If you have an older Roadtrek or many other older RVs you likely have a Magnetek Converter/Charger (newer Roadtreks have inverter/chargers like the Tripplite). Magneteks are very common in the RV world. Your fuses and circuit breakers will be inside the cover of the converter box. For those not familiar with the differences, a converter takes 120 VAC (volts alternating current – like in your house) from either plugging into shore power or from your generator and “converts” it to 12 VDC (volts direct current — like your car battery). An inverter takes 12 VDC and “inverts” it to 120 VAC. There is a loss in doing this — it is always better when running off batteries to run 12 VDC appliances rather than using 120 VAC appliances on an inverter — your batteries will last longer. The battery charger for your house battery is built into your converter or your inverter, depending on what the RV manufacturer choose to install.
The Magnetek was the choice of many RV manufacturers for years. The problem is that if you have a low battery and plug into shore power that Magnetek can take several days to fully recharge your battery. Why? It is a very simple single-stage charger. Also, if you leave your camper plugged in for too many days, it will likely “boil” (overcharge) your batteries, meaning not only making a mess, but also requiring you add distilled water often (if you have a standard wet cell batteries). If you have gel or AGM batteries you may avoid the mess and you can’t add water, but it will shorten the life of your batteries. The maker tried to pick a middle of the road charging level, but the result is bad at both ends. We believe some later model Magneteks did have two-stage charging.
The solution is an upgrade to your old converter to add a three-stage charger. You could replace the entire converter, but the easy solution is one of the upgrades that use the original RV Magnetek converter box and circuit breakers (for the 120 VAC side) yet replace the guts and the fuse board (12 VDC side). WFCO and Progressive Dynamics both make upgrade kits to the Magnetek. We bought the PD4600 that was the recommended upgrade for our model of Magnetek. All the upgrade kits offer filtered power for all the 12 volt circuits, unlike the original Magnetek. You will have extra fuse positions available so you can add more 12 VDC circuits if desired (we added three, 12 VDC outlets).
We purchased ours from www.BestConverter.com where Randy was helpful with advice (he sells both the WFCO and the PD upgrades). If you don’t mind dealing with lots of wires (label them) you can do it yourself. There are good instructions and it is not difficult. Be sure to disconnect both shore power and your house battery before you work on the converter. And be sure you label which fuse goes to what on the provided page to leave inside the box. If this is more than you feel capable of tackling you can have a RV shop or someone like Dan Neeley (itinerate Roadtrek handyman) do it for you. The Progressive Dynamics upgrade has LED lights by each fuse which light up when a fuse is blown (very nice) and a green LED that shows which mode the 3-stage charger is in. Using the tiny button near the green LED you can force the charger into any of the 3 modes, which can be useful at times.
With the upgrade our battery does charge much faster and we can leave our Roadtrek plugged in while setting at home without worrying about overcharging the battery (as long as we turn off the solar). The Progressive Dynamics 4600 charger has a Boost mode of 14.4 volts (to bring the battery up to 90 percent of charge), Normal mode of 13.6 volts (to complete the charge), and a Storage mode of 13.2 volts to maintain the charge. See the charge profile chart to the right. The LED status light is on solid green in Boost mode, on fast blink in Normal mode and slow blink in Storage mode. We wish the Boost mode was a bit higher than 14.4 volts, but it is a big improvement over the original system. It is possible to do major (and expensive) upgrades to RV charging systems, but upgrading an old Magnetek Converter is a substantial improvement for a modest cost.