Remote start is draining my battery, why? What to do? (2023)

Do you find it difficult to start your car after installing a remote start system? Want to know why this happens and what you can do about it? You've come to the right place because we've investigated this question and we have the answer for you.

The remote start system leads to parasitic power consumption from your car battery. If you don't use the car for several days, this eddy current draw can drain the battery to the point where it no longer has enough charge to start the car.

We'll talk more about the remote start feature and why it drains your car's battery power in the following paragraphs. Learn about the other factors that can affect how much current your car draws from the battery to start the engine in the following sections.

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Remote start is draining my battery, why? What to do? (1)

What is eddy current consumption?

ONEparasitePower draw, or parasitic battery drain, is anything that consumes energy in your car after the engine has been turned off.

Remote start is draining my battery, why? What to do? (2)

In older cars, the car battery has only one main function: to provide the energy needed to start the engine. Since then, many technological improvements have been made to the car.

Technology regularly adds new features to cars. Some of these improvements introduce features that require a constant power supply, even when the engine is off. With the emergence of new technologies for cars, the need for electric power from the car battery is increasing.

Unfortunately the car's battery has improved very little. For example, the amount of electricity you can supply and store stays pretty much the same. Leaving the headlights on overnight drains a modern car's battery, just as it did in the past.

Therefore, it can be difficult for a car battery to keep up with the increasing energy demands of a modern car.

(Video) Here's Why Your Car Battery Keeps Draining

In older cars, the battery only needs to power smaller systems like the internal clock.

When the ECU was released, the number of devices that required power increased.

Car data memory requires a constant supply of electrical power. As soon as the power supply is interrupted, the information is lost. This includes settings and preferences.

Every appliance that requires electricity has an energy consumption index. This consumption is measured in milliamps. The capacity of a car battery, on the other hand, is measured in ampere-hours.

We'll talk more about this in a later section.

Effect of temperatures on batteries

Remote start is draining my battery, why? What to do? (3)

At temperatureThe changes affect your car's battery capacity. Car battery capacity decreases when it is cold and increases when it is hot.

This is one of the reasons why it can be more difficult to start your car on winter mornings.

Car battery manufacturers typically measure their battery capacity at around 77 degrees Fahrenheit.

When the temperature drops to the freezing point, battery capacity is also reduced by 20%. If it continues to drop to -22 degrees Fahrenheit, the battery capacity will also drop by 50%. On the other hand, battery capacity increases by up to 12% when the temperature rises to 122 degrees Fahrenheit.

Changes in battery capacity due to temperature changes also affect battery life.

Even though low temperatures reduce battery power capacity, battery life is increased as a positive side effect. Even if you lose up to 50% of your capacity at -22 degrees Fahrenheit, you can increase health by up to 60%. On the other hand, the life of a car battery is cut in half for every temperature increase from 15 degrees Fahrenheit to over 27 degrees.

(Video) Car key fob draining / eating batteries quickly and dead. Fix the problem for all models.

These numbers apply not just to traditional lead-acid batteries, but to all types of batteries that use the same lead-acid core technology. Whether your battery is gel, AGM or sealed, you can expect the same variations in capacity and life as temperatures change from high to low.

A look at parasite extraction numbers

Devices in your car thatconsumeelectrical energy after turning off the engine contributes to the discharge of your car's battery. When the engine is running, the alternator takes over the task of providing electrical power. The alternator converts the engine's mechanical energy into electrical energy.

However, when you turn off the engine, the task of powering the devices that are still working (or still working) is left to the car battery.

An average car battery has a capacity of 70 Ah or ampere-hours. This is the capacity when the battery is new and intact. The capacity of a car battery decreases as the battery ages.

Also, battery voltage drops as it loses charge. This means the battery doesn't have to be completely drained before you lose the ability to start your car.

Therefore, you must keep the battery charge above 50%. Battery voltage drops to 12.2 volts when dropped to 50%.

So let's keep the capacity at 35 Ah so we don't have problems starting the car.

The typical stray power consumption of modern automobiles is between 20 and 50 milliamps.

If the parasitic consumption of a car is 50 milliamps, it can consume 1.2 Ah per day. This means that a car battery with a capacity of 35 Ah is completely discharged in 29 days.

Note, however, that the calculations assume perfect conditions. The battery is assumed to be fresh, there are no ground wires drawing additional power, and you are trying to start the car at 77 degrees.

If you try to start your car on a very cold morning, you can lose up to half of that capacity. This means that normal charging will drain the car's battery in about two weeks during the winter.

(Video) Car Battery Drains Overnight Or After Days Of No Use! PARASITIC DRAIN

Parasitic Remote Start Train

Remote start is draining my battery, why? What to do? (4)

Remote starters use a higher amount of power due to the type of wireless connection you have with your phone or remote. When you look at your phone, the battery drains faster when any of your wireless features are active, including your Internet connection. A remote start module has similar power consumption.

The longer the range of your remote start system, the greater the stray load on the battery.

Remote start functionsbodiesthey consume a little less energy, as they combine it with the rest of the vehicle's parasitic load to avoid draining the battery quickly. However, this "lower power consumption" is still high, as it can be around 60 to 75 milliamps.

An aftermarket remote start system consumes much more power because there are no power consumption benchmarks that match the power consumption of the product. In addition, they have fewer resources to research and develop a project that uses less energy.

On average, aftermarket remote starter modules can consume anywherefora80 milliamps to more than 1000 milliamps.

Factory installed remote starter

Let's try to calculate how quickly parasitic consumption will drain your battery with a factory remote trigger or drone.

First we add 75 milliamps to the original 50 milliamps from before and we get 125. We convert to amps by dividing by 1000 and we get 0.125. Then we multiply by 24 hours and we get 3 Ah or 3 amp-hours.

So we divide the capacity of 35 Ah by 3 Ah and we have 11.6 days, or just under 12 days. In winter, this is less than a week. And it will decrease as your battery ages.

aftermarket remote starter

Let's try a spare remote start. As the consumption range is very wide, we used a lower value of 150 milliamps.

Adding this to the original drawing gives us 200. Converting to amps and multiplying by 24 hours gives us 4.8 Ah. So we divide the capacity of 35 Ah by 4.8 Ah and we get 7.2, just one week.

In winter it's only three or four days.

(Video) Most Common Battery Drain Causes And Fix For All Cars !!!!

What if you are using an aftermarket remote starter that draws higher current? If you have additional aftermarket devices in your car, the overall parasitic attraction is greater. In addition, improper installation of aftermarket remote starter systems can cause the wiring to be grounded, consuming additional electrical power.

Therefore, a remote start that drains the car's battery is an expected result.

How to prevent the remote start from draining the battery?

Remote start is draining my battery, why? What to do? (5)

The best solution to prevent a remote start system from draining your car's battery is to disable it. However, disabling it will make your remoteboot system unusable. you can no longer use it.

Another option is to install a lockout switch. The switch allows you to easily turn it off when you don't need it to save battery power and turn it back on when you need to use it.

If you use your car on a daily basis, it can recharge the energy lost by the remote start system. Remember that short trips are not enough to fully recharge your car's battery.

However, when you think about it, is it worth experiencing the inconvenience of a dead battery when you least expect to be able to remote start your vehicle?


Remote start is draining my battery, why? What to do? (6)

A remote start system is an additional parasitic drain on your car's battery that can leave you with a dead battery when you least expect it.

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Why is my key fob draining my battery? ›

A key fob will constantly try to communicate with the car. And that does cause a slight drain on the battery, but generally that won't completely drain a healthy car battery,” says Mike Monticello, Consumer Reports' road test manager. “The key fob is, in a sense, causing the issue.

Why is my starter draining my battery? ›

The starter will draw a charge from the battery. If it's drawing too much, that's a clear indicator that's has failed. The vehicle may still start; however, it will continue to draw too much power and will drain the battery.

Can auto start drain battery? ›

The short answer is: Yes, it can. It could also drain the battery even faster if you repeatedly try to start your car with a faulty starter.

Does remote start drain key fob battery? ›

In as much as starting the car will drain your battery, yes. If you mean while not being used, your car has systems that are always “alive” even when you turn off the ignition.

How long does a remote car starter battery last? ›

Typically, a car fob battery should last between three and four years. Additionally, there are a number of signs that will tell you when your fob battery is dying. The first sign is reduced signal strength. Most modern fobs can send a signal to your vehicle from up to 50 feet away.

How long do remote batteries last? ›

Under normal or moderate use, the batteries in a remote control should last up to 3-6 months. IMPORTANT: If you do not use the remote control for an extended period of time, remove the batteries to avoid possible damage from battery leakage. NOTES: Do not use a fresh battery with an old one.

Can a remote starter mess up your car? ›

People have come to believe that remote starting puts unnecessary strain on your car's engine, which is not true. Whether you're sitting inside of your car or remote starting from the comfort of your home, your engine will not react any differently.

Can remote starter cause electrical problems? ›

There is one instance, however, where a remote starter could needlessly tax your battery. If your car did not come with a remote starter and you want to install an aftermarket model, improper installation could lead to issues with your battery and electrical systems.

How do I know if my alternator is draining my battery? ›

If the engine starts but dies immediately, your alternator probably isn't keeping your battery charged. If a jump starts and keeps your car running, but the car can't start again off of its own power, a dead battery is probably your answer.

How do I disable my remote start? ›

Press the remote start button (which looks like a circle with an arrow on the end), and hold for about two seconds, or until you see the parking lights turn off. From inside the vehicle, turn the key to the on position, and then turn it back to the off position.

How do I turn off remote start? ›

To turn the vehicle off after remote starting, press the Remote Start button (2X) on your key fob once. The parking lamps will turn off. Note: To turn the vehicle off, you may have to be closer to the vehicle than when starting due to ground reflection and added noise from the running vehicle.

How do I fix my remote start? ›

If your remote starter system isn't working properly, try replacing the battery in your fob. You can find replacement key fob batteries at Batteries Plus. Most remote starter fobs run on 2032 lithium coin cell batteries. This one may seem obvious, but if your vehicle is not in "Park" your remote starter will not work.

Can remote start damage alternator? ›

The Damage Myth

The truth of this is, a properly installed, high quality system will not cause any damage.

Does the battery charge with remote start? ›

While remote starting won't recharge your battery, it will help with some of the other issues that lead to battery failure. Remote starting and letting your engine idle for just a few minutes will warm up the fluids that may have thickened in the cold.

How much does it cost to replace battery in car remote? ›

Key Fob Battery Replacement

Generally, these batteries cost $10 or less, though some fobs require two batteries. Battery specialist shops and dealers will often replace the battery for free since it only takes a moment or two.

Should I remove battery from remote when not in use? ›

If the remote control is not being used for a long time, it is better to take out the batteries. This way, you will avoid any possible leakage or discharge of the batteries and a possible damage of the remote control.

Can a remote work without batteries? ›

When the piezoelectric crystal is pressed, the generated energy makes the IR LED (IR1) glow, thus sending a signal to the receiver circuit. This signal is received by IR2 in the receiver to perform the function as per the program. Thus, the remote can work for years without any battery.

What batteries are best for remote control? ›

Two of the most common remote control battery types include rechargeable lithium ion and alkaline batteries. Rechargeable lithium ion batteries - These remote control batteries are easy to charge and minimize the need for purchasing replacement batteries.

Is remote start on a car worth it? ›

Good for Your Engine

Remote car starters allow you to start your car remotely before you're ready to drive, giving your car time to warm up. By giving your engine enough time to warm up before driving, especially in cold weather, you will increase the life and performance of your engine.

What would drain a car battery overnight? ›

This happens when something – a glovebox light, an amplifier, any electrical component – is pulling power from the battery when it shouldn't. Since the alternator isn't generating vehicle electricity, the problem component pulls from the battery, slowly draining it overnight until your vehicle won't start.

What are the signs of a weak alternator? ›

7 Signs of a Failing Alternator
  • Dim or Overly Bright Lights. ...
  • Dead Battery. ...
  • Slow or Malfunctioning Accessories. ...
  • Trouble Starting or Frequent Stalling. ...
  • Growling or Whining Noises. ...
  • Smell of Burning Rubber or Wires. ...
  • Battery Warning Light on Dash.
24 Aug 2020

What are signs that an alternator is going out? ›

Dim Lights. An early warning sign that your alternator is going bad could be dim, flickering lights. This symptom could show up on any or all of your dashboard lights, reading lights, headlights or other lights. The alternator is supposed to provide the electricity for your car's lights.

Why does my remote start turn on by itself? ›

Sometimes there can be a short in the key fobs relay system and it is possible for an electrical surge to start the cars ignition on its own. This can happen at anytime and is a serious safety issue that should be addressed as soon as possible.

Why does my car keep starting on its own? ›

Sometimes a bad starter solenoid, instead of preventing the engine from starting, may cause it to start on its own without the key being turned to the “start” position.” This less-common problem can be dangerous and should be addressed immediately.

How long does it take for remote start to turn off? ›

Once remote engine start has been initiated, the engine will stay running for 15 minutes before shutting off.

Does all remote start turn off automatically? ›

With most remote start systems, the engine will shut off if the driver does not arrive and get in the car within 10-15 minutes of having been started. And if the driver changes their mind, most key fobs and smartphone apps have a "kill switch" to turn the vehicle off.

How much does it cost to get remote start fixed? ›

Generally, you can expect anywhere from $150 to $500 for professional installation of a remote car starter.

How much does it cost to reprogram a remote starter? ›

The price can range anywhere from $50 to $200. The actual price depends on a few different factors, such as: Type of key fob. If the key fob includes a transponder key or keyless ignition, it could cost more to reprogram than a simple key fob.

How much does it cost to reprogram remote start? ›

While it's hard to give a universal estimate, the general cost is between $50 and $250 for reprogramming. Here's a look at some factors that can determine price: Fob Type: Smart keys with a transponder (RFID), keyless ignition, or other extra features tend to be more expensive to reprogram.

Can a solenoid drain a battery? ›

Because of that, solenoids are the crucial link between your starter and ignition. However, the solenoid itself doesn't drain your battery. There's no onboard computing or lights. It only serves as the connection that ignites your engine when you turn the key.

Can a key fob mess up your car? ›

In this post, we're going to talk about some of the common remote starter myths and whether or not a remote starter can mess up your car. The short answer to this question is no, but let's talk about a few other common myths that lead people to think a remote starter will mess up their car.

Can a cell phone mess up a key fob? ›

Like many newer cars, these cars use a wireless key system. Unfortunately, they're discovering that mobile phones receiving calls while in contact with the keys can scramble the electronic code on the keys… making them into useless paperweights.

Does leaving your keys in the ignition drain your battery? ›

Leaving the keys in the ignition can drain the battery, eventually killing it. This happens due to the constant flow of electricity, which can overheat the ignition coil and cause it to fail over time. If the ignition is left in the ACC position, the battery will drain even faster.

How do I reset my remote starter? ›

Press the Lock button on your remote car starter. Within five seconds of turning it on, turn your key back to the "off" position (or press the start button again). Repeat the on-off cycle three more times—you'll do four in total.

How do I know if my battery is bad in my key fob? ›

Signs your key fob needs a battery replacement.
  1. If your key is not giving out any signal.
  2. If you have to press the button repeatedly before your vehicle accepts the signal.
  3. If your key remote is inconsistent or unreliable.
17 Feb 2022

Can remote start cause problems? ›

As with all electrical devices, remote start vehicles run the risk of experiencing unforeseen electrical issues at any given moment. While the chances are slim, you always want to be prepared for a situation where your key may not work.

What problems can a key fob cause? ›

Here are some of the most common problems you could experience with your car's key fob that you should be aware of and prepare for.
  • Batteries Going Bad.
  • Stolen Vehicles Due To The Key Fob Being In The Vehicle.
  • You Can Override The Key Fob In Some Situations.
  • Have A Backup Key Available.
2 Dec 2021

What blocks the signal of a key fob? ›

Keeping your key fob safe

All you need is a little metal. You can achieve this protection by securely wrapping your key fob in a small piece of aluminum foil. The foil will block the electromagnetic signals of the fob, making it impossible for a relay box to pick them up.

Can someone block my key fob? ›

Signal Blocking pouches can stop access to your vehicle by blocking your car key fob from transmitting its code to the vehicle, as the pouches are lined with layers of metallic material. The pouch which has a metalic lining Image, which prevents signals from the remote key fob being intercepted by unwanted individuals.

Can a magnet wipe a key fob? ›

A static magnetic field does not damage a vehicle key or the built-in transponder for the anti-theft device.

How far should I keep my key fob away from my car? ›

The vehicle and fob communicate using low-power radio signals that are only effective when the fob is within approximately 36 inches of the car door or ignition start/stop button.

How far should a key fob be stored from the car? ›

He calculates that the car computer signal can read the fob from between six to 10 feet away, he recommends anything beyond that as a safe distance to store or hang up your keyless entry remote. For most car key fobs, the battery life is three to four years with normal use, Freeman says.

What happens if key fob leaves vehicle? ›

A: Leaving the device in the car, or even within the proximity communication range, may be detrimental. Quite often, the transmitter and receiver continue to communicate. This may keep the vehicle's controller area network bus and modules awake. That can kill the car's battery.


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