The Hota Thunder AC6 is really old tech. This was a cheap, knock-off charger when it was new 10 years ago.
And, at 50 Watts maximum charge rate, it is a slow charger. It might charge a 6S pack at a maximum of 2A. And forget about parallel charging multiple packs.
While I can't find the manual, I'd bet it doesn't have a automatic charge setting for "Storage" either.
Normally, you'd monitor the charger and battery when you are charging in case something goes wrong. And with an automatic balancer charge-mode and 100% cutoff, that means sticking your head out the door once in a while to see if the garage is on fire.
But having to manually halt the charger when all the cells in a pack reach 3.7v is a pain and not something you are likely to do on a regular basis.
I'd add a "new charger" to the list of things you may need to buy.
In the mean time, make sure you use the balance charge mode.
Last edited by ticedoff8; 06-14-2022 at 08:48 AM.