May 31, 2022 / by Danny Mavis

Cars need regular maintenance. You’ll have the oil and filters changed at regular service intervals, and spark plugs and timing belts if you do more miles. The same goes for brakes and tyres. But how many of us have stopped to think about the car battery? Not until the electrics start playing up, or the car won’t start at all you know your battery is going down the path of dinosaurs.

If you use your car daily, then such scenarios are almost unlikely. Batteries top up charge with the engine running, and longer trips help here. But if you only use the car for the short run to the shops, or for the odd weekend getaway, you can be in for a nasty surprise. All car batteries deplete over time, and those that don’t get duly charged are quicker to die out.

A dedicated battery charger will put the juice back into the battery. This is good for all the right reasons. You don’t want to be left in the middle of nowhere with a car that won’t start because the battery’s called it quits. Chargers are one way to go, but you can also install a car battery monitor. This keeps you informed about battery health, and the level of charge remaining. A purposeful 12v monitor for car is also quick to call out any issues with the ignition and charging systems, and spare you costly repairs down the road.

battery monitors

Why Have a Car Battery Monitor?

Battery monitors are small, inexpensive devices loaded with benefits. They constantly monitor the level of charge in the battery, so you know whether it’s charging and to what extent, as well as if the battery is discharging, even with the engine on. This is important in maintaining the car battery in good working condition, and prolonging battery life cycles so you don’t have to dig deep for a replacement battery. By keeping batteries charged, drivers avoid the risk of sulphating or leaky batteries that can cause significant damage under the bonnet. This in itself can soon become a serious risk to your health and safety.

Monitoring charging levels also means avoiding the risk of overheating or overcharging batteries. These are precursors to problems with the ignition and alternator tasked to charge the battery, and car battery monitors can pinpoint cranking issues even if the battery is perfectly fine.

monitor for battery check

Monitors can be used with ordinary lead-acid or lithium-ion batteries. You can also hook them up to the main battery in any vehicle, or a secondary battery. A single monitor can track the health status of up to 4 batteries at a time.

How Battery Monitors Work

Installing a battery monitor in the car is simple and quick. Pop up the hood, loosen the battery terminals and connect the red lead to the positive terminal and the black lead to the negative terminal. Tighten the terminals and install the app. Once up and running, the monitor will connect to your mobile device via Bluetooth and display voltage. A 12 Volt battery that’s fully charged will show 12.6V or more, but if your car has been garaged for longer periods, then this will be lower. The same applies to auxiliary batteries that haven’t been used for quite some time.

checking monitor on the car battery

With the engine on (even at idle), you get confirmation that the battery is charging. Damaged, and batteries at the end of their life cycle will record faster-discharging levels, so you know it’s time for a replacement.

Handy Features

For the asking price, you’re getting a lot. Simpler and cheaper units display charge levels with a series of indication lights (red to green). LCD screens feature monitors that cost a few dollars more, and integrated Bluetooth pairs the monitor with mobile devices.

Besides charge and voltage levels, a 12v monitor for car can perform cranking tests to evaluate the charging system health and the electrics in general. Most monitors will also have historical data of previous charging cycles to give you a better picture. Some may also record the duration of trips. All data is stored and easily accessible with the phone app, without ever having to lift up the bonnet. Units can function via Bluetooth up to 10 metres, so they can be installed in larger vehicles, as well as trailers, boats and caravans and work seamlessly.

checking the battery on laptop

Protective features also help. Monitors have reversed connection protection so there’s no damage to the battery or monitor even if you didn’t follow the connection tips above. In addition, there’s a short circuit and surge protection, that protects the battery, wiring and electrics when too much voltage is supplied.

Pricing and Buying Tips

Basic units are extremely cheap, but also limited in functionality and features. They miss out on Bluetooth connectivity, as well as basic protection features. All monitors however have accurate voltage readings. Australian brands will be tested and approved before hitting shelves and have detailed instructions for setting up and use. You can shop directly from manufacturers, or get your car battery monitor from well-stocked automotive stores.