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Powering Heaters with DC (Direct Current)

Every heater type that we sell at O.E.M. Heaters can be built to your specification for direct current operation. We have provided heaters for operation on voltages from 3VDC to 84VDC. Some typical 12V silicone rubber heaters and 12V heat trace cable are available for online purchase with quantity discounts. We will be posting 24V heaters soon. If you have a specific requirement, give us a call at (866) 685-4443, fill out one of our contact forms, or send us an e-mail.

Can I Run That Heater on 12 Volts DC?

That's a question we hear quite a bit. If the heater was designed to operate on 120V, then the answer is, "You can, but it's not going to get very warm." However, if you have a heater that's designed for 12 volts AC then the answer is, "Yes, you can!"

Does It Matter if I Apply AC or DC?

No, provided that the AC voltage is equivalent to the DC voltage. AC (alternating current) voltage is usually represented as its RMS, or "root mean square," value. Luckily, AC voltage has a sinusoidal waveform, and the RMS value can be calculated easily without the need for complicated mathematical equations, shown below:

Voltages listed for power outlets and appliances are given as their RMS value. Therefore, a 120V standard American outlet actually supplies a peak voltage of about 170V. An interesting historical note: the RMS value of an AC signal was commonly referred to as the signal's "heating value," owing to the fact that the power - or heat, if you will - that was dissipated by a resistance was equal regardless of whether the applied voltage was DC or AC. The graph below shows the AC waveform compared to the RMS and peak values:

How Applied Voltage Affects the Power Output of Your Heater

Let's start with the basics: an electric heater is a resistive device; that is, it provides opposition to current flow when a voltage is applied. When it does so, it dissipates power in the form of heat. We can calculate how much power a resistive load can handle using the following equation:

As shown in the equation, the maximum power the heater can supply is dependent on the current that can be supplied. This current is restricted by the the current carrying capacity of the power source, but can also be limited by the gauge of the wire. This being said, low-voltage DC heaters will need more current to supply an equal amount of power as a heater that runs on 120V or 240V. If you have an existing heater that you'd like to run at a lower DC or AC voltage, you can calculate the new wattage using the equation below:

As an example, let's say we have a 120V 1000W cartridge heater in stock and our customer needs the same kind and size of heater but for 24V. If we plug those numbers into our equation, we can calculate that the heater will have a heat output of 40W while plugged into a 24V power supply. Using this equation can be useful for customers who are looking for lower-voltage and -wattage heaters, but don't have the time or the money to get a custom heater built for them.

What are Some Common Uses for DC Heaters?

  • Crystal Oscillators - Many consumer electronics rely on crystal oscillators to provide a real-time clock or other time related measurements. In order to ensure accuracy, the crystal oscillators must be kept in a temperature-controlled crystal oven.
  • Remote Applications - Batteries and solar panels can be used as a power source when line voltage is not available in remote locations such as barns, cabins, and park outposts. Batteries in ATVs, RVs, and boats could also provide power when cabin heaters are needed.
  • Diversion Loads - Wind, hydro, and solar power use diversion loads to redirect excess power to a heating element. In wind or hydro applications, excess power can cause overspeeding and possible damage to the equipment, and applying a diversion load can prevent this from occurring.

What Kind of DC Heaters Can I Purchase?

Here at O.E.M. Heaters, we can make custom heaters in virtually any voltage. The most common heaters requested for DC applications are flexible silicone rubber and cartridge heaters. If you're still not sure which product is right for you, we'll be glad to help you figure it out.Give us a call at (866) 685-4443, send us an e-mail at sales@oemheaters.com, or fill out a contact form.