When your hybrid car battery dies, you’ll experience one or more things while driving. A loss of power followed by a slew of dashboard lights and the inevitable stall out is the most likely scenario.

Even though a hybrid vehicle has an internal combustion engine, it won’t work in isolation from the electrical system. Both Ev and internal combustion systems have to be functioning in tandem in order to propel the vehicle forward. When the hybrid battery pack fails, the car computer detects a malfunction with the drive system making the whole car dead in the water.

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Table of Contents

Symptoms Of A Dying/Dead Hybrid Battery

Just a quick note, if you already didn’t know. Hybrids also contain a 12v battery like a traditional gas engine car. These smaller batteries are used generally to power the accessory system in your car. These can go bad as well and will cause some issues but the majority of this article is focused on the larger high voltage battery pack that’s used in the Ev drive system. A quick way to tell if your 12v battery is dead is to try things like the radio, headlights, and door locks. If these things work then your 12v is probably ok.

Although there are a few different iterations of hybrid drivetrains, most show similar symptoms when they begin to lose full usage of their hybrid battery. If you experience any of these symptoms it’s a good idea to have your mechanic, or preferably someone who specializes in hybrids, check out your battery.

Loss Of Mpg

Loss of mpg is common when the high voltage battery pack is on its way out. The pack may not hold sufficient charge anymore and will cause the engine to run longer.

Loss Of Power

Hybrid vehicles are designed to give a maximum output when both the gas engine and Ev system are running at full capacity. The hybrid battery pack has a range at which can operate normally, when the pack reaches the lower end of the spectrum it will reduce the amount of power it can output. This is noticed in a lack of power.

No Start

When you start your hybrid vehicle the power control unit checks to see if all systems are running appropriately. If there is a deviation from the parameters, the vehicle will refuse to start and will show battery warning lights.

A hybrid battery pack is made of individual cells grouped together to create one large battery pack. Those individual cells have to maintain a state of charge within a specific range. If any one of them drops below that, the whole pack essentially shuts down.

Solutions For A Dead Hybrid Battery

So your hybrid battery is dead, what can you do? Depending on what vehicle you have you might have multiple options. For example, the Toyota Prius is the best-selling hybrid of all time and has many documented cases of dead hybrid battery packs. If your car is more obscure, like the Porsche Cayenne hybrid I have, your options may be more limited.

Get rid of the car

So the first and obvious solution for dealing with a dead hybrid battery is just getting rid of the car. It’s the easiest way to move on especially if you’re interested in a vehicle anyway and in some cases it might be the only cost-effective solution.

Sell It

Selling your car is the most straightforward path. Listing it for sale privately, and on sites like Facebook marketplace make it easy nowadays to unload almost any car.

When selling a car with a dead hybrid battery, be upfront about it. Don’t try to hide the issue, it’s in poor taste, and buyers might even have some legal recourse against you.

There are also companies that specifically buy hybrids with dead battery packs, like Carbrain.com

Junk It

If you can’t find a buyer for your car, the good old-fashioned junkyard is always there for you. There are always local scrappers willing to take your vehicle off your hands. Since hybrids have a higher than normal amount of precious metals, you might even get some money for it.

Lastly, if all else fails or you need a tax write-off, plenty of companies are willing to take your car in as a donation.

Repair battery

If your car is in good condition and you want to keep it might be worth repairing. Cars like Toyota Prius’ are well documented in their hybrid battery repairs.

The reason most hybrid battery packs fail comes down usually to a few bad cells. If you can isolate these bad cells and replace them with either new or used ones, you can have your battery pack working again.

If you’re handy this is a very cost-effective solution. Places like eBay have tons of used batteries for you to buy and swap out with the dead cells. You’re going to need a few tools like a voltage tester to narrow down which cells are bad but it isn’t too complicated once you’ve watched a few Youtube videos.

Replace Battery

If replacing cells isn’t an option for you then replacing the entire battery pack might be. There are a few ways to go with this as well, and depending on your budget one might be better than the other.


Used batteries are a good e option, especially if you’re trying to keep costs low as possible. Just note that used batteries may give out later on, and you may have to end up replacing them again. Used batteries also won’t be as efficient as new ones so don’t expect brand new capacities.


New OEM batteries will be the most expensive option but will give you the quality your car came with as standard. Also, you don’t have to worry about possible fitment issues or compatibility. This may be important to you if you’re looking to keep the vehicle as original as possible.

New Third Party

Since the invention of hybrids, third-party vendors have been there to supply parts. Generally, this is the most affordable way to get a brand new battery pack in your hybrid. Battery technology is increasing every day, and third-party vendors may make a battery for your car that has superior charging and capacity than the original. Unlike OEM manufacturers who have to stick to parts originally offered in your car, third-party vendors are free to update and innovate.

Just check out Project Lithium for an idea of what third-party innovators can do with hybrid batteries.

Dr. Prius has engineered an upgraded battery pack for most Toyota’s replacing the nickel-metal hydride cells with lithium creating a superior battery. The best part is you can order the cells, and do it yourself!

How To Prevent A Dead Hybrid Battery

Hybrid engine

The first step in preventing a dead hybrid battery is understanding how your hybrid system works and the battery chemistry in it.

To keep it short we are going to talk about the two main types of hybrid drive systems, parallel and series.

Parallel hybrids can use the electric motors and the gas engine individually to power the wheels or in combination.

Series hybrids only use electric motors to drive the wheels and use the gas engine as a generator to recharge the batteries. To learn all about the different systems check out the wiki on hybrid drivetrains.

Next up is battery chemistry. Again there are two main types, NiMH (nickel-metal hydride) and Li-ion (Lithium-ion).

Clean Filters

Hybrid battery packs, specifically if air-cooled, will have filters to prevent dust from entering the battery pack. When these get clogged the battery can overheat from lack of airflow. If your vehicle has this cleaning it once a year is recommended.

Get Some Highway Miles

Even though hybrids perform better in city driving, you need to flex their muscles on the highway once in a while. If you only drive short distances then the batteries never deplete optimally. This is bad because it is shortening the window of charge. You’re essentially overcharging your battery.

The best way to think of it is like a cell phone. This has all happened to us at some point with overcharging our phones. If you keep a phone constantly on charge and never let the battery get low enough between charge cycles it loses its capacity.

The same thing happens to cars. Fully cycling the battery is important and long drives allow that to happen. Try to use Ev only mode in town to drain down the battery before a long highway trip to ensure good charge cycling.

In sum

When your hybrid battery dies you’re at a crossroads. It’s decision time, whether to repair or replace, and that can be tough. There are ways to figure out how to make the right decision, like we discuss in our article is it cheaper to repair a transmission or the car, so if you need a little help that can guide you.

So if your hybrid battery dies which decision is right for you?

As an Amazon Associate We earn from qualifying purchases. Amazon and the Amazon logo are trademarks of Amazon.com, Inc, or its affiliates.

We might receive commissions if you click on our links and sign up/make purchases. However, please know this does not impact our reviews and comparisons. We try to keep things fair and balanced to help you make the best choice for your needs. Thanks.

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