“The battery won’t charge…” We hear these words very often at the Horsham Repair Cafe. It’s true that batteries don’t last forever, but we can make a drastic difference to its life expectancy. The original hybrid car, the Toyota Prius, uses a large traction battery. Many are still running 20 years later. So, how can the Prius keep the battery working efficiently for 20 years when some phone batteries only last three? Why do some household battery devices (vacuum cleaners for example) sometimes become useless after two years?
The Prius car battery has two advantages: It’s a very high quality battery – as you’d expect in a car that costs tens of thousands of pounds and the car electronics ensure it never discharges below 20%. Unfortunately, there’s not much you can do about the quality of the battery in your phone, vacuum cleaner or laptop, but you can keep it charged.
Discharging any battery to zero soon results in chemical changes that reduce the battery’s capacity to store electricity. Any battery in a low state of charge should charged immediately to avoid damage.
When a battery is about 80% full, the charging current will need to be progressively reduced to avoid over-voltaging the battery. This often means it’s quicker to get an 80% charge to get the battery back in use, rather than wait for the full 100%.
Of course, marketing departments will claim that the vacuum cleaner has a ‘run time of up to 90 minutes’. Or the electric car has a ‘range of up to 240 miles’, but these claims assume the battery is run from 100% to 1%. The Engineering Department would like to say the vacuum cleaner has a ‘run time of 70 minutes’ and the car ‘has a range of 190 miles’ – but the marketing guys will always win the day!
Batteries also self-discharge. Even if you don’t use the device, the battery charge will slowly disappear. The electric leaf blower or laptop that you charged months ago will, almost certainly, have a permanently dead, ruined battery.
So, maximise the life of your rechargeable batteries by never letting the battery charge go below 20% and charge it monthly, even when it’s not being used.
We spend £5 million a week on batteries. Shops which sell batteries must recycle them, however most end up in landfills, causing hundreds of fires. Take your batteries back to any shop that sells them to recycle them.
By Andrew Gadd, Horsham Repair Cafe Volunteer