Does anyone use solar for charging batteries?

I've read a lot of battery posts as it seems to be a pretty regular topic on this forum.  Pretty sure I will stay with the SLA.  My small SLA is a bit of a beast but it will work for now.

I did do a "search" and let me just say, "Solar" pulls up an a lot of posts.  There was a post from 2012 (DIY Battery Box) where DanWulf posted his setup complete with a solar charge controller and a small panel that really caught my interest.  Many mentions of harnessing Solar Power while out on the water but very little in the way of actually showing how people did it.  Too small of a panel and the exercise is pointless.  To large of a panel and it will be in the way.  The charge controller also needs to be kept dry...

Are people using Solar Charging on the water.  If so, what are you using and how are you setting it up?

I use a 7amp SLA to power a HOOK-5 and run it with the screen as bright as it gets.  It's at 12.6 volts when I start and eight hours later, it's at 12.4 volts.

Don't know what size (amps) your SLA may be, but even a 6amp should be good for at least two days.

Given the discharge rate of an SLA battery, would on-the-water solar re-charging be worth the initial cost?

My SLA is a 35AH, so a smaller SLA is in my near future.  I already have a few small solar panels and a small charge controller just collecting dust and patiently waiting for my next "that was a really dumb idea to come along" haha.  I'll be running a Dragonfly 4PRO and anticipate the wifi to be used by the kids a fair amount.  However, that's getting off topic...

Many posts I've read recommend that people carry a spare battery with them.  Wouldn't it be more efficient to have some method of re-charging on the water?

Google "Solar Kayak" and click images.  It's certainly been done...  I'm assuming more people than just DanWulf (very few posts) and PolePole (I never did find the full review of the Goal Zero).  I've found a few old posts where members have mentioned they wanted to try solar.

I don't know that initial costs are all that high for solar in the scale we're talking about.  Even in Canada where we pay way more than our friends to the south on pretty much everything!  A flexible 20 watt solar panel and a 10 AMP basic controller with USB outlets built into it, can be had for about $55 on Amazon.  A 20 watt panel can produce just over 1 amp per hour in optimal conditions.  So we're only talking about 20 watt panels and at most 30 watt panels.  After that, the size becomes overwhelming.

I don't know how much $$$ forum members here have spent playing with Blue Bricks, LiPo, AA setups, etc. to simply resort back to the SLA battery?  Pretty sure many have spent a lot more than $55 CAN ($45 US) though.  Granted, it's hard to put a price on having fun!