As mentioned in another thread, I had the Batteries in my electric scooter replaced (into their 10th year). I chatted with the bloke who fitted the batteries about recycling or reusing the old batteries (installed 2013). Eventually we decided to try and attach (via a sophisticated battery management system*) these relics to my house SLA batteries. That was about 6 weeks ago. Wunderbar. It seems to be working well. Despite still not having half of the power from my roof top panels (broken inverter) available, moving into winter it seems I can still reach 100% charge on the SLA's, even when I use the scooter every 3-4 days. It's been getting cloudy the last couple of days so I'll be interested to see how it goes.

* https://www.amazon.com/DALY-LiFePO4-.../dp/B08PFPNNJG