Considerations on the installation of the Xantrex XC3012

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By Michael MacLeod, Hali #1352 (1997), Vancouver, BC


We bought and installed a Xantrex XC3012 battery charger last week about the same time as John Nixon's review appeared [here]. Fortunately, John seemed moderately favourable to this Xantrex offering.

However, only after doing the installation, talking "battery talk" with a friend who designs and builds DC power supplies, and re-reading John's review were we able to begin to appreciate how much John has put into that review. It is worth reading and re-reading before making a decision on what battery charger to buy.

As I am incapable of speaking to the technical issues, this post will restrict itself to some practical aspects of dealing with the XC3012 in the context of a 1997 Catalina 34 where the battery charger is located in the galley sink cupboard beneath the built-in garbage can.

As John's review makes clear, the XC3012 comes with a small detachable control/display panel. The detachable character of this panel is particularly useful in our application because it would be awkward to open the cupboard doors beneath the galley sink and stoop down to look at the panel beneath the built-in garbage can each time you wanted to see battery charging information. Far better to have the panel where it will catch your attention.

For us Catalina 34 owners, it is also a good thing that the control/display panel is detachable because the height of the XC3012 with the panel in place in its plastic housing atop the main body of the XC3012 unit would make it well nigh impossible to place the XC3012 beneath the built-in garbage can.

As it is, the plastic housing for the control/display panel atop the XC3012 becomes (we think) redundant once you decide to mount the panel remotely. Removing the plastic housing shaves a few inches off the height of the XC3012, with the result that the XC3012 unit fits quite nicely immediately beneath the built-in garbage can. But don't be complacent about the height. Locate the XC3012 as high as you can beneath the garbage can to give you working room below the charger, where you will need the room to get at the terminals, control connections, and AC connections.

In addition to housing the removable control/display panel, the plastic housing might serve some purpose in protecting the ventilation at the top of the XC3012 from water. But given where we located the battery charger (beneath the shelf that supports the garbage can) we didn't think sacrificing the plastic housing was too risky from this point of view.

The plastic housing is secured to the "roof" of the XC3012 by four screws. To get at these screws, you need to open up the XC3012, but even then it is only possible to get at the heads of two of the screws. (This plastic housing -- like the plastic shell that goes over the front of the XC3012 that we also discarded - looks like something of an afterthought by Xantrex.) We unscrewed the two screws whose heads we could get at then resorted to cutting the other two screws with a hacksaw where they emerged from the XC3012 main box and entered posts in the plastic housing. We fished the screw heads out of the main box and threw away the plastic housing. (Did we also lose any chance of making warranty claims?)

The new XC3012 is larger than the old Alltech Flyback 20-3 that it replaced on Hali and therefore it needed a bigger backing plate. We glassed 1/2" plywood beneath the garbage can to enlarge the old backing plate. With a coat of white bilgecoat over the new fiberglass, the backing plate now looks almost like part of the original construction.

Where to locate the control/display panel remotely was an issue. The "telephone wire" that connects the control/display panel to the XC3012 is short, so placing the panel any distance from the battery charger involves getting a new telephone wire with connectors or getting an extension. The good thing is that these four-wire connectors and telephone wires are universally available.

We first considered installing the control/display panel about calf height at the port side of the salon table aft settee, just next to our newly installed battery compartment ventilator. (For discussion of installing a battery compartment vent, see Ron Hill's reply #33 and Jon Schneider's reply #34 at http://c34.org/bbs/index.php/topic,4313.30.html.) There (on the outside of the settee battery compartment) the control/display panel would be readable by anyone sitting at the chart table, but probably only if you formed the conscious intention to read it and went looking for it. This location on the outside of the settee battery compartment would have had the advantage of a very short control cable run from the battery charger. In fact, the original control/display panel cable would probably have sufficed. But we finally decided that that location was not one where most people would expect to look for an instrument and not one where reading the control/display panel could happen routinely and unintentionally as we wanted, so we cut the control/display panel into the white wall beneath the electrical panel above the chart table where people can see it easily at any time. We fished the control/display panel's four-wire control cable up behind the electrical panel and there added an extension cable to the battery charger.

