Sorry in advance - I have some likely-stupid Seiko battery questions.

The second hand on my solar Padi Prospex (SNE499P1) started jumping a few months ago and then stopped last month (I bought it new in June 2019). Not thinking about it being solar, I took the back off to replace the battery. But, when it dawned on me that it's solar, I reassembled and placed it under a lamp - and it is ticking away again. Two questions:

1. How long should it take (under lamp or daylight) for the battery to regain full charge, and should I expect it to hold this again (similar to new) once recharged? Apparently the battery should last 10-15 years, so it's still young. I have been guilty of leaving the watch in the kitchen cupboard, so I'll let it see more daylight in future.

2. The battery in the watch is a TS920E. But, this looks to the wrong battery for the module inside the watch (which is the V157). The TS920E looks to cover modules V172-V176, and the V157 should use the MT920 battery. If I'm buying a replacement battery, which one do I go for?

I'm sourcing my info from a watch battery website, nothing more technical.

Thanks for your time.