I have more fingers and toes than there are fuses in my classic Land Rover. The engine has no electrical components save for the alternator and the glow plugs. Even the fuel delivery is mechanical. So, I take cues from my trusty Defender and try to keep my auxiliary electrical systems as simple as possible. On the supply side, I have a 100 amp-hour AGM house battery connected to an old-school solenoid-style isolator and a couple of solar panel inputs—one for the permanently mounted 100-watt module on the roof and a second wired in parallel for a 100-watt portable panel. On the output side, I run a SnoMaster 12-volt fridge, a water pump, an air pump, and a handful of house lights. The system works well, but both the battery management and monitoring could stand an upgrade.
When Redarc offered an opportunity to test their BCDC1225D In-Vehicle Battery Charger and the Bluetooth-enabled BSEN500 Smart Battery Monitor, I jumped at the chance. At Expedition Portal, we are fans of Redarc electrical components and accessories. Nearly every editor at our little publication has installed a Redarc component in one of their vehicles or another. The quality and longevity of these Australian-made products have proven over time to be of the highest grade, and they are intuitive to use. A little-noted but important stand-out feature of Redarc electronics is their clear and concise installation and operation instructions—the best in the industry, in my opinion. For the DIY overlander, this is invaluable, especially when dealing with electrical systems, which can be confusing and frustrating to design and install—more on this below.
The Redarc BSEN500 Smart Battery Monitor and instructions.
Redarc told me that the aim of both the CBDC1225D and the BSEN500 is to offer “the missing pieces in a puzzle for builds with constrained budgets and where extra space is scarce. [Y]ou can run a simple BCDC and house battery with the Smart Battery Monitor and have access to critical information about your power levels.” This is an appealing approach for a spartan application like mine, where I want to keep things uncomplicated but add some functionality and more sophisticated battery charging.
BCDC1225D In-Vehicle Battery Charger | $465
The BCDC1225D is among the most basic of Redarc’s 12-volt battery chargers. However, this does not mean it’s not built to the same standards as some of the more feature-laden products in the company’s lineup. Its solid-state operation and 25 amp current rating are perfect for my modest battery bank, and the built-in maximum power point tracking (MPPT) solar input (32 volts max) means I could eliminate the standalone charge controller for my roof-mounted solar module. It’s not often that adding a component to an electrical system simplifies the entire operation. That solar input on the BCDC1225D also runs on Redarc’s “Green Power Priority” firmware, which prioritizes solar charging for the auxiliary battery whenever possible, whether your vehicle’s engine is running or not.
This battery charger also features a multi-stage charging algorithm that automatically optimizes charging profiles for any common battery type, including AGM, gel, standard lead acid, calcium, and LiFePO4, and it also works with either low-voltage style or standard alternators. With compact dimensions (4.7 x 1.5 x 6.5 inches), the BCDC1225D fits in tighter spaces, like the battery box under my Land Rover’s passenger seat. The fully sealed case is both water and dust-resistant, making it suitable for some under-hood installations. In terms of installation, following those crystal clear instructions I mentioned above and moving methodically, I removed my old battery charger and mounted and wired up the BCDC1225D in about 45 minutes. It started working the moment I made the final connection—truly plug-and-play and easy enough even for the novice.
The best thing you can say about an electrical accessory is that it works without knowing it’s working. The BCDC1225D hums along in the background with no drama, just doing its thing, and it likely will for a long time to come. One convenient feature I miss with my former solenoid-style battery charger is the emergency starting circuit. On the old isolator, I could press a button, which would swap circuits, meaning I could start the truck with the auxiliary battery if the main battery went flat—a tool I’ve used several times, especially after the Defender had sat for an extended period. Most electronic battery chargers don’t have this capability, including the BCDC1225D.
The BCDC1225D Battery Charger was small enough to mount in my battery box with the auxiliary battery, making wiring a snap.
BSEN500 Smart Battery Monitor | $189
The BSEN500 Smart Battery Monitor adds an extra layer of functionality when paired with the BCDC1225D battery charger. It offers instantaneous monitoring of several metrics crucial to keeping your auxiliary battery functioning at the top of its potential without adding too much complexity to the system. The monitor links up to the Redarc RedVision app on a smartphone (iOS or Android) via a Bluetooth 5.1 connection with a claimed 137 feet of range. I measured 161 feet of range in testing with my iPhone 11 Pro, which is impressive reach. The BSEN500 measures voltage and current in and out in real-time, and it constantly updates the battery charge level and charge-remaining status—in theory.
The compact BSEN500 Smart Battery Monitor mounts in small spaces.
In a surprise twist, I struggled with the installation of the BSEN500. The three-wire design is dead simple, and the tiny form factor (1.8 x 2 x 4.7 inches) made it easy to find a nook to mount it. However, after configuring the device with the Redarc Configurator app, and linking up to the RedVision app to start monitoring the battery, I couldn’t get the charge status tool to read anything other than zero. The voltage and current readings, both under charge and under load, were highly accurate (as confirmed with my multimeter), but the charge status graphic remained stubbornly empty. With some help from Redarc’s excellent customer support, I discovered that for the BSEN500 to work correctly, it needs to be the only component connected to the auxiliary battery’s negative terminal. In my case, I had two other circuits wired to that post: the portable solar panel negative lead from its solar charge controller and the negative side of the Blue Sea fuse block that sends power to my accessories.
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- The battery charge status feature in the RedVision app at first failed to work.
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- The clarified wiring solution offered by Redarc.
To get the Redarc smart monitor firing on all cylinders, I needed to rewire significant parts of my auxiliary battery system. This meant ordering more components, like an insulated negative stud for the ground connections, and more wire, connectors, and terminals. Was it worth it? In the short run, I think so. Having the RedVision app’s ability to predict the battery’s charge-remaining status is likely far better for the health of my battery and the sake of the perishables in my fridge than the dumb (and not terribly accurate) eBay-special digital in-line voltage meter I was using previously.
Learning Curves
There are two ironies here. First, after singing the praises of Redarc’s installation and operation instructions, the BSEN500 Smart Battery Monitor took a lot more effort, head-scratching, and extra material to install and get running than expected. After a second and closer reading of the language in the user manual, I think I could have eventually reached the solution Redarc’s customer help did. But that’s an ex post facto evaluation, and the literature might benefit from more clarity. Second, an important question remains: am I actually better off using an app to keep tabs on the auxiliary battery? Adding one more system in the vehicle that leans exclusively on my smartphone seems like a step backward in terms of simplicity, given the original mission of my build and the spirit of the Defender. Whether the extra information warrants the added complexity is ultimately up to the user.
Read more: Redarc Launches the Alpha150 Lithium Battery for Extreme Conditions
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