Rick's Free Auto Repair Advice

How to buy a car battery charger

How to buy a car battery charger

There are lots of car battery chargers online and in auto parts stores. Many of the cheaper models are obsolete and shouldn’t be used with modern batteries. Here’s a guide on how to buy a car battery charger.

What features you need in a charger

1) The ability to charge SLI, FLD, EFB, Spiral AGM and AGM car battery types

Most older vehicles have a standard flooded lead acid battery (FLD) or starting, lighting ignition (SLI) battery.

But newer vehicles , those with start/stop technology use either an absorbed glass mat (AGM) or enhanced flooded battery (EFB) battery. AGM and EFB batteries require a different charging routine than flooded lead acid batteries. Spiral wound (Optima) batteries are AGM but require a battery charger that’s rated for spiral wound AGM types.

If you own a boat, you’ll need a charger that’s rated to charge a marine/deep cycle battery.

Some electric start outdoor power equipment engines like lawn mowers use a gel cell battery. Gel cell batteries also requires a different charging method.

2) You want a charger with a “recondition” mode

When a battery sits in a discharged state for a long period of time, sulfate crystals form on the plates. The longer it sits, the harder the crystals become. To break down the crystals and restore the battery, you need a charger with an automatic reconditioning phase.

Look for a battery charger with a recondition feature. It’s also called a battery desulfator feature with temperature compensation. As you’ll see in the next section, temperature compensation is critical when charging a battery, so you want that feature when it comes to de-sulfating your battery.

3) The charger should have a soft start mode

Many intelligent battery chargers won’t even start the charging process if they see a completely dead AGM/EFB battery. That’s where a soft start feature comes into play. It gently charges the battery enough to get the voltage up to the point where the charger can recognize that it’s in a state to be charged normally.

4) Get a  charger with multiple amp setting

Some battery chargers list high amperage, like up to 100 or 150 amps. Those high amp setting should only be used for jump starting a vehicle, not charging. Car batteries should NEVER be charged at any rate higher than 30-amps.

In fact, high charging rates create high heat, which is the #1 killer of car batteries. When it comes to charging a battery, low amps and slower charging time is the best way. So don’t get carried away with high amperage charging. High amp charging will get the job done faster at the risk of shortening your battery’s life.

2-10-20 is a good option. Use the 2-amp setting to slowly charge the battery overnight. Use the 10-amp setting to recharge the battery in 1-2 hours. Use the 20-amp setting to get your battery up and running in about an hour.

Who makes the best car battery charger?

There are really only two major brands I recommend: Clore/solar and Schumacher. These two companies have been in the battery charging business for decades and they’re the brands the pros use. Of the two, I highly recommend the Clore/Solar brand.

If you shop on Amazon, you’ll see the NOCO brand. I’m not a big fan of NOCO. You’ll also see the CTEK. CTEK is a very good brand and in the price range for the their battery maintainers, but I think their prices for full battery chargers are outrageous. My advice is to stay away from all the other brands.

clore car battery chargers

Clore car battery chargers

©, 2021 Rick Muscoplat

Posted on by Rick Muscoplat

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