[Elecraft] What size Solar for 7 Ahr Battery w/K2

[Paul]

I've been looking at foldable solar cell supplies. They come in 
approximately 10, 15, and 20 watt sizes. The cost difference between 
the 10.4 (.75 amps) and 15.6 (1 amp) watt units is $20 and the 
difference between the 15 and 20 (1.4 amps) watt units is  $45 
respectively)

I can see that getting the most Amps one can afford would be good if 
you were going to run your gear (K2) directly off solar - with 
(Don's) controller of course. But if you are running off a battery so 
you go solar cells to controller to battery to rig then it seems if 
you get a solar unit that delivers more amps then you'd want to push 
into the battery for charging, that you are spending money for a 
"High End" that you would never use.

So if a charging amps of .5 amps is recommended, and given the 
variability of solar output, 1 amp would be reliable - then would 1.4 
even be recommended?

That is, it is one thing to justify the extra cost vs the extra 
performance. But if the extra performance doesn't matter, or many 
isn't even desired, then that is an overriding  reason not to buy 
more then needed.

Does that make any sense? That is, is the 15.5W array (1 amp) a 
better match to the 7 Ahr battery then the 20.8W (1.4 amp) array? Or 
should I go for as much solar amps as I can afford that will fit 
within the physical contraints of backpacking and kayaking?

73,
Paul