CreviceSucker said:
So if its 72 Watts load x 24 hr >> = 1728 Wh
1728 divided by 12.0 = 144 Ah
3 x 120 Ah batteries = 2.5 days of runtime
4 x 120 Ah batteries = 3.3 days runtime which is okay
is that interpretation correct ?
with deep cycle AGM what depth of discharge does their amp hour rating include ?
I guess a big part of this will be the honesty (quality) in the battery rating
That is not nearly enough Battery power to be able to supply that amount Amperage,
The thing you need to take in to account is you can't drain the batteries down using the full 120 Amps, To be able to use that amount of power you would need 6 X 120Ah Batteries because you don't want to be draining them down below 50% for 2 and a half days,
To work out the exact power requirements We need True power Draw specs from every Item being used, Not Quoted figures from the back of a manual or a DATA Sheet because out of thousands of hours of testing I have only found one Item that actually used the Stated Power Figures,
I have a conversion Calculator If you want to know what size Solar Kit you need where you type in the figures of whats per Hour and how many hours a day it will be running and it will tell you what size Basic system you need and then it will adjust those figures to what you will actually need, and it will list the Sun Hours for that month but because you are in Australia you have to reverse the figures because the Aussie winter is 6 months ahead of the UK winter, So what happens in January in the UK happens around May/June time,
Another thing that is Always over looked is when WE talk of SUN HOURS, Where you might get 6 hours of good sun in winter where those panels are working from 60 to 80% of their ability so a 500w panel is putting out IE 300 to 400w for 6 hours that 2400watts The Panel is still collecting power early morning and in the late afternoon where it will provide between 15 to 30% of its Capacity So at around 20% it could be putting out 200 watts for about 2 hours in the morning and around 300 watts in the afternoon, So with 2400 + 200 + 300 you could get 2900w throughout the day, On the other hand if it is Cloudy all day then you might only get 25Amps for the whole day which is Only 300 watts per Day, This is why you need 6 X 120 Batteries in order to have the power in reserve, and If you get 2 or 3 Cloudy or rainy days in a row then you are going to need a 30/40 Amp Charger just to keep the batteries at a safe level.
First thing you need to do is work out the correct Wattage Needed,
Then Match your Solar Panels to your power needed then Match the Batteries to the Panels, By Rights for every Watt of Solar you Need you must have at leased 1 Ah of battery Power, So if you need 1200w of Panels then you need 1200 Amps of Batteries,
As a Rough Guide take the figures from the manuals and add them up and post them here and I will workout what you need, List the Item and the wattage and how many hours each item will be running then I can give you the figures to match,
Hope that helps.
