How To Charge a Motorcycle Battery

A motorcycle’s battery is essential for lots of key functions, so it’s important to keep it well charged and in a good condition.

While a battery will automatically recharge when you’re riding, it’ll also discharge when left idle for long periods – so it’s important to charge it at regular intervals. Here’s everything you need to know about when and how to charge a motorcycle battery.

How often should you charge a motorcycle battery?

From lights through to electrical ignitions, motorcycles contain lots of parts that depend on a functioning battery, if you let the battery fully discharge, you’ll be left with a motorcycle that won’t start.

Avoiding this situation is easy, and when you’re riding regularly, your motorcycle will take care of recharging the battery automatically for you, with the alternator creating alternating currents that power the electrical system and recharge the battery.

However, when left idle for long periods – a common occurrence over the winter months – a motorcycle’s battery will discharge. If left long enough, a battery can fully discharge, which is something that can’t always be fixed.

That’s why it’s important to regularly charge a battery whenever you’re not riding your motorbike for long periods. At a minimum, you should be charging it at least once a month.

However, for older batteries where performance will naturally have deteriorated over time, charging may be necessary more frequently.

What type of battery charger do you need?

Before charging a battery, it’s important to make sure you have the correct type of charger. Here are a few important factors to consider:

  • Voltage – Motorcycles will use either a 12-volt or 6-volt battery, and a charger’s voltage needs to match that of your battery. For example, a 12V charger should only be used with a 12V battery. You can find out your battery’s voltage from the top of the battery or in your user manual.
  • Amps – The higher the amps, the faster a battery will recharge. For example, a 2 amp hour charger (or 2AH) provides two amps per hour of charge – so would take four and a half hours to charge a 9 amp battery. Using a high-amp charger will charge a battery quicker but can damage a battery over time, leading to a shorter life.
  • Type of battery – From lithium to lead acid, there are various types of batteries, and you’ll need a charger that is compatible with the battery your motorcycle has.

There are also a few different types of chargers to choose from:

  • Smart chargers – This the easiest way to charge a motorcycle battery. These types of chargers will detect what state your battery is in and then modify the charge to its needs. They will then keep the charge at an optimal level to prevent overcharging, meaning you can leave a battery connected to a smart charger over a long-term period.
  • Trickle chargers – These are like regular chargers you would use for other appliances and will charge a battery continuously by a certain amount until unplugged. To prevent overcharging, you need to monitor the charging process and turn the charger off at the right time once the battery is fully topped up.

Charging a motorcycle battery

Now you’ve determined which type of charger you need, it’s time to charge your motorcycle’s battery. Here’s a step-by-step guide:

Locate the battery

A simple place to start, but you need to know where your battery is located. On most motorcycles, the battery is housed under the saddle, but there are lots of models where this is different. If you’re unsure, consult your owner’s manual.

Where to charge the battery

This will depend on the length of your charger and where your motorcycle is parked, but you can either remove the battery to charge it or connect the charger with the battery still on the motorcycle. We recommend removing the battery before charging. When doing so, make sure you remove the negative cable (usually black) first, before removing the positive cable (usually red).

Top tip: Both red and black cables can be used in negative and positive terminals but are coloured to make differentiating between the two terminals easier. Black cables should be used for negative terminals with red leads connected to positive terminals. However, you can also check for a – or + symbol next to any terminal, in case the wrong-coloured wire has been used.

Charging the battery

  • Start by connecting the charger to the battery. Most batteries have integrated leads, or these will be supplied in the box. You need to connect the negative port of the charger to the negative terminal of the battery using the black wire, and the positive port of the charger to the positive terminal on the battery using the red wire. These terminals will be clearly labelled with a + or - symbol.
  • Then, plug the charger in and turn it on – it should have a light indicating that it’s on and that the battery is charging.
  • If you’re using a smart charger, you can leave this plugged in and it will automatically keep your battery charged to an optimal level.
  • However, when using a trickle charger, you’ll need to monitor the charging process and make sure you disconnect the charger once the battery is charged. Most chargers will have a light that displays when the battery is fully topped up. If you leave the charger connected after this point, the battery will become overcharged.
  • Before disconnecting the charger, make sure it is turned off. You then need to disconnect the negative lead first, followed by the positive lead.

How long does a motorcycle battery take to charge?

Maintaining a battery and keeping it charged to an optimal level can take time – but you can make life much easier with the use of a smart charger!

Smart chargers like the Halfords Smart Motorcycle Battery Charger (4A) will automatically detect the condition of the battery and charge it in an appropriate mode, with settings for both lead acid and lithium batteries. There’s also no risk of overcharging as they automatically maintain a battery’s charge at an optimal level. That means you can leave them plugged in permanently without having to worry about how long it’s been sat charging.

On the other hand, trickle chargers require more monitoring as they need to be unplugged when the battery is fully charged to prevent overcharging. How long a battery will take to charge will depend on the amp hour of the charger – the higher the amp hour, the quicker it’ll charge. For example:

  • 10 amp hour battery = 10 amp charge per hour = 4 hours to charge 40 amp battery
  • 2 amp hour battery = 2 amp charge per hour = 20 hours to charge 40 amp battery

Although it may be tempting to opt for a more powerful charger, slower charging tends to be better for a battery’s long-term condition, so it’s usually wiser to opt for a less powerful charger around two amp hours.

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