411 on equipment needed 2 set up 6/51watt panels

If this is to be a 12 volt nominal system then start by adding up the wattage of all the PV modules and divide by 12. If its 6 X 51 then you have 306 watts. If you 8 X 51 then that would be 408 watts total.
I chose the lesser of the two, 306 watts for, this example of how I would caculate the system.
So, 306 watts divided 12 volts equals 25.5 amps.
Now the NEC and UL together demand the addition of 156% to that amperage when sizing; wires, fuses, disconects, and charge controllers.
So then, 25.5 plus 156% equals 39.78 amps.
A 40 amp charge controller with nothing smaller than #8 awg THHN copper wire and 40 amp disconnects and 40 amp fuses where needed. You can go through all of the temperature rating and conduit fill calculation if you want to, but I feel that the 156% takes care of all that. One thing you may want to do though is consider line loss from wire length. Chances are in a short wire run that 156% will cover that as well.
Now to size the battery bank.
I like to calculate that based on what the needs are and then size the PV array but since you have the PV array I will start there. We know the PV array will put out 25.5 amps at 12 volts, but for how many hours a day will it do this? I am going to say 3.5 hours. Thats what it is where I live on the shortest day of the year Dec. 21.
3.5 times 25.5 equals 90 amp hours a day.
ok, 90 is 20% of what? That would be 450 amp hours at 12 volts of battery storge. Now you will need too round this up when when you start to look at buying batteries. Site conditions have a lot to do with these calculations as well. Your region as well as weather paterns and avialable unshaded sunlight from 8:00 am to 4:00 pm on the PV array will all have a bearing the autonomy of the system.

Another way of calculating wire size and fuse's and charge controllers is to take the Isc which stands for Impedance short circuited, or the same as amperage short circuited, from the label on back of the PV module. For a 51 watt panel that will probably be around 3.5 for a 12 volt nominal PV module. While you are looking check the voltage on the label as well if its 12 volts nominal the the Vmp or Volts at maximum power (or what I call working voltage) should read some where between 16.5 to 17.5. Whats the brand name?
Getting back to wire size, take that Isc value and add the 156% I mentioned on the previous post.
What that 156% is for, 125% to satisfy the NEC National Electrical Code in addition to 125% to satisfy UL Underwriters Labratories.
125% x 125% = 156%
The reason for this is because they believe that under just the right set of circumstance a PV module will exceed its Isc value. Some of those circumstance are; freezing temperatures while there is a certian kind of cloud that cause a magnifying effect at its edge while there is a short circuit. Very rare, but it could happen and if it does youll want wire big enough to carry those amperages safely.
Getting back the calculations. I will use 3.5 for the example. 3.5 + 156% = 5.46
5.46 x 6 = 32.76
But thats not the end of it calculating this way.
There is derating of the wire for the number of current carrying conductors in a conduit. Also, the wires temperature rating, the ratings of the terminals in the disconect, ambient winter time air temperatures, line loss, etc., etc.. Suffice it to say that after all of that calculating you will still come up with something just under 40 amps as I showed in the previous post.
Go to www.sandia.gov/pv and high light -Publications - then - Codes - and then - John Wiles Code Corner - to learn more about calculating your PV source circuits.