When was the last time you thought about your vehicle battery? Odds are pretty good, it’s been a while. The battery is just one of those parts no one thinks about, despite it’s importance. We all know what purpose it serves, but few of us know how to take care of it or how long it should last.
Here’s what you need to know about your Toyota’s battery, both in terms of how long it should go and how to protect it. We’ll also answer some of the same questions about the Prius battery system too.
Standard Lead Acid Battery Design, Lifespan, And Common Causes of Failure
The standard car has what is called a lead-acid battery. These batteries contain plates of lead and plates of lead dioxide. The plates are submerged in a solution of roughly one third sulfuric acid and two thirds water. The chemical reaction between the solution of sulfuric acid and water and the lead plates produces electricity. There are six cells in a standard battery that produce roughly two volts each. Therefore, the battery produces a total of twelve volts. The battery can be recharged, which reverses the chemical reaction.
Running a Lead Acid Battery
Modern lead-acid batteries operate on a shallow cycle. This means that the battery sends electricity to the engine for a short period when the engine is being started. Afterwards, the battery is recharged by the alternator. The flow of electricity from the battery to the engine and from the alternator to the battery are nearly equal. The batteries are specifically designed to last as long as possible. However, they will only last a few years at best.
Lead-Acid Battery Failure
Lead-acid batteries can fail for any number of reasons:
- Age – Batteries have a limited number of charge/discharge cycles before they’re no longer effective.
- There may be a short in the battery and/or the walls of a battery cell may break, reducing capacity.
- The most dangerous type of failure, however, occurs when a battery is overcharged. Overcharged batteries may explode and spray acid everywhere, and 99% of these situations are caused by careless battery charging…if you’re charging your vehicle battery, be sure to follow directions.
But most of the time, lead-acid batteries fail because they’re old. New vehicle batteries last 3-5 years on average, assuming they’re cared for properly.
Maximizing Battery Life
If we’re talking about Prius batteries, there’s not a whole lot you need to do beyond pay attention to your vehicle’s dashboard. If we’re talking about a standard 12V starter battery, there are a couple of things you can do to maximize battery life and performance:
- Periodically clean the terminals. There’s a clever little tool called a ‘terminal cleaner’ that makes this process easy-peasy. Just grab the brush inside the tool, scrape away any corrosion (dried white residue), and then coat with petroleum jelly. If the corrosion is really bad, you’ll want to remove the connectors and clean the terminal using the larger part of the tool.
- Avoid draining your battery. If you drain your starter battery to the point where you need a jump start, you’ve likely caused permanent damage to the battery and shortened its’ life. Therefore, take care not to leave interior lights on, leave accessories plugged in, etc. that can “kill” your battery.
- Avoid short trips. A drive that only lasts a couple of miles puts a strain on your battery, as it’s hard for the battery to recharge the energy lost during starting. If you can avoid these super-short trips, your battery will maintain a full charge and that will extend battery life.
Finally, extreme temperatures can shorten battery life. If you can keep your vehicle garaged, your battery will probably last a few months longer (at least if you live in a climate where there are very cold or very hot temperatures during the year).
What About Toyota Prius Batteries – How Long Can They Last?
The Prius has two batteries: A high voltage battery for running the car, and a low voltage battery for running the computers. The low voltage battery is basically a standard car battery, which means you’ll want to replace it every 3-5 years.
The high voltage battery, on the other hand, is what makes the hybrid powertrain “go”, and it’s a nickel metal hydride unit that should last for 150k miles (or longer). Many first generation Prius owners have gone over 200k miles without any substantial change to battery performance. Tests by Consumer Reports have found that the batteries on ten year-old, high mileage Priuses had not lost any of their power or efficiency. New or newer Prius batteries are even more advanced than these 1st generation units.
Finally, if or when it’s time to replace the hybrid battery pack, pricing is reasonable. Your old pack can be recycled, and you’ll often be given a discount on your next Prius battery if failure occurs and you ‘trade in’ your old non-functional unit. Currently, most replacement Prius batteries are sold for about $2500…not cheap, but not so expensive that a vehicle with a bad battery must be scrapped. (see GreenCarReports for more info about repair costs and frequency, and of course you can check our Prius part pricing here)