Following Stu Jackson's advice (see reply #8 at http://c34.org/bbs/index.php/topic,973.0.html), we recently decided to treat our two 4D house batteries as one bank when discharging from them. To do this, we now use the "Both" switch all the time when operating under battery power. However, as the XC3012 can charge, and monitor the charging of, three batteries (or three battery banks), it seemed a waste to treat both house batteries as one bank when charging them. Accordingly, we set up the new charger so that it charges and monitors each of the house batteries separately. (We think that by charging each house battery separately we get more appropriate charging of each battery and specific information --from the control/display panel--about the condition of each battery.)

The Xantrex XC3012 comes with only one temperature sensor but with a capacity to handle three temperature sensors. Xantrex recommends the use of a temperature sensor with each battery or battery bank that is separately charged. Apparently the charger assumes a default temperature when there is no temperature sensor but achieves better charging when a temperature sensor provides actual battery temperature data to the charger. Since in our installation we are charging each house battery separately, we bought a second temperature sensor.

To do the installation work, you will need to remove the "shelf" beneath the galley sink.

We found there was just sufficient room beneath the new charger to install a three gang terminal bus that is needed to connect the AC power feed to the battery charger's input pigtails.

The XC3012 has three positive and one common negative terminals. You will want rubber terminal boots on the battery wires and over each of these terminals. We haven't found a good place to get these but fortunately there were already good ones on the two positive battery wires. The Xantrex-supplied terminal boots don't seem perfectly suited for the task but we used one of them on the common negative terminal. Making the terminal connections in the limited space beneath the sink is a challenge but do-able. (As mentioned previously, remember to situate the charger as high up beneath the built-in garbage can as possible.)

Clicking the "telephone connectors" of the temperature sensors and remote charger monitor into place on the base of the XC3012 is relatively easy but it is finnicky work to get them out again. When trying to disconnect them, I was cursing and asking myself whether Xantrex engineers every do usability testing. Don't click these connections into place until you are sure you won't likely have to remove them any time soon.

We haven't connected our independent starter battery to the XC3012 and haven't decided whether we will. Hali's starter battery is used little -- since we solved a hard starting problem with huge help from this board a year ago (see http://c34.org/bbs/index.php/topic,3347.0.html), Hali has started first time every time -- and is charged every time the engine runs. But there is a third positive terminal on the XC3012 to which the starting battery (or perhaps an AGM battery for the windlass as Jon Schneider is contemplating) could be connected to.

We have set the XC3012 to three-stage charging. So far, it seems to run like a charm. We haven't had enough experience with the system yet to know whether it will go into the pseudo-inactive float mode that John Nixon mentions in his review.

For the next few weeks anyway, we are likely to be "pluggers", that is, leaving Hali plugged into shore power when we are away from her, and "chargers", that is, leaving the new battery charger turned on while we are away from Hali.

We had run Hali's house bank down a bit in the days when we were swapping out the old Flyback 20-3 and installing the new XC3012. After the XC3012 was installed and we were still on the boat, we saw the system bulk charging and absorb charging but never getting to float charging. We saw a surprising 15.7 volts of charging at one point...and are still not sure what was going on. A few days later, we took Hali out and on returning to the dock and plugging the system in, the charger very quickly was in float charge mode. So it seems to have brought the batteries back to full charge.

Given that Hali has all lead acid batteries and her house batteries could be set up as one bank and her starting battery does not need to be charged from the AC-DC system, we could have purchased the Xantrex TrueCharge+40 and probably been happy with it. However, the price difference between the Xantrex XC3012 and the TrueCharge+40 was so small here in Vancouver, that we opted for the newer XC3012.