How Long Does It Take to Charge RV Batteries?

Most RVs use the lead acid batteries. These batteries are efficiently charged using the constant current constant voltage technique. Besides, the charging process occurs in 3 distinct stages that each take significant hours to complete before the batteries are fully charged.

So how long does it take to charge RV batteries? A single new RV battery charging time is about 12-16 hours to be fully charged. Once you decide to charge the battery, do not interrupt the power. Ensure the power source is connected for those hours to ensure maximum battery charge capacity is achieved.

The 3 stages of charging include:

Stage 1:

Constant current charge is the bulk charging that accounts for 70% of the total charge. It last about 5-8 hours.

Stage 2:

Topping charge accounts for 30% of charging. Last about 7-10 hours. It ensures full charge is achieved. However, once the battery has been used for sometime full charging at this stage does not occur due to issues such as sulfation.

Stage 3:

Float charge accounts for self-discharging and tries to maintain the battery at its full charge capacity attained in stage 2.

This guide provides you with must know concepts of RV batteries including

Expect to get more insights about

1 Charging RV batteries

  • How do I charge my RV battery?
  • What size of generator do I need to charge my RV battery?
  • Does RV battery charge when plugged in?

2 Maintaining RV batteries

  • Tips for maintaining RV batteries
  • Can an RV battery freeze?
  • Should RV batteries be removed in winter?
  • How much Epsom salt do you use to rebuild a battery?

3 Deep cycle Batteries

  • Recommended deep cycle voltage and amp readings
  • How long does it take to charge a deep cycle battery?
  • What happens if deep cycle battery freezes?
  • How do you bring a deep cycle battery back to life?
  • Can you overcharge a deep cycle?          
  • How do I know if my deep cycle battery is bad?

4 General

  • How many batteries do I need for my RV?
  • How much do RV batteries cost?
  • How long should house batteries last in an RV?
  • Should I cover my RV in winter?

5 Should you wire RV battery in parallel or in series? (video)

1 Charging RV batteries

How Do I Charge My RV Battery?

There are several ways you can charge your RV battery depending with the type of power source you have. Most often, RV batteries are charged via a converter that converts the AC power to DC power.

Alternatively, charging can be done directly by the DC power from a solar power, wind power, or the tow vehicle’s alternator among others.

If uncertain of how to do it, consult your electrician. However, these are common ways used to charge an RV battery.

Ways to Charge RV Battery

Converter charging:

You can hook up the camper to an electrical grid using a 30 amp or 50 amp converter at state park, camp ground, or national park. Small campers use 30 amp and large campers use 50 amp. At home you can use a 15 amp or 20 amp outlet.

Generator charging:

Used when the place you are traversing has no power. It is common and can use either gas, diesel, or propane as the power source depending with the generator model.

The advantage of using the generator is that your AC appliances could be running at the same time the battery is being charged.

Alternator charging:

Best alternative especially for extended trips. Although the disadvantage of this technique is that your charging vehicle will have to be idle for those hours you are charging. Thus, your schedule is more likely to be disrupted.

Solar power:

Solar panels get connected to amp controller, that prevents overcharging, then its connected to the batter.

What Size Generator Do I Need to Charge My RV Battery?

A 300 watt generator has the capability of handling majority of 10 amp chargers. Thus, if you use a 30 amp charger you will need to step up to a 600 watt generator.

If uncertain of what output your generator offers then consider shutting of your generator and testing the current voltage of your batteries. A fully charged 12 volt battery should read about 12.6 volt for it to be at its full capacity.

Majority of portable generators such as the “contractor” style tend to have a lot of “electrical noise”, a few spikes, and is not a “clean electricity”.

Clean electricity comes from generators that offer pure sine wave that in turn guarantees the safety of your electronics. Some good example of pure sine wave generators is the Yamaha and Honda among other brands.

Does RV Battery Charge When Plugged In?

Yes. Whenever the RV is plugged in, the coach batteries do charge. Thus, the battery will always have charge. Thus, you can be powering other devices such as the refrigerator to enhance cooling.

Make sure the RV is parked in a level ground for maximum functioning of the refrigerator.

