A 400 Watt 200 V bulb is supplied with 100 volts power consumption by the bulb will be

So you want to set your rig up for Solar but you are not sure what size of set up you need? This blog is designed to give you the tools needed to be able to work out exactly what are you are drawing from your rig's batteries and what type of solar set up you need. Knowledge is key when setting up your rig for solar so the more information you have on each and every one of those home comforts devices you plan to take away with you the better. If anyone has a question pop it in the comment section below. I will try my best to answer everyone.

How to work out Watts, Amps and Volts

A larger solar panel will collect more energy in less time, but just how big does the solar panel need to be?

The power consumption of appliances is usually given in Watts. To calculate the energy you will use over time, just multiply the power consumption by the hours of use. For example:

10 watt device used over 3 hours equals 10 x 3 = 30 Watt

How to convert Amps to Watts

The energy in Watts is equal to the electric charge in Amps times the voltage in volts:

Watts = Amps × Volts

Example

If your device doesn’t have the Watts labelled on it, then it should at least have the input Volts i.e. 240V and the Amps AC it draws such as 240V – 1.5A. You can then use the equation Watts Volts x Amps so 240v x 1.5amps = 360 Watts.

How to convert Watts to Amps

The electric charge in Amps is equal to the energy in Watts divided by the voltage in volts (V):

Amps = Watts / Volts

Example

Find the electric charge in Amps when the energy consumption is 300 watts and the voltage is 240 volts.

300 Watts / 240 volts = 1.25 Amps

Do I need a battery?

Solar panels are commonly used to charge a battery – not to charge a device directly. There are a couple of reasons for having batteries. Solar panels might not generate enough wattage to directly power an appliance, but they can build up a higher wattage via a battery. Secondly a battery can regulate the power going in to the appliance at a constant rate. When solar panels are charging a battery it is usually at a varying rate which could harm an appliance if not regulated.

Battery capacity is measured in Amp Hours (e.g. 120Ah). You need to convert this to Watt Hours by multiplying the Ah figure by the battery voltage (e.g. 12V) – see calculations above.

AH refers to amp hours. This rating is usually found on deep cycle batteries. If a battery is rated at 100 amp hours it should deliver 5 amps of power for 20 hours or 20 amps of power for 5 hours.

When choosing a battery, keep in mind the equipment you will be powering and the time in which they will be running. Theoretically a 100Ah battery can deliver 5 amps over a 20 hour period (and so on). Taking into account the average small campsite - with a small 45W fridge running for 6 hours, 3 hours of 15W lighting and 20W of other electronic equipment - the minimum consumption to be expected is 335W. Take this wattage and divide it by the voltage, 12V, gives 28Ah. With the aim of leaving 50% in the battery brings the requirement to 56 Ah per day. A smarter battery setup would be to use an iTECH120 120Ah lithium battery. This new type of battery is a fraction of the weight of old style AGM batteries. AGM batteries usually weigh 35kg but and iTECH120 battery weighs just 13kg. You can also use more of the battery capacity in an iTECH120 - 80% which means its usable Amp Hour rating is similar to a 200 Amp Hour AGM. View our 12v lithium battery range. They are Australian designed and built for our harsh environment.

What size solar panel do I need? 

Solar Panels power generation is commonly given in Watts e.g. 120 Watts. To calculate the energy it can supply the battery with, divide the Watts by the Voltage of the Solar Panel.

120 Watts / 18v = 6.6 Amps

Please note that Solar Panels are not 12v, I repeat Solar Panels are not 12v. Any one who works out the Amps of a solar panels using 12v as the voltage calculation does not understand solar or has been misinformed. All solar panel voltages should be marked in the item description of our website or on the unit itself.

The size of the solar panel required to charge a lithium battery depends on the lithium battery's capacity.

What size solar panel do I need to charge a 100AH battery?

100AH Lithium Battery x 12V = 1200WH

1200WH / 8H = 150W of solar panels.

What size solar panel will charge a 120AH battery?

To calculate the solar panel required to charge a 120AH lithium battery, use the following calculation:

120AH Lithium Battery x 12V = 1440WH

1440WH / 8H = 180W of solar panels.

Which solar panel size to charge a 200AH battery?

