The Vehicle is a 2001 Kia Carnival TDIC

When the stock battery finally gave way, we replaced it with a motolite 3sm battery, the non-maintenance free ones where you're still able to add distilled water. I noticed that it is quite smaller than the one it replaced but it also has "six" rows.

Btw we use the vehicle 3 times a week which means not everyday. After a few months of trouble-free operation, when i was trying to start the car, it just wont start. the instrument lights are bright, the starter is cranking, the glow plug light on the instrument panel comes on and comes off. after a few cranks the battery dies down. I cannot jumpstart it because its an AT. so i connect it to our other car's battery and it starts right up. If we use it again tommorow, it starts right up. but after a day or two, same thing happens again:confused:

What could be the culprit here.. :confused:

btw i've noticed that after some time the terminals gets filled with these dried up battery acid.