Bad battery? Any ideas?

[throwedgsx]

So last night i was on my way home and i decided to do a third gear pull down a straight stretch of road. I went about half throttle and it started spitting and stuttering. I went WOT that it started popping and backfiring. It backfired once really loud and i backed off and the lights went dim and my voltage dropped to 11 volts and my battery light came on. Is my battery shot and there's not enough voltage to go WOT?

 

[wibblersnatch]

It's a possibility. Kind of sounds like your alternator is bad. Take the battery and alternator to autozone or somewhere similar and have them tested.

 

[BootlegGreg]

+1 for alternator. Your alternator is not charging the battery. Your ignition is sucking up so much juice at WOT that your battery is almost dead. Your battery might recover if you get it a good charge and fix the alternator.

 

[throwedgsx]

Right now i have a small Honda battery in the car from Napa. And its only rated at 450 cold cranking amps and 225 load test amps

Also when i start the car up when it's warm, my voltage will sit at around 11-11.5 volts until i rev it to about 3000 rpms. So the alternator is doing its job and charging the battery. But it's like the battery doesn't have enough power for the high voltage draw at WOT

 

[DevilDoug]

Also when i start the car up when it's warm, my voltage will sit at around 11-11.5 volts until i rev it to about 3000 rpms. So the alternator is doing its job and charging the battery. But it's like the battery doesn't have enough power for the high voltage draw at WOT

battery is bad. it is not accepting the charge from the alternator.

then again the alternator may not be workign at its full capacity. check voltage directly from the alternator, dont read the gauge. also try this:

turn car off, take test leads from multimeter and put on battery terminals, take note of voltage, have someone crank the car and take note of voltage drop.

i would also look into your fuse terminal, i have had cars with a broken connection on the fuse box that would move around and cause the car do lose power, sputter, spit, and do all kidns of funky shit. check loose connections and dirty terminals, also check ground wires.

 

[throwedgsx]

turn car off, take test leads from multimeter and put on battery terminals, take note of voltage, have someone crank the car and take note of voltage drop.

What is the voltage drop across the battery going to tell me?

 

[DevilDoug]

it will tell you if the battery is bad...i dont remember what exactly a faulty battery's voltage drop is (.96volts or more?) can someone specify this? meaning the battery is bad if the voltage drops too far when you crank it. now obviously the battery IS going to drop voltage when you crank it...but its a specific number or higher that makes the battery no good.

obviously if it goes from 12.5volts to 10.8 volts when you crank it...that battery is no good.

 

[wibblersnatch]

Your alternator should be putting out more than 11 volts, even at idle. When a battery is fully charged it should have roughly 12.5 volts under no load. Take the car somewhere and have them load test the parts. The alternator also has to have a good amp output as well, nit just voltage.