This is my wife's friend's car, a 2021 Hyundai Venue.
It did not come with a block heater, and did not start this morning (or even turn over) even with a boost. It was a chilly -32°C this morning.
I removed the battery, brought it home, thawed it out, and charged it.
It passed the load test (Schumacher resistive tester - 100 A for 10 s - with flying colours.
I now have it on my ampacity-testing rig, drawing about 8 A. Here's the set-up:
View attachment 253915
The battery is original, and is rated at 45 A-h and 410 CCA. In perfect condition, then, it should supply 8 A for over 5 hours.
What if it quits at 4 hours (< 80%)? 3 hours (< 60%)?
Is there a rule-of-thumb for when the battery should be replaced?
Thanks!
P. S. Regarding the absent block heater, I won't install one in this weather, but will lend her my magnetic surface-mount 200 W heater.