I suppose the battery could be bad but 2 brand new batteries back to back seems unlikely. The alternator is good as I don't have any problems if I drive the car at least for a short trip every day. I can go months without problems if I drive it every day, it's that once I leave it for a day.Yes. Do have your battery checked. Do have your alternator checked as well. Many auto shops do this with ease (and at very little cost).
If both areas are "good", simply park vehicle Friday night, remove one of its battery cables and leave battery disconnected until Sunday night. Sunday night (after sitting for 48+ hours), reconnect battery cable and give it a try. If battery is dead, then battery is "self draining" (even if tested good). If battery good, then something inside vehicle is draining the battery (aka: Parasitic drain).
True story: One of my previous vehicles had a 100% good tested battery and 3 days later (if vehicle sat that long), its battery would be flat dead. Disconnected its battery the long weekend and found it the problem areas. It's 2 month old battery was self draining - even though it tested 100% good. This might be root cause for your vehicle as well....
Hope this helps.
Like I said I find it unlikely that 2 new batteries would be doing the same thing.That happened to my 2013 Venza back in 2014. The oem toyota battery after 1 year of use would only hold charge for 4 days max. I ended up replacing it with an AGM battery and it lasted me 7 years.
Did you recharge the battery back up to 100% by any chance? Do you turn on the headlight when driving?
Thanks I'll check it out.if the battery is good, the alternator is good, and the battery is getting an adequate charging while driving. Then you are left with only one explanation...your battery is experiencing an abnormal current draw while the car is sitting, aka parasitic load on the battery. There are several yt videos on the subject and several threads on this forum on how to test for this condition.
So I did see it could be the a/c relay, I will be replacing it tomorrow to see if that cures the problem.There's a couple of recent threads in the specific battery topic on parasitic drain that might help.
"unlikely" STILL needs to be ruled out with a proper load test of the battery and checking it's internal resistance and CCA.Like I said I find it unlikely that 2 new batteries would be doing the same thing.
I know the battery and the alternator are both good because I do frequent long weekend drives (over 100 miles) with both headlights and a/c on with no problems at all.
If you google it there are stories of people who started having this issue within the first year, for me it was after 5 years but like one of the posters have said I drive around now with a power pack and jumper cables in the car at all times.