If you have a car that comes with an OBD2 system, you might be curious if keeping the OBD2 dongle connected at all times could drain out your battery. Well, the answer to that question depends on a few different things.
This post has everything you need to know about balancing OBD2 convenience and your car’s battery life. Read on to get the answers and ensure you never get that sinking dead battery feeling again!
Understanding OBD2 Devices and Battery Drain
Most OBD2 scanners do not have their own power source; instead, they draw power from your car’s battery.
Whether an OBD2 device will drain your battery significantly or not depends on whether it has a sleep function.
After turning off the engine for a certain period (usually around 1 hour), OBD2 adapters with a sleep function use minimal power.
On the other hand, devices without a sleep function may draw more power and lead to battery drain.
Factors Affecting OBD2 Battery Drain
Type of OBD Device: Some OBD2 devices are designed to be energy-efficient and have a sleep mode. While others lack this feature and may consume more power.
Driving Routines: Frequent short trips and multiple engine starts can affect your battery’s health. Long drives and daily usage are less likely to cause battery drain issues.
Battery’s Health: The overall health of your car battery plays a crucial role. Aftermarket batteries may last around 4 years, while original ones can last up to 6-8 years.
Battery Coding: Some vehicles require battery coding after replacement, especially those with start-stop systems and battery management control modules.
Parasitic drain: An unrelated electrical issue like a stuck relay, bad diode, or wiring short could be draining the battery and may not be related to the OBD2 device. Monitoring the current draw with the OBD2 disconnected can help determine if the drain is from the adapter or another system.
Many users have reported leaving Bluetooth OBD2 dongles plugged in for 1-2 days without experiencing battery drain issues.
However, this can vary depending on the OBD2 adapter’s quality and your car battery’s condition.
Regularly driving your car and maintaining a fully charged battery can reduce the risk of battery drain.
If your OBD2 device is not equipped with a sleep function or is poorly designed, it may contribute to battery drain. Signs of OBD2-related battery drain include:
Vehicle battery dying overnight: This is a clear sign that something is drawing current while the vehicle is off. If the battery dies repeatedly, an OBD2 adapter drawing power could be the culprit.
Dimming headlights when connecting OBD2: When initially plugging in or turning on the OBD2 adapter, the added current draw can briefly dim the lights. This may indicate the adapter is drawing more power than expected.
Battery light/warning comes on: The battery/charging warning light turning on after installing an OBD2 device could indicate it is imposing extra load and draining the battery.
Trouble starting/cranks slow: Extra current draw from the continuously powered OBD2 adapter could slowly drain the battery overnight, making it harder for the starter to crank and turn over the engine.
Mileage or drive time before stalling decreases: Parasitic drain will gradually deplete the battery charge. As this increases, the vehicle may stall out sooner or die during a drive.
Voltage drop when adapter plugged in: Using a voltmeter with the vehicle off. Then, you may see a voltage drop across the battery terminals when plugging in the OBD2 adapter if it draws excessive current.
Battery tester shows low charge: A diagnostic battery tester can reveal lower charge levels than expected, pointing to extra drain from accessories like an OBD2 dongle.
Adapter feels warm when disconnected: Heat from the adapter itself can indicate current flowing through it even with the vehicle off, slowly discharging the battery.
Here’s how you can prevent OBD2 battery drain
Choose Quality OBD2 Devices: When getting an OBD2 scanner, make sure to pick a good one with sleep function. This way, the device uses less battery power when not in use, thanks to its energy-efficient design from reputable brands.
Consider Your Driving Habits: If you use your car regularly or take long trips, it’s generally safe to keep the OBD2 device plugged in. However, unplug the device to avoid draining the battery unnecessarily when you’re not driving your car.
Battery Extension Cable: Use an OBD extension cable with a switch to avoid constant plugging and unplugging, This lets you easily turn the OBD2 device on and off as needed.
Leaving the OBD2 device plugged in while driving is generally safe, as the device draws minimal power when the engine is running. The alternator constantly charges the battery while the engine is on, reducing the risk of battery drain.
However, if your car will be parked for an extended period, it is advisable to unplug the OBD2 device.
While the device may not draw excessive power, it can accumulate over time and lead to battery issues. Especially if your battery is weak or old.
How much does OBD2 contribute to battery drain compared to other factors?
The contribution of OBD2 to battery drain is generally minimal compared to other factors that can affect your car’s battery health.
When properly designed and equipped with a sleep function, OBD2 devices consume only a small amount of power from the battery when the engine is off.
Here is a table that shows how much different components typically contribute to battery drain:
| Component | Current Draw (mA) |
|---|---|
| OBD2 adapter | 20-60 |
| Infotainment system | 100-200 |
| Security system | 15-100 |
| Comfort systems | 100 |
| Safety systems | 100 |
| Lighting | 50 |
As you can see, the OBD2 device is one of the lowest contributors to battery drain. The infotainment system, security system, and comfort systems are all much larger contributors.
However, it is important to note that if you have a faulty OBD2 device, it could be drawing excessive current and causing a battery drain.
If the current draw is more than 60mA, you may have a faulty device.
Conclusion
In conclusion, most OBD2 scanners do not significantly drain your car’s battery, especially if they have a sleep mode. However, it is essential to consider factors like the type of OBD2 device, your driving routines, and the battery’s health. To prevent any potential battery drain issues, it is recommended to unplug the OBD2 device when the vehicle is parked for a long time.
Remember, proper maintenance of your car’s battery and using a quality OBD2 device can help ensure a smooth driving experience without any battery-related worries. Enjoy the benefits of OBD2 diagnostics and use it responsibly to keep your car running at its best. Happy driving!
Frequently Asked Questions (FAQs)
How often should I check my vehicle’s battery health?
It is recommended to check your battery’s health at least every six months. Especially before extreme weather conditions like winter or summer, as temperature fluctuations can impact battery performance.
Additionally, if you notice any signs of battery issues, such as slow engine cranking or warning lights, it is advisable to have the battery checked immediately.
Can an OBD2 scanner test the battery?
Some advanced OBD2 scanners can test the battery’s health by accessing the vehicle’s battery management system. These scanners can provide information about the battery’s voltage, state of charge, and overall health.
However, not all OBD2 scanners have this capability, so it’s essential to check the product specifications or consult the manufacturer to ensure the scanner can perform battery tests.
Does OBD2 show battery voltage?
Some OBD2 scanners can display the battery voltage.
This feature allows you to monitor the battery’s voltage in real-time, providing insights into its current state of charge.
By monitoring the battery voltage, you can assess its health and determine if it requires maintenance or replacement.
Is OBD2 always powered?
No, OBD2 devices are not always powered.
When the vehicle’s engine is off, and the ignition is turned off, the OBD2 device may still draw a small amount of power for maintaining communication with the vehicle’s onboard computer.
However, as mentioned earlier, many OBD2 devices are equipped with a sleep function that reduces power consumption during extended periods of inactivity.