A man is drawing the attention of internet users after revealing a trick to find out how long your car battery will last.
The clip was shared by comedian Sidney Raskind on his Facebook page. He said he recently discovered the trick and couldn’t believe he had lived his whole life without knowing it.
“Here’s something I wish I’d known before I turned 30. Your car battery tells you how long it lasts,” he said in the video, which has already accumulated over 100,000 views.
Next, Raskind, who owns a Honda CR-V, went to his car to demonstrate. “Open the hood. Right here. RC85. That means you have 85 minutes of radio on, door open, and engine off before the battery dies.”
While most internet users were quite impressed by the explanation, it’s not exactly correct. According to the website Motor 1, the “RC” label printed on most 12-volt car batteries stands for Reserve Capacity, and it doesn’t refer to how long you can use the radio with the engine off.
Reserve capacity is a standardized measure defined by the Battery Council International as the number of minutes a fully charged battery can deliver 25 amps of current before its voltage drops below 10.5 volts — approximately the point at which it can no longer keep the car running or power its accessories.
Simply put, reserve capacity is a measure of endurance under load and should not be used as a time indicator for watching Netflix on your infotainment screen while the car is off.
Therefore, if your battery label reads “RC85,” it means that, under controlled lab conditions, the battery can supply 25 amps of current for 85 minutes before reaching its limit.
This measurement is very useful for mechanics and engineers because it provides an indication of how long a battery can keep a car’s vital systems running while the vehicle is moved to a safe place if the alternator fails on the road, for example.
Knowing this, it’s clear that RC is not simply a timer to determine how long you can use an accessory, especially since each component (radio, lights, etc.) consumes different amounts of power. Still, the higher the RC, the longer the battery life — which is quite useful for vehicles with high electrical demand or those that make frequent short trips.
At the end of the day, checking your battery from time to time is very important. On it, you can find the date code, usually a combination of letters and numbers such as “C24,” which indicates when the battery was manufactured (in this case, March 2024).
According to Consumer Reports, it is recommended to replace your battery every three to five years. Whether you need to replace it sooner or later depends on factors such as heat exposure, usage patterns, and vehicle type.
Photo and video: Facebook. This content was created with the help of AI and reviewed by the editorial team.
