There are some really good portable multi - stage chargers with high amp rate charging that have dissapeared from the market in the last 2 years.
Blame the "mommy " generation for suing manufacturers for their own stupid mistakes in how they misuse equipment.
There are way too many electronic devices created to be recharged or used on shorepower. Manufacturers never concidered usage in RV 's .
Any method used to desulfate or properly speed charge a battery (including Mex's favorate methods) requires common sense. Disconnect the battery -bank from the 12 volt circuits while using these chargers.
Otherwise use the charger that came with the RV. Safe for "clueless " use and on equipment installed in newer RV 's but not the best for long term life of batteries.