Had the car at the dealer about a month ago, they did the 105k service and noted the battery was weak. I elected to go to the auto parts store, they confirmed a weak battery, I bought a new one. It was 3.5 years old, my first battery also lasted about 3.5 years. Never had to jump the car or noticed any problem starting prior to this.

Two weeks later - car would not start and needed to be jumped. I took the battery back, they checked and confirmed that the battery was defective, installed a new battery.

Two weeks later - car would not start, needed a jump. Back to the auto parts store, they say the battery is within limit (but on the low side), alternator is within limits but also on the low side (just over 14v). Also noted that the positive battery clamp is loose and will not fully tighten, they added some dielectric grease and did the best they could to attach the positive terminal as well as it could be. They were very cool about it but asked me to have everything else checked out at a shop to make sure there is not a different problem, for example a current drain. If nothing else is found, they will replace the battery again.

So, I have an appointment Tuesday at the dealer. I suspect the main culprit is the poor connection at the positive terminal, but curious what your thoughts are, or if I should have anything else looked at? Also, has anyone else experienced problems tightening the positive terminal on their RDX? It seems to be tightened all the way down, to the point where forcing it will probably just snap the threaded part off. I thought this was odd, as I assumed battery terminals were a somewhat standard size. Thanks!

 

Start by changing both battery cables , they are most likely the cause of why your battery is going dead.

 

And don't cheap out on them either. Get the best ones you can.

 

I have experienced this issue with a few Hondas. I also have a very effective and very cheap fix: Battery post shims

https://www.napaonline.com/en/p/NW_7...saAte-EALw_wcB

Link is just an example. You can get something similar at any auto parts store. They are made of lead and conform to the battery post.
Never cut off the clamp and put one of those replacement on! If you must replace the clamp, buying the whole cable is the only right way to do it.
I used the shims after pricing the replacement cable on my last Honda.