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I decided to do this video after I needed to design a dimmer to work with the Lippert Linc remote receivers. As well, this has been a popular add-on for many RV'ers, and like an almost urban legend, people get on the bandwagon to buy one particular dimmer without adequately researching others, or more importantly, realizing some dimmers are better than others. So I decided to do this shootout to show a cross section of what is available to RV'ers as well as cut-to-the-chase on properly selecting a dimmer. Note that this discussion is limited to 12VDC LED dimmers. There are 120VAC dimmers available, but in the RV environment, DC dimmers are more appropriate.
Background Information: In the shootout, I will be mentioning items such as high-side, low-side, switch-mode drivers, linear-drivers, PWM, duty-cycle, and others. If you are not familiar with these terms, I encourage you to watch my "All About Dimmers" video which I created as a support video for this review.
In this shootout, I review 10 different dimmers, all of which are PWM:
 Salient Characteristics
LED types. In reality, when a LED is connected to a dimmer, it becomes a load, and the dimmer becomes a power supply of sorts. And like many other power supply/load situations, the characteristics of the load affects the efficiency and operability of the power supply.
The simplest, and most behaved load is a pure resistive load. You wil find this kind of load with most LED strips. The example shown here is an actual dimmer having a resistive load applied, and as you can see, the output of the dimmer is a fairly good looking PWM square wave. What we want to see is straight transitions from 12V to 0V, as this represents a minimum heat impact to the dimmer's switching component (typically a MOSFET). We can also see that the transition fully traverses the 12V to 0V range (the solid yellow line across the bottom represents 0V.
However when the same dimmer is applied to a Linear LED driver which you will find in many puck lights, it represents a non-linear load. It is the result of the load actively changing it's current demand throughout the PWM cycle. This results in the mis-shaped PWM waveform, and you may notice that as the transition goes from 12V to 0V, the output "ramps" down to the low voltage rather than going down straight, and never quite reaches 0V, but raises back up with the next PWM pulse. This distorted part of the waveform can increase heating on the dimmer.
Finally, some LED drivers found in Puck Lights are Switch-Mode. They are generally more efficient (less heat loss) for the light fixture itself than the other two types, but they present a very lon-linear load to a PWM dimmer as shown here. In fact often there is minimial dimming, or in many cases no dimming. And as you can see, the 12V to 0V transition is not even close, which can result in significant heat issues in the dimmer itself. Remember that these three waveforms are from the same dimmer, but with different types of LEDs.
As I was developing the test setup, I quickly realized my iTech 8511 150Watt DC Electronic Load could provide a constant resistance for resistive load tests, and it could be programmed to mimic a variable load, it could not replicate the Linear or Switch-Mode load that is required to provide an accurate result. Therefore another solution would be required.
The solution ended up being the purchase of 8 Linear Driver based puck lights. This is as simple as it can get (other than the financial cost). As each puck light is rated for 4W, this represents a 32Watt total load. And since most RVs would likely have less than 8 puck lights in any one circuit, this should cover real-world situations. And besides, if I discover my RV has switch-mode puck lights, then I have a supply of replacements. The only real issue here is to use sufficient wiring (I used 16AWG) so as not to skew the test results from excessive voltage drop.
 In this first test setup, I used the puck lights as the load, then varied the intensity of the dimmer to the required levels and recorded the results. Not shown is the LUX meter that I used to record the LUX test data. These tests represented the real-world condition when dimming linear-mode puck lights.
 In the second test setup, I replaced the puck lights with my Constant Resistance DC electronic load, just to see if I could replicate the rated ampacity claim of the dimmers. The constant resistance would represent the least demanding load (of course notwithstanding the amount of current it demanded). This type of load represents LED strips, and while you will never likely occur such high-current loads, it was useful as a method of stressing the dimmers to their maximum.
Testing. I ended up running 90 individual tests (10 dimmers x 9 test parameters) to compile the following data:
For the sake of brevity, I am not publishing the individual test data as it would fill several pages with data, so I presented the data in the form of graphs, which are more meaningful when comparing dimmers.
Idle current is the residual or "parasitic" current when the LED lights are turned off by the dimmer. This is useful for determining the most acceptable dimmer in a boondocking environment. However, anything under 10mA is really not that significant (unless you are operating multiple dimmers). A 10mA load would require 8,000hrs (332 days) to completely discharge an 80AH battery. That is below the threshold of the battery's self-discharge rate. Dimmers with a 0mA result have an On-Off switch that completely removes power from the dimmer.
The light output intensity is a measurement of the total LUX output of the 8 lights driven by the dimmer. A Lux = Lumens per Square Meter (and my light meter only measures LUX). In each test, the power supply delivered 13.8VDC, and the dimmer was set to full brightness. The results show a slight variation in the output level of each dimmer. The differences can be attributed to wire size, effeciency, and design of the dimmer. However as a practical matter, the whole purpose of a dimmer is to reduce the light output, so the differences probably fit into the "measureable but not significant" category. However, the light output differences may track other characteristics, which may be significant, such as dimmer internal heating.
This chart shows the measured power across the set of 8 LED light fixtures by calculating measured Amperes x Voltage. Of interest is this chart is not exactly in synch with the maximum LUX output chart from dimmer to dimmer. For example, the PCA_EPL101x dimmer required the most power, yet did not have the highest output. This tells me there may be some inefficiencies, which may be due to factors such as the heat dissipation capability, terminals or wires used for the connection, PWM frequency, orientation (low side vs. high side) or the characteristics of the switch (MOSFET, etc) used.
The temperature raise is shown in RED which represents the full (100% bright) output, while the BLUE lines represent the minimum brightness - at the threshold of being off. For example, at 100% brightness, the Generic 8A Dimmer will see a 6.5DegF increase in it's internal temperature. This is an important graph, as it shows the likely internal heating of the dimmer. Realize though that this chart is in free-air, and some dimmers are intended to be mounted into walls and cabinets. Such mounting is likely to increase the temperature of the dimmer due to the restricted airflow.
The last test is similar to the previous test, however the dimmer is operated at it's advertised ampacity. For example, the Generic 8A Dimmer was operated under a resistive load that was adjusted so the dimmer delivered 8Amps; the PCA EPL101x dimmer was set to 4.2Amps, and so on. The two exceptions (shown in green) were dimmers that had a capability exceeding 10Amps (my power supply is limited to a 10Amp output). The full load test could be considered the worst-case scenario, and the two RED results are tests that I aborted because of the temperature rise. I won't state these dimmers are unsafe at full load, but rather I did not have the means to safely test these dimmers at higher temperatures. What I learned from this result is that for the lowest dimmer heat output, it is prudent to operate ANY dimmer at less than their full capacity. For example, I tested the RV-Project dimmer at 10Amps, but I recommend using it with loads that require no more than 5Amps.
Dimmer selection criteria. Rather than recommend a particular dimmer, I have provided the information you need to make an informed choice. The major criteria is:
 And if you are using a dimmer such as the PCA EPL101x, consider mounting it into a metal panel, or at the very least, using an aluminum backing plate to help dissipate the heat.
Dimmer Shootout Video.
 
Additional Sources: American Technology Components AH-SLD-5-HS01
RV-Project LHPDB-1A
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