Overcharging.

hello
On Octopus Flux night charge 2-5am. Can you overcharge your batteries if you charge it for the 3 hrs?
If the batteries are at 80% can you only charge them for 1 or 2 hrs only?

Thanks

The BMS will stop you overcharging. You absolutely could charge your batteries faster than you strictly need to though. This isn't a massive issue but it will be slightly less efficient and place slightly more wear on the batteries.
If you ever use PredBat then you can configure it to charge as slowly as possible whilst still being full by the end of the cheap period. That's a lot of complexity though if you only want to reduce the charge rate and I imagine they are designed with full rate charging in mind.