12v Solar Panel Wiring Diagram: Solar panels are quite straight forward to install. The solar panel will provide a steady charge to your leisure battery allowing you to run your 12v appliances for longer without needing to hook-up to mains power.
It’s important that your power usage, recharging and battery capacity are suitably balanced.
The below equation is one you’ll find comes up repeatedly when working with 12v electrics. It will prove really useful when considering the battery capacity, power storage and power consumption.
Volts (the strength of power supplied via your battery) times by Amps (The rate of current along your electrical wire) = Watts (The amount of power required to run an appliance)
Volts x Amps = Watts
e.g. 12 Volt x 4 Amps = 48 Watts
Similarly, 48 watts/12 volts = 4 Amps
This equation will help us identify the essence of your daily power consumption, from that daily consumption calculation it’s possible to create a power fulfilment plan based on how, where and when you plan to travel. Incorporating, solar, split charge and 240v power options.
To figure out your daily power usage (and how much you need to recharge your batteries), you first need to know the power consumption of your 12v appliances. This information, measured in watts, is usually found on the appliance body.
Take an LED reading light as an example. If it’s labeled as 5 watts, this means it uses 5 watts of power each hour. So, if you use the light for 3 hours daily, it consumes 15 watts per day.
Grasping these basics helps you better manage your campervan solar power and 12v electrics.
The average medium sized campervan may have the following usage of appliances:
- Fridge (50 litre compressor) 24w x 24hours = 576watts (The 12v fridge may have a start up wattage rating of 60watts but only be running 40% of the time, therefor it’s average hourly use is 24watts)
- Lighting 8w x 5hours = 40 watts
- 12v water pump 20 watts
- Diesel/gas heater fan driven 25w x 2 hours =50 watts
- Laptop 50w x 2 hours = 100watts
- Phone/tablet charger and USB devices = 20 watts
- 1000watt invertor to run 800watt microwave for 15minutes of use = 200watts
- Total daily use 1006 watts
If the average daily power consumption is 1006watts then we can assume below:
- Total 1006 watts x 120% (spare capacity) = 1207watts per 24 hours period is required
If we use the formula given earlier we can divide 1207 watts by the voltage in use (12v) to work out the Amp/h of stored power required.
- 1207watts/12v = 100Amp/h
A good AGM battery can be discharged by 70% therefore we need 2 x 100 amp/h AGM batteries, as they will provide 140amp/h of available stored power. (our requirement is 100amp/h)
