Over the past couple months, I’ve been testing 4 of the best battery monitors for RVs, boats, and 12V to 48V solar systems.
After installing and setting up each monitor, poring over their product manuals, performing charging and discharging cycles, and testing extra features such as Bluetooth and midpoint monitoring, the Victron SmartShunt is my favorite battery monitor.
It’s the easiest to install, works with virtually every type of RV and solar battery, has built-in Bluetooth for remote monitoring, and is one of the most customizable and accurate battery monitors I’ve used. Plus there’s a water-resistant version with an IP65 rating for wet or marine environments.
If you’re on a budget, I think the AiLi 350A Battery Monitor is a good bare-bones monitor that has the necessary features and settings you need to monitor your batteries for cheap. It’ll perform the basic functions of monitoring your battery’s voltage, state of charge, remaining capacity, and charging or discharging current.
The 2 other monitors I tested are also great options. Keep reading for my full battery monitor reviews and recommendations.
Quick Recommendations: Best Battery Monitors
Here’s the TLDR version of my reviews:
- Top Pick: Victron Energy SmartShunt 500A
- Budget Pick: AiLi 350A Battery Monitor
- Best Screen: Renogy 500A Battery Monitor
- Upgrade Pick: Victron Energy BMV-712 Smart 500A
Video: Best Battery Monitors for RVs & Solar Batteries
I made a video version of this review which gives an overview of each monitor and walks through my testing. Check it out below and consider subscribing to my YouTube channel if you like videos on lithium batteries and DIY solar projects!
Top Pick: Victron Energy SmartShunt 500A
|Battery voltage range:||6.5-70V||Bluetooth?||Yes|
|Shunt current rating:||500A (1000A, 2000A models available)||Max battery capacity:||9,999Ah|
|Claimed accuracy:||± 0.01 A, ± 0.01 V, ± 0.1 Ah, ± 0.1% SoC||Operating temperature:||-40 to +50°C (-40 to +120°F)|
Pros: Works with 12-48V lithium and lead acid batteries, easiest to install, highly customizable, has Bluetooth
Cons: No screen, one of the pricier options, mediocre Bluetooth range, ‘alarm’ feature isn’t very useful
Best for: Those looking for a great battery monitor with Bluetooth
Victron SmartShunt Review
After testing all these monitors, the SmartShunt ended up being my favorite. It’s pricey, but — given its combo of features — I think it’s actually a pretty good value.
It doesn’t have a screen, but Bluetooth comes built in, so you can use the free VictronConnect app to monitor your battery bank from your phone or tablet.
The lack of a screen makes the SmartShunt the easiest to install. You could even just mount the shunt to your battery using double-sided mounting tape, which is a relatively common solution among DIY solar enthusiasts. Or you can use a couple screws and a drill to mount it to a wall. Then you connect the shunt to your battery bank like normal and you’re ready to start monitoring.
Everything takes place in the app, including adjusting settings and monitoring your battery’s state of charge, voltage, current, and other specs. The Victron monitors are highly customizable and have a lot of settings you can adjust. It’s a little overwhelming at first, especially since a lot of the settings make no sense the first time you read them.
Fortunately, Victron has a detailed product manual and there are plenty of excellent YouTube videos on the SmartShunt that will help you dial in the settings for your battery. And, ultimately, the extra customization helps the monitor be more accurate.
The app also stores historical data and has a trends report which you can refer to to see things like how your battery percentage or the charge or discharge current has varied over time. Advanced users will rejoice at all the extra information.
The main gripe you’ll see about the SmartShunt is that its Bluetooth range isn’t very good. When I tested its uninterrupted range in a backyard, I measured 90 to 100 feet. That’s certainly not bad.
But I then tested the SmartShunt’s Bluetooth range when the monitor was inside the battery compartment of my dad’s fifth wheel, surrounded by electronics and walls that could interfere with the signal. I measured 30 feet, around 70 feet less.
