud in the contacts) then I would have no problem running an auto parts store brand. Granted I would not give the factory one as a Core, repair it, and keep it as a spare for when the autoparts one dies then warranty the autoparts one. That autoparts store Lifetime warranty has it's perks.

 

I went through alt hell years ago in my 78 Datsun pickup
I carried a spare battery for a month after going through 3 rebuilt alts and finally getting a new OEM fixed it.

 

25 years ago I bought a fuel pump and water pump from Autozone for a GM vehicle, fuel pump lasted 2 days and water pump failed 3 months after install. I learned my lesson but they end ran me this time since the dealer bought it lol.

 

I had a friend, who was also a mechanic, and he always bought the auto parts store stuff for his personal vehicles solely for the cheaper price and lifetime warranty. I'm talking u joints, brake pads, rotors, axles, alternators, starters etc. Needless to say he spent almost every weekend replacing something on his car, towing his car, and taking the part back under warranty.

I'm the exact opposite, I'll pay the extra money for OEM and be done with it! It's worth it to me for piece of mind and more free time.

The easy answer to your question is when the alternator is only putting out 12v, that makes it difficult to charge a 12v battery. Once they hit the 11's, they will probably leave you stranded. A new alternator would put out 14.2 - 14.4, an aging (but still good) alternator would be mid 13's. The more electrical draw, the hotter the outside temp, the less output. You can easily test with a voltmeter on the battery while running.

 

Exactly. When I was a much younger man I was a total Cheapskate looking for the lowest price, with the passing years I'd like to think some wisdom has come my way. I have better things to do with my time than laying under a car cussing and nothing sucks more than being broke down on the side of the road.

 

Replace it when it dies. I've been driving since 1974 and bought my 1st alternator 2 years ago for my Tacoma. At the time it was 9 years old with 175,000 miles on it. It is hard to predict how long electrical parts will last. You could buy a brand new truck and lose the alternator at 30,000 miles, or it might still be going at 300,000 miles.

On some inexpensive and easy to replace parts it makes sense to replace them a little early just to be safe. Others can be observed and it is easy to see when they are getting close to being worn out. But not with most electrical parts.

 

Sweet, thanks for the info guys! To clarify I was asking when I should replace it before it craps out, no need to upgrade with how little power 8 currently draw.