won't my car battery start it is new as well as the alternator?

Question

it won't hold a charge

Answer 1

If it won't hold a charge it has an internal short or has no electrolyte

Answer 2

Couple of things to check,...

Turn on your head lights, and ask someone to watch the headlights as you try to start the vehicle.

1. Are the headlights bright? They should be reasonably lit.

When the car is started, the lights should dim just a bit.
If this is the case, it is probably not the battery.

If they go out completely, then you either have a bad or drained battery, loose battery cables, shorted starter, or weak fusible link.

. Borrow a DC voltmeter from someone. ( be sure you know how to use it ).
. With the vehicle not running, measure across the battery. Red is positive, and black is negative.
The voltage should be about 12V.
Turn on the headlights, the voltage should still be about 12V.

Start the vehicle, get someone to help you to jump start the vehicle if necessary. Use ear plugs if you have them, and safety glasses. ( batteries can explode).

( Always connect the red positive to red positive first on both vehicles, then connect the first black jumper on your bad vehicle to the battery ground post and the last connection is made to the chassis or motor mount of the good vehicle, not to the battery. Because when you make the last connection, there will be a spark. It is very important that you don’t make sparks near a battery, especially on the one being charged ( the bad one). This is why the last connection is made on the good car away from the battery post. ).

If it still doesn’t start when jumped, the problem could either be the starter, fusible link, or solenoid.

Turn on the head lights, they should be bright.
( if not, the problem could be the fusible link, but probably not)

After the vehicle is started remove the jumper cables.
( try not to leave both vehicles running for too long with the jumpers attached, only as long as is needed)
( Always remove the cables in the reverse order, so break the connection at the good car at the motor/chassis location not at the battery).

Measure the battery voltage while the vehicle is running.
It should read about 13.8V ( about 14V to 16V).
If you measure only about 12V or less, the alternator is NOT working.
If this is the case, first thing is to check the fuse panel. The fuse for alternator charging may be blown. The fuse should be labeled, but check your owner's manual for fuse location.
If the fuse is ok, the alternator is probably not hooked up correctly or is defective. ( most likely is the fuse is blown)

Also when the jumper cables are removed, watch the headlights, they should not dim much. If they grow dim right away, you probably have either a bad battery, bad alternator, bad battery connection, or bad fusible link.

OK,
( IFF ) if and only if,
( When the jumper cables are removed, with engine running AND the battery voltage is about 14 to 16V with the motor running and headlights are bright, and engine running smoothly then:
Drive to Autozone, where they will diagnose the problem for free.
( you might call ahead to be sure)
Wal-Mart also can diagnose a bad battery or alternator. Wal-Mart will replace the battery ( paid and installed for about $45).

But you said the battery and alternator are new.

So I suspect the fuse is blown under the dash that is responsible for charging ( "alternator" or charging fuse).
Probably, when the installer connected the alternator wires, they did not disconnect the battery negative terminal first, and popped this fuse.

If this is the case, then your battery is not charged.
You need to borrow a battery charger, and let is slow charge for a few hours, then switch to normal charge.
If the charger has a "Start" position, do NOT use this position, as it will destroy your battery of left there for more than a few minutes.

What about using another car to charge your battery?
Answer: It will take a lot longer than you may think.

Jumping your car to another car, and letting the other car charge yours while yours is off
( Do Not run both at the same time while jumped for any longer than is needed for jumping),
will add charge to your battery, but will take a long time. A lot is lost in the connection. If you try this, allow the good vehicle to idle for at least 2 hours charging your battery.
Don’t rev the motor, this doesn’t help. The alternator of the good car controls the charging, and is independent of motor speed.
But be sure only the good vehicle is running, not both.

After charging,
Disconnect the charger.
Measure the battery voltage with the vehicle off.
The battery should read about 12V.
Turn on the headlights, they should be bright.
If the battery voltage is less than 11.5V, the battery is probably bad.

Try to start the car, it should start.


May the force be with you...


Austin Semiconductor

Answer 3

I bet something is staying on that should not be. Check the light in the glove box, trunk, dome light, etc.

Answer 4

you may want to make sure the posts are clean.
also, a new item is no guarantee against it being defective

Answer 5

its your starter.its drawing out the juice in your battery.check the starter.

Answer 6

There could be a problem with your Starter.