When we bought the RV we knew that the house batteries, the ones that power everything that runs on 12 volts with the exception of the engine systems, were pretty old. Simple checks showed that they still had life left in them though, and they seemed to be another part of this aging rig that the previous owner had kept well maintained. As we got into the renovation stage, however, their age and dying condition made themselves apparent. At some point, the water levels in the batteries boiled down below the tops of the plates and basically ruined them. We didn’t check the water levels in the deep cycle batteries before we moved the RV from Lynchburg, VA (the dealership where we bought it) to Frederick, MD (where we stored it), so we didn't realize how low the levels were.
Our converter is a Progressive Dynamics 9100 series, it’s a decent starting point but is not a “smart charger.” After the batteries were damaged from the lack of water, I added the PD9105 Charge Wizard to the converter and tried to bring them back to life. I installed it as a "last-ditch" attempt to save the batteries. The Charge Wizard turns our converter into a smart multi-stage charger and maintainer. It monitors the batteries voltage and automatically charges them at the optimal voltage. It also has an “equalization mode” which comes on at 14.4 volts every 21 hours for 15 minutes and helps prevent battery plate sulfation. If we had installed this sooner the original batteries might still be working, but that is water under the bridge now (pun intended).
While dealing with the flat tire and forced Boondocking in Beckley WV, we stress tested the house batteries, and they failed. So the next day it was off to a Starbucks to search the internet for a couple 6 volt deep cycle batteries. The previous owner had fitted two Interstate Brand 235 amp hour GC2 batteries, wired in series to provide 12 volts. This is a good basic setup for a motor-home; and to avoid any rewiring we wanted to stick with it.
There weren’t many options to pick from nearby as it turned out. Only a couple auto parts stores had the correct batteries in stock and they were low spec and high priced. Sam’s Club had the right batteries in stock and with a fresh October date code after reaching the ones at the back of the rack. Buying batteries is a little like buying milk, reach to the back and get the freshest ones in stock. (side note: consider bringing a volt meter with you to check the condition of the batteries in the store, you want your new batteries to be in the same good condition, this is particularly important if the store doesn’t rotate their inventory very well).
So with two brand spanking new batteries we headed back to the RV, in the rain…(I should note the forecasts for our area were for uninterrupted rain and drizzle, perfect for doing electrical work.) But part of this lifestyle is adapting, and learning to roll with unplanned things. Out came the awning to provide some protection from the elements and with a rubber door mat on the ground to provide something to place the batteries on, I got to work.
Our house batteries live under the entry steps like many other motor-homes. It's not a bad location per se, but it leaves something to be desired with respect for working space. Enter one of those clever devices that is so simple it can barely be called a tool. On a whim I had bought a “battery lifting tool,” a scissor action implement which grabs the sides of a large battery and grips them tighter as you pick it up. This tool is needed when your batteries don’t have a built in handle of any kind. Considering batteries weigh about 65 pounds each and ours were located in a tight box which only gives access from the top, this tool helped immensely.
Besides fighting to squeeze the old batteries out of their home and scraping the thick anti-corrosion gunk from the cables, the transfer went surprisingly well. The new batteries were almost fully charged from the store and with 36 hours on the smart charger in the motor-home, before we left the campground they were doing great. We saw less voltage drop when we next stayed overnight in a Walmart and some of our high draw DC systems, like the motor that moves our living room slide-out seems to be running better.
