A Change for the Better for our System

For the first five years, our system had as its central control unit a product called the Infinity 6 from Sunselector. The idea behind this unit was to provide a single, easy to install charge control system, input breaker system, DC load breaker and main system safety disconnect all in the same box. This eliminated the extra conduit, wires and control systems from different manufacturers that often clutter typical solar energy power rooms. In the Infinity 6, Sunselector had a great idea that unfortunately has not withstood the test of time in the real world. Don't get me wrong, I still love the basic premise, a single box with all the necessary breakers and safety components that greatly simplifies installation, but the heart of the system, the Omnimeter, has failed me too many times for me to consider it a viable product.

The Omnimeter was designed to monitor the entire system for volts, amps, amphours, and kilowatt-hours. In the configuration used in the basic Infinity 6 the Omnimeter was set to provide these four values for the charge circuit, the DC load circuit, the inverter circuit and the battery bank. If it had simply been designed as a meter it might have worked without problems. But it was also designed to provide charge control. The Omnimeter was programmed to monitor the batteries and the charge circuit and to close a relatively simple mercury switch to either charge the batteries when they needed it or to shut off the charge when the batteries were full or there was no input from the charging circuit (in my case, my PV panels). The meter registers both positive and negative values to indicate current flow into or out of a particular part of the system.

This is where, I believe, the Omnimeter has failed to live up to its promise. Since I first installed the Infinity, I have gone through at least a half-dozen Omnimeters. They have failed in a variety of ways. Some of them simply wouldn't maintain their accuracy. I would see, for example, a reading of -.3 volts on the DC load circuit when I knew there were no drains or loads on that circuit at the time.

The Omnimeter allows for a setting to indicate the maximum capacity of the battery bank, in my case, 1050 amphours. Yet from time to time the meters would lose that setting and default to the maximum setting of 2000 amphours for no apparent reason. I have also had the inverter amphour readout jump to 32,768 (the maximum readout of the meter) during times when I have used the generator to charge the batteries through the inverter's integrated battery charger. The meter is designed to (and usually does) measure the cumulative amphour charge from the inverter/charge to indicate how much current has been added to the battery from the generator.

I have had at least 3 different meters (including the one currently in the system), simply lock up and be unusable, requiring me to pull the main breaker to the system and set the whole thing up from scratch. To add insult to injury, when the lockups occur the system stops charge controlling. Fortunately whenever that has happened the system has failed in an open condition, meaning that no power was flowing from the panels to the battery bank. This is inconvenient in that it always seems to happen on sunny days and I lose the charge I would otherwise have gotten, but it is better than failing closed and allowing an unregulated charge to flow to the batteries, which could have caused overcharging and potentially catastrophic results.

Since the last lockup occurred I have decided to make a change to my system. Since I do like the features of the Infinity such as the individual breakers for the PV charge and DC load and the readouts for the different parts of the system, I am going to keep the Infinity in the system. The one thing I will change is the charge control. I have purchased an RV Systems Solar Boost 50D MPPT charge controller.

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The Solar Boost is the white box to the left of the Infinity 6. The black wire coming out of the top of the 50D is the ground wire. One trick to the upgrade is to make sure all the ground connections in the Infinity are isolated from the Infinity's internal PV ground. The addition of the 50D requires that all grounding be done through the controller to make sure the digital readout accurately shows the current flow. The grounding wire connects to the grounding block on the DC load side of the Infinity 6 and assures proper grounding and bonding of grounds throughout the system. The Solar Boost employs a technique known as maximum power point tracking to deliver up to 20% more current to the batteries. It is also designed to prevent too much current flow by regulating its output to a maximum of 50 amps. Even though my panels are rated to produce a maximum of 39 amps the Solar Boost will allow me to realize as much as 50 amps under the right conditions. And it costs much less than buying 20% more panels.

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An internal view of the Infinity prior to the conversion. The black unit at the lower left side of the Infinity is the switch that used to provide the charge to the batteries. That has been removed and the 50D wired in its place. The output of the 50D is run through the shunt at the center left so the Omnimeter can still monitor the current flow to the batteries.

The Solar Boost 50D also has a digital readout, which will give me another way of checking the power and voltage of the panels and to crosscheck against the Omnimeter's readings. Since I'm convinced that the problem with the Omnimeter is based in its charge control system, I will be able to bypass the charge control parts of the Infinity 6 and use the Solar Boost instead. This way if there is problem with the Omnimeter or the meter locks up again, the only loss will be in the meter readouts and the charge control will be unaffected.

By maintaining the Infinity I will still have the advantages of the all-in-one safety circuits and breakers that I so like about the Infinity without the flakiness of the Omnimeter's charge control function.

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Wagonmaker Press
Thomas W. Elliot