It all started about 2 months ago when my civic(190000km) wouldnt start after sitting for 2 days in above freezing temperatures. Jumped it with little difficulty but wanted to check the battery regardless, turns out its good, the battery is about a year old and was cheap but I wanted to make sure.
I did buy and instal new battery terminal connectors, cut back some of the wire because it had heavy corrosion.
Still would die if it sat for too long, so through process of elimination the alternator is next on my list. Swapped it out but never got a chance to test the old one or let my car sit and wait for it to die. Seemed to do the trick, for now.
Fast forward to the holidays, I was going out of the country for a week and still didnt fully trust my vehicle, so i removed the battery because the temperature was going down to -25 C. Got home, aside from my locks being frozen (and now broken, but thats a different problem) it started fairly well. Drove it all day running errends, dies 12 hours later(extremely cold out but still). Boost, die, locks frozen, boost, die.
Boosted it, drove for 30 min, got gas, dead.
Now it warm out, 5 C, boosted it, runs fine for a couple days, listen to the radio for about 10 minutes with engine off, cuts out, dead again.
Went and got the battery tested again, its fine still.
Is something draining the battery? Bad ground? Corroded wires? How would I pinpoint that?
There is an aftermarket radio( nothing special) and an after market autostart which constantly give me issues, auto start currently doesnt work, it beeps and the interior lights go on but it doesnt seem like an ignition attempt is made, locks on fob work fine.