Energy is messured in Btu "British Thermal Unit".
1 Btu is the amount of energy it takes to raise the temerature of 1 pound of water 2 degree Farhrenheit at sea level. 1 Btu is equal to 1 standard match.

solar project

When charging a battery one shouldn't charge the battery with any more than 5-10% of the batteries Amp/hour capacity if the batteries ampHour is 255 then the battery should recieve no more than a 25Amp/hour charge.
A battery should not discharge more than 0-20% of the batteries amp/hour capacity.
Which means that one or more appliances should not draw more than 55Amp/hours from the 255Amphour battery.

OK finally I got some information about what it would take to run my domestic 616kWh refridgerator on batteries.

So the fridge uses 616kWh per year so its energy rating tells me.
That breaks down to 1.69kWh per day or ~1700watts a day or 71watts per hour (71 watt-hours)
The Fridge requires 110Vac (110 Voltage alternating current) so a inverter is required to convert the DC current into AC running the DC current through a inverter means I will need to add 20% to my AC power consumption. Not sure why that is at this stage but I will find out why later.

So with the 20% in mind my fridge uses 85watthours to run.
To prevent damaging the battery I can use only 50% of the battery. This is called "Depth of Discharge" I should not let it drain bellow 50%.

8-D 225-255 Amp hours 12 Volt Used in Solar Electric Systems (= 2700 - 3060 wattHours ? )

If the 8-D battery was fully charged then I could run the fridge off it for 16hours beyond this time the battery would be more than 50% discharged (Should not discharge the battery beyond this point to prevent damage)

So how long would it take to charge the 8-D battery with a Solar Panel that outputs 1.2Amps @ 15Volts (18watts) 255/1.2 = 212hours to full charge this battery.




U1 34 to 40 Amp hours 12Volt 408 watthours would run the fridge for 2.2hours at which point the battery is 50% depleted (asuming a linear depletion)
40/1.2 33hours to charge the battery with a 1.2Amp 12Volt solar panel.
If I want uninterupted power to the fridge then I would need 15 solar panels


40watts 12Volt = 3.33 Amps 12hours to charge a U1 battery.

85watts 12Volt = 7.08 Amps 5.6hours to charge a U1 battery

If I buy a solar panel that outputs 1.2Amps @ 15Volts (18watts) then a battery that requires 30 amp-Hours to be fully charged it would take 25hours to charge and with 2 panels it would take half as long.

It is posable to over charge a battery that is why it is important to buy a overcharger.

To increase the amp-hour out put of the system I need to add another battery. For example a 12Volt 30amp-hour outputs 30amp-hours to double this out put to 60 amp-hours I need to add another 12Volt 30amp-hour battery.

How to double to Voltage ouput or amperage output.
I have a 12Volt 30Amp battery.
I want to double the Voltage output to 24Volts
Connect them in a series
connect 2 of the above batterys like this; positive to negative positive to negative
I want to double the Amperage to 60 amps.
Connect them in parralel
connect 2 of the above batterys like this; positive to positive negative to negative.

If a 20 watt solar panel received 5 hours per day of full sun, then you would have generated 100 watt-hours of energy.
So if I was using a 20 watt compact flurescent bulb with the inverter (we'll call it 25 watts because the inverter uses some energy) then you could run the light bulb for about 4 hours with the energy you produced that day.
If I had a battery that holds 35amp-hours or over 400watt-hours of energy, then I could light the light for 12+ hours before I needed to recharge, but its better to charge sooner.

1.68 kWh per day to run my fridge

A battery stores energy.
Slower Charging and discharging batteries are more effcient.
Alkaline and NiCad batteries are abouty 65% effient.
Lead-Acid batteries are 85-95% effient.

All Deep Cycle batteries are Lead-Acid this includes Wet batteries and Gell Batteries and AGM (Dry Batteries).
Gelled batteries need to be charged slowly, and at a lower Voltage.
AGM (Absorbed Glass Mat) also called "Starved Electrolite" Have all the advantages of Gelled but can take more abuse

Major aplications are:
Automotive
Marin
Deep Cycle: backup power, solar PV, RV and boat power.

Starting or Cranking batery used to start cars
Deep Cycle battery used to store energy and run apliances. Deep Cycle bateries have much thicker plates than Starting bateries (Automotive batteries) thicker plates last longer, one of the main reasons why batteries fail is because of "Positive Grid Corrosion" The positive plate gets eaten away and over time ends up as sediment at the base of the battery. So thicker plates equals longer life.


Battery Size Codes...

• 4-D 180-215 Amp hours 12 Volt Used in Solar Electric Systems.

Remember Amp hours is the number of amps produced in a given hour

• 8-D 225-255 Amp hours 12 Volt Used in Solar Electric Systems

How long would it take to run my Whirlpool Fridge on a "4-D 180-215 12 Volt "
The Fridge requires 60Hz 15-20 Amps 115 Volts.
Its energy rating is 616kWh per year.
1.68kWh per day

Solar Project

I am about to ebark on a journey to see if I can build a solar powered generator. I know I could easily buy one but what fun would that be.

The text bellow is me gathering information much like a bird gathering what ever it can to start building its nest some will be discarded some set aside and pondered and other stuff will be used all will be usefull.

What does amp hours mean ?
-- The number of amps used or produced in a given hour. Batteries are rated in amp hours.
-- This is normally measured at a 20 hour rate. The amp hour rating is the number of amps a battery will supply for 20 hours at 80 degrees F before dropping to 10.5 volts, multiplied by 20 hours. ie If a battery can supply 5 amps for 20 hours then it is called a 100 Amp Hour battery.

What does it cost to run my laptop ?
In order to run my laptop the transformer can recieve 100V-240V ~ 1.2A-0.6A 50-60Hz and Outputs, a Direct current (DC) of 15Volts and 5amps = 75 watts refered to as 75 watt hours or .075 kWh smaller apliances are messured in watt hours.
So @ 12c kWh my lapt0p costs me .9c per hour

The utility company charges you for Wattage not amps or Volts. They bill in Kilowat hour (kWh) ussage (1000 watts = 1 Kilowat) average house hold uses 10,215 kWh a year
Wattage / Voltage = Aperage
Amperage * Voltage = Wattage

Great website for understanding how much it cost to run things http://michaelbluejay.com/electricity/cost.html