I replaced the charger/converter in the WFCO (World Friendship Company) Model 8955 power center that came installed in my Escape 19 with a Xantrex Truecharge 2 40A charger/converter. This would seem to be an odd thing to do since they both claim to be 3 stage chargers and the WFCO unit is rated at 55 amps while the Xantrex is only 40 amps, but I assure you that there is method to my madness.
To explain why I replaced the original charger, I have done a comparison of the 3 stage charging systems of the old WFCO charger and the new Xantrex charger. The information is taken from the their manuals.
- The WFCO charger in “bulk” mode uses a constant voltage of 14.4V for a maximum of 4 hours. The manual does not say what else besides time could cause it to switch out of bulk mode but I assume that it would be when the battery reaches a certain voltage. I should also mention that constant voltage is the most common way to charge a lead-acid battery and is recommended by most battery manufacturers. This means that the charger output voltage is fixed and the current going to the battery decreases as the battery voltage rises. While this is a very safe way to charge a battery, it can take a long time because the charging current keeps decreasing.
- The Xantrex charger in “bulk” mode uses constant current. This means that it puts 40 amps into the battery until it detects that the battery 80% charged. The result is that the battery charges much more quickly which is important when charging using a generator.
- The WFCO charger uses a constant voltage of 13.6V. This mode provides the 12 Vdc and current required by the 12 Vdc RV appliances, as well as slow charging the battery. The documentation does not state when it switches to float mode.
- The Xantrex charger uses a constant voltage of 14.4V until a full charge is detected.
- The WFCO charger uses a constant voltage of 13.2V. When the converter senses a demand, the converter automatically returns to the “Absorption mode”.
- The Xantrex charger uses a constant voltage of 13.5V and the charger is able to provide current to its full rating to power auxiliary DC loads on the battery.
- The WFCO charger does not claim to offer this.
- The Xantrex charger monitors the battery voltage and will begin a charging cycle 21 days after the last completed cycle, or when the minimum battery terminal voltage drops to below 12.5 V.
As you can see from the above, the two companies have different definitions of what constitutes bulk charging and absorption charging. In my opinion, the WFCO charger doesn’t really have a bulk mode. For most campers, who only go a day or two without plugging in, none of this really matters. The charging algorithm of the WFCO charger is quite conservative and should help the batteries last a long time. It is only for odd people like myself, who almost never have shore power and who charge the trailer batteries from a generator, that will really notice the difference. My charger should bring my dual 6V batteries from 25% charge to 80% in about 1.5 hours.
The other reasons that I replaced the charger are:
- Reliability: The Xantrex charger is simply a better quality unit.
- Onboard Control and Status Display Panel with a Remote Panel option: There is panel right on the charger that shows the charging current and allows the user to change some settings. I installed the remote panel that displays the status of the battery and the charging current and allows me to change a number of variables that are not available on the panel that is on the charger itself. The panel is shown in one of the pictures below.
- Battery type setting: I am using AGM batteries which have slightly different charge characteristics than flooded batteries. I set this once on the charger and it deals with it.
- Temperature compensated using manual setting or a probe: Excessive heat can kill a battery very quickly. The temperature at the battery can be set on the charger or a remote probe can be attached to the negative battery terminal which is what I did.
- Current limiting: I can set the maximum current that I want the charger to put out which limits the current that it draws. This allows me to run my air conditioner and charge my battery at the same time without overloading my generator.
While I was installing the charger, I made a few other changes as well:
- Added a digital voltmeter accurate to 2 decimal places and made a table for my batteries so that I can read the current state of charge.
- Changed the wiring from the charger to the battery from 10 gauge to 6 gauge to reduce the voltage drop. I also installed a ground buss bar and fed it with 6 gauge wire.
- Installed a battery cut-off switch that is capable of handling large currents.
- Installed a 50 amp fuse right at the battery.
- Installed a pair of Lifeline 6V AGM batteries.
I started by removing the WFCO charger from the bottom of the power centre. Then I cut two slots in the back of the charger bay to capture the feet of the new charger.
I wired the charger in exactly the same as the old one but I used 6 gauge wire instead of the original 8 gauge. I slid the two back feet of the charger into the slots that I had made and screwed down the two front feet.
This picture shows the electrical panel after I was done which looks the same as it did before I started. The bright red switch next to the electrical outlet is a high current battery shut-off that I installed. It isolates the battery from the trailer electrical system but still allows the batteries to charge as I drive even if it is turned off. The switch that usually comes with the trailer would not be able to handle the current that the new charger puts out so I chose not to have it installed when my trailer was built.
This is the back of the electrical panel showing the captured charger feet at bottom of the charger bay, the battery switch, the buss bar that I installed for the negative polarity connections, and the 6 gauge wire that I used for all of the high current wiring.
From top to bottom is the input power monitoring display panel that I covered in another post, the Xantrex control and monitoring panel, and the battery voltage display.
This is the table that is posted to the left of the battery voltage display that allows me to see the state of my batteries. I made it specifically for my Lifeline GPL-4CT AGM batteries from the manufacturer’s data. I also have one that I made for the Trojan T-105 batteries that I had in my old trailer. The Xantrex remote panel also displays the current state of charge but only full/half/low which is not enough detail for me. As you can see from the table, the voltage difference between a full battery and a dead battery is very small which is why I had to ensure that the voltmeter that I installed was accurate and would display two decimals. It is not good for the battery to run it too low so I try to charge when it is at 50% and never let it go between 25%. This is indicated on the table by the colours of the different voltages.