I am just starting my first solar run with two 85 wpa (>170 wpa) modules,
and I am told a 20 amp charger will do nicely for both
of them (I am using 2 130 ah each gel batteries – I have a generator backup
and an additional charger for a bad weather scenario.
All in all, my equipment is on the generous side
(what else do you NEED to run but a medium-sized computer system?)
– a 10 amp solar charger might do, too.
Remember that batteries do not like to be charged rapidly
but slowly, and that they do not like to be discharged below about
80 percent (even good ones, never mind car batteries).
I would have used a 170 wpa panel and one 250 ah battery,
but these items are bulky and heavy and I thought it best
to get items that one person alonecan still handle – one of
my batteries weighs about 40 kilos, but the bigger one
would have been more than 75 
Remember that the batteries should always be the strongest part
of your setup (but if I had gotten the batteries that would have lastet me a dozen years, I would have had to lay out about 3000 Euros for that alone…)
so I chose the cheaper gel type, they should last about 5 years maybe,
constantly but cautiously used.