I've always wondered why you're always putting electricity in it and it turns out that you've been going round with a shagged alternator?

Don't tell Mrs TB. She'll remove your nads! 
When we had 3 cars, pre Chinese Sniffle, one - usually the Battlebus - would go weeks on end unused. And the Battlebus needed lots of electricity due to knackered (sheared) glowplugs. That said, it never, ever failed to start.
During and since the pandemic, my car doesn't get used much at all. And if its not used for more than about 10 days, it will go on charge.
Batteries don't like to be left in a partially discharged state

So, yeah, I have had my money's worth from this charger
