As useful as it would be for batteries to last forever, mobility scooter batteries and indeed ALL batteries will eventually stop working. Did you know, however, that the root cause of battery failure is usually human error? In particular, the number one battery killer is incorrect charging.

“Very few batteries die a natural death, they are murdered”

– Philadelphia scientific.

This means that we have to start our blog article by saying that there is no simple answer to the actual question ‘how long do mobility scooter batteries last’. Strident’s batteries, for example, have been manufactured with a 10-year design life – but our blog explains why we don’t shout about that too much because it is the equivalent of a car manufacturer publishing a miles-per-gallon figure that no-one experiences in real life.

The reality is that the lifespan of your battery depends on numerous factors, such as:

  • frequency of use
  • range used
  • terrain travelled over
  • the combined weight of mobility scooter and rider
  • charging regime
  • charger used

But the top factor, by far, remains the charging regime and equipment used – and so we can at least help you to identify how you can maximise the lifespan of your power chair or mobility scooter battery.

testing mobility scooter battery

The main cause of battery death – incorrect charging

Poor charging management, whether that’s overcharging or undercharging, is the main reasons for battery failure. This is because a great deal of mobility scooter users are not told about, or don’t fully appreciate, the impact poor charging management can have on your mobility scooter battery.

Before we get into how you charge your batteries the right way, let’s take a look at the effects of overcharging and undercharging your battery can have.

Overcharging mobility scooter batteries

A common question we get asked is, can mobility scooter batteries be overcharged?

The simple answer to this is yes.

Whilst it is much more difficult to overcharge a battery than undercharge one, the consequences can be more serious. Overcharging typically only occurs in three situations.

  1. The charger is broken or severely worn, so it does not switch itself off when it reaches maximum capacity.
  2. The charger is too big (higher power than needed) resulting in the battery receiving too much charge and, essentially, you end up ‘frying it’.
  3. You’re using a ‘cheap’ low-quality charger that is not delivering the correct charge or failing to monitor the battery state thus allowing charging of the battery past its limit.

Whilst there are fewer ways to overcharge, the consequences are much more severe. Overcharging mobility scooter batteries has a much more sudden impact than undercharging does. If you significantly overcharge a battery for 2-3 hours then there is a high chance you will cause irreparable damage to the battery plates – even a new battery – in a very short space of time.

Undercharging mobility scooter batteries

Let’s flip the above and answer the question, can mobility scooter batteries be undercharged?

The same answer applies here – yes! It is possible to undercharge your battery.

It’s much more common and actually very easy to undercharge your mobility scooter battery (and sometimes not even know you’re doing anything wrong). The consequence, technically, is that the lack of charging fails to break down the sulphates within the battery and so doesn’t condition the battery in an optimum way.

Undercharging can happen in a few different ways:

  1. Not charging your mobility scooter overnight after every use. This results in a build-up of sulphate which prevents the battery from reaching 100% capacity (although it may still say this on the scooter battery gauge).
  2. Using a cheap or faulty charger. This can result in a smaller amount of charge actually feeding the battery, which means that the battery will run flat quicker.
  3. Leaving your mobility scooter uncharged and unused for long periods of time. For example, if you don’t use your scooter throughout the winter months. You should still fully charge your battery around every 6 weeks.

Undercharging mobility scooter batteries causes a much slower failure than overcharging does. But, every time you undercharge your scooter, you are shortening the lifespan of your battery, even if you are not completely ruining it.

Top Tip: Making sure you are using the correct charger could reduce the total spend on batteries over the life of a mobility scooter.

Trying to use your mobility scooter with little or no charge

First of all, you should try to avoid letting your mobility scooter battery run completely flat. Aside from potentially being stranded with no means of transport, it can cause serious damage to your battery.

Due to this potential damage, most mobility scooters now have a lower power limit at which point the power will cut-out. This is usually somewhere around 9.6 volts on a typical mobility scooter battery.

Do be careful that, if you were to completely drain your battery, you might find that if you left your mobility scooter for 30 minutes that your its battery gauge may miraculously show some charge and the battery may even come to life again. This is because that whilst they’re not being used, the battery is actually self-charging. But do please be aware, using your scooter in this reduced state will further damage the battery life.

Top Tip: Avoid draining the battery on your mobility scooter and don’t be tempted to think ‘there is a little bit of charge left’. Both can ultimately shorten battery life.

To provide you with a better understanding of how the internal components of a battery work, we’ve put together a short video pointing out the features of a Strident battery.

How to charge mobility scooter batteries (the right way)

Remembering our main question about ‘how long do mobility scooter batteries last’ – we return again to the question of whether you are charging your mobility scooter batteries correctly to get the most from them.

Here’s a step by step process of charging your battery the right way.

  1. Get a quality and intelligent charger. This provides a stepped charging process that will safely charge your mobility scooter battery and actually improve its longevity.
  2. When you get your new battery, fully charge it in case it has been sitting in storage for a while.
  3. After you’re finished with your mobility scooter for the day, even if you have only used a relatively small amount of battery power, put it on charge and leave it overnight. This avoids leaving the battery in what is termed a ‘neutral state’.
  4. If you’re not using your mobility scooter for a time, ensure you still charge it every 6 weeks if connected, or 3-4 months if disconnected from the mobility scooter.

Whilst this might sound slightly unexpected, the advice is that you should also change your charger every few years. Whilst there may be no moving parts in a charger, there are still electronic components that wear out such as transistors and capacitors. A single faulty component can easily lead to overcharging or undercharging.

The video below shows you how Strident’s three-stage chargers work.

Are expensive batteries better?

Once again, the answer is related to usage. Treat an expensive battery badly and it might fail as quickly as a standard one. However, treat a standard or expensive battery the same and there is a very high likelihood that the expensive batteries will last longer even though they carry that higher price tag. These batteries will have higher quality components that last longer – e.g. the battery plates – and there will be a higher quality manufacturing process.

Cheap batteries:

You may have stumbled across some cheaper batteries, which, on the outside, look exactly the same as a more expensive battery. They may even show the same charge capacity in a brand new state. But, when you look at the internal components of the battery, however, there is often a clear difference in the quality and quantity of lead being used.

You should be careful when buying a new battery since, when tested, cheap and more expensive batteries may return the same results. Take a closer look at the specifications and ask your mobility dealer to explain the differences in performance and life expectancy of the battery.

Taking extra care with a purchase is important as it is actually a few months down the line when you would notice a difference in performance. If you were to test two batteries, one cheaper with less, low-quality lead, and one more expensive with thicker plates and lots of high-quality lead, you would see that, over time, the cheaper battery has less and less capacity compared to the more expensive one.

Top Tip: If you want to make a long-term purchase decision for a higher quality battery, your slightly more expensive battery can actually save you more money over time. As long as you look after it!

Can testing batteries incorrectly have an effect on battery life?

The main issue in testers damaging batteries again comes down to overcharging. In some cases, it has been known for people to test mobility scooter batteries with standard automotive battery chargers that run ‘drop tests’.

A drop test works by suddenly drawing a large surge of power from a battery (as if you were trying to crank a car engine). This method works fine for cars since car batteries have a larger capacity, but smaller mobility scooter batteries designed for a steady delivery of power over a course of time can be damaged by drop tests.

Top Tip: Testers for mobility scooter batteries should be conducting a discharge test to measure ‘current control’, so be sure to always use a proper mobility scooter battery tester.

If you want any advice on how to care for your battery and keep it in tip-top condition, we’d be more than happy to have a quick conversation with you.

Get in touch with us

If you’re looking for a new, high-quality, battery for your mobility scooter, take a look at our range of Strident batteries in our brochure.