I recently bought two US brand 6 volt batteries for $99 apiece to replace two Trojan T-105's that had lasted around ten years. I bought them from Powertron in Santa Ana, CA. They told me that US brand batts are just as good as Trojans. I replaced the original WFCO converter/charger with a modern Progressive Dynamics PD 9245 unit that has different charge levels including desulphation mode that will maintain batteries much better. I also have a Trik-L-Start installed that keeps the starting battery up while rig is plugged into 120vac. All systems require checking battery electrolyte levels and adding distilled water to keep the plates covered as well as keeping connections clean.The PD 9245 is simple to install and has a remote "pendant" with LED's that lets you monitor what the charger is doing.