VL2020 Rechargeable Battery for Car Key Fobs: What You Need to Know Before Replacement

When a car key remote starts working only at very short range, responds intermittently, or stops unlocking the vehicle altogether, the first thought is usually simple: replace the battery.

For many modern key fobs, that means opening the cover and installing a CR2032 or CR2025 coin cell. But some older automotive remote keys are designed differently. Instead of using a disposable coin battery, they use a small rechargeable battery soldered directly to the circuit board.

One of the common batteries found in this type of key is the VL2020 rechargeable coin cell.

The VL2020 looks similar to ordinary CR-series coin batteries, but it is a very different product electrically. Choosing a battery only because the diameter and thickness look correct can result in poor performance or even damage to the charging circuit.

This guide explains what a VL2020 battery is, why it is used in some car keys, how it differs from CR2020 and ML2020 batteries, and what you should check before ordering a replacement.

What Is a VL2020 Battery?

VL2020 is a 3V rechargeable lithium coin cell based on vanadium lithium chemistry.

The model number also tells us its basic physical size:

• 20 – approximately 20 mm in diameter

• 20 – approximately 2.0 mm thick

Typical VL2020 specifications include:

Specification	VL2020
Battery Type	Rechargeable lithium coin cell
Chemistry	Vanadium lithium
Nominal Voltage	3.0V
Nominal Capacity	20mAh
Charging Voltage	3.25–3.55V
Diameter	20.0mm
Height	2.0mm
Typical Continuous Drain	0.07mA
Operating Temperature	-20°C to +60°C

The battery is designed for applications with very low continuous current consumption where long service life and repeated charging are more important than high energy capacity.

Automotive remote keyless entry systems are one such application.

Why Are Rechargeable VL2020 Batteries Used in Car Keys?

Some vehicle keys are designed with an internal charging system.

Instead of opening the remote every few years and replacing a disposable battery, the manufacturer installs a rechargeable coin cell inside the key. During normal vehicle use, the battery may receive small amounts of charging energy through the key's internal charging system.

This allows the key to operate for many years without routine battery replacement.

That is why some rechargeable car key batteries are:

• soldered directly to the PCB;

• fitted with metal tabs instead of being placed in a removable holder;

• sealed inside the key housing;

• difficult to replace without opening the original key shell.

The VL2020 is particularly suitable for this type of application because of its compact dimensions, 3V nominal voltage and ability to handle repeated shallow charge and discharge cycles.

VL2020 batteries are also used outside automotive applications, including memory backup, RTC backup and other low-current electronic devices.

VL2020 Is Not the Same as a CR2020

This is probably the most important point when replacing a car key battery.

A VL2020 and CR2020 may have similar physical dimensions, but they are not the same battery.

VL2020

VL2020 is rechargeable.

It is designed to work with a compatible charging circuit and has a nominal voltage of approximately 3V.

CR2020

CR2020 is normally a primary lithium coin cell.

It is designed to be discharged once and then replaced. It is not intended to be recharged.

Installing a non-rechargeable CR2020 in a key that actively charges its battery is therefore not recommended.

Even when the battery physically fits, electrical compatibility matters more than appearance.

For automotive key repair, always identify the original battery before selecting a replacement.

VL2020 vs ML2020: Similar Size Does Not Mean Direct Replacement

Another common source of confusion is the ML2020.

Both VL2020 and ML2020 are rechargeable 3V-class lithium coin batteries, and both use a 20 mm diameter and approximately 2 mm height.

However, their electrical characteristics are different.

Feature	VL2020	ML2020
Chemistry	Vanadium lithium	Manganese lithium
Nominal Voltage	3.0V	3.0V
Typical Capacity	20mAh	45mAh
Charging Voltage	3.25–3.55V	2.8–3.2V
Diameter	20mm	20mm
Height	2mm	2mm
Rechargeable	Yes	Yes

The higher capacity of the ML2020 may look attractive, but capacity alone does not determine compatibility.

