Off Grid Solar and Wind Power Houses

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 rating)

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]

Hi I have had solar water heating fitted and I watched the owner measure the temperature of the condensor in the sun. It reached 170 celsius I dont know if your going to get these kind of temperatures from a hand made water heating system and I only had them fitted because I was old. It does not seem to complicated and the collector prices have come down now. Anway see this solar water heating company its got some great drawings in it and the owner paul was helpfull