Remember, Your RV Charging system has FAILED and you are camping. When you get any type 12 volt charger from Walmart or any vendor, THAT charger is just supposed to charge a low/dead battery. NOT run any 12 volt loads. So, when people here talk about charge rate and Smart chargers, you are talking apples and oranges. What you want is at least a 20 to 40 amp stand alone battery charger. Remember, you are not only charging a DEAD battery, you are also in need of supplying enough amperage to run the various 12 volt appliances in the RV in conjunction with your battery. So, you want a charger that will charge the Battery and also have enough guts to supply at least 20 to 30 amps of DC power to the RV. That means you will want to install a simple Xmas light type timer on the 120 cord of the charger to turn it off at times to prevent overcharging when your RV amp loads are minimal to keep from overcharging your batteries. This is critical if you only have 1 battery. Having 2 or more it is not that critical about overcharging or boiling the batteries. So, buy a quality charger that has multiple AMP charge control. This type thing is just to get you thru the failure until you the get the RV system fixed. Doug
