I went to austozone today because I noticed a burning smell under the hood near my battery and also some corosion thats been around the plugs as well. The guy tested my battery and amp and the amp read 130v and the battery was fine, but also mentioned that it looks like I am running completely off the battery and that is why the corosion keeps coming back. He says I need to buy a new altenator but for some reason, I dont buy it because if the volts are there, I assume something else can be done. Also, I am running 2 subs off a 2200 watt amp as well. But this happened before I put that high amp in. What should or am I supposed to do? Help ASAP. Oh, i have a 99 F150 5.4 V8.

 

I would think that if your truck is running entirely off your battery it wouldnt take long to kill the battery, then the next time you went to start it it would be dead. An old method to check the alternator is to remove the negative cable on the battery while the truck is running, if it continues to run the alternator is fine, but if it struggles or dies you most likely have an issue with the alternator. The high power amp is probably not helping you any-you may want to look into a high performance battery and a high output alternator to handle the demand of the amp
just my .02-but im also not a mechanic
-also autozone should actually be able to test your alternator if you take it to them

 

Well he did test it and it read at 130 but he said it is acting like there is no connection which is not good, therefor the altenator must be replaced. He made it seem like the amp and battery was not communicating. Im going to go test it now.

 

Install a capacitor for the amps that way the power excursions from the subs thumping will be supplied by the Cap and not the alternator

 

X2-have a sufficient sized power capicotor for your amp, makes a huge differance on power supply

 

Easy answer to that, if your alternator wasn't charging the battery, it would go dead very fast......If your still driving it and it's cranking fine, your alternator is charging it. You may need to clean the terminals to get a better connection, but use the spray on stuff to stop the corrosion from coming back, it works, I use it on all my vehicles. You can use a voltmeter to check it at the battery, think it should be like 13.9 or something. Do a search and see, just the battery would be 11.xx or something, can't quite remember. It would be even lower if the alternator isn't charging.

 

I think I found the problem, maybe not. When I took the negative terminal off the battery, I noticed a light of some sort come on from the back of the altenator. I dont know if it is a bad wire or what, but I dont think a light should be coming on. Oh, and the truck was running fine with the negative terminal off too. What do you guys think about that now? Can I get a new cable for the altenator?

 

my son hasa system in his truck also. the connecters were always coroding until in put the cable cleaner and protector on it .
i got arisol cans at autozone or somewhere.
good stuff saves on the metal

 

The corrosion is from the charging acid fumes out of the battery.
The hi power amp isn't helping things as it causes the battery to recharge more than it otherwise would.
All terminal coatings do is isolate the metal surfaces from the effects of the fumes.
The situation is still there otherwise.
Any battery that is charged more often will fail sooner from internal plate aging due to the extra discharge/ recharge cycles.
Excessive charging for whatever reason drives the water out of the electrolyte and will run low at some point.
All part of a consumable part use.
The guy didn't really tell you much about the health of your charging system.
Was a battery load test done to tell you what the relitive state of battery health is?
Was the alternator max charge voltage or current measured?
You could have gotten the same answer he gave with a $10 multimeter accross the battery terminals.
You still don't know what you have.

 

bluegrass, what about that light or flash coming from the back of the altenator from a location where a cable is coming from? Is that normal? Should I get a more powerful battery? Is there a more simple answer to all of this? This sucks. I dont know if my truck is going to die when I am out and about.

 

I think your seeing a brush arcing.
The higher the load the more arcing.
The arcing should be minimal if the brushes are not worn down, the comutator is in good condition etc..
These are the things that wear out over time and higher currents will accelerate it even more.
Bad battery with one bad cell will call for continious charging in excess of normal and wears the brushes, can reduce fuel mileage from the load, etc.
Hi current draw calls the whole sytem to work on the edge of reasonable expected life, so any one or more faults in the whole system will become apparent, much quicker.

 

What would you do if you were me then?

 

The honset answer is this.
2200 watt amp is way to high for the alternator and battery you have.
With age on all of it, it's worse yet.
Heres how it goes; IF... the alternator is the 110 amp size for example, that means the max allowable power it can safely supply short term is 15 volts times 110 amps = 1650 watts.
Way lower than your amp takes and does not include starting, nite lights, A/C etc.
To boot, this alternator rating is peak short term only and not to be run at those levels continiously because of over-heating.
Maybe that's what you smell
Peak amp power is now drawn out of the battery and makes the battery take power out of the alternator to keep it up.
The constant extra charging is an extra wear on the alternator when you are playing the sound system.
I would upgrade to a larger alternator and at least an 800 to 1000 amp hour battery.
Then you are still running near the limit even with a 160 amp alternator at 2400 watts peak only, capacity.
Note these power figures are at 15 volts and not at 13 because the alternator regulator has to raise the output voltage in order to force charging current back into the battery and the rest of the truck sees the same voltage at the same time..
Think about an ambulence, police car and other trucks and cars that have a lot of power equipment in use. They all must have upgraded power systems in place to survive over the long term..

 

Well bluegrass. Im drinving to work and what do you know? About 15 miles before I get to work, maybe 10, my battery meter drops and everything shuts down pretty much but I am able to drive the rest of the way to work. When I get there and try to re-start the engine, it wont start. I then look at the cable behind the altenator and remember how I described a light from behind it? Well, that cable just comes right off with ease and I am screwed, the battery wont hold a charge. I go to walmart to replace it for free and I tape up that cable so it wont start a huge spark like it did earlier. So, I dont know much about altenators, so I am thinking that I can just buy another cable for the back of it or do I have to buy a whole new altenator? Why me????

 

This sounds like the same problem my brother-in-law had with his 1992 F-150.
His stereo system was stolen so he used a local Cartronics shop that his insurance company contracted with for a replacement system.
The boneheads thought they were doing him a favor by upgrading him to a
1000 watt amp(he previously had a small sub amp - maybe 100watts). Needless to say after a few days he had a melt down at the alternator cable that feeds the battery. The idiots at Cartronics would not own up to their mistake and after several weeks worth of hassle his insurance company finally reimbursed him for a new alternator and cable.