How Long to Charge a Motorcycle Battery?

My Honda CB500X getting charged with the Battery Tender.

When a motorcycle battery is not in use, it will lose its charge leaving you with a dead battery if you don’t maintain it properly. If you find yourself with a dead battery, you can get it back to operating condition by connecting it to a charger. Then wait.

So, how long does it take to charge a motorcycle battery? At least 6 hours and up to 24 hours. A brand new lead acid, 12 volt battery under a constant-current charge, will take 5 – 8 hours to charge up to 70%. The remaining 30% will require another 7 – 10 hours before it is ready to install on the motorcycle. A new, sealed, pre-charged battery is generally charged to 80% when you buy it, and should be connected to a charger for 4 – 6 hours to reach maximum charge before putting it in the bike.

Now, you might be thinking, that’s great for a new battery, but how long will it take to charge the battery that’s already on my bike? That depends on several factors. So, let’s dig into the basics of motorcycle batteries, how to charge them and how to keep them charged.

Common Types of Motorcycle Batteries

In keeping with the main topic of this article, I don’t want to get too deep into the nitty gritty of battery technology. But, I would like to mention a couple of basics.

Lead Acid Batteries

These are probably the most common type of battery. They consist of Lead plates in each cell and are filled with a mixture of sulfuric acid and water. The chemical reaction between the two create an electrical charge. When you buy a new lead acid battery you will have to fill each cell with acid that is provided when you purchase the kit. Don’t worry, it’s not as hard as it sounds. You will then connect your trickle charger to your battery and let it sit for about 24 hours to get a full charge. Install it into your bike and you’re ready to go.

Lead acid batteries require regular maintenance, and this is something that a lot of people neglect. The fluid in the battery cells will evaporate and the cells can dry out. This is the quickest way to destroy the battery. So, it is smart to include a battery check along with your regular maintenance routine. If a battery cell is running low of fluid, top it off with distilled water. DISTILLED water. Not beer.

One important thing to note: this type of battery must be installed upright or you risk leaking battery acid all over your bike. And that would be a disaster.

Gel Cell and AGM Batteries

These are both a type of sealed lead acid batteries. When you buy one new, it will already be charge about 80%. These are by far the easiest battery to own. They require no maintenance other than keeping them connected to the tender when the bike is parked. Because they are sealed, you don’t have to install them upright, giving you more options for placement on a bike. One tip, however, is to connect a new battery to a float charger for at least 4 to 6 hours to bring it up to 100% before you install it on the bike.

Lithium Ion Battery

The Lithium Ion motorcycle battery is newer technology. It is incredibly light weight, 1/3 the weight of a lead acid battery, and requires very little maintenance. They tend to last longer than other batteries when properly maintained. But, there are a couple things to be aware of when considering a Lithium Ion battery, such as their higher price tag.

Lithium Ion batteries are known for giving you much more power in a cold start, making it perfect for larger bikes or for staring your bike in freezing weather. However, you need to following a specific procedure when doing a cold start.

  • Crank the engine for about 5 seconds. you’ll notice it cranks very slow and won’t start.
  • Let the bike sit with the power on for 30 seconds. This will warm up the battery.
  • Now, crank it again and your bike should start right up.

One word of warning; with a lead acid battery, if you accidentally leave your headlight on and drain the battery, you’ll still have the ability to recharge it. However, if you do that with a lithium ion battery, you will cause permanent damage to the battery. It will be toast.

How to Keep Your Battery Charged

To get the most life from your battery you need to keep it optimally charged and not allow it to get too drained. There are some easy steps you can take to keep your battery ready to go.

Keep it on a charger

A Battery Tender should be a staple in any motorcycle owner’s garage. See the current prices on Amazon.  It is the easiest way to keep your battery fully charge in between rides and during the off season. The Battery Tender is a trickle charger that feeds a consistent current flowing to your battery and will switch to float mode once your battery reaches 12 volts.

Battery Tender isn’t the only brand of charger on the market. There are plenty to choose from. You can charge your motorcycle battery with any charger, but, it is highly recommended that you use a charger that has an automatic mode that will switch off or switch to float mode before charging it higher than 2 amps. An unattended battery that’s allowed to charge more than 2 amps will bulge or even explode, spewing battery acid everywhere. Yikes!

Check for Parasitic Draw

Do a parasitic draw test. The purpose of this test is to see if there is a leak, so to speak, where your battery power is being drained. Some small amount of battery drain is normal, say, if you have a clock or alarm on your bike that is always on. But these leaks can also be caused by a short or poor ground wiring. Any drain more than an amp, should be investigated and repaired. Checking for parasitic draw is simple.

  1. Check your bike’s manual to see how to access your battery
  2. Disconnect the negative cable from the terminal
  3. Take a basic voltage/Ohm meter and set it to amps
  4. Place one meter lead on the negative terminal, and the other meter lead on the negative cable.
  5. The meter should read Zero amps.

If it reads anything more than zero, and you don’t have any accessories on your bike to draw that power, then you need to investigate further and correct the issue. Before you know it, your battery will be drained one amp at a time.

Keep your Electronics to a Minimum

Riding with a lot of electronic accessories can stress a battery and drain it faster than normal. If you have a lot of accessories such as a stereo, GPS, or heated gear, be sure to purchase a battery that is designed to accommodate all those gadgets. And, be aware that your battery will be stressed during long rides. Plan accordingly if you’re going on a multi-day ride and bring a Battery Tender Jr. with you. You will need at electrical outlet to plug it in, so, that may take a little imagination depending on where your staying.

When Should You Replace Your Battery?

It’s a good idea to include a battery check to your usual maintenance routine. Every time you change your oil, why not check your battery charge. Physically inspect your battery for leaks, bulging, corroded terminals and connectors.

Check the voltage. Connect a multimeter to the positive and negative terminals and set the meter to volts. Your meter should read between 12.7 volts to 13.2 volts. This is a fully charged battery. If it reads 12 volts or less, its time to replace it.

Check the voltage under load. To do this test, you’ll connect the meter as described above. Start up the motorcycle and rev the engine up to 3,000 rpm and check the meter. A good battery will read about 9 to 11 volts consistently for 30 seconds. Anything less, and it’s probably time to replace it.

In summary, batteries are close to maintenance free, but they cannot be ignored completely. Be diligent about keeping your motorcycle connected to a trickle charger like the Battery Tender. Keep your lead acid battery topped off with distilled water. Incorporate a physical battery check and a voltage check into your regular maintenance routine.

These good habits will keep your bike ready to pack up and ride at a moment’s notice, and will prevent you from getting stranded in a motel parking lot with no power.

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