11 Reasons Your Motorcycle Battery Died Overnight


motorcycle battery died overnight

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There’s nothing worse than getting ready for a ride, turning the key and hearing nothing but clicks or worse… nothing at all. In this post we’ll take a look at some reasons your motorcycle battery died overnight.

The good news; Some of these are easy no brainers.

The bad news; You may have to take a deep dive into your motorcycles electrical system, which can be really confusing if your unfamiliar.

Back to the good news;

Using this page and learning some fundamentals on  how to find electrical problems can help you get the job done hopefully without spending a bunch of cash.

You didn’t turn the key off

It happens to even the most seasoned riders…

You think you that you have the motorcycle completely shut down when you don’t. You walk away and go do your thing until the next day.

There are many motorcycles where it’s possible to pull the key out of the ignition before it reaches the full ‘off’ position. Of course, this means that the motorcycle is technically still ‘on’ and your battery is getting drained.

I’ve done this very thing several times being in a hurry to get off of my bike. I get the kickstand down and the bike settled and give the key a quick flip and a yank and off I go.

It was a bad habit that I had to change due to too many close calls!

Take a quick look

After you’re parked the motorcycle and you shut it down, take a quick glance at your ignition and make sure that your key is really in it’s off position.

If you have a motorcycle with multiple instruments or a dashboard, take a quick look to ensure that everything is powered down.

The last and final thing I’ve tried to make a habit of is doing quick walk around as I get off of my bike. Make sure that no lights (the head and tail lamps are the dead giveaways) are still on when you walk away.

Too many accessories

Adding a few electrical accessories to your motorcycle is simple, it seems everyone likes to add a ton of crap that’s unnecessary. What you wind up with is a rat’s nest of wires and the potential to overload the motorcycles electrical system and drain your battery.

Placing too big of a load with accessories can stress the battery and reduce its lifespan (motorcycle batteries are supposed to last two years, but you usually don’t get all of that).

If you’re going to be messing with your bikes electrical system and wiring extra’s into it, you may want to consider adding a voltmeter into the mix so you can keep a close eye on the electrical system.

Want to incorporate electrical accessories like heated vests, mp3 player and auxiliary lights? Consult your mechanic, but you may want to consider connecting all of your extras into a distribution box and using the voltmeter monitor them.

Remember this;

If you add too much, your motorcycle alternator may not be able to keep up and you may need to upgrade that as well.

Whenever I thought of adding something to my bike that wasn’t functional, my mechanic friend put it to me like this:

The more accessories you add, the more that has to be removed when there is a problem. This means that you’ll be paying more money in repairs to take stuff off so you can even get to the problem. Then it has to be put back on.”

Remember the more stuff you add, the more potential for a system failure that can drain your battery.

For my motorcycle, I tend to be a minimalist. No accessory goes on my motorcycle that doesn’t serve a function. Those functions revolve around safety and comfort not aesthetics.

A Short in the electrical system

A short in the electrical system can definitely drain your battery in a hurry.

But the thing is;

Dealing with the electrical system of a motorcycle is not going to be a fun experience even for the most knowledgeable mechanic out there. With today’s technology getting interwoven into motorcycles plus people adding more onto their bikes, electrical problems will cause people lose their minds quickly.

The result will be to immediately to jump on the phone to make an appointment with your local mechanic.

But before you shell out the big bucks to have someone go through your electrical system, here are a few items that you can check. Understanding how to load test your motorcycle battery can help you get started getting to the bottom of what’s gong on.

Battery – If you think you have an electrical short as a result of your battery being dead you can already rule out that your battery is the problem.

Check your main fuse – A main fuse that’s blown or faulty will cause all of the electrical components on your motorcycle to die. This will make it seem as if you have problems with your electrical system when all you really have is a bad fuse. Checking this right away can save you hours of frustration. Pro tip: Keep a few extra’s of these on hand when you ride.

Look for bad or broken wiring – Any wiring that doesn’t look protected, has bad connectors or the wiring’s exposed could be causing you a short in the electrical system.

Bad voltage regulator/rectifier

motorcycle rectifier
The Rectifier in a motorcycle electrical system turns AC current into DC current.

The regulator/rectifier is one unit newer motorcycles but may be two separate items in an older bike.

Having a bad regulator is problem that happens frequently in motorcycles that have high mileage. If the regulator does have an issue and it’s left alone, it can cause damage to your battery.

What does the rectifier in a motorcycle do?

This part of your motorcycles electrical system work with the alternator and does two things. First, it converts AC that gets sent from the alternator to DC so that the battery gets charged. It delivers this power within limits (similar to a trickle charger) so that the battery doesn’t get overcharged and damaged.

Any excess power output is converted into heat and dissipated.

Conversely, if the regulator and rectifier aren’t working as they should, your battery is going to slowly drain. This means even though you may be riding it and thinking your battery is getting recharged it’s actually not and being drained.

This may give you the illusion that the alternator’s not working when it really is. Before tearing into your alternator, you going to want to take some time and give the rectifier a test with a multimeter. It should read no lower than 13.5 volts and no higher than 14.5 volts.

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Corroded connections

Corroded electrical connections can cause a heap of problems to the electrical system of motorcycles.

In today’s modern motorcycles that have tons of wiring a quick example would be a sensor that may not be working as it should.

Take some to check any of your motorcycles wiring that you can either see or get to easy to see if the wiring is connected properly or corroded.

If you plan on doing any cleaning whether with a product or a do it yourself remedy, make sure that you disconnect your battery from the system so you don’t get yourself zapped.

If the battery terminal themselves are corroded, it could b symptomatic of a bigger problem with your battery. The corrosion can stem from anything from overcharging the battery to the battery itself leaking hydrogen gas.

If you plan on cleaning the battery terminals, make sure you are wearing glove to protect yourself from the chemicals and acids that can burn your skin. There are a bunch of different products and methods you can use to clean corroded motorcycle battery terminals.

The Alternator and Stator isn’t working

The Alternator and stator work with each other to help generate the power it takes to start your motorcycle and power all of the goodies mounted on it.

The Stator is connected to the alternator and is the stationary part of it. The flywheel on the alternator rotates around the Stator to generate AC power for the motorcycle.

If your having trouble keeping your battery charged after a ride, either the Stator or alternator might be the next culprit to investigate. Just like the regulator, if either of these two doesn’t produce enough power back into the system, your battery will begin to drain every time you start or ride it.

You’ll want to test each of these items separately if you can to try an isolate which one is the culprit. For example, It’s possible for the stator to be fine and the alternator to be bad.

Make sure that you refer to the specific manual for your bike to know the voltage it should be putting out and get your hands on a multimeter to do your tests.

The ground connection is bad

A common overlooked culprit for dead motorcycle batteries is poor ground connection between either the frame and battery. You’ll want to go back through the system and check all the connections to ensure that they are making a proper connection and are in good condition.

Other problems that can cause problems with grounding are corrosion, rust, ground straps that are connected properly.