Today car didnt want to start, got it jumped took it to auto zone test results battery is Toast, no good.... thank goodness for warrenty....my question what causes this and the guy said the alternator is fine

also when im cruising in hear at high rpm car back fires more then it used to what could it be

 

Something is draining the battery probably.... Audio Amp left on, faulty interior lights,alarm going off...

Battery could be shorted out... Backfire could be from unburned fuel (running rich).... o2 sensors,iacv or cat is probably at fault (clogged)

Also is your tune up... up to date? You could also have a misfire going on.

 

only thing i havent changed are spark plugs everything else is up to date, even the ecu was tuned

 

Cheap batteries have thinner lead plates which could distort. The plates could be touching.

 

replace spark plugs they were brown , old couldn't even see the white tip no more and it help'd

 

they just wear out the cheaper they are the less life you can expect, also if you have some large stereo system that wouldn't help.

 

i have no system, only thing i can think of last month i hit a speed bump really hard, flattened my header....maybe battery was damaged by the force of impact

 

how old was it, want brand, and how much those cheap batteries you get maybe a year or 2 tops....seriously. even if you used it a lot when the car was off/ran it dry several times that will contribute to it's wear.

 

What kind of battery is it?

 

If you're having cold weather, that may have pushed it over the edge.

 

When the active material in the plates can no longer sustain a discharge current, a battery "dies". Normally a car (or starting) battery "ages" as the active positive plate material sheds (or flakes off) due to the normal expansion and contraction that occurs during the discharge and charge cycles. This causes a loss of plate capacity and a brown sediment, called sludge or "mud," that builds up in the bottom of the case and can short the plates of a cell out. This will kill the battery as soon as the short occurs. In hot climates, additional causes of failure are positive grid growth, positive grid metal corrosion, negative grid shrinkage, buckling of plates, or loss of water. Deep discharges, heat, vibration, fast charging, and overcharging all accelerate the "aging" process. Approximately 50% of premature car battery failures is caused by the loss of water for normal recharging charging due to the lack of maintenance, evaporation from high under hood heat, or overcharging. Positive grid growth and undercharging causing sulfation also cause premature failures.

Found this easy enough, also, the big vibration (header hit) can cause internal damage as lawn mowers experience short battery life because of bouncing etc..