Series/parallel battery amp hour question!

[ClydesdaleKevin]

Just to refresh my memory:  With two coach batteries, in series, voltage doubles and amp hours stays the same...and in parallel, voltage stays the same and amp hours double, correct?

All four of my solar panels were delivered today with no shipping damage, and each panel is putting out 21 volts.  So now I have to design my storage battery system.  I only have room for 2 coach batteries in the stock location (under the steps in the doorway).  So, assuming my above statement is true, that using 12 volt batteries hooked up in parallel leaves the voltage at 12 volts, and doubles the amp hours, I'm thinking of going with Trojan AGM 12 volt batteries instead of Trojan wet cell 6 volt batteries.  That way my amp hours doubles, and I can expand the battery bank into either storage compartment on either side of the entry door with more Trojan AGM 12 volt batteries without having to worry about hydrogen gas and acid venting.

Am I correct?

Thanks!

Kev

(p.s.:  My charge controller will bring the 21 volts X 4 down to charge voltage, so I'm not worried about that number right now).

[tmsnyder]

Yes, 2-12V batteries in parallel gives you 12V and 2x the amp-hours capacity.   How many watts are the panels?

[ClydesdaleKevin]

Yes, 2-12V batteries in parallel gives you 12V and 2x the amp-hours capacity.   How many watts are the panels?

100 watts each, for a total of 4 panels/400 watts.

Kev

[tmsnyder]

That's a lot of juice! 

[ClydesdaleKevin]

That's a lot of juice! 

Yep!  It should be more than enough, but there is room on the roof to expand latter on if I want to add more panels.  Batteries are my biggest issue.  I only have room for two coach batteries in the stock location...so I am thinking of going with AGM batteries so I can add more batteries to an unventilated compartment if necessary later on.  Or I guess I could add a box to the compartment and then ventilate the box to the outside.  Decisions decisions...

Kev