If you have a large 200AH lithium battery, the calculation would be as follows:

200AH Lithium Battery x 12V = 2400WH

1440WH / 8H = 300W of solar panels.

My rule of thumb with solar is that you can never have too much; there will be times of the year when you will not get 8 hours of sunlight, there will be overcast days and other factors that prevent you from getting a full day of solar.

Using the above calculation will give you a rough guide as to what you need at a minimum; however, it is recommended that you always have more than the minimum.

Another consideration is how much of your battery power do you use in a 24 hour period, if you are only using 50% of the capacity then your solar requirements reduce by 50%.

Click the following link to view iTechworld’s solar blanket range designed specifically to charge lithium batteries the most effective way.

Inverters

The power inverter converts your storage battery power into the 240 volts AC that runs your appliances. Unless you only run 12 volt DC appliances you will need a power inverter to supply your AC.

There are 2 types of Inverters

Pure sine wave and Modified sine wave.

The Pure Sine Wave matches the power to that of which you get from your Electricity Supplier, its clean and you can run any appliances safely even sensitive equipment.

The Modified sine wave used to be considered a dirty power but some aren't as bad as they used to be, you can use this inverter type for  things that don't have sensitive electronics for example fridges, cookers, pumps, You may have to be careful with some appliances such as laptops and TVs so check first.

Check out the iTechworld range of inverters HERE

Charge Controllers/Regulators

All Solar Panels 30 watts and above need a Solar Charge Controller/Regulator. A Charge Controller/Regulator is necessary to protect the batteries from over charging and supply them with the proper amount of energy to promote long battery life. If the charge isn’t regulated it can have a damaging effect on the battery being charged.

Check out the iTechworld range of Charge Controllers/Regulators HERE

Article author

Ian

Power
(Watts)

Old style incand-

escent

Mains voltage

halogen

CFL

LED

250

25

18

4-6

3-4

500

40

28

7-9

5-8

800

60

42

11-14

8-12

1100

75

52

14-17

11-17

1500

100

70

19-23

15-23

Bulb light output is measured in lumens. The table shows the required lumen output of an LED, when used to replace old style incandescent and halogen light bulbs. Also shown are the typical wattages of bulbs.

2. Consider lifetime cost

Choose the light bulb that will cost you the least in the long run.

Two of the main differences between lighting technologies are lifespan and efficiency. For example, while a halogen bulb is cheaper to buy than an LED, a good quality LED lasts 5-10 times longer and consumes a quarter of the energy.

The table below shows the total lifetime cost over 10 years for a 800 lumen LED bulb, compared with CFL and halogen alternatives.

A 10W LED bulb would cost $39 in total to buy and run over 10 years. Over this time, five 42W halogen bulbs would need to be used at a total cost of $148, or two 12W CFL bulbs would be used, at a total cost of $48. These figures are based on lifetimes of 6000 hours for CFL and 2000 hours for halogen; an LED price of $10, CFL price of $6, and halogen price of $3. The electricity rate is 28.55¢ per kilowatt-hour (kWh).

3. Get the mood of your light right

A Cool White bulb is used on the left and Warm White bulb on the right.

CFL and LED light bulbs are available in a range of colour temperatures, allowing you to customise the mood of your space.

Warm White is a soft, warm light similar to incandescent and halogen bulbs, suitable for living rooms and bedrooms.

Cool White is a neutral light suited to studies and kitchens, and for task-based applications such as kitchen benches, garages and workshops.

Daylight is a colder light similar to midday daylighting conditions. It can appear harsh, un-relaxed and even sterile, but may be good for bathrooms and laundries.

4. Lighting your home

Combination of general and accent lighting.

Most rooms need general, ambient lighting complemented by task-specific accent lighting.

Ambient lighting radiates overall at a comfortable brightness level. Have a central ambient light source in all rooms.

In addition, have task lighting that can be switched on and off according to your preferences and needs. For example, lamps for reading or sewing, and extra lighting over kitchen benches and bathroom mirrors.

Accent lighting may be useful to emphasise paintings, house plants, or collectables. Directed downlights are ideal for this purpose.

5. How light bulbs compare

For more information about energy-efficient lighting, visit www.energyrating.gov.au/lighting.