ok my car sometimes doesnt start the alt is good i had it tested and the battery is at 100%

when the car is off is at 12.5 volts when the car is starting it gets down to 7.2 volts and when is on its at 14.4

is that normal?

 

Not sure how you tested the battery but it's either severely under rated from what it should be or it's shot. If it was used at one time to start the car ok, it is now shot. No battery should drop below 11 volts when cranking. A defective starter will cause the voltage to drop and crank slowly but it can't go that low on a good battery.

You may also have a bad starter but I know you have a bad battery.

 

thats what i told my dad but he didnt think that i was right
thanks

 

can auto zone check if its the starter and the battery

 

the battery says its 315 amps is that enough

 

is that CCA ?, or CA ?

either way, I'm surprised it starts

 

so its way too low?
if it is should i get an optoma red top

 

Sounds like a lawn & garden battery. Should be 600 or above.

Don't get an optima battery unless you have a charger that can handle it. Conventional chargers will not work correctly.

 

i got it wrong it is a cca 630