A battery monitoring system is an essential piece of equipment especially when boondocking or dry-camping off-grid. Without one, there’s no way to accurately see how much battery power you’re consuming or how much is remaining.
Unfortunately, most RVs don’t come with a battery monitor. That’s a problem if you plan to camp off-grid and store your own power. A battery monitor is like a fuel gauge for your battery bank. Now imagine if your car didn’t come with a fuel gauge. You’d definitely need one. Right?
There are many battery monitoring systems out there to choose from, but which one should you buy?
Good news! There are several good battery monitors available for those of us who rely heavily on our RV batteries for power. I’ll share my top picks. But let’s first talk about what you should look for when shopping for an RV battery monitor in 2021.
- What To Look For in an RV Battery Monitor
- Top Rated RV Battery Monitoring Systems
What To Look For in an RV Battery Monitor
Battery monitoring systems have evolved quite a bit over the last few years. The most popular units have very modern displays, Bluetooth and WiFi capabilities. Their firmware is even updated regularly via a mobile app.
All battery monitoring systems first need a way to measure energy flowing in and out of your battery. A quality battery monitor will use those measurements to calculate and display a variety of battery metrics in a meaningful way.
Does it Provide Essential Battery Information?
Here are the key battery system metrics you should be able to see in real-time.
- How much energy is going into your batteries (charging) and coming out (consumption) at any give point
- View energy consumption both as power (in Watts) and as current (in Amps)
- Percentage of your total battery capacity remaining (like the battery gauge on your smart phone)
- Amount of time remaining before your battery is fully charged or depleted (based on current electrical usage)
- Historical power consumption (optional: A nice feature for long term analysis, but not essential)
TIP: Use the battery monitor to see how much power a piece of equipment uses. Simply power up the piece of equipment and watch how much the current or power draw value goes up.
Does It Come With a Shunt?
A shunt is an essential component of a battery monitoring system. It’s a small device connected to your negative battery cable that measures all energy flowing in and out of your battery. The measurements are sent back to the monitor control unit in real-time.
The monitor uses the measurements from the shunt to calculate consumption (power going out) as well as charging energy (power going in) over time. Adding or subtracting from the available battery capacity helps determine the overall percentage available (battery state-of-charge).
Note: It is very important that all energy flowing in or out of the battery goes through the shunt. Equipment connected directly to the battery, bypassing the shunt, will cause inaccurate battery status readings.
Is it Programmable?
The monitor should to be able to accommodate battery banks of different sizes and types. At a minimum, you’ll need to set the battery capacity (in Amp Hours) and system voltage (12, 24 or 48 volts). Setting the battery chemistry (Flooded, AGM, or LiFePO4) may also be necessary.
Advanced monitoring systems like the Simarine PICO system have additional programmable parameters to help the system learn from your charge/discharge cycles and determine capacity based on historical data.
Does it have Programmable Events, Triggers and Alerts?
Certain battery system conditions may require you to take action. Having the ability to program automatic triggers and alerts for critical battery capacity, current draw, voltage level, and temperature values is very useful.
For example: Say you have a residential refrigerator running 24/7 and want to be alerted when your batteries dip below the 50 percent mark. At that point, the battery monitoring system could trigger your generator to automatically turn on until the batteries reach 80 percent then shut off. You could leave your RV for the day with peace of mind.
Is the Display Easy to Read, Operate and Understand?
Anyone in your RV should be able to view the state of your batteries and how much power you’re using at a glance. You shouldn’t need be a technician or have to read a manual in order to get this basic information.
That’s why I’m a big fan of a big battery gauge like this one shown below. Anyone can understand that.
Sure there are a ton of advanced features included with most battery monitoring systems, but the basic information should be readily visible and non-cryptic.
Is the Firmware Upgradable?
It’s essential to be able to apply software fixes and upgrades when they are released by the manufacturer. Technology advances rapidly and modern computer controlled equipment like this should be as future-proof as possible.
Legacy battery monitoring equipment used to have serial ports that can be connected to a computer for updates. The process was frankly a pain. Those days are long gone.
Today, I’m not likely to invest in an expensive computer controlled component that can’t programmed and updated via Bluetooth or WiFi.
That’s perhaps one big reason behind the success of companies like Victron and Simarine. Their equipment is modular and can communicate and share data. Add in mobile device compatibility and you’ve got a winning combination for ease of use and system updates. It’s just what we’ve now become accustom to.
Other Useful Features
Here are some other handy features many higher end battery monitors may include. Expect to pay a little more for these features.
- Ability to monitor a second battery bank (such as a motorhome starter battery)
- Temperature sensor input
- Ability to share information with other equipment or larger equipment network (i.e. Victron VE.Smart Network)
Note: It’s worth mentioning that for just a few bucks, you could get an inexpensive device like this that will give you basic power in/out readings without the bells and whistles. I often use them for small projects, but expect to get what you pay for.
Top Rated RV Battery Monitoring Systems
Here are my top picks for RV battery monitoring systems available on the market that meet the criteria outlined so far.
Victron BMV-712 Battery Monitor (Most Popular)
The Victron BMV 712 series battery monitor is a very popular option especially as part of a larger Victron equipment network. No Victron equipment? No problem. It works just great as standalone battery monitor too.
See the Victron BMV-712 Monitor in action.
With its built-in Bluetooth capability, the BMV-712 can is fully controllable and programmable via the mobile app. This is going to be the preferred way to program it. You could also program it from the display panel, but it’s a bit more difficult.
I know lots of RV owners with this system who really like it.
Victron Smart Shunt (Best Buy for the Money)
If you don’t need a fancy mounted display, the Victron Smart Shunt is something to consider. Everything you’ll need for monitoring is included on the shunt itself.
Just install the shunt on the DC negative side of the battery bank and connect the thin wire to the DC positive. That’s it. The rest is done via the Victron Mobile App.
Victron’s Smart Shunt meets all the requirements of a quality battery monitoring system. It just doesn’t have a mountable display unit. Watch this video to see it in action.
Like the BMV-712 the Smart Shunt is also fully compatible with Victron’s VE.Smart Network and works seamlessly with other Victron equipment or as a stand-alone monitor.
In my opinion the Smart Shunt is the best buy for the money.
Simarine PICO Battery Monitor (Best Usability and Most Versatile)
The SIMARINE PICO Smart Monitor includes battery monitoring. It also has the capability of monitoring storage tank levels and other voltage sources.
The SIMARINE PICO ONE package is my top pick for usability primarily because of the well designed user interface, ease of use. The PICO system also has a great modular architecture that I really like. The package includes a combo shunt module which also has inputs for a couple of tank sensors.
See the PICO system in action in this video.
The downloadble mobile app can be used for remote monitoring and keeping the unit updated with the latest firmware. With the exception of firmware updates, all settings can be controlled from the touch display as well.
The PICO STANDARD package includes more sensor inputs and can be expanded with additional SIMARINE modules.
Blue Sea System M2 SoC Meter
The Blue Sea M2 SoC Monitor has a compact easy to read OLED display for monitoring the state-of-charge for one battery bank. The shunt is included.
You can also monitor up to three voltage inputs and even program it to trigger a remote generator start.
See the Blue Sea M2 in action.
Unlike the Victron and Simarine systems, this monitor has no wireless connectivity or mobile app option. Nope, it’s not the fanciest tool in the shed, but it performs the basic functions well and is worth including in this list.