How to Charge RV Battery While Driving

How To Charge RV Battery While Driving

As an RV owner, you rely on your battery to power the comforts of home while you are out on the road. This is especially the case when you are boondocking, and you don’t have access to an external power station. If your battery runs out of juice overnight, you can find yourself in a pretty uncomfortable situation. Just think of all of the items that rely on your RV’s battery power:

  • Television
  • Phone charging stations
  • Heating and air conditioning
  • Refrigerator/freezer
  • Freshwater pump to use rv shower head
  • Sewage ejector

One of the best ways to ensure that you have adequate battery power is to charge your RV battery as you drive. Unfortunately, one of the more common complaints people have is that even after a long trip, their battery doesn’t have the staying power they need.

rv and internet

How to Take Care of Your RV Battery?

If you want your battery get and maintain a good charge as you drive, you need to take care of your RV battery just like you should apply reliable roof coating for rv to take care of your rv’s roof. You can start by understanding a bit about how your battery works. 

Your RV battery is a lead acid battery. There are multiple cells each connected with one another. Every cell outputs about 2.1 volts. That means the standard 12 volt battery has six cells. It outputs about 12.6 volts. The battery in your RV is made of plates of lead and lead oxide that are submerged in a battery acid solution of 64% water and 36% sulfuric acid. It’s important to remember that your battery does not make electricity. Your battery stores electricity. The amount of electrolyte and the size of the lead plates in your battery are the two factors that determine how much charge your battery can hold.

If your battery simply cannot hold much charge, it doesn’t matter how far or how fast you drive. You have to start with a battery that is capable of maintaining the amount of charge that you want.

Your battery will also perform better and maintain a charge longer if you take the following steps:

  • Flip the disconnect switch to off when you aren’t using your battery.
  • Don’t overcharge your battery.
  • Avoid extreme temperatures.
  • Test your battery with a multimeter.
  • Keep your battery clean.

using proper gear in RV

Equipment You Need to Charge Your Battery While Driving

Before you begin working on this project, you’ll need to have the right equipment.

  • Anderson Plugs
  • VCR (Voltage Control Relay)
  • High Quality High Amperage Cables

Steps to Charging Your Battery as  You Drive

The first thing to understand is that your RV has a built-in generator. It’s the alternator. That’s what keeps the battery in your engine compartment charged, and it’s why your battery has enough power to operate your radio, headlights, etc. even after your vehicle stops running.

Your house battery or RV battery works a bit differently. In most setups, you either charge your battery at power stations, from a portable charger, or by solar. Here, your goal is to connect your house battery to your alternator so that it picks up a charge as you drive, just like your engine battery does.

Method 1: Using an Isolator to Charge Your Battery

This is really the simplest method. The isolator connects your RV house battery bank to your starting battery or engine battery. Both batteries are charged as you drive. However, when you shut  your engine off, the isolator disconnects the two batteries. This way, as you use your rV to power your fan, lights, fridge, etc you don’t drain your engine battery.

The isolator works by passing power through to your house battery. It’s important to understand that the isolator has no regulating capacities. It simply transfers the power it receives. The amount of amperage and voltage that is passed to your house battery depends on the power of your alternator.

Pros: The Benefits of Using an Isolator to Charge Your RV Battery

  • This is the least expensive method when compared to battery to battery charging.
  • You will enjoy relatively fast charging.
  • You can use your isolator to jump start your engine battery during an emergency.

Cons: The Pitfalls of Using an Isolator 

  • It’s hard to determine  how long it will take to charge your house batteries without experimenting.
  • The unregulated power is a bit risky until you fully understand how your particular setup will work.

Method 2: Using a B2B (Battery to Battery) Charger

A B2B charger works by taking the amperage and voltage that is output by your vehicle’s alternator, then regulating it to a predictable and constant flow.

Pros: The Benefits of Using a B2B Charger

  • It is somewhat safer than an isolator.
  • You can regulate the amperage making charging more predictable.
  • You can create a specific charging profile to meet your needs.

Cons: The Downside of Using a B2B Charger

  • B2B chargers are bigger and bulkier than an isolator.
  • It’s more expensive.

What Type Of RV Battery Should I Use

Final Thoughts: Isolator or Battery to Battery Charging

Of course, most people want to know which of these solutions is better for them. Unfortunately, most resources on this topic treat people as if they must be trained electricians to understand all of this. Instead of doing that, let’s keep things as simple as possible.

The pros and cons are already listed above, but for many people, the following is the most important. The isolator is simply easier to use. It’s also smaller and quieter. You do get more control with a B2B charger, but you will invest more time and labor in installing it. B2B chargers also generate more heat.

Whatever you decide, there are a few things to keep in mind. First, get to know your RV’s alternator. Speak to a mechanic to determine whether or not you need to upgrade your alternator to get the charge you want as you drive. In addition to this, remember that charging as you drive is just one option. You can supplement with solar, shore power, or a portable charger. The best thing to do is assess your power needs, understand your own capabilities when it comes to doing this kind of maintenance project, then decide how you want to proceed. 

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