My car won't reliably start-up

Last week, I needed to move my Subaru from the driveway, it sluggishly turned over and started. Later that day, I went to move it back into the driveway and it wouln’t turn over at all. However, my dash lights on buttons were glowing. It then randomly started up for my husband a couple hours later and he pulled it into the driveway. The next day, he had to jump the car to start it up and he took it to the shop where they replace the corroded heads of the battery cables. Said the cables were okay and that the battery was charged (would a no-good battery show decent charge simply because it was jumped?). The following day, the Subaru started up fine for my husband who went to run an errand, but upon returning to the car in the parking lot, found it unable to start, again! I met him with our 2nd car and jumped the Subaru, then followed him to the Subaru dealer shop. Their master mechanic has yet to determine what’s going on. Please, any and all ideas welcome. We JUST bought this used Subaru in August, praying it’s nothing serious. Thanks!

I had a '79 Fiat that had the same problem (except it did not have corroded battery cable termials). After much messing around with starter relays and such, discovered it was bad ground connection. Replaced the positive and negative battery cables and did not have any problems for the rest of the time I had the car (17 years). My feeling is that if the cable heads were corroded, the rest of the cable could have problems , especially where they connect. You might want to have the cables replaced or at least checked (especially the ground).

I would just have the main cables replaced.

Was the battery load tested or did they simply check the voltage? If the car is being started often, but only being ran a few minutes at a time it’s possible starting the car is using more power out of the battery than is being replaced by running for only a few minutes, therefore depleting the charge in the battery. I would also suggest checking the cable connections at the starter and ground to make sure they are clean/tight. If the car will start with a jump it’s either something to do with the battery, cables or charging system. Most national chain auto parts stores will test the battery and charging system free.