7 Reasons A Motorcycle Battery Drains While Riding

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Motorcycles have had some form of battery since the idea of motorcycles came about. As time goes one, batteries have become more efficient in the way they power a motorcycle, but that doesn’t mean they’re flawless.

Battery issues are completely frustrating. It’s even more frustrating when you’re out for a ride and notice you’re losing power and/or the battery is completely drained when you get home.

Why does a motorcycle battery drain while riding? There are several reasons why a motorcycle battery drains while riding including a bad battery terminal connection, corroded battery terminals, a bad stator, a bad rectifier/regulator, too many electrical add-ons, too old of a battery, and if you have a newer motorcycle, an automatic shut-off will happen if the battery cable vibrates loose.

Having dealt with every battery problem imaginable through the dozen or so motorcycles I’ve owned in the last few years, I’ve been able to get a good idea of exactly how motorcycle batteries work and why it would drain while riding. This article will explain further why it happens in addition to other helpful information if you find yourself in this situation.

Reasons A Battery Drains While Riding

It’s never a good sign when your motorcycle is struggling to stay running while you’re out for a ride. There could be multiple reasons for something like this, but the likely reason it’s happening is due to the battery.

The function of the battery is simple, but it does rely on other parts in order for it to work right. The first reason a motorcycle battery may drain while riding could be due to a bad terminal connection. The terminals on a battery are the two small metal rods that stick out on either side on the top.

When a motorcycle has a bad terminal connection, that means the battery cable either has a poor connection or isn’t connected at all. The battery should be charging through the stator while it’s running, but if there’s a bad connection, your battery won’t be getting much of a charge.

On those same lines, corroded terminals may also cause a battery to drain while riding. It’s possible for battery acid to develop on these terminals which means there’s a barrier between them and the cable that connects to the stator. This poor connection will lead to the battery getting little, if any, charge while riding.

If the terminals seem to have a good connection, your next (and probably likely) reason your motorcycle battery drains while riding is because of a faulty stator. The stator on a motorcycle is basically an alternator, just in a simpler form.

The role of the stator is to charge the battery while the motorcycle is on. When a stator has gone bad, that means the motorcycle is running off of battery power alone which will quickly drain it. Batteries were not made to power the bike while it’s running, only mainly to get it started. See my other article here to learn more about how a motorcycle stator works.

The regulator/rectifier of a motorcycle is part of the alternator system but is usually found apart from the stator. Batteries aren’t able to store AC current so the regulator/rectifier converts power into a type of current the battery can store. If the regulator/rectifier has gone bad, that can cause the motorcycle battery to drain while out for a ride.

When the regulator/rectifier isn’t doing it’s job, that could mean it’s not converting the power into voltage the motorcycle can store which leads to the battery not really getting any power at all.

Aftermarket modifications or additional electrical add-ons could also cause a motorcycle battery to drain. Such add-ons may includ LED lights, phone chargers, etc. It’s possible for the wiring to have been done wrong when these types of add-ons where installed on a motorcycle.

When these are used while riding, they use additional voltage from the battery especially when there’s poor grounding. Since these are taking up so much juice from the battery, the battery will drain during a ride and may not be able to start the motorcycle during the next start-up attempt.

A battery draining while riding could also be simply due to a bad battery. This is more likely to happen if the battery is old or expired. A typical motorcycle battery should last up to 48 months, or 4 years. But it’s not uncommon for them to quit before that. Take a look at the expiration date of your battery; if it’s close, it may be time to get a new one.

The last reasons a battery drains while riding a motorcycle applies mostly to newer motorcycles. Some newer motorcycles will shut off if a battery cable vibrates loose. This is a defense mechanism engineered in order to prevent the cable from hitting a ground and causing a spark. This usually results in a sudden shut-off from the motorcycle.

The Battery’s Role

The battery’s main role on a motorcycle is to get it started. Unless you have additional electrical ad-ons, that’s basically all the battery does. Once the motorcycle is on, the stator takes over and is what helps the bike run while also recharging the voltage the battery had to use to get the motorcycle started.

You may not notice your motorcycle battery is draining while you’re riding it until you go to start it up again for the next ride. But as we’ve previously discussed, other underlying problems will manifest itself through the battery noticeably draining while riding the motorcycle.

The battery’s role is simple, but if it doesn’t work right the entire motorcycle may not be able to run. Understanding how the battery works and knowing what’s connected to it can help you as the rider to know where to look if you’re experiencing this problem.

How To Know If The Battery Is The Issue

When you’re motorcycle is acting up, there are a few conclusions most motorcycle riders have. And most of the time it’s the battery. There are a few symptoms you can look for to know if you’re truly dealing with the issue of the battery draining while you ride your motorcycle.

The first and most obvious symptom is your motorcycle losing power and acting more sluggish as time goes on. The motorcycle may even die at some point. You’ll also notice any lights become more dim in this scenario.

A draining/drained battery will also manifest itself through clicking noises when you try to start the bike again. This clicking sound is coming from the motorcycle trying to draw power from the battery but is unsuccessful.

The last and one of the most obvious ways to tell if your motorcycle battery continues to drain while riding is if you can jump start it or charge it and it works great afterwards. This doesn’t necessarily mean it’s the actual battery, so be sure to go through the check list discussed earlier to see what the real culprit is.

What To Do If Your Battery Dies While Riding

One of the most aggravating things a motorcycle can do to us riders is leave us stranded because the battery won’t work. I’ve been there many times myself and had to get creative with how I got myself home.

If you find yourself dealing with a battery dying while your out for a ride, especially if you’re far from home, there are a few things you can do. First, check all the connections to the battery and make sure everything is snug.

You also have the option of getting a jump start either from another motorcycle or from a car. You’ll need to proceed with caution if you get a jump start from a car since there’s a risk of ruining the motorcycle battery. Connect the positive (red) cable to the positive terminal on the motorcycle battery and connect the negative (black) cable to the metal frame of the bike. Then connect the positive cable to the positive terminal of the car battery then the negative cable to the negative terminal.

Do not turn the car on. You can attempt to start the motorcycle without starting the car since the battery is powerful enough to emit enough voltage to the motorcycle.

Lastly, you can attempt to do a push start your motorcycle since you may not have the battery power to get it started. To push start a motorcycle, you need to get it rolling fast enough that the compression of the engine will start the combustion cycle.  Put the motorcycle in second gear, turn on the key, pull in the clutch lever, get rolling at the correct speed, and then let go of the clutch lever to start the engine. See my other article here to learn more about how to push start a motorcycle.

This article has been reviewed in accordance with our editorial policy.

Kyle Cannon

Kyle currently works as a mechanical engineer and graduated with a minor in automotive engineering. He loves restoring motorcycles, has a vast knowledge of how they work, and has sold his restoration projects to customers from all over the United States.

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