It’s a fact that most motorcycles’ batteries will become discharged if the bike is left alone. This is particularly true for bikes that have trackers fitted, as these inevitably draw power from the battery to offer their protection. So although it is a small amount of current, it is only a matter of time before an unattended bike will have a flat battery.
This can be annoying at best and scrap the battery at worst. It is annoying because you come to the garage for your first ride in some time and the battery is dead. If you’re lucky, you can jump-start it and go for a run – hopefully the charge you get back into the battery will see you through your ride.
However, in the worst-case scenario, the cells in the battery can become damaged to the point where they simply cannot hold a charge and the only solution here is to replace it. And while motorcycle batteries generally are less expensive than car batteries, for example, it’s still an expense you could do without.
How to avoid flat batteries on your motorcycle
The solution, of course, is to leave your bike with its battery on charge when it’s not being used. This is particularly true for bikes that are laid-up for winter and in this case, a battery optimiser/maintainer can be useful, as it not only charges the battery but it carries out a series of conditioning cycles. These put some load on the battery so that it isn’t simply under constant charge, as this can also, paradoxically, damage the battery and reduce its capacity as well.
One point you should consider is what kind of battery your motorcycle uses. Lithium batteries are becoming more popular as they can offer better performance than traditional lead-acid ones. However, they require very different charging characteristics and as such, you should be careful not to pair the wrong charger with the battery, as this can have a negative effect on the battery and can even be dangerous.
The best motorcycle battery chargers:
CTEK CS ONE
Tested by Richard Newland for five months across six vehicles
Quality 5/5, Value 3/5
"Dead batteries are like flat tyres – utterly infuriating and one of the least glamourous replacement parts in biking. But critical to your riding pleasure. While you can’t prevent punctures, you can prevent dead cells with a battery charger and conditioner. And this one from CTEK is superbly clever. Not only does it do everything you’d expect: charging, recovering, conditioning and maintaining whatever vehicle battery you connect it to (and yes, it’s does them all from Lead Acid to Lithium-ion in all wet, AGM, Gel and other forms) – it does it without any programming from you."
"Simply connect the leads – which are disconcertingly both black because the CS ONE is so clever that it detects polarity so you can’t connect it wrong however hard you try – plug it in, and it’ll do the rest for you. The Adaptive Charging Technology will detect every facet of your battery, and even alter its charge voltage based on the ambient temperature to ensure you battery charges at the optimum rate – and doesn’t fry.
The unit then analyses and diagnoses what’s needed, before merrily getting on with it. The display atop the charger keeps you up to date with progress, and once you’ve got a full white ring of illumination, your battery is tip-top. And if you do want or need deeper intervention, simply download the CTEK app to your phone and connect to the CS via Bluetooth, giving you an on-phone control panel and additional functions. If you prefer a wired battery connection so you can just plug-n-charge without needing battery access, the required lead is £4.99 extra and extension leads are £14.99.
I’ve used it on four bikes with three different battery types, one old VeeDub camper and a modern family car – and it tackled all with ease."
We've included the Ring RSC706 in our top battery chargers, but have given it a more thorough separate review, which you can read over here.
Perfect for bikes kept in a shed or a portable garage-style shelter with no access to mains power, this solar charger will trickle charge a battery to keep it healthy using just solar energy. Of course, the charging rate will depend on the time of year as well as the weather but Oxford quotes from 10mA to 100mA and the solar panel can be fixed inside a window, though it is also described as 'weather resistant'.
NOCO GENIUS2UK Fully-Automatic Smart Charger
Best small charger
This diminutive smart charger is designed for motorcycles, quads, snowmobiles and more and looks after both 6V and 12V batteries. It will help de-sulphate batteries and recover them as well as charge AGM, gel, lead-acid and lithium-ion batteries. It can also be used as a long-term maintainer without overcharging the battery and features clever touches including a thermal sensor, which doesn't allow overcharging in hot weather or undercharging in cold.
OptiMate 1 Duo
Best budget battery charger
The entry-level charger/optimiser form OptiMate will maintain any kind of 12V battery, including lead-acid, AGM or gel and lithium and keep a bike's battery healthy throughout storage. It provides a relatively low 0.8A charge rate for motorcycles that are largely used infrequently and operation is automatic, delivering only what the battery needs.
CTEK MXS 5.0
Most versatile battery charger
CTEK has an enviable reputation for chargers and conditioners and this is its bread and butter charger. the MXS 5.0 is hardy (IP65 rated), reliable, and clever. It's reasonably good value too. Like its CT5 counterpart above and the NOCO, is reconditions as well as charges batteries (lead-acid batteries) - good for cars and motorbikes - via an eight-step program that helps prevent the plates in the battery sulphating, which can reduce its life and capacity.
OptiMate Solar 10W
Best solar battery charger
Using a 10W solar panel (bigger sizes up to 80W are available), this charging system will also work perfectly for storage facilities with no access to mains power. The solar panel supplies energy to a charge controller to make sure the correct voltage and charge are supplied to the battery and it has three modes; save, charge and maintain for long-term storage. The 10W panel will supply a maximum of 0.83Amps in ideal conditions, perfect for motorcycles.
OptiMate 4 BMW
Best for BMW CAN-Bus
With BMW motorcycles using CAN-Bus technology (Controller Area Network Bus, which allows systems to communicate effectively), this improvement in efficiency also means a different approach on occasion. This charger from Optimate can either connect directly to the battery or via a 12V power socket and will test the battery before applying the appropriate charging current. It is good for lead-acid batteries and can be left for long periods to maintain its condition. Comes with BMW DIN plug cable.
Oxford Oximiser 3X
This unit looks after all types of battery, including lead-acid, lithium and gel and has three charging modes; low-current for motorbikes, higher current for cars and a winter mode for looking after batteries in storage. It will recover deeply discharged batteries and cycle-charge them to prevent the plates from sulphating and is fully automatic.
Oxford Oximiser 601
At the other end of the charging scale from Oxford is the 601, a charger/optimiser that is designed for lead-acid and gel-type batteries and can manage up to 30Ah sized items. The charger selects the appropriate charging rate and if there is a load on the battery, such as a tracker, for example, adjusts the rate accordingly. It will also help recover batteries that are deeply discharged and can be left connected for long periods, such as over winter.
Gear Gremlin Intelligent
This basic-looking item from Gear Gremlin is fully automatic and will save, charge and maintain all lead-acid 12V batteries. It will help recover sulphated batteries, which have reduced efficiency and will automatically select the most-suitable charging rate. It also float-charges batteries for long-term storage maintenance.