Battery light

I have a 2007 Tacoma, just noticed today that the light came on. Pretty sure that it’s the alternator but wanted to get someone else’s advice. Few weeks ago I noticed some whining that only lasted for a day and eventually stopped. I read that it was probably caused by the alternator, but it did go away, so not sure what’s happening. car seems to be running fine but does seem to not be as loud as normal if that makes sense. If anybody has any suggestions, let me know. Going to try to take it somewhere as soon as possible but closest mechanic is 1 hour away

 

Have you checked if it's charging or not (battery voltage should be about 13.2-14.8v with the engine running)?

See the post below for further info/testing of the charging system.
https://www.tacomaworld.com/threads/2nd-gen-information-diagnostics.784008/#post-28042155

 

Haven’t checked it yet but will, just got a 1200 watt battery in October so I don’t feel like it’s the battery dying but could be

 

The battery light has nothing to do with the health of the battery, it is there to indicate a charging system problem.
Most often when it is on with the engine running the alternator is not charging, whether it's a bad alternator or something else that can be determined with a few simple checks as outlined in the link I posted above.

 

For a layman like me, what kind of battery is this?

 

100 amp?

Watts / Volts = Amps

Maybe he means cranking amps?
If so 1200 is a lot. That was an expensive battery.

 

I don't think I have seen a battery with that kind of CCA so was curious to the type of battery. Maybe having that larger size battery may be the root cause of a failing alternator that is struggling to charge it.

 

which brand of battery? you might have to change the alternator output to keep it properly charged

 

I went through this (intermittent battery light) on a roadtrip in my 2009 tacoma last spring. My situation was complicated by the fact that I was towing a shitty U-haul trailer, making it a littler harder to determine with certainty what was going on. I thought a short in the trailer wiring could have been causing extra draw on my battery or extra demand from my alternator or something else above my non-expert level of comprehension.

What I found to be most helpful was to plug in my code reader (cheapo from Harbor Freight) while driving and monitor the voltage in the live data settings-- I was able to see that it was jumping all over the place, from ~10 v up to ~14.2 v. I would expect a properly functioning alternator to be pretty consistent in the 13.5-14.2 v range under normal conditions, so this convinced me that my alternator was bad. Made it to the next town and swapped the alternator in an O'Reilly's parking lot, good as new.

I may have just gotten lucky, but my advice would be to pick up a cheap code reader and see if you can figure it out!

 

So. They say the 2nd gen alternator stock charges less for fuel economy. But it still charges.

good way to know that is carry a cheap harbor freight multimeter for that purpose.

like folks said. Light typically indicates a charging problem.

CTEK is good. Get yourself one cheap. Use it overnight. If you still have problems after that, could be battery or alternator. But you at least tried to save it, and sometimes that works. Have a warranty.

good batteries cost less and are easier to do than an alternator. Which at this point is old.

I’ll assume there’s nothing crazy like a parasitic draw.

a cheap gauge to have constant visual of battery voltage would be cool…

dealerships can have nice test equipment, but it’s the dealer. Probably more of a thing if your buddy works there and you hand him your keys. Or if you work there and fuck with the car on a Saturday.

I’m not sure what supporting work can be required to upgrade an alternator to higher watts while replacing. Probably at least JeepCables 1/0 or something. For future accessories in mind like lights and winch.
Or if that has any effect on power ports people commonly connect power stations to, for running a fridge. Or second battery somewhere.

but those cost more and a stock type of alternator would be cheaper. If anything the pulley on the front of it is probably worn.
At this age it’s not uncommon for an alternator to fail on any other car. And all brands use the same supplier. So I don’t see why the Tacoma would be any different.

might be time to find a deal on RockAuto slap it in and be done with it. Though idk what brand is best, and if there’s any notable difference regarding labeling. Ie reman, rebuilt, new, etc.
people generally say new is best, but that also costs more.
Supposedly some places when they do and mark as reman or rebuilt they do a halfass job and it’s not every part replaced to truly be good as new.

 

Maybe this guy? And highly doubtful a stock Taco can charge that fully. Need a voltage booster prolly. But i'm betting it's just the alternator. Specially if it's original.

 

that thing looks big and heavy, hopefully doesn’t cause sheet metal to crack or tear

 

I'm running a similar battery. like 1 pound less. Hasn't fallen outta my wheel well yet. I joke cause I had a friend with a Ranger recently have his truck yeet the battery onto the street.

 

Are you positive that really happened? Your friend can charge you with a negative story about him.

 

Hopefully not, that's a marine battery. Does not belong under the hood of vehicle

 

YEET

WTF is that?

 

Really happened. He was really amped up afterwards. Here's a screen snip from the video he took of the aftermath. His tire ate 1/4 of the battery away. Right to the plates.

 

Why not? A yellowtop optima is popular under the hood of a truck. It's identical to the marine blue top, but the blue has added terminals. A deep cycle battery is excellent if you run a lot of electrical or want power when the truck is off.

 

Ranger yeet battery onto tire, pretty wild.

Op, your going to have to open the hood & look at what’s going on. Visually without tools, you might see battery terminals growing big mushrooms. Or a loose battery cable at the ground points or starter. Or a worn belt. Or battery terminals didn’t get brushed before attaching to the new battery.

We can all guess but using a keyboard to diagnose is using the wrong tool.

I’ll throw my guess in, maybe when the new battery was installed, the terminals weren’t tightened good.

Get yo hands dirty, then let us know what you found.