I just went by fuse rating, either way, just compounds my point. Its no replacement for an alternator or charge pack.
Late to the show as usual!
There is no fuse rating on that page.
Of course it is no replacement for an alternator or charge pack, and it never claims to be, nor does the OP seem to be looking for that.
i'm gonna say there a waste of time
a while ago i had a toyota granvia that wasn't charging properly the battery was good but the problem was the alternator not putting out enough current so i thought i would try a solar panel to try n keep the battery topped up
the solar panel i got was one was about 3 foot across by a foot or so wide i forget the exact spec but it was far better than the average dash mounted solar panels
on an average day it would produce a constant 300 - 500 miliamps the maximum stated output was 2 amps but unless you lived in the sahara desert it wasn't happening
the ambient current draw of the granvia was around 300 miliamps which wasn't a problem with a healthy battery and alternator but with a dodgy alternator it was a bit of an issue
the solar panel made no difference at all the parasitic drain was enough to cancel out the benefits of the solar panel
you'd have to invest in a pretty substantial panel to make enough difference to put some charge back into the battery
Interesting readings, that panel certainly seemed to perform poorly, however that drain is also quite large.
Unless someone has actually purchased this exact solar panel and measured the output I think it unfair to generalise. It even manages to get a 4.4/5 star rating on Amazon from 95 reviews.
Given the stated ratings, the panel should in theory be able to maintain a good charge level for a reasonable number of days on top of what the battery would normally last.
Without real data it would be impossible to say how many. And of course, the battery also naturally loses charge over time which I did not take into account with the basic calculations that I did.
There is also the question of what the needs are, for example if you expected this charger to keep the battery topped up after leaving the car for 6 months I would guess that is not likely. However if you only need the car to start after say 2 weeks instead of 1, that is more likely.
But again, without any real figures it is impossible to say whether it will work in this case or not. Even the position the car is parked in will play a huge factor in how much sun the panel gets, as well as what angle the panel is at etc.