Switching Made Simple
Do the benefits of digital switching call for a conversion on your boat? A few of the big players are betting on it.
Until recently, digital switching has only been available on new, high-end boats. Today there are quite a few systems on the market for used boats from several different manufacturers, with more coming.
So, what’s a digital switch and why should I care? That’s a reasonable question, and the answer can be a little involved. When compared to traditional mechanical switches, the biggest benefits are reduced weight and automation—all in a weather-sealed, highly reliable package.
Traditional DC switching and power distribution starts with a centralized electrical panel where large cables run from the batteries. For each circuit, wiring runs from the panel to the point of use. On my boat that means that loads like the freshwater pump, located a few feet from the house batteries, run all the way from the batteries to the panel and then back down to the pump. So, power for a load that is 3 feet from the batteries travels through about 20 feet of wire. The number of circuits on a modern boat—which can add up to hundreds or even thousands of pounds of wire—are greatly reduced by making the change to digital switching.
On my boat, our salon lights can be turned on in two locations. That means there’s wire running to each switch plus another (traveler) running between the switches. Adding another switch can be a difficult, time-consuming task. With digital switching, additional switches—or other controls, like an MFD—connect to the NMEA 2000 backbone of the boat, dramatically simplifying installation.
A traditional circuit has quite a few connections, each of which is a potential source of corrosion and trouble. Plus, mechanical switches have moving parts that are subject to failure. Digital switching circuits typically bring in a single source of power and then have a single connection to each load. (There aren’t individual connections for circuit breakers, switches and the load.) Most digital switching modules are well sealed against the environment, utilize solid state switching and offer a degree of reliability that traditional mechanical switching simply can’t match.
Digitally-switching circuits open a world of possibilities. For example, it’s possible to read the freshwater tank level from the NMEA 2000 network and turn off the freshwater pump if the level drops too low. Or, a circuit can be set to turn itself off after a specified delay. Plus, with more advanced digital switching systems the trip threshold can be set on a per-circuit basis.
When digital switching was first introduced to the marine market, it commanded a substantial price, required certified installers and was designed only for installation on new boats. But, as the market has matured, manufacturers have started offering products that are less expensive and easier to configure. Entry-level panels are available for as little as $250 for six circuits. I constructed a sample system with traditional mechanical switches for six circuits and it came to about $200 (sans dimmers), which is built into most basic digital switching modules.
Two big players in this space, Maretron and CZone, both have digital switching products that can be retrofitted by a pro installer or handy boater and are expected to cost under $500. Maretron’s CLMD12 is a 12-circuit digital switching unit. Each circuit has programmable trip thresholds, current monitoring and dimming available. Two of the 12 circuits handle a maximum of 12 amps, six are rated at 10 amps and four are rated at 5 amps. But each of these circuits can be set to trip at lower current levels—using Maretron’s G2Analyzer software—if a smaller circuit needs to be protected. Final pricing for the CLMD12 hasn’t been set, but Maretron expects it to carry a suggested list price of $495, making the per-circuit cost pretty affordable at just over $41.
CZone’s Contact 6 Plus is a $250, six-circuit digital switching unit compatible with the full line of CZone digital switching and monitoring products. At about $42 per circuit, the pricing is right in line with Maretron’s CLMD12 and also comparable to traditional mechanical switching. Each of the six circuits in the Contact 6 Plus can handle a maximum of 15 amps of 12- or 24-volt DC. The simpler Contact 6 Plus doesn’t have the software-configured trip thresholds of the Maretron switches; it uses ATC blade fuses for circuit protection and doesn’t have the ability to monitor current consumption. CZone’s physical fuses means you’ll need to keep spares on hand in case you blow one. (And consider how accessible the unit is for such replacements.)
If you’re going to use your CZone system with other NMEA 2000 devices on the network, you will need to build a configuration in the CZone Configuration Tool and upload it to the CZone components on the network. The powerful configuration tool makes it easy to configure an advanced system. You can save the file to an SD card and use an MFD to load it onto the network. This is nice, as it means no additional hardware is needed to configure your system.
CZone offers their keypad controls in six- ($220) and 12-button versions in both portrait and landscape orientations. When the Contact 6 Plus is operating in stand-alone mode with a smart harness, the push buttons can be configured to behave either as on/off toggle switches or as one-button dimmers through a series of button presses. The labels on the panel are adhesive and the keypad comes with a sheet of 60 common labels.
Digital switching isn’t just for new boats. I’ve installed both of these systems on my own boat in only a couple of hours. If you’re taking on a project that requires new circuits, there is no reason to steer away from one of the low cost, highly touted digital switching options on the market.
This isn’t to say there’s not a learning curve with digital switching, because there is, but I believe the benefits easily outweigh the potential complexities. Any time I look at new systems or paradigms on a boat, I try to answer one question: Will this make boating better, easier or more fun? With digital switching I believe the answer is a resounding “Yes.”