However, if you will leave the RV continuously plugged in you need to be cautious of your battery life or risk causing damages. When the battery is continuously charging the electrolyte levels decreases and you will need to top up distilled water at least once a month as a way of maintenance.

Failure to be checking the electrolyte levels and not adding distilled water at least once a month risks the electrolyte from drying out.

Since conduction occurs when the battery electrolyte is in liquid form the battery can be rendered dead and malfunctions if prolonged charging continues with no maintenance.

2 Maintaining RV batteries

Tips for Maintaining RV Batteries

The following are some of the guidelines for safety and effective maintenance of the RV batteries:

  • Ensure charging is done in well ventilated place since the hydrogen gas emitted when charging is highly explosive
  • After every trip, make a habit to recharge your batteries to minimize possibilities of sulfation that can make your batteries dead.
  • Before attempting to power your fridge with the RV batteries ensure you have a backup because the battery will be drained.
  • Be checking the electrolyte levels and ensure it reaches the recommended level.
  • A top up with distilled water should be done to prevent the battery from drying out and making the battery dead.
  • Caution should be taken when topping the water since overfilling can cause acid spillage. Acid is highly toxic.
  • Store your batteries well and prevent freezing. NOTE: You should never charge a frozen battery
  • Do not charge at temperatures above 49 degrees Celsius to prevent an explosion.

However, sometimes you can be charging your battery in between use. It may not necessarily be with zero charge.

Can an RV Battery Freeze?

Extreme cold temperatures such as those experienced during winter period can actually freeze your RV battery and even make it dead. What freezes is the electrolyte (the liquid) in the battery.

Freezing of the electrolyte causes it to expand, the battery cause can crack, and the battery becomes damaged which may make it to completely fail to work when needed.

So, should I disconnect my RV battery for winter?

If possible, it is recommended to disconnect your RV battery after it is fully charged and store inside a garage or a shed that has much warmer temperatures than outside to prevent from freezing.

Other than charging and storing in a warmer environment, consider insulating the battery. You can buy an insulated battery box in which you can put your charged battery for storage.

Insulation further protects your battery from freezing much better even when the battery is discharging itself than an insulated battery.

The table below show an overview of possible freezing temperatures when the battery has a specific charge in it. It is evident that a fully charged battery is less likely to undergo freezing than an uncharged battery.

State of ChargeFreezing Temperature (Degrees Fahrenheit)

Should RV Batteries Be Removed in Winter?

Yes. It is recommended to remove your RV batteries during the harsh winter period when you do not intend to use the RV. Before storing the battery, ensure it is fully charged.

Store in a clean, dry, and a much warmer shed or a garage if you have. Fully charge the battery in Spring or when you need to use the RV.

It is important to fully charge your battery to minimize the risk of it going dead due to discharging or due to freezing.

A fully charged battery freezes when temperatures and below zero degrees Celcius by 55 to 60 degrees. On the contrary, an uncharged batter freezes much faster at temperatures of about 20 degrees below zero.

How Much Epsom Salt Do You Use to Rebuild a Battery?

To rebuild your battery, use 8 oz or 1 cup or 250ml of Epsom salt. Stir the salt in 150 degrees Fahrenheit until it fully dissolves.

Please note that too much salt increases chance of corroding the lead plates and the internal connectors that in turn destroys the battery effectiveness.

Add the solution to the battery cell as much as it can take. Ensure your do not overfill the cells. Also, do not pour undissolved salt into the cell. In the instance you lack Epsom salt, you can use caustic soda.

Once complete, close all the battery caps. Slowly charge using a low charge power source. You need to be patient since the result is not instantaneous.

It can take even a month. Besides, it is not a guarantee that the battery will bounce back to life.

3 Deep cycle Batteries

Recommended Deep Cycle Voltage and Amp Readings

The following is a table with the recommended recharge times of deep cycle batteries using either a 5 amps, 10 amps, or 20 amps power source.

The open circuit voltages of the battery is also indicated. Multiply by 3 for 6 volt batteries or 6 for 12 volt batteries to determine the unit voltage.

