Alternator?

[Super ranger 01]

Hey guys. I just have a quick question maybe one of y'all can ask for me. I have a 2001 Ford Ranger 4.0 four-wheel drive I have now went through two batteries the alternator is charging but seems to be a low charge that it keeps until it kills the battery totally... is there a reason why the alternator is keeping such a low charge on the batteries or do I do just need to replace the alternator?

 

[Dirtman]

Need numbers.

What is the battery voltage with the truck off? Should be 12.5v - 12.8v, any lower and the battery is low. Needs a charge or is dead.

Once the truck starts voltage should shoot up to around 14.5v then slowly settle down to around 13.5v after 10-15 minutes. Test these 3 voltages directly at the battery. Then test these 3 voltages again but attach the positive lead of your dmm to the alternator battery feed b+ and the negative lead to the alternator case. The numbers should match both ways, if not you have a bad wire or ground issue. If they are low on both tests, alternator is most likely failing.

Also may want to check for a parasitic draw. Something could simply be constantly draining your battery slowly. A stuck relay, dome light not shutting off, shorted radio circuit etc.

 

[Super ranger 01]

Need numbers.

What is the battery voltage with the truck off? Should be 12.5v - 12.8v, any lower and the battery is low. Needs a charge or is dead.

Once the truck starts voltage should shoot up to around 14.5v then slowly settle down to around 13.5v after 10-15 minutes. Test these 3 voltages directly at the battery. Then test these 3 voltages again but attach the positive lead of your dmm to the alternator battery feed b+ and the negative lead to the alternator case. The numbers should match both ways, if not you have a bad wire or ground issue. If they are low on both tests, alternator is most likely failing.

Also may want to check for a parasitic draw. Something could simply be constantly draining your battery slowly. A stuck relay, dome light not shutting off, shorted radio circuit etc.

Ok...thanks dirtman..i can always count on u guys havin great info