BMM88Mustang

The past few weeks I have had to jump my 88 5.0 more then 4 times. I just got a new alternator last mounth. How can you tell if the problem is from a bad battery or not. I checked the voltage and it was at ten volts. I charged it up, and checked the voltage again. Now it was alil above 12 volts, I tryed starting the car and it was turnign over then would just start making a clicking noise. After trying to start the car i checked the battery voltage again and it was 11 volts. Can any one tell me if its def the battery or maybe another problem?
Thanks in advance

5IVE.OH

Run your car and while it's running remove the negative battery cable, if it stalls it's the alternator, if it keeps running then it's the battery.

Archion

How low does the voltage drop when you are trying to start it, it should not drop below 10v on a full (8hr) 12v charge.

hammeron

with the car running, the battery voltage should be around
13.5 - 14vdc.....if it is, then the alternator is charging properly.

Archion

That is only safe on pre computer cars, do that on an ecm equipped car and you risk buying an ecm. and it is not always true.

Colorado_Mustang

Time for an Optima Red Top.

Or you could just take your battery to your local auto store and have it tested...

hulian

i work at autozone if you bring it there they can test the battery for free. your standing voltage should be around 12.4 when the car is running anywhere from 13.45 to 14.5. if the battery drops below 10 volts when there is a load on it, it is most likely bad. like one person said you can't always tell if the alternater is bad just by unhooking the battery, a lot of your newer cars will die as soon as it is unhooked since the car must a power source to run the computer.http://www.autozone.com

Battery for a
1988 Ford Mustang

Item Part
No.

DURALAST 58-DL 7 YR $10.00 $49.99
** 540 cold cranking Amps (675 cranking Amps) **
-> 2 year free replacement <-

GOLD-DURALAST
Direct fit 58-DLG 8 YR $10.00 $69.99
*** 610 cold cranking Amps (760 cranking Amps) ***
-> 3 year free replacement <-

corvetteguy

Make sure all the battery terminals are
brite and tight.
Don't dissconnect the battery terminals
when running the voltage will go
dangeriously high with an alternator.
When car is off it is possible the new altinator
is discharging. I had to return a NAPA
alternator after a weeks worth of discharge.
With car off measure the battery voltage once an hour and
see if it is going downhill.
Take the wire off the altinator and see if it stops.