Percentage ChargeOpen Circuit Voltage per cellHours Charge @ 5 AmpsHours Charge @ 10 AmpsHours Charge @ 20 Amps

How Long Does It Take to Charge a Deep Cycle Battery?

The actual time depends with the battery size. However, generally deep cycle battery take long time before it reaches a full charge. The charging hours can further increase if you are using a low amp charger.

A deep cycle battery could be rated at 80+ amp hours. It has a storage capacity of 1 amp per hour at 80 hours.

Thus, starting from a discharge state a 2 amps deep cycle battery could take about a couple of days to be fully charged say about 48 hours when charged with a low current battery charger.

What Happens if a Deep Cycle Battery Freezes?

Once the battery freezes it is rendered dead. It is because the electrolyte expands when freeze. It can cause cracking of the battery case. Also, the plates get damaged in the process.

Thus, the battery becomes useless since you will need another replacement to power your RV.

So, to minimize the inconvenience you are likely to face when your battery freezes simply store it well and have it fully charged before storing.

If the storage time will be long, consider reading the voltages and recharge it in between storage. Fully charge the battery when you want to use it.

How Do You Bring a Deep Cycle Battery Back to Life?

Confirm the remaining charge in your battery. Measure the voltage using a voltmeter. For a 12 volt battery, if the charge ranges between 10-12 volts then you can be able to return it back to life and it will function well. However, stop wasting your time for a battery whose charge is below 10 volt because it dead.

Restoring Your Dead RV Battery to Life

One of the ways to restore you battery to life is by using an Epsom salt. The following is a step by step guide of the restoration process:

Step 1

Heat half quart distilled water to 150 degrees Fahrenheit

Step 2

Dissolve 8 oz. of Epsom salts in the water

Step 3

Remove battery cell caps

Step 4

If the battery are sealed find “shadow plugs” that cover opening of battery cells and drill through

Step 5

Drain battery fluid

Step 6

Using a plastic funnel, add the Epsom solution to each battery cell

Step 7

Insert plastic plug to cover the drill holes or do a replacement of the battery caps

Step 8

Shake the battery well to evenly distribute the Epsom salts

Step 9

Recharge the battery using a slow charge for 24 hours

Step 10

Re-install in your RV

Can You Overcharge a Deep Cycle Battery?

Yes. It occurs when the RV is always plug in or plugged in for much longer duration that the maximum battery charging hours. The excess current from the charge voltage then flows to the battery. The water in the electrolyte boils and begins to decompose.

As charging continues, the more the electrolyte heats up. Water evaporates, and the electrolyte can dry. The battery can be damaged if the process continues and can be rendered dead.

You may also wonder, can you undercharge a deep cycle battery? Yes. Undercharging occurs when you apply too low charging voltage in a manner that the current flow is terminated before fully charging the battery.

As a result, the electrode becomes covered with some lead sulfate. In turn, the overall battery capacity becomes reduced.

A battery that stays for long in a discharged state risk undergoing sulfation. In turn, the overall full capacity of the battery becomes reduced. Prolonged sulfation will also render your battery dead.

How Do I Know if My Deep Cycle Battery Is Bad?

You may experience problems with your battery perhaps working fewer hours than expected or simply not working at all.

You need to conduct test before ascertaining whether or not your battery is bad. Ensure you test your battery after long period of storage before recharging and using it.

The following are ways to check your battery

1 Inspect the battery

Check for discoloration, excessive leaking, crack of plastic, bulging or bumping case, or broken terminals all can be an indication that your battery might have a problem.

Loose and broken terminals can trigger short circuit and is dangerous. Presence of short circuit can be evident by presence of a burn or melting. Extreme short circuit can trigger overheating and even explosion of the battery an event that is disastrous.

A bulge case can indicate overcharged battery. Inspect for other physical openings, cracks, holes, and splits that may cause the battery to stop operating.

Ensure to label such batteries as unsafe. Check the electrolyte level and refill to the indicated level. Drying battery triggers sulfation and the battery can be rendered dead.

When the battery has plenty of fluids, the color of the battery turns to brown or dark. Such is an indication that your battery is dead and can be rendered useless. You actually need to replace such a battery.

2. Measure the voltage readings

State of ChargeVoltage

It is important to note that

  • 0 volts can indicate that the battery underwent short circuit. It is actually dead
  • If charging and battery cannot go above 10.5 volts, the batter has a dead cell. It is still useless unless you try bringing it to life using Epsom salt. Though, it’s not a guarantee that it will work.
  • If battery is fully charged but it is 12.4 volts and below then the batter has undergone sulfation.
  • Sulfation occurs when battery discharges. Crystals cover the plates. The process reverses when battery is charged soon enough.
  • Prolonged discharging can cause excess sulfation and battery can go bad

3. Load test the battery

Fully charge your battery. Test the load using a digital voltmeter. Measure the voltage readings.

4 General

How Many Batteries Do I Need for My RV?

The number of batteries to use depends with the capacity of each battery and the needed output power you need for your RV. You can use one or several batteries combined to get the needed power.

Besides, if you can plug in the RV to a power then you can run your RV without batteries. Use these guidance to determine the number of battery you need for your RV.

Determining the Number of Batteries for RV

You can use

  • One 12 volt 24 group battery (deep cycle) to provide 70-85 AH
  • Two 12 volt 24 group battery, wire in parallel to get 140-170AH. Parallel connection increase amps hour and not voltage
  • With sufficient space, you can switch from standard 12 volt battery and use two 6 volt golf cart batteries, wire in series to get the needed 12volts and provide 180-220AH. Series connection increase voltage an not amp hours
  • With extra big space, combine four 6 volt batteries wired in series/parallel to get 12 volts and double AH capacity

How Long Should House Batteries Last in an RV?

RV batteries are designed to last at least 6 years. However, this is usually not the case since many RVers tend to replace their battery every year or once in every two years.

Lack of proper care and maintenance of the battery is the main cause why batteries do not last as designed.

Extend Your Battery Life

The following are some tips you can practice to extend your battery life

Recharge in timely manner.

A charged battery prevents sulfation from occurring. Sulfation is a process in which small crystals form around the plates and if it occurs in extended period it can destroy the battery.

Prevent complete discharge

Do not let your 12 volt battery go below 12 volts. Yes. I mean that. A fully charged battery is at 12.6 volt. When it reaches 12 volt it is already below or at 50% discharged.

Be sure to measure your voltages using a voltmeter set in DC mode for those using the digital voltmeter.

Charge When Battery is Halfway Discharged

Batteries that are charged at 50% tend to last longer than those charged when the battery is at 20% charge

Prevent extreme temperatures.

Hot temperatures and overcharging cause the electrolyte to dry. Failure to add distilled water on time is likely to render the batter dead.

Extreme cold temperature freezes the electrolyte that in turn destroys the plate and battery case making the battery dead.

Maintain recommended electrolyte level

Add distilled water which is the best to top up your electrolyte level. If you lack distilled water add mineral free water. Note that regular tap water contains calcium and can cause calcium sulfation.

Only add water to the electrolyte after charging and not vice versa. Although, if the plates tend to be exposed add water then charge the battery. Once the battery is fully charged top up the water to fill each cell.

Recycle your old batteries

How Much Do RV Batteries Cost?

The prices vary depending with brand and its voltage and power capacity. Thus, depending with the power output you desire, you may have a variety to choose from.

The cheapest battery is about $48.25 which is the Apex Group UI RV battery. The most expensive batter is about $699.88 which is the Lifeline GPL-8DA deep cycle RV battery.

So, what is the best battery for RV use?

The following are some of the best RV battery you can purchase for your RV. These are deep cycle RV batteries:

1 Optima 8016-103 D34M BlueTop Starting & Deep Cycle Marine Battery

  • Quick to recharge
  • Good resistance to vibrations
  • High reserve capacity
  • Light weight
  • Unique design
  • Acts both as a starting and a deep cycle
  • Easily damaged on slight hit

2. Odyssey PC680 Battery

  • Withstand impact, vibrations, and shocks
  • Quick to recharge
  • Features non-spillage AGM
  • Sturdy and rugged construction
  • High flexibility and can be mounted in various positions
  • No technical support.

3. Universal UB121000-45978 12-volt 100AH Deep Cycle AGM Battery

  • Good resistant to harsh weather, vibrations, and shock
  • Can be used in multiple purposes
  • Performance can be regulated using a valve on it
  • High flexibility and can be mounted in diverse positions
  • The stainless steel hardware is quick short

4. VMAX857 12-volt 35AH AGM Battery Marine Deep Cycle Battery

  • The plates are durable and strong
  • Offers high resistant to shocks and vibrations
  • Recovers faster after repeated deep discharge
  • Non-spillable and non-hazardous
  • Tough tank offers added protection
  • Hold charge for much shorter time compared to other deep cycle batteries

5. Renogy 12-volt 100Ah Deep Cycle AGM Battery

  • Does not easily undergo over-discharging
  • Maintenance free, leak proof, and spill proof
  • Can store solar energy
  • Can be used as power back up for daily use
  • Multipurpose
  • Heavy weight

6. WindyNation 100AH 12-volt AGM Deep Cycle Lead-acid Battery

  • ABS plastic is strong and durable as a housing case
  • Well sealed preventing leakage and spillage
  • Has heavy duty plates
  • Can be used for solar charging and recreational vehicles
  • Hub terminals are short

7. Odyssey PC925 Battery

  • Suitable for extreme temperatures
  • Highly flexible and can be mounted in various positions
  • High recharge efficiency
  • Highly efficient as a shock and vibration absorber
  • Long life cycle
  • Heavy

8. Optima 8052-161 D31M BlueTop Starting & Deep Cycle Battery

  • Good at handling spillage and vibrations
  • Can be easily mounted
  • High reserve capacity
  • Highly durable and rugged construction
  • Multipurpose use as a deep cycle and as a starter
  • Large and heavy

9. Battle Born Batteries 12-volt 100 Ah LiFePO4 Deep Cycle Battery

  • Light weight and retains power
  • Multipurpose usage
  • High tolerance to numerous recharging
  • Can be used for boats, recreational vehicles, and off-grid power
  • Self-protection against deep discharge, overcharging, and harsh weather
  • High price tag

10. NPP 6-volt 225-amp NP6 225Ah AGM Deep Cycle Battery

  • Minimal maintenance needed
  • Easy to use and install
  • Resistant to harsh weather, heat, chemicals, and other elements
  • Sturdy and rugged case
  • Multipurpose
  • Drains faster in comparison to other batteries

Should I Cover My RV in the Winter?

It is recommended to always cover your RV during winter. Covering protects your RV from damages from the harsh weather that includes blustery winds, extreme cold temperatures, and accumulating snow. Proper RV storage saves you the cost of having to do expensive maintenance the next time you need to use it.

Safely Store Your RV During Winter

The following are some of the ways to safely store your RV during winter:

Store it in a shed or a garage.

If you do not have you can consider renting a shed during winter.

Rent space

You can browse the Sparefoot website and find the nearest local storage space available to store your RV.


If you do not have a shed, a garage, or renting is beyond your budget, consider applying  a cover over the RV. You can use a tarp covers from Amazon. Also, you can by the covers from Camco and ADCO manufactures.

Caution Before Covering your RV

Please note, before covering your RV ensure to

  • Clean and dry both the interior and exterior of your RV. Do not forget to clean your waste tank.
  • Get help from a friend or family member to help you cover the RV
  • Caution should be taken on the corners and edges to prevent tearing the material during the process of covering
  • Ensure your antennas on the RV roofs are flat.
  • Manually maintain your RV. If you cannot afford the above storage options take full responsibility of removing the piling ice, falling leaves/sticks, and any other object from your RV. Honestly, the experience is not good since it is too cold and is not fun to do.
  • You are likely not to frequently maintain your RV with this technique. So, just set a budget for proper storage of your RV.

5 Should you wire RV battery in parallel or in series? (video)

Watch this video to understand the ways you can wire your RV battery especially when you have lots of load and you want to connect two or more RV batteries.

Lithium Batteries: Should I Wire in Series or Parallel?

Recent Posts