1995 Mitsubishi Galant Dying Battery

MOENK5

MEMBER
1995 MITSUBISHI GALANT
4 CYL
2WD
AUTOMATIC
150,000 MILES

I have a 1995 Galant and have trouble keeping charge in the battery which was recently replaced. The alternator has been checked twice and was performing well both times but I am having issues about every other week with the battery dying while I'm driving. The lights begin to dim, and the battery and emergency brake lights begin to dimly light before the car breaks down. If I fully charge the battery Im good to go for another week or so. The other week it was giving me the signs of a break down, then snapped back to life and I continued driving for 50 miles. What are some possible causes for this condition?

1 Reply

KHLOW2008

MECHANIC
41,814 POSTS

Hi moenk5,

Thank you for the donation.

Symptoms indicates a charging problem and possible causes are :

1. Faulty alternator. It could be failing intermittently and testing might not be conclusive. Get a vlotmeter and with engine running, test the charging rate between battery terminals. It should be between 13.5 to 14.5 volts without load.

Turn on AC and headlights, It should not drop below 13 volts.
Remember to run the engine for a few minutes before performing testings.

2. Slipping belting. Check belt tension and crank pulley harmonic balancer. If the hamonic balancer is bad, it could be slipping on the crank pulley and this would reduce the alternator rpm and cause charging deficiency.

3. Bad connection between alternator and battery. Compare charging rate between battery terminals and the rate between the alternator main post to ground, They should be similar.

4. Bad ground circuits. Check alternator bracket and ground between engine and body.