Is my WFCO converter/charger killing my batteries?

WFCO converter will work with the Trojan batteries just fine. The only time you would have issues is if you fail to check the water level and add distilled water as needed. We used a pair of 6V GC2 batteries for a few years but I wanted to change to an LiFePO4 battery. That required a change to a different converter module suitable for it. 

The part that confuses/concerns me is the 14.8V that Trojan recommends.  My charger doesn't put that out.

Originally posted by StephenH I wouldn't be concerned with equalization. If they were 12V running in parallel, then it might be an issue. Since they are 6V run in series, equalization is not the issue you think it is. Just think of it as one 12V battery. You don't worry about equalization with your tow vehicle's 12V battery. Don't worry about it with the Trojans, provided you keep track and don't discharge them below 50% and don't leave them discharged. If you can't leave the RPod plugged in, charge them and then use a battery disconnect (connected on the positive side) or disconnect the battery by removing the negative terminal leading to the RPod. Periodically check and charge if needed.

This is not quite correct. The reason the Trojans want a higher charge voltage and occasional equalization is because they are not the same chemistry as automotive batteries. The deep cycle golf cart batteries use antimony as a lead alloy which allows them to tolerate deeper and more frequent discharges but at the expense of higher water consumption, higher charge voltage, and higher equalization requirements than auto start, lights and ignition (SLI) atteries.

So you could either consider getting a separate charger to equalize the Tojans occasionally, or "trick" the WFCO into spending more time at higher charge voltage by turning it off and back on occasionally. This is not an exact science but depends on frequency and depth of discharge as well as temperature and charge rates. Trojan is being very precise in their requirements for warranty purposes.

Understood. In that case you might want to consider getting a DC power supply which would allow you to adjust voltage and current levels manually to the values you want, in this case as prescribed by Trojan. The benefit of the adjustable power supply is that you could set it for batteries with different requirements in the future, or even for others uses. You could eave your batteries on the WFCO on a day to day basis, but use the power supply at intervals per your or Trojan's specs.

Yes I think the conductors are 6 awg. At 40A and 15 ft that's about 0.6V drop, or about 5%. Pretty typical for 12V systems But don't forget that the charge current tapers off quickly as battery voltage increases and the cells teach full charge.

If you really want to do this precisely, you can get a charger with voltage sense wires and a remote temp sensor which can accurately measure voltage and tenp directly at the battery terminals and compensate accordingly. That is commonly done on large battery systems (for example large off grid solar applications) where there is a big capital investment and battery warranties to maintain. But IMHO you are overengineeing for a little 200 amp hour battery system.

Even in the Trojan maintenance manual it suggests getting chargers without equalization modes to perform the high voltage charge function by turning them off and back on.

An inexpensive way to evaluate if you need to and how well you are equalizing is to get a hydrometer and check the electrolyte specific gravity at the top of the cells. If a deep cycle battery needs equalizing its cells will have their electrolyte stratify and have lower and variable SG at the top of the cells. Jus hit them with any charger or power supply and let the gasses mix the electrolyte until the SG's are the same in all the cells. Equalization done.