How to tell when to replace a hybrid battery

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Curious if your battery is going bad? Don’t worry; you’ll know. A big red “triangle of death” on the dash gauges, along with a check-engine light, maintenance-required warning, and multiple annoying beeps. Here are some warning signs to look for to try and avoid getting to that point:

Reduced power

Manufacturers list hybrid specs using “total system horsepower” of the gas engine and electric motor(s) combined. You are also used to the performance of this total package. As a battery starts to fail with limited capacity, the reduced storage of the battery means it drains easily, so it leans more on the small gas engine for power. Without the battery powering the electric motor, you’ll feel the lack of torque around town. The vehicle has sluggish power on acceleration, and you find yourself using more throttle to maintain speed.

Reduced fuel economy

Since you have less power in a hybrid with a failing battery, you’re pressing the throttle further or having to hold it down longer to get up to speed. This extra use of the gas engine directly relates to increased gas usage. Without the ability to cruise in electric mode, the hybrid keeps the gas engine on, lowering your fuel economy and draining your wallet.

Twitchy battery status

Let’s say that when you parked your hybrid last night, you noticed the battery was mostly full. Yet, when you went to start it the next morning, the battery status showed nearly empty. What’s going on here? Draining overnight is a common warning sign of an aging hybrid battery. It’s called ‘negative recalibration, the instruments are reading the false full status from the surface charge of the battery, and not its actual status.

How to prolong hybrid car battery life

Odds are your hybrid battery life will end around the same time the vehicle sees the end of its service life. Hybrid batteries are built well and should last you several years. However, there are drivers that are heavy on the throttle, drive in extremely hot and cold temps and run their cars to the limit. That will limit the battery life. Here’s how to try and avoid doing that:

Service the car on-schedule

There’s a handy book that comes with all vehicles that most drivers ignore and leave in the glove compartment. Don’t be that person; read your owner’s manual. In the maintenance section, you will find the manufacturer’s recommendations for service, including hybrid components. This won’t be very much maintenance, or very often, but it can prove critical to hybrid longevity. Proper maintenance will help the battery, and the rest of the car, live as long as possible. 

Charge plug-ins correctly

Again, look through that handy owner’s manual. There are several kinds of charging systems and speeds available, but you want to use what the manufacturer recommends. If your owner’s manual says to only use Level 1 or 2 charging, then going with faster charging causes excess heat, which could damage the battery, reduce its capacity, or even cause a fire. Trickle charging helps your standard 12V battery live longer, and slower charging seems to work best for plug-in hybrids and EVs too.

Avoid extreme temperatures

Remember, heat is the enemy. Keep your hybrid battery at a reasonable temperature with a climate-controlled garage. That’s not always an option, but even an insulated garage is better than getting directly blasted by the sun’s heat. Park in a parking garage or shady parking spot when you can and use a sunshade or heat reflective tint on the windows to keep the interior cooler.

Regularly screen the battery

Curious about the health of your hybrid battery? While engine health can be checked with a compression test or oil analysis, you can get similar information on battery health through a stress test. This is usually performed by a dealership using professional diagnostic tools, but it provides a clear look at your battery health. These tests can show you which cells or modules have deteriorated, which opens up the more affordable option of just replacing the individual modules.


Battery reconditioning systems vary widely in complexity, user-friendliness, and price. There are a lot of different products out there, but they all perform the same function correctly discharging and recharging the hybrid battery to prevent dendrite formation, which maximizes battery capacity. If you want to keep your car for another 15 years, buy a brand-new battery and the car will perform perfectly. Do periodic reconditioning, and you’ll keep it for the rest of your life.


Nelson Xavier Ssenyange

Team Leader

Germax Autos, Spares & Garage Ltd

Lukade Road, Naalya




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