When we return from camping I usually remember to unplug the RV from the Chevy Tahoe. Chevy battery stays charged and RV always goes dead unless I plug an extension cord from the RV to the garage 120v that keeps the RV battery charged.
I have the battery charger connected to the Chevy Tahoe battery with RV not connected.
With battery charger on 50 amp charge is will charge for 1 second then turn off for 7 seconds, over & over & over. It will take a week to charge if the charger only stays on 1 second each 8 seconds.
With battery charger on 10 amps it charges for 3 seconds they turns off for 7 seconds, over & over & over. It will take a week to charge the battery if it only stays on 3 seconds of every 10 seconds.
With battery charger on 2 amps it stays on all the time. 1000 amp battery will take 500 hours to charge on 2 amps.
I need an old school battery charger that stays on.
The battery charger is Harbor Freight brand it has always worked good before but batteries were never completely dead.