How to select the right car battery charger
A vehicle battery is an expensive investment. More often than not, the need to replace the battery creeps up on you. Instead of starting up the engine, you are stranded calling the breakdown services or a mate to jump-start you.
A large number of vehicle batteries will not last their intended life-cycle of typically five years. Poor battery maintenance, mainly overcharging and undercharging, are the reasons why your battery fails too early. Select the right battery charger and you will not be caught out flat or forced to change your battery before its time. Here is how:
Which 12V battery charger do I need?
The 12V battery charger you choose depends on the vehicle or vehicles you have. The vehicle, its engine size and its age determine the type of charger that is best suited to keeping your battery alive.
In other words, not every battery charger will work for every vehicle. And, if you have more than one vehicle, eg a car and a motorcycle, it is important that the final choice of battery charger takes both vehicle batteries into account.
How do I choose the right charging rate (amps)?
Your vehicle battery has a 'power' rating expressed as Ah (amp hours). This is how you select the battery charger with the right charging rate (amp):
- Most vehicle batteries are rated in Ah (amp hours): Check your car battery's Ah rating.
- Take your battery's Ah rating and divide it by 12: That is the upper end of the battery charger amp rating you look for.
- Take your battery's Ah rating and divide it by 24: That is the lower end of the battery charger amp rating you look for.
- If your car battery has 120Ah, this means you are looking for a charger with a charging rate of between 5amp and 10amp - the greater the number of amps, the faster the battery is charged.
What is the right car battery charger for my vehicle's battery?
Different vehicle battery chargers work with the different car/vehicle battery types as shown below. As a rule of thumb: New vehicles will need a 'smart' charger and older vehicles with wet batteries may use a standard charger.
- Lead acid or 'wet' batteries are the traditional automotive battery type and can be charged by both standard chargers and smart chargers.
- Gel batteries are predominantly used for 'deep cycle', leisure/caravan or marine/boat batteries. Due to their sensitivity to overcharging 'smart' chargers are required.
- Calcium batteries require a higher charging voltage and are more sensitive in general, therefore they must be charged with a 'smart' charger. Calcium batteries require regular maintenance charging to avoid a potentially deathly deep discharge.
- NiCd batteries require a specialist charger that is designed for this battery type but also then is able to charge all other vehicle batteries in your household.
- AGM batteries used in a large number of START/STOP vehicles allow for a higher charging current for a faster charge rate and also need a regulated charging voltage meaning that 'smart' chargers are required.
Which car battery charger features are important?
Classic cars, cars at second homes, or motorcycles laid up for winter are typical candidates for connecting a battery charger long-term. 'Smart' chargers are the best solution here: Once the battery is fully charged any additional charge is only applied when required. Alternatively, a trickle charger can be used.
If the car battery is sufficiently large and of type 'Lead-Acid', a high powered standard charger may be suitable which then may include an engine start function for immediate jump-starting, if required.
'Smart' chargers up to 4A are usually IP65 weatherproof, safely allowing the charging of a battery outdoors. Nevertheless, avoid placing it on the ground where the charger could submerge partly or fully in rainwater.
Battery maintenance functions, eg a '7 stage intelligent charging cycle', include features to recover a deeply discharged battery and special battery desulphation routines to prolong battery life and improve performance. The additional cost of a fully integrated intelligent smart charger is not so high and it almost always makes sense to make that additional investment.
Some of the Ring chargers have a very low profile, only about 1 inch deep. That makes them very easy to fit securely under the engine bonnet, away from sticky hands when the car is parked in front of the house.