Last week we covered the things you should consider for your dual battery setup in your vehicle such as the type of vehicle, alternator, electrical accessories you want to run and the length of time that’s going to be spent free camping.
In this blog, we’ll delve a bit deeper into why these factors are important and as a result, will help you decide the best dual battery system for your setup.
We’ll talk a bit more about the three main types of battery chargers on the market; Smart Battery Isolators, Dual Battery Charger, and .
Smart Battery Isolators
Smart Battery Isolators have been used for a number of years and offer an effective approach for using your vehicle’s alternator to charge the second battery whilst the vehicle is running. Its job is to also protect the start battery from going flat by isolating it from the secondary battery when the engine is turned off.
A battery isolator will recognise when the vehicle engine is running and charge is going to the starting battery via the vehicle’s alternator. It will do this by sensing battery voltage, and when the start battery reaches 13.2 volts on a 12-volt system, it will connect and start charging the secondary battery.
When the engine is turned off, and therefore the alternator is no longer running, once the start battery drops below 12.7 volts the isolator will disengage the secondary battery. This will stop any loads connected to the auxiliary battery from also draining the battery.
A good analogy for this is to think of the Battery Isolator as a tap between the batteries and the alternator is a pump feeding the start battery. Once the pump (alternator) fills the start battery to a point (13.2v) the isolator detects this and turns on, allowing the feed going into the first battery to pass onto the secondary battery. Therefore the pump feeds both batteries at the same time.
This type of setup is recommended for vehicles that have a fixed vehicle alternator, can be installed under the bonnet and if you’re on a budget. If your setup meets none of these criteria, the next level up is an In-vehicle battery charger, also know as a DC-DC battery charger.
Why they are better
The problem with using your vehicle’s alternator as the main charging source for a secondary battery is that a majority of vehicle alternators after 2010 do not put out more than around 14V after driving the vehicle for 10 – 25 minutes. Deep cycle batteries, which are predominantly used as secondary batteries, generally require charging at higher voltages which mean if they are being charged solely by the alternator they’re often left undercharged.
Providing the correct charge to a battery is a bit like filling your tank with the correct fuel for your engine. You wouldn’t use diesel in your petrol engine and on the higher end of the scale you would be better off supplying high octane fuel to a performance petrol engine.
Therefore, a DC-DC battery charger is recommended as it is designed to effectively charge a secondary battery to 100% ensuring the prolonged life of your secondary battery. An In-vehicle battery charger applies the correct voltage level to achieve a full state of charge, while controlling the amount of current flowing into the battery, so that it doesn’t charge too quickly and cause unwanted damage.
An In-vehicle battery charger may also be necessary when you have to install the secondary battery away from the alternator due to space restrictions under bonnet, as a DC-DC battery charger can overcome voltage drop from long distances. Which is becoming increasingly common in modern vehicles.
In addition, quality DC to DC battery chargers are designed to also work with any type of alternator or vehicle voltage as it can operate and sense a wide voltage range.
Portable solar panels are a great way to keep charge of your vehicle’s battery
The BCDC Dual Input range from INZIN for example, is able to charge batteries from solar (with Green Power Priority) and the vehicle’s alternator simultaneously. It works with all alternator types including smart alternators and with a range of battery types including lithium iron phosphate.
Battery Management Systems
If you really want to get the most of out of your dual battery setup, then the crème de la crème would have to be a battery management system.
A battery management system has all the bells and whistles, combining the features and benefits of a Smart Battery Isolator, Dual Battery Charger and more. The Manager30, for example, is six products in one and offers a variety of features unlike anything else in the market. Its features include;
– DC-DC Battery Charger
– 240V charger
– Battery Isolator
– Load Disconnect Controller
– MPPT Solar regulator
– Remote Monitor
The Manager30 lets you see how your battery is charging and monitor where the charge is coming from
Green Power Priority
The Manager30 has a high-performance MPPT Solar Regulator that ensures you can extract every last watt available from your solar panels throughout all conditions. Normally with most systems you would need to choose whether to take power from your solar panel, or the vehicle charging system, or from 240V, however with the Manager30 it can accept all available power from the solar panels first, before using the vehicle’s alternator or 240v power. This means that the vehicle has less work to do when solar is available, meaning fewer emissions and more fuel consumption savings.
Load Disconnect Controller
The Manager30 Load Disconnect Control has the added benefit of ensuring your batteries are not over-discharged by your loads, warning you when the battery is nearly flat so you can take action to remain powered up.
If your loads do turn off because you weren’t present when the warnings occurred, The Manager30 allows you to over-ride the Load Disconnect and get power back for a further 10 minutes. This allows you to get a charge source started so you are not caught out fumbling around in the dark.