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300 Watt Dump Load (12-Volt) Technical Specification

300 Watt Diversion/Dump Load Resistor for 12-Volt Battery Banks

Technical Specifications:

(Internal resistance of the resistor = 0.73 ohms)
Dump Voltage 
(controller by charge controller)
Current Through Resistor
(Amps)
Power Dissipated by Resistor
(Watts)
12.5 17.4 217.0
13.0 18.1 234.7
13.5 18.75 253.1
14 19.44 272.2
14.5 20.1 292
15.0 20.8 312

To protect your expensive wind generator, battery bank and alternative energy system from potential destruction, choose a dump load that exceeds the maximum output of your complete system by at least 20%. For example, suppose you have a max. power 600 Watt wind turbine and a max. power 400 Watt solar panel (600 Watts + 400 Watts = 1000 Watts total) hooked up to your battery bank. In this case you will need a 1200 Watt dump load to safely operate your system (20% more than 1000 Watts = 1200 Watts). These 300 Watt resistors can be wired in parallel to dump 300, 600, 900, 1200 Watts, etc. For the previous example, you would need four of these 300 Watt resistors wired in parallel to dump 1200 Watts.

Resistors Wired in Parallel

Consult the following chart for how many Watts can be dumped as a function of the number of 300 Watt resistors wired in parallel (See the image below for a diagram showing how to wire resistors in parallel).

# of Resistors Total Power Dissipated (Watts)
1 300
2 600
3 900
4 1200
5 1500

Note: The following simple formula can be used to determine dumping Watts as a function of the number of 300 Watt resistors wired in parallel:

Total dumping Watts = (300 Watts) x (# of resistors wired in parallel)

Installation and Safety Precautions

WARNING! These resistors must be installed in a location where air can flow. If you decide to mount the resistor(s) in an enclosure, the enclosure must be very well ventilated. We advise that your enclosure have many holes or vents in it so that air can move in and out of the enclosure.
These resistors "use" energy by converting it to heat. When these resistors are dissipating energy, their surfaces will be very hot. The resistors must be mounted on a heatproof surface and protected from accidental contact from people or anything else. You can mount them on a piece of metal with fire-proof insulation behind the metal. Wire mesh can be used to enclose the resistors to prevent people or anything else from coming in contact with them. Wire mesh is a good choice because it does not block air flow to the resistors. It is the customer's responsibility to make sure that the resistors are used safely and properly.