If you’ve ever walked out to your car and found a dead battery, you know how important it is to have a car battery charger on hand. Nobody has time to wait for roadside assistance or a jumpstart from a good Samaritan, which is why most people invest in a battery charger for additional peace of mind.
A good battery charger is a wise decision for any household, but you must ensure that it’s a reliable product. Otherwise, you could end up in the same boat with your engine not starting.
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Editor’s Note: On July 23, 2024, we published an updated version including a check for technical product changes, a comparison chart, and upgraded the format for an easier reader experience.
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Buyer’s Guide: Choosing the Best Car Battery Charger
Owning a decent battery charger is something you want before you need it. You might not appreciate the benefit of having one of these at your house until your car battery is dead. Then, you’ll realize their worth and be glad you made the investment.
When you select an automotive battery charger, there are several factors you’ll want to consider. Fundamentally, you want access to all the features you need to get your car running quickly or keep the battery fully charged. So here’s what we recommend keeping an eye on.
Voltage
Many modern chargers are compatible with all car batteries, regardless of their size. Top car battery chargers handle both 6V and 12V vehicles with ease.
Amperage
An entry-level battery charger comes with either 10A or 20A capacities. If you want something midrange, you’ll opt for a 20A charger with a 55A to 100A boost mode. If you’re a professional who routinely works on vehicles, it will make the most sense to invest in something up to 60 A for the standard charge mode and 275 A for the jumpstart mode.
Safety Features
Ensure that the battery charger has short-circuit, overload, over-current, overcharge, and overvoltage protection so you stay safe at all times.
Maintenance Mode
The maintenance mode exists to maintain a fully charged cell using minimal power. This mode applies when the car sits for long periods or moves into long-term storage.
Trickle Charge
A trickle charger feeds power to the battery at a slow and steady rate. Once fully charged, the unit automatically goes into float mode. This mode prevents overcharging the battery. Some chargers start trickle charging at 85% of the full charge, while others wait until 95%. Whenever it kicks in, the trickle charge helps to maintain a 100% full charge at a tiny rate while keeping the battery safe from overcharging.
Battery Diagnostics
Some of the best car battery chargers have safeguards that signal users when the battery isn’t connected correctly. Additionally, you’ll find a range of models that feature internal testing mechanisms to detect sulfated, discharged, or bad cells.
FAQ
You always want to be sure you are charging your car battery correctly. The wrong volts or high amperage settings can lead to overheating or charging it too fast. Leaving the charger unattended or not using it correctly is another mistake people often make.
Luckily, most high-quality chargers have safeguards that protect the battery from getting overcharged. These “smart” chargers taper the charging rate as the battery approaches full capacity. Afterward, it will automatically switch off when the charge is full and go into maintenance mode. Charging your battery overnight with the help of a smart charger usually achieves a complete charge. For proper use, always check the operating guidelines of your battery charger.
A trickle charger can prevent a battery from draining if you have vehicles in storage or don’t start them too often.
Basically, a car battery trickle charger is a device that helps maintain the power of your battery and prevent self-discharge, so you never end up with a flat battery. Essentially, it charges slowly at a low current.
Be aware that older chargers can also lead to overcharging your battery if powered on for longer than necessary. Thus, look for a trickle charger that automatically shuts off when the battery reaches a full charge. Otherwise, you must monitor the battery and disconnect it yourself.
Not all trickle chargers come equipped with this automatic feature, so consider a float charger (also called a “smart charger”). Float chargers have intelligent technology that switches off when the charge is complete and starts again when the charge falls to a specific level.
How long you leave the charger connected to the battery depends on the type of charger and the amount of power your battery needs to reach 100%. Generally, manual chargers require close monitoring since they will not shut down automatically once the battery is at full capacity and warrant disconnecting the cables.
Smart 12V battery chargers have evolved into intelligent, microprocessor-controlled battery charger-maintainers that turn on and off to avoid overcharging. They also have the ability to recondition car batteries. Moreover, they can detect weak batteries and automatically shut off power if the user crosses the battery cables.
Refer to your battery charger owner’s manual for information on how to tell when your battery is fully charged.
Using a battery charger for supplying power was a common function in older models. Most newer models have an electronic safeguard that stops them from providing voltage to anything other than a battery. Thus, you cannot use them as a power supply.
A car battery charger must be disconnected after charging a battery to optimal voltage.
On the other hand, a battery tender or maintainer can stay connected to a battery for longer periods. These devices detect a drop in voltage, automatically switch on to recharge at low current, and then shut off once the battery reaches full capacity.
Battery tenders are ideal for storing parked vehicles over long periods.
We’ve outlined the best portable car jumpstarters available. Let’s get started and find the one that serves your needs!
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