RV batteries dead; trickle charge or fast charge is better?

Deep cycle batteries like a slower charge. make sure they have distilled water in them. If you plug your RV in, your onboard charging system should charge the batteries.

I'm plugged in also and have had starting problems. I found out the plug-in charges the battery that turns on the lights but not the engine. There are connections between the two sets of batteries. My connections had been damaged, which is why the starter couldn't pull from the other batteries (that were plugged in). Also, the rv uses marine batteries that need trickle charge.

So check your battery connections and hook up to a slow charger.

RV batteries (house battery) can be of several types and each type has different charging recipe.If you have the old fashioned lead acid batteries where the cells are accessible you have to top off the water in each cell with distilled water. Carefully pour water from a small cup til the water reaches about an inch from the top and automatically forms a cup shape! That is just the right amount of water in the cell. Next replace the caps and plug your RV into the wall, the built in charge will take care of charging the batteries. If you are going on a trip then you can allow your alternator from the engine to charge the batteries while you are driving (generally takes about 3 to 4 hrs of driving to get the house battery bank fully charged during day time driving). Best to plug the rig in and let the system charge your batteries, but if you need to do this manually then many of the big box stores have what they call smart chargers which sense the type of battery our you can set it to charge the specific type and it also varies the rate of charge depending on various things like type, temp, condition etc.

If you want to save your batteries from year to year add a total shutoff to isolate your batteries that will extend the service life of your batteries.

How To Charge Rv Battery

RV's use a marine battery that is made to be fully drained and fully charged multiple times unlike a car battery. So a slow trickle charge is always better, I use 12v 2amp for a few hours and it does great

A handy device is a 2-amp / 6-amp / 10-amp battery charger.

For large battery's of 30-amp or more, use the 2-amp setting for over-nite charging.

The 6-amp setting is good for a 4-hour charge.

10-amps is kinda' high rate of charge.

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2-amp and under is a trickle charge.

That is your recommended charging rate.

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Purchase a multi-meter.

Also called a Volt-OHM/amp meter.

12-volt battery's are actually 13.2 volts at their very best.

12.7 volts is the low side of a very good battery.

A battery showing 12.4 volts requires attention.

Charging voltage is 14.4 volts.

After charging a battery allow it to just sit for 2-hours to determine its standing charge.

(which should be 13.2 volts to 12.7 volts)

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slow is always better