Pay attention to your battery

Usually lurking under your bonnet, the battery is one of the most important items in your 4WD, because let’s face it, if it doesn’t work properly, then neither does anything else.
Yet it is largely ignored - and often neglected - until it does let you down.
But has the battery really let you down, or have you let it down? The reality is that you have probably let yourself down through simply not paying a little attention to that plastic box full of electricity nestled in an out-of-the-way corner of your 4WD.
While the average battery life is around three and a half years, with proper maintenance most batteries will last far longer. So what is exactly involved in “proper” maintenance of a battery?
According to AA Mobile Battery Services, there are five major points that should be taken into consideration -
First is ensuring that your general engine condition is good. Poor engine condition can overload the battery, so keeping the engine in top condition with regular servicing is – and let’s face it, should always be – a priority.
Secondly, under-charging and over-charging will quickly reduce the battery’s life, so regularly checking the charge rate is also important.
 Keeping your battery clean is another consideration, as this can reduce the rate of battery discharge. Using hot, soapy water to clean the case is recommended, remembering to dry it off well. Also, ensuring that the terminals are kept clean is important.
Checking that your battery is secure at all times is also important, as vibration can cause damage to the battery case and plates. Inspect the terminals regularly too, because loose terminals can also cause problems.
Finally, regular use is an important factor in keeping your battery in top health. Without regular charging, your battery will run down, simple as that. AA Mobile Battery Services recommends that you try to take at least a steady one-hour daylight drive each week.
While this is all fine and well if the vehicle is your daily-driver, it isn’t quite so practical for a dedicated off-road 4WD. This is where a good trickle-charger comes in; keeping the battery topped-up with juice, while not over-charging it.
Ensuring your battery never runs completely flat is a very important consideration, as every time it does run flat, the battery loses a bit more life. If, however, it does run completely flat, then proper charging is vital to its longevity.
Most people think a quick 15-20 minute drive on the open road is enough to charge the battery, but in reality it takes much longer than that. In fact, a run from Auckland to Taupo is more like it.
Instead, charging the battery overnight using a good-quality trickle charger is the best way to do it. Over-charging is also damaging to a battery, so a charger that won’t continue to charge when the battery is full is important.
But it isn’t just old batteries in older cars that require regular maintenance; new vehicles require regular attention too, as the demands placed on their batteries is also far higher.
While it seems counter-productive in this energy-conscious era that we are building vehicles that demand more and more current, this is the reality as the vehicle-buying public expects more creature comforts and more safety and driver-aid functions.
Whereas the power requirement of a vehicle electrical system in the 1970s was 600W, it had more than tripled by the year 2000. Now, there is a power requirement of up to 8kW in the starting phase alone!
Where we once had the single body control module (BCM) commonly performing several vehicular functions, such as the central locking, power window and anti-theft systems, we now have electronic brake force distribution, parking distance control, multiple air bag circuits, adaptive cruise control, lane change assist; the list goes on. All of these functions are live under normal driving conditions, and they are drawing considerable battery current to remain active.
Couple these safety functions with complex navigation and entertainment systems, electric seats and the many other added luxuries which are growing in presence, and you are left with a considerable amount of total current draw.
While modern batteries – and the associated charging systems that keep them topped up – are designed to deal with all extra demands placed on them, adding accessories for your off-roading also places extra demand.
Winches, fridges, inverters and the like all run off your vehicle’s battery, which is why, if you have a number of these power-draining accessories, you should consider making that battery plural and add a dual battery system to your 4WD.
A dual battery system adds another battery to your 4WDs electrical system, leaving the original battery to deal with the ordinary demands placed on it by the car’s electrical systems, while the additional battery deals with the accessories.
The second battery should be either a deep cycle type, designed for slower release of energy – as opposed to a normal “starter” battery which is designed for large fast outputs – or a hybrid which combines the features of both.
Most 4WD vehicles have a factory installed 80 or 100 Amp alternator capable of providing enough current to partially charge a large deep cycle battery.  However, a vehicle’s alternator was never designed to fully charge (100 percent) the main vehicle battery.

 It was however designed to maintain the charge of the main vehicle battery and run the electrical loads (i.e. lights, radio etc.) once the vehicle is running.
By introducing extra batteries into the vehicle’s charging system with the expectation that the alternator will recharge them from a partially or fully discharged state, is not feasible. 
These problems have been exacerbated with the introduction of ECU controlled and temperature compensating alternators. These alternators can be found in late model vehicles such as the Toyota Prado with the D4D engine. They reduce the alternator output voltage to approximately 13.5 volts when the temperature under the bonnet reaches its predetermined level. So the charging of auxiliary batteries, regardless of where they are located, has now become more difficult.
New battery types (i.e. gel, AGM) also play their part in the ever-increasing challenge for the vehicle’s alternator to fully charge the auxiliary batteries.  In addition, most battery manufacturers recommend charging at around 1/10th to 1/5th of the AH rate.  So for example a 100AH battery should be charged at around 10-20A for optimal charging and battery life.
Taking all these points into consideration, it is recommended to charge using an in-vehicle, multi-stage charger rather than just relying on the alternator.  A multi-stage charger for the correct battery type will deliver the best charge possible to a battery.  Bigger current is not necessarily better when it comes to battery charging.
Your battery supplier or 4WD store will advise on the best needs for your purposes.
Having a dual battery system means you can operate these accessories without fear of draining the battery and becoming stranded.
Different types of dual battery kits are available, depending on your needs, such as the dual battery kits offered by Ironman 4X4.
Ironman’s 140 amp dual battery manager module engages when the main battery reaches 13.4 volts and allows both batteries to be charged simultaneously. When the voltage drops below 12.8 volts (i.e. the engine has stopped) the Ironman module disengages, isolating the batteries so you cannot run both flat. The dual battery monitor displays the voltage levels of both batteries and eliminates the possibility of draining the starting battery as long as your accessories are connected to your auxiliary battery.
Ironman’s 275 amp dual battery kit performs an automated parallel function which allows two separate batteries to be charged as one. When the main battery reaches 13.7 volts the kit engages, allowing charging of both batteries.
When the voltage drops below 12.2 volts the kit disengages, protecting the starting battery which does not have the accessories connected to it. The kit has an emergency parallel function (a manual override system) if you need both batteries linked.
Whatever your needs, if you are considering adding a dual battery kit to your vehicle, it is strongly recommended you should discuss your needs with a battery expert before starting on any project.

 

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