The charging circuit inside the device was designed around a particular battery chemistry and charging voltage. Replacing a VL2020 with an ML2020 without confirming the charging circuit is therefore not a good idea.

When repairing a key fob, the safest approach is simple:

If the original battery is VL2020, use a compatible VL2020 replacement unless the charging circuit has been specifically verified for another chemistry.

What Does VL2020/HFN Mean?

When searching for replacement VL2020 batteries, you may see model names such as:

VL2020/HFN

The battery itself is only part of the replacement.

For PCB-mounted applications such as automotive keys, the terminal configuration is equally important.

VL2020 batteries can be manufactured with different solder tabs and terminal orientations. These tabs determine how the battery fits onto the circuit board and where the positive and negative contacts connect.

HFN is one of the available horizontal terminal configurations for the VL2020 family.

Before purchasing a replacement, compare:

• battery diameter and thickness;

• positive and negative polarity;

• distance between solder tabs;

• tab direction;

• tab angle;

• PCB mounting position;

• original battery marking.

A battery with the correct voltage but the wrong terminal arrangement may not fit the original key PCB.

Which Car Keys Use VL2020 Batteries?

Rechargeable VL2020-type batteries are commonly associated with certain older automotive key fobs, particularly designs where the battery is permanently soldered to the PCB rather than installed in a removable battery holder.

They are frequently searched for as replacement batteries for some older European vehicle remote keys, including certain BMW and MINI key designs.

However, vehicle compatibility should never be determined by brand name alone.

Even keys from the same vehicle manufacturer can use different batteries depending on:

• production year;

• key design;

• vehicle model;

• market;

• keyless-entry system version;

• PCB revision.

For example, one version of a vehicle key may use a rechargeable soldered battery while another uses a replaceable CR-series cell.

For this reason, Cowon recommends opening the key and checking the original battery marking and terminal configuration before ordering.

How to Check Whether Your Car Key Needs a VL2020

Before buying a replacement battery, use the following checklist.

1. Check the Original Battery Marking

Look for markings such as:

VL2020

or

VL2020/HFN

The original model number is the most useful reference.

2. Check Whether the Battery Is Soldered

Many rechargeable key batteries have metal tabs spot-welded to the cell and soldered onto the circuit board.

If the battery simply clips into a holder, the key may use a conventional replaceable CR battery instead.

3. Compare the Terminal Position

Do not order based only on “VL2020”.

Compare the tabs carefully with the original battery.

A different tab direction can make installation difficult or impossible.

4. Confirm Polarity

Make sure the positive and negative terminals match the PCB.

Reversing polarity can damage the battery or key electronics.

5. Check the Charging System

If the original key uses a rechargeable battery, replace it with a battery designed for that charging system.

Do not substitute an ordinary disposable coin cell simply because it has the same size.

Common Signs of an Aging Car Key Battery

Rechargeable coin cells do not last forever.

After many years of use, their available capacity gradually decreases.

Typical symptoms include:

Reduced Remote Range

You may need to stand closer to the vehicle before the lock or unlock button works.

Intermittent Operation

The remote works sometimes but not consistently.

The Key Works After Driving but Fails After Storage

If the internal battery temporarily receives some charge during vehicle use but loses that charge quickly, the rechargeable cell may have lost much of its original capacity.

Buttons and PCB Are Working but RF Performance Is Weak

If the circuit board appears normal and the switches are functioning correctly, battery degradation is one possible cause.

These symptoms do not automatically mean that the battery is faulty. Antennas, switches, charging circuits and other electronic components can also fail.

Battery condition should therefore be checked as part of the overall repair process.

Can You Replace a VL2020 Car Key Battery Yourself?

Technically, yes, but it is usually more complicated than replacing a CR2032.

Many keys using rechargeable VL2020 batteries were not designed for routine user battery replacement.

The repair may require:

• opening a sealed or bonded key housing;

• removing the original soldered battery;

• soldering a replacement cell;

• checking polarity;

• avoiding excessive heat during installation;

• resealing or replacing the key housing.

For an experienced electronics technician, this is generally a manageable repair.

For someone without soldering experience, using a professional key repair service may be safer. Excessive soldering temperature or incorrect polarity can damage the battery or PCB.

Why Terminal Quality Matters

For a normal loose coin cell, most attention goes to voltage and capacity.

For a soldered automotive key battery, the terminal is part of the product.

Poorly positioned tabs may create mechanical stress during installation. Incorrect tab thickness or spacing can make soldering difficult, while unstable connections can result in intermittent key operation.

When sourcing VL2020 batteries for repair shops, distributors or automotive electronics businesses, it is therefore worth confirming the terminal drawing before placing a bulk order.

Photos of the original battery and PCB are often enough to identify the required configuration.

Buying VL2020 Batteries for Automotive Key Repair

For professional buyers, the ideal VL2020 supplier should be able to provide more than just a bare coin cell.

Depending on the project, buyers may require:

• VL2020 rechargeable coin cells;

• HFN or other terminal configurations;

• custom solder tabs;

• OEM terminal processing;

• bulk packaging;

• sample quantities for compatibility testing;

• technical drawings;

• transportation documentation.

Cowon supplies coin cells and customized battery solutions for electronics manufacturers, distributors and repair businesses.

For automotive key battery projects, customers can send us:

1. the original battery model;

2. clear photos of both sides of the battery;

3. PCB photos;

4. terminal dimensions if available;

5. required quantity.

Our team can then check the suitable battery and terminal configuration before quotation.

VL2020 Replacement Checklist

Before placing an order, confirm these five points:

Battery model: VL2020
Voltage: 3V rechargeable
Battery size: approximately 20 × 2 mm
Terminal configuration: must match the original PCB
Polarity: must match the original battery

If any of these specifications are different, confirm compatibility before installation.

Frequently Asked Questions

Is VL2020 rechargeable?

Yes. VL2020 is a rechargeable lithium coin cell. It should not be confused with disposable CR-series coin batteries.

What voltage is a VL2020 battery?

The nominal voltage is 3.0V.

What is the capacity of VL2020?

A standard VL2020 has a nominal capacity of approximately 20mAh.

What size is VL2020?

The cell is approximately 20mm in diameter and 2.0mm high, excluding solder terminals.

Can CR2020 replace VL2020?

Generally, no.

CR2020 is normally a non-rechargeable primary battery, while VL2020 is rechargeable. A device designed to charge a VL2020 should not simply be fitted with a CR2020.

Can ML2020 replace VL2020?

Not automatically.

Although both batteries have similar dimensions and nominal voltage, their charging voltage specifications and chemistry are different. The original circuit design should be checked before substitution.

Is VL2020 used in BMW or MINI keys?

VL2020 batteries are commonly searched for and used as replacements in certain older rechargeable BMW and MINI key designs. However, battery type can vary by model, production year and key version.

Always inspect the original battery before ordering.

Why does my VL2020 car key battery have solder tabs?

Many rechargeable vehicle keys use a battery permanently connected to the PCB. Solder tabs provide a secure electrical and mechanical connection and also allow the battery to fit the original board layout.

Can Cowon provide different VL2020 terminal styles?

Terminal requirements vary between devices. Cowon can help customers check battery dimensions, solder-tab orientation and customized battery requirements according to the original sample or drawing.

Need a VL2020 Battery for Your Car Key Project?

If you are looking for a VL2020 3V rechargeable coin cell battery for automotive key fobs, remote controls or other PCB-mounted electronics, send Cowon a photo of your original battery and its terminal layout.

For distributors, automotive key repair businesses and electronics manufacturers, we can also support sample testing and bulk supply.

Contact Cowon for VL2020 battery specifications, terminal options and wholesale quotation.