30 feet was enough for me to be able to connect when walking around outside of the fifth wheel, but I couldn’t venture too far away or else I’d lose connection. If your battery bank is far from where you spend your time, such as in a separate building on your property or a couple floors down in a basement, then you might find the monitor’s limited range frustrating.
Lastly, both Victron monitors I tested have a few extra features. They can do midpoint monitoring, monitor the voltage of a starter battery, and monitor your battery’s temperature if you buy Victron’s temperature sensor.
The Bluetooth, Victron build quality, and level of customization make this my favorite battery monitor. It will still be overkill for some people who simply want a screen that displays battery percentage, but for most I think it’s a worthwhile investment.
Full review: Victron SmartShunt Review
Budget Pick: AiLi 350A Battery Monitor
|Battery voltage range:||8-100V||Bluetooth?||No|
|Shunt current rating:||350A (100A model available)||Max battery capacity:||999Ah|
|Claimed accuracy:||± 1% A, ± 1% V, ± 1% Capacity||Operating temperature:||0 to 35°C (32 to 95°F)|
Pros: Cheap, works with 12-48V lithium and lead acid batteries
Cons: Limited settings to adjust, lower max battery capacity, no alarm features, doesn’t have Bluetooth
Best for: Those on a budget; those looking for a no-frills battery monitor to see basic specs such as voltage, percentage, and current
AiLi 350A Battery Monitor Review
The AiLi monitor is the clear budget option in my mind. It performs all the necessary functions of a battery monitor for a fraction of the price of the other options in this review.
Its screen tells you the battery percentage, battery voltage, charging/discharging current, and remaining amp hours. That’s all the information most people will need from a battery monitor. It doesn’t display time remaining, which can be useful to get a sense of how much longer your battery will last.
You can set your battery’s effective capacity (which goes up to 999 amp hours on this monitor), reset battery state of charge to 0 or 100%, and input a zero-capacity voltage. And that’s it. It has the basic settings and nothing else.
Its 350-amp current rating is lower than the 500-amp ratings of the other monitors in this review, but still plenty high for most RV and DIY solar electrical systems.
Installing it was easy once I had the right tools for the job. You need a drill, screws, and a 2 1/8″ hole saw or slightly bigger (with pilot drill bit). You make a hole with the hole saw and friction fit the monitor inside. There is an included mounting bracket which helps with friction fits in larger holes.
The cord that powers the screen is quite short. You may have to buy AiLi’s extension cord in order to mount it in your desired location, which can slightly increase the cost of this monitor. But even if you have to also buy a hole saw and an extension cord, it’s still likely to be the cheapest option.
When I performed charging and discharging cycles, the AiLi monitor worked as expected and was, as far as I could tell, accurate. The AiLi has no alarm feature, so the only way to know that your battery is running low is to look at the monitor.
It’s cheap and simple and it works. It doesn’t have any nice-to-have features or settings, but it’s a worthwhile upgrade from the basic voltmeter that comes with most RV and boat electrical systems.
Best Screen: Renogy 500A Battery Monitor
|Battery voltage range:||10-120V||Bluetooth?||No|
|Shunt current rating:||500A||Max battery capacity:||9,999Ah|
|Claimed accuracy:||± 1% A, ± 1% V, ± 1% Capacity||Operating temperature:||-10 to +60°C (14 to 140°F)|
Pros: Works with 12-48V lithium and lead acid batteries, has a large screen that displays all your battery specs at once, has a programmable low-capacity alarm
Cons: Doesn’t have Bluetooth, has limited settings to adjust
Best for: Those who want a well-made battery monitor with a large screen and/or a low-capacity alarm
Renogy 500A Battery Monitor Review
Though the Renogy monitor wasn’t my favorite, there are 2 things that make it a good option for a lot of people. The first is the screen, which was by far my favorite.
You can see all the important specs at once — like battery voltage, battery percentage, and charging or discharging current — which sounds trivial but is actually a big convenience over the AiLi and BMV-712 screen that show just one spec at a time.
The monitor also gives you an estimate of time remaining on the battery, which is useful when you’re running loads that draw more or less a constant amount of power, such as lights or chargers.
The second thing is that you get a low capacity alarm which can alert you when your battery is running low. You input the capacity at which you want the alarm to sound, and then the monitor starts beeping and flashing to alert you your battery is running low.
Installation if relatively easy, requiring a jigsaw or drywall saw to cut out a rectangular hole which you then friction fit the monitor inside.
The Renogy monitor isn’t that customizable in its settings, but if all you want is a good monitor with a large, helpful screen, then this is a great option.
Full review: Renogy 500A Battery Monitor Review
Upgrade Pick: Victron Energy BMV-712 Smart 500A
|Battery voltage range:||6.5-70V||Bluetooth?||Yes|
|Shunt current rating:||500A (500A shunt included, but 1000A, 2000A, 6000A shunts available for purchase)||Max battery capacity:||9,999Ah|
|Claimed accuracy:||± 0.01 A, ± 0.01 V, ± 0.1 Ah, ± 0.1% SoC||Operating temperature:||-40 to +50°C (-40 to +120°F)|
Pros: Works with 12-48V lithium and lead acid batteries, has Bluetooth with great range, has a programmable alarm and relay
Cons: It’s the expensive monitor I tested
Best for: Those who want a battery monitor with both Bluetooth and a screen; advanced users who want the most features and customizability; those looking for a monitor with excellent Bluetooth range
Victron BMV-712 Smart Review
For over $200, the Victron BMV-712 is the only battery monitor I tested with the both of best worlds — Bluetooth and a screen. It’s also a great premium battery monitor with lots of extra features that I think make sense if you’re an advanced user or in need of a monitor for a large, expensive battery bank.
The BMV-712 has all the same settings as the SmartShunt to help you fine tune it for your battery type and improve its accuracy. Unlike the SmartShunt, the BMV-712 has a programmable audible and visual alarm that you can set for when the battery drops below a certain percentage or hits a certain voltage. Once the alarm is triggered, the screen starts flashing and the monitor starts beeping.
There are 3 ways to install the BMV-712, which makes it the most flexible of the monitors with screens.
First is to use a 2 1/8″ hole saw to drill a hole in your wall, fit the monitor inside, and secure it using the included attachment sleeve. This requires you to get your hand behind the wall, which isn’t always possible. The second way is to drill a hole with a hole saw and then use the included mounting plate.
The third way is to buy Victron’s wall-mounted enclosure and mount the monitor that way. This way is best if you can’t or don’t want to drill a large hole in your wall.
The Bluetooth range on this monitor is phenomenal. When I tested its uninterrupted Bluetooth range in a friend’s backyard, it still connected when I was 150 feet away. I actually ran out of room to walk, so the range may have been slightly more than that.
And when I tested the monitor’s Bluetooth range while it was inside the battery compartment of my dad’s fifth wheel, I measured a range of 100 feet, which was 70 feet more than the Victron SmartShunt in that situation. That’s a huge difference. That gives you plenty of range to monitor your batteries from outside your RV, on the deck of your boat, or even from another building on your property.
Like the SmartShunt, the BMV-712 has a second port on the monitor which can be used to monitor your battery bank’s midpoint or the voltage of a starter battery. You can also connect a Victron temperature sensor and monitor your battery’s temperature.
The main other feature that you get with the BMV-712 is a programmable relay which you can trigger when the battery hits a certain state of charge or voltage setpoint.
Ultimately, I think most people don’t need the BMV-712. I’d only begin to recommend this monitor if you want the convenience of the Bluetooth and screen combo or if you need its great Bluetooth range. There are maybe some other edge cases where it makes more sense than the SmartShunt, but I expect those will be limited.
Full review: Victron BMV-712 Review
How to Choose the Best Battery Monitor for Your Needs
Battery Voltage & Capacity Ratings
Before considering anything else, make sure the battery monitor you’re considering is compatible with your battery bank.
Most battery monitors work with virtually all types of RV and solar batteries, regardless of whether they’re lithium iron phosphate (LiFePO4) or lead acid batteries. But the two main things to look at are the battery voltage and capacity ratings.
Battery voltage range: All the battery monitors I tested are compatible with 12V, 24V, 36V, and 48V lithium and lead acid batteries. These are by far the most common battery voltages I see in RV and DIY solar systems. But if your battery bank is a different voltage, check that it falls within a monitor’s voltage range before buying.
Battery capacity rating: Budget battery monitors tend to be able to handle battery banks with amp hour capacities of 999 amp hours or less. The AiLi monitor falls into this category. More premium battery monitors tend to be capable of handling battery banks with amp hour capacities of 9,999 amp hours or less.
Shunt Current Rating
100A-350A: Budget battery monitors tend to have shunt current ratings of 100 to 350 amps. Though that is less than the more premium options, that is still a significant amount of current that most small RV, boat, and solar electrical systems are unlikely to exceed.
≥500A: The premium battery monitors I tested all had current ratings of 500 amps, and some of them had upgraded models available with current ratings of 1,000 amps or more.
Being able to monitor your batteries from your phone is a worthwhile upgrade in my opinion. However, a lot of battery monitors do not have this feature.
Bluetooth monitoring in a battery monitor works in conjunction with a free mobile app provided by the brand. Victron is the main brand that offers Bluetooth monitoring in their battery monitors, although it doesn’t come built-in to every monitor they offer.
However, Bluetooth monitoring is certainly not necessary. If a battery monitor doesn’t have Bluetooth, it will have a screen that will display all the necessary specs such as battery percentage, battery voltage, and charging or discharging current.
Some battery monitors let you program alarms to alert you when the battery capacity is running low, or when the voltage hits a certain setpoint. The alarms fall into 2 categories:
Audible and visual alarms: Monitors with these alarms start flashing and/or beeping once the battery reaches the set capacity or voltage. They are the most useful in my opinion, because they’re best at getting your attention.
In-app alerts: Monitors with companion apps sometimes have ‘alarms’ that are actually just in-app alerts. These are far less useful at grabbing your attention because you need to open up the app to see them.
The alarms can always be disabled if you don’t want them.
Operating Temperature Range
If your battery monitor will be placed outside, or in a building or vehicle without AC, then look at a monitor’s working temperature range before buying. Some of the cheaper battery monitors, such as the AiLi monitor I tested, don’t work below freezing or above 95°F.
Note: If your batteries will also be placed outside, consider their working temperature ranges as well. For instance, lithium iron phosphate (LiFePO4) batteries should not be charged below freezing unless they have low-temperature charging protection.
If your battery monitor will be placed on a boat or in another environment where it could get wet, pay attention to the IP rating of the monitors you’re considering. The Victron SmartShunt has a new IP 65 version which is rated for use in marine environments.
The Bottom Line
After testing 4 of the best RV and solar battery monitors for over 2 months, I think the Victron SmartShunt is the best battery monitor for most people. It’s easy to install and set up, it works with nearly every type of RV and solar battery from 12 to 48 volts, and it has Bluetooth which lets you monitor your system from your phone using Victron’s free mobile app.
For those on a budget, I recommend the AiLi 350A Battery Monitor. It doesn’t have Bluetooth or any extra features, but it performs all the basic functions of a battery monitor for a fraction of the cost of the SmartShunt.
The Renogy 500A Battery Monitor has my favorite screen of all the monitors I tested and lets you see everything you need to know at a glance. And the Victron BMV-712 is a premium battery monitor that has both Bluetooth and a screen.
Ultimately, all the monitors I tested work well and, once installed, will let you see how much battery your RV, boat, or solar system has left the same way you can see your phone’s remaining battery percentage.
A small ask: If you found my battery monitor reviews helpful and are planning to buy one, please consider please consider buying through one of my affiliate links below. I’ll get a small commission (at no extra cost to you) which will help fund more reviews like this one. Thank you! 🙏