To determine the size of the fuse needed for the solar system, do the following calculation: Watts of solar /12V (or 24V) = amps + 10 amps. For example: 240W solar / 12V = 20 amps +10 amps = 30 amp fuse. Also, many controllers have a built in fuse as a secondary protection.
In most cases, a solar system fuse is required between a solar panel and its charge controller because fuses and circuit breakers protect the wiring from overheating. This also avoids any appliances from catching fire or being damaged in the event of a short circuit.
How to size the fuse? To determine the fuse size needed between the charge controller and battery bank you simply match the amperage rating on the charge controller. For instance, if you have one of our 40Amp charge controllers, we would recommend using an 40Amp fuse.
What Fuse Size for 300W Solar Panel? For three 300-watt panels wired series, and assuming each panel comes rated of 11.7 amps for Isc, you'll need a fuse that can protect against a minimum of (11.7 x 1.56) = 18.2 amps. Rounded off, the solar panel fuse rating for this system would be 20 amps.
The MPPT is 45A. The fuse should be above normal current draw but below cable size - so between 45A and 50A!
Solar Panel fusing
In the case of panels in parallel, a 30-amp fuse is required for each panel. If your panels are smaller than 50 watts, and use only 12 gauge wires, then 20 amp fuses are required.
To connect your solar panel to your charge controller you will need some solar cable and a 20 amp inline fuse.
For a single 100w panel a 10A fuse is normally adequate.
300W Pure Sine Wave 12V to 240V Inverter
It consists of two 75cm lengths of 10AWG (6mm2) cable (one for the positive side of the circuit and one for negative), with ring terminals at either end and a 40A ANS fuse on the positive.
If your solar system's volts were 12 and your amps were 14, you would need a solar charge controller that had at least 14 amps. However due to environmental factors, you need to factor in an additional 25% bringing the minimum amps that this charger controller must have to 17.5 amps.
40-amp 240-volt circuit: 40 amps x 240 volts = 9,600 watts.
Since the Maximum Series Fuse Rating is 15A, we know that the wires, diodes, connectors, and other internal components of the actual solar panel can handle a max of 15A.
You'll need to input the largest rated branch load (or largest motor) and also the sum of each branch load. The recommended main fuse size is based off the sum of all amperages + 125% overcurrent for the largest branch (or 250% for the largest motor).
In other words, a 100-amp electrical service should be expected to provide no more than 19,200 watts of power load at any given time.
The formula is 30 amps X 120 volts = 3,600 watts.
For an appliance rated at 700W or less, a 3A fuse should be fitted. 2. For appliances above 700W, a 13A fuse should be fitted. All modern appliances should have the power rating marked on them.
30 Amps x 120 Volts = 3600 Watts. 3600 Watt can also be written as 3,6 kilowatts or 3,6 kW.
10A of max current, then the fuse should be 10A x 1.25 = 12.5A, so 12A fuse will be fine, also need to use proper wire gauge that can handle at least 10A.
The fuse should be sized to protect the wire. With a 30 Amp charge controller I would use 10 AWG wire and a 30 Amp fuse.
To determine the size of the fuse needed for the solar system, do the following calculation: Watts of solar /12V (or 24V) = amps + 10 amps. For example: 240W solar / 12V = 20 amps +10 amps = 30 amp fuse. Also, many controllers have a built in fuse as a secondary protection.
5AWG Inverter Cable With 80A Fuse (for use with 600W inverter)
400w draws 1.67 amps. 3 amp fuse will be fine.