Originally posted by mybigunit
I just looked at the batteries how do you know which battery is the best?
Have a look at 'recreational' or 'deep cycle' batteries, these are designed to provide a steady current flow over a long period of time. There are
a 3 main types available that all have their pros/cons:
Flooded cell which is the typical design found in vehicle batteries using liquid acid electrolyte
Gel cell where the electrolyte is in gel form rather than liquid
AGM (Advanced Glass Mat) which uses liquid electrolyte but is absorbed in a dense matting of glassfibres between the electrodes
Both AGM and Gel types are more reliable in terms of lifespan but can be damaged by overcharging, particularly the Gel cells. Also, as these two types
are commonly 'sealed' units (you can't top up the electrolyte) greater care must be taken with charging/discharging levels
What is AH?
Basically Amp/Hours (Ah) indicate the amount of current that each battery can store and discharge until completely drained.
For instance, a 100Ah battery would theoretically give you 10hrs @ 10A current, and as you mention that you are looking at 4 units, if you wired them
in parallel, would give you 4x the Ah rating at the common voltage of all the battery units (series wired will give you 4x voltage at the common Ah
Here's a useful link on batteries and Amp-hours: Understanding Amp Hours
If your still at the design-stage of your system, start with working out what your power requirements will be, and from there look what system voltage
you'll want to work with (12V/24V/48V note: the higher the voltage, the proportionally lower the current and vice-versa).
This should give you the size of inverter needed and you should then end up with an optimum output figure to guage the size of solar array or wind-gen
wattage needed to charge the battery bank
Hope that helps any
edit: checkout the link in my sig...a very informative site for all things DIY power related
[edit on 17-12-2008 by citizen smith]