Best 12V 24V car battery tester in Winter: Foxwell BT705

One tip of Winter Car Care: Battery

It’s often more difficult for a battery to operate in cold weather than it is for a battery to operate in warm weather. As a result, a battery that’s merely weak during the summer could turn into a dead battery during the winter. Our advice is to have a volt test performed on your battery before winter starts to make sure it’s still in good working order. If it isn’t, buy a new battery as soon as possible so you’ll never have to worry about being stranded or left in a cold parking lot with a car that won’t start.


How to Keep Your Car Battery Alive Through a Frigid Winter

Car batteries aren’t as trouble-free as some other parts of your car. They work best in warm climates, and need to be constantly fed with energy to keep those internal chemical reactions balanced—even when the car it’s attached to isn’t being driven often.


Store a car battery long enough, and it’s guaranteed to discharge, no matter the temperature (we’re looking at you, Californians with garage queens). In particularly bad scenarios, a depleted battery’s electrolyte gets to freezing temps, and crack the internals (and sometimes the case itself). Store your batteries properly, though, and these problems won’t happen.


Buy the right equipment.

Conveniently, effective battery chargers cost less than buying a new battery every year. (Translation: You have no excuse.) Just don’t cheap out and get a “dumb” trickle charger; models that have a float, storage, or maintenance charge mode are preferred. Often called tenders—many of which are made by the Kleenex of the charging world, Battery Tender—they have intelligent circuitry inside to cycle on and off and keep the battery at the right level without overcharging. They’re perfect for winter lay up or any kind of long-term vehicle storage.


Prepare the patient.

Before attaching the leads, inspect the battery’s terminals and cables, cleaning off any corrosion and replacing worn parts. This is also a good time to apply some dielectric grease to prevent further corrosion. Then it’s as easy as slapping on the included alligator clips—red is positive, black is negative. If you’re fancy, you can permanently install a quick disconnect. Just be sure the charger is unplugged or off before making the connections.


Charge and test.

When it first starts up, the tender might be in charge mode for up to a couple days but should then switch to its storage mode, usually signified by a light on the tender. If it doesn’t, or you have doubts that the charger is doing its job, a multimeter set to voltage can verify the state of charge; just unplug the charger before testing. A typical tender will charge a 12-volt battery to 14.4 volts and let it go no lower than 12.6; any lower than that after the initial charge up and there may be a problem with the battery or the charger.


The alternatives.

You can remove the battery and bring it inside where it’s (presumably) not freezing, but it can still discharge over the season. If you choose to remove the battery and put it on a charger, keep it in the garage, since charging creates hydrogen gas, which is a fire hazard. You can skip the wooden block between battery and concrete floor, though; with modern plastic cases, there’s no longer a chance of the damp floor causing discharge.


Following this advice will prolong the life of your battery, saving you money and aggravation in the end. There’s still no easy solution to winter weight gain, though.


Best Foxwell Battery Tester BT705

Best 12V 24V car battery tester in Winter: Foxwell BT705


The Foxwell Battery Tester BT705 is one of the most comprehensive testing devices you can buy. It will accurately test regular Flooded, AGM Flat Plate, AGM Spiral, and Gel batteries, allowing the user to analyze the battery health status to calculate the actual cold cranking capability of the battery and its aging status. Multiple rating systems are supported, including CCA, BCI, CA, MCA, JIS, DIN, IEC, EN, SAE, and GB.


Foxwell BT705 tester works on 12-volt and 24-volt charging systems and ensures the output voltage of the generator is normal, that the rectifier diode works correctly, and the charging current is normal.


In addition, there’s a comprehensive cranking test to check the starter system, cranking voltage, and cranking time in milliseconds, so ensure the starting motor works correctly. Battery tests can be done in as a little as 3 to 5 seconds.


The Foxwell Battery Tester features a premium quality copper clip and wire, so it maintains a stable connection throughout the testing process. There’s a 7.8-foot cable attached, so testing can be done from inside the vehicle. At the end of that cable are all-metal spray gold clamps, which are more solid and durable than normal clamps. A large backlight LCD displays all the information, while the device is fairly straightforward to use thanks to menu-driven operation.


Foxwell BT705 is available with several different languages: English, French, German, Russian, Spanish, Dutch, and Italian.


Safety features on Foxwell BT705 include short circuit protection and spark proof protection.



Versatile tester, compatible with wide range of batteries and rating systems, works on 12v and 24v, quick testing, multi-language support, long cable


Cons: menu can be a bit confusing


What is a Car Battery Tester?

A car battery tester is a device designed to test the state of your battery. If you’ve taken a look at our list of products, you’ll notice that there are some testers that are extremely basic, while others will offer more data and information on your car’s electrical system. The type you choose to buy is entirely up to you, but it’s generally recommended to have a basic tester handy so you can replace your battery before it’s entirely dead.

More complicated testers will do a more thorough job and can even test your car’s alternator for potential issues.

Why Do I Need a Car Battery Tester?

You want to purchase a car battery tester so that you can routinely check the state of your car’s battery. This way, you know exactly when your car’s battery is on its way out, allowing you to get it replaced before it completely dies and can’t hold a charge. Most testers are affordable and they’re a minor investment to save you from a potential headache of being stranded unexpectedly.

How to Check Your Car’s Battery?

Once you’ve purchased a car battery tester, it’s time to see what condition your battery is in. Most testers will come with detailed instructions on how to operate the specific device, but here are some general steps and tips to follow.

1.Before you start to do anything, it’s always recommended to wear a pair of rubber gloves and goggles when working with your battery. Gloves and goggles will protect your hands and eyes from acid.


2.Start by making sure the ignition of your vehicle is off and all the lights on your car are turned off.


3.Connect the positive lead on your battery tester to the positive terminal on your battery.

4.Connect the negative lead on your battery tester to the negative terminal on your battery.


5.Check the voltage of your car’s battery. If it reads somewhere above 12.6 volts, then your battery is in great condition (100 percent). A voltage reading around 12.4 volts means your battery is in good condition – approximately 75 percent. A value of 12.2 volts is about 50 percent, which means readings of 12.2 volts and lower indicate a bad battery.


6.Once you’re done checking your battery state, remove the negative terminal first. If the clamps aren’t coming off easily, you will want to use a battery terminal puller to remove them.

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Best 12V 24V car battery tester in Winter: Foxwell BT705