I have an early 2012 233S and so probably the same converter as you. Mine is a WFCO 8955. Here's the manual (WFCO 8900 Converter
You can use your existing converter with a dual-battery bank. In your case, you are looking at two 6-volts wired in series. The converter essentially sees this as one big battery.
The WFCO's three stages are:
- Absorption Mode at 13.6 Vdc range
- Bulk Mode for when the converter thinks the batteries are less than 50% charged will give 14.4 Vdc for a maximum of four hours.
- Float Mode is a trickle voltage of 13.2 Vdc if the RV is not being used for approximately 48 hours.
You need to be aware of a couple of issues to do this right:
First, the WFCO doesn't really enter into bulk mode that easily or for long enough to adequately charge my two 6-volt batteries (Trojan T-145s). Also, many deep cycle batteries need a higher voltage than the converter can provide.
You can change out the WFCO, which is just a fair converter, for a PD that Turbo recommended or you can use a portable charger.
Since Trojan batteries need 14.8 volts and because I haven't changed out my WFCO, yet, I use a portable 40amp 3-stage charger from Stanley that hits the mark. I charge through the converter for convenience and when I am using the trailer, but use the charger when I am at home.
Second, sulfation occurs when a lead acid battery is deprived of a full charge, which will happen if the converter cannot charge to its recommended volts as explained above. Crystals form within the battery and eventually larger crystals reduce the batteries active capacity. See Sulfation and How to Prevent it
The WFCO 8900 series does not
have the ability to de-sulfate the batteries so periodic reconditioning is recommended to maintain a battery's optimum performance and prolong its life.
On a healthy battery bank, reconditioning mode on my charger sends a series of electrical pulses to break up the crystalline form of lead sulfate and turn these chemicals into useful battery electrolytes. There are better devices to de-sulfate than the reconditioning mode on my portable, but this works for me as my batteries are only 18-months old and I had done this from the start.