Power Inverters for Covert Surveillance - Before Plugging In! January 06, 2018

Before Plugging In, five things you need to know


Power inverters fall into the category of a must-have for your arsenal of covert surveillance gear.  Inverters make it incredibly easy to use 120VAC equipment in a mobile environment, and now you can find them for as little as thirty bucks at your local auto parts store.  But, before you go plugging in, here are five things that you need to know that could save you a lot of money, and help ensure mission success.  

1. You may not need one!
Power inverters are horribly inefficient and can be taxing on a vehicle's power system.  So if you can avoid using one altogether, then do it!  

If the device to be powered uses a power supply, check it's attached specification label.  If the output spec reads anywhere between 11 and 14 VDC, in all likelihood you can avoid using an inverter as your vehicles power system will provide 12 volts on average. 


If your device to be powered falls into range for 12VDC operation, you then have a few options.

    a. Use an inverter anyhow out of sheer convenience in a one-time, short duration mission.
   b. Obtain a new power input cable that matches the power supply terminated end, and wire that new cable into the vehicles power system.

   c. Sacrifice the power supply by cutting the output lead, and then wire it into the vehicles power system.  If you do this, I highly recommend cutting in the middle so that you can later re-solder the cable together, if needed.  Also, ensure that you maintain positive and negative polarity correctly.  

2. Not Created Equal - Modified vs. True Sine Wave
There are two primary flavors of power inverters, modified sine, and true sine wave.  All of the inexpensive inverters (less than $150) output a modified sine wave (MSW).  These MSW inverters do a wonderful job of producing 120 Volts but often do poorly at replicating smooth alternating current waves found in a home or office AC outlet.  This modified wave can wreak havoc on delicate surveillance equipment.  Additionally, if you're operating motorized gear...you'll likely notice the equipment getting warmer than normal.  


Conversely, power inverters with a true sine wave (TSW) do a great job at providing 120 volts, and smooth alternating current waves.  Obviously, TSW inverters are ideal and will ensure proper equipment operations. The big drawback is the price...they typically start around two-hundred dollars.  However, the increased price is often worth it as they don't have the same potential for equipment damage as MSW inverters do. 

3. Peak Wattage vs. Working Wattage
Wanting to make their product more appealing, almost all power inverter manufacturers will advertise peak wattage versus the lower number of working wattage.  So when buying, always read the fine print, and buy one based on working wattage which is the maximum constant use rating.  


To buy the right inverter with sufficient working wattage output, obviously, you need to know what wattage of your surveillance equipment.  Somewhere on the surveillance device or its associated power supply, the spec label should indicate wattage.  

If the device doesn't show wattage but does provide voltage and amperage information, you can easily calculate, Wattage = Amps x Volts.  As an example, a PTZ surveillance camera that consumes 3amps at 48VDC uses 144 Watts of power. 

To make the math even easier, there are several online wattage calculators.  Here is a simple and easy one to use from RapidTables - Amps to Watts Calculator

4. Check your 12 (12VDC)
As mentioned previously, power inverters are inefficient little beasts, they demand a lot current from your vehicles power system.  So when using them, ensure the following:

    a. The vehicles battery and charging system is working correctly.  Otherwise, the additional current demands of an inverter could leave you stranded...even if you have the vehicle running while the inverter is being used. 
   b. Ensure the vehicle power point to where the inverter will be connected, provides sufficient amperage.  Most small inverters consume below 20 amps under load and will work quite well being attached to most cigarette lighter outlets.  Bigger inverters drawing more than 20 amps under load will need a dedicated circuit connected directly to a battery. 
   c. Ensure the power inverter has a low voltage cutoff.  This is especially important for operations to where the vehicle will not be running, or you're using a 12-volt battery outside of a vehicle. 

5. Be Safe 
Just as you would with 120VAC power outlets in your home or office, treat voltage output from power inverters with care.  Power output from inverters carry the very same risk of electrocution, and in some ways more so as the vehicle itself can conduct electricity, and there is a strong likelihood of moisture being introduced to a vehicle. 


To help minimize the risk of electrical shock, many of the TSW inverters will include a GFCI (Ground Fault Circuit Interrupter) which is identical to the GFCI found in bathrooms and kitchen outlets.  

I sincerely hope this article has been or will be helpful to you.  It's my personal mission in life to help educate law enforcement on how to maximize the use of surveillance technologies.  Towards that mission, please sound off if you have something to add to the article by emailing me, or posting in the comments below.  

Thanks for reading!

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