How to Charge RV Deep Cycle Battery? Everywhere From All Electricity

An RV house battery literally powers your life in an RV (recreational vehicle). It will probably be your power source when dry camping unless relying on a connection to the grid or an expensive generator. 

Without a charged RV battery, your appliances and key infrastructure like water pumps won’t work. Make a mistake while charging the RV deep cycle battery, and you shorten its life at best and kill it then and there at worst. 

If you want to know how to charge RV battery banks, understand there are a few steps you should take every time.

  • First, turn off the RV. Set the emergency brake, just to be safe.
  • Open the access panel for where the batteries are stored. Put on gloves.
  • Remove the battery cables starting with the negative (black) one first, then the positive (red) cable.
  • Clean the connections. You can mix two spoonful of baking soda with water to make a paste to clean the connections if you don’t have something else on hand.
  • Once the paste is on the connections, use a wire brush to scrub the corrosive material off. Wipe away the paste and any residue with a rag.
  • If you have a lead-acid battery, this is the time to open the fill cap to check the water level. If water is needed, only add distilled water. Fill it to the fill line. Don’t over-fill or else the battery could explode when you charge it.

If the water levels are fine or the battery will never need water added, you’re ready to attach the charger to the battery regardless of the type of power source you’ll be using to charge it.

01. How to Charge an RV Battery with a Generator?

If the RV has a built in generator, this is simply a matter of turning on the generator and letting the battery charge. If the RV has a place to plug in a generator to a built-in converter, you’d need to connect the generator to the electrical system correctly and then turn it on. 

However, you need to be careful since not all RV generators are designed to be a battery charger. In these cases, you’ll need a converter to turn the 120 volts power it generates into something you can connect to the battery. 

Choose an inverter built-in Generator!

A 3-stage battery charger can charge your RV battery using generator power; this could be installed in place of the existing converter in the RV or may even be built into a new, high-end RV. 

This is where buying a generator with a built in inverter and 12 volt plugs you can connect to the battery make life so much simpler. 

How long to charge RV battery with Generator?

Charge time will depend on the battery size, the amps from the generator, what is running at the same time (and draining power) and how low the battery was to begin with. A battery at 20% will take about four times as long to charge as one at 80%.

When you’re charging an RV battery with a generator, check the charge regularly. Don’t overcharge it, since this can cause it to explode.

What can be happen If you did a mistake?

Conversely, you’ll want to wait at least an hour after you’ve checked the electrolyte and added water to the battery or else it could explode when you try to charge it.

This is an issue even if you have VRLA batteries; their valves are designed to release the traces of hydrogen gas that can build up as a battery ages, not a veritable explosion of hydrogen gas. Don’t leave converters plugged in to a battery.

Yes, the converter attached to your smart generator will charge the RV battery as well as your laptop. 

Converters can boil an RV battery dangerously!

However, these converters can boil an RV battery as well. This is when you may need a hydrometer to check the specific gravity of the battery to see if you need to add water or just get a new deep cycle battery.

If you’re concerned about fuel for a generator, remember to take the opportunity to charge the RV battery via an RV converter/charger whenever you have power from the grid.

What converter can ensure the Safety?

A 3 stage converter will fully and safely charge the RV battery better than the 2 stage converter that comes with many new RVs; a side benefit of these units is that they’re smart enough to stop sending power to the battery when they sense it is full.

02. How to Charge an RV Battery from a Vehicle?

You can often charge an RV battery from a vehicle. And you can do it using the same jumper cables you use for charging a dead car battery.

  • First and foremost, park the car near the camper battery. Note that you will always want to turn headlines when you park, since this will drain your battery fast and slows down any charging process. Turn off all accessories in the RV, too.
  • Leave the car engine running.
  • Remove the caps to the car battery and that of the RV battery.
  • Connect the red clamps of the jumper cables to the positive post for the RV battery. Then attach the black cable to the car battery. This cable will be connected to the negative pole of the RV battery.
  • Let the car engine run until the RV battery is charged.
  • Remove the black clamp from the RV battery, then from the car battery. Then remove the red clamp from the RV battery and then the car battery.
  • Replace all the battery caps.

Your battery should now be good to go, assuming you didn’t over-charge it or try to charge a battery with too little electrolyte to receive the charge.

03. How to Charge an RV Battery While Driving?

If you have a tow vehicle, you could in theory run that vehicle’s engine and let it charge the 12 volt batteries. However, we’ll leave ignore that for safety reasons and the fact you may not be towing an operational vehicle along with your RV.

Can you charge an RV’s 12 volt batteries while driving?

If you are pulling a 5th wheel or towing a trailer, many trucks can provide a charge you can use to charge the recreational vehicle battery. It will be a trickle charge, so it won’t charge a depleted battery. 

Getting around this could require rewiring your vehicle and trailer, such as replacing 12-gauge wire with 8-gauge wire. Or you could wait until the truck is stopped and then charge the 12 volt battery from the truck’s battery per the process described above. 

Another Option is Battery To Battery Charging System

Another option is getting a battery-to-battery charging system. You’ll probably want to consult with a mechanic to install something like this, much less make sure it is safe to use while driving.

04. How to Charge an RV Battery with a Solar Panel?

Solar panels are always a trickle charge, slowly delivering power to your battery. The key to successfully charging an RV battery with a solar panel is to not drain the battery at the same time. Turn off the lights, don’t use the water pump and let the solar panels just charge the battery.

However, you’ll also need to take care to take weather into account when you want to charge an RV battery with solar panels. If it is cloudy or somewhat shady, give the panels extra time to charge the battery. 

Extra roll out pads of solar panels

This is where having extra roll out pads of solar panels to charge an inverter so you can charge your cell phone or small electronics can save your RV battery while keeping you from being too bored.

If they’re already mounted to the RV and connected to its power system, just make sure everything inside the RV is off and the converter is set to charge the battery. In other cases, you have to wire the solar panels to the battery to charge it.

For more complex systems, such as when you have multiple solar panels, you’ll need a charge controller; this device will disconnect a battery from the solar panel while those with an MPPT circuit maximize power generated by the solar panel as well.

If your solar panels are unregulated and/or unsupervised, they may fail to charge the electrolyte. In a worst case scenario, they’ll boil off electrolyte, eventually killing the battery.

05. How to Charge an RV Battery at Home?

This is one of the simplest processes. You could use an SMPS adapter or other charger that converts power from the grid to 12 volt DC.

For example, an AC powered float charger designed for charging 12 volt batteries could do the job. You’ll plug that into the wall and connect it to the battery. Then let it charge.

Once done, disconnect and put it all away. In short, this process is similar to charging any other rechargeable battery in your home. 

Disconnect the wire from ground

Disconnect the ground wire of the RV battery so it doesn’t drain while in storage. If the battery is left in the RV, start disconnecting everything else that will slowly drain the battery of power.

Even when they’re off, they drain milliamps of power.

This isn’t as bad as a gaming console using almost as much power in sleep mode as when active, but it will kill the battery if left alone. The solution is to unplug the radios, smoke detector, propane detector and so forth.
Remember, Freezing destroys flooded cell batteries

If you’re going to leave the RV battery in the garage or store it outside (including in an RV parked outside), make sure the battery doesn’t freeze. Freezing destroys flooded cell batteries, though this isn’t as much of an issue with other types of batteries.

For example, AGM batteries resist freezing better. Never charge a frozen battery, since the mixture of heat and ionized hydrogen can cause an explosion.

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John S.

Hello guys! I'm a 37-years-old author, traveler, writer, blogger, and a camper. I enjoy life as much as I can and love to visit beautiful places in my RV. That's why while traveling I have decided to dedicate some time to share my experiences with everyone that might be interested in traveling, camping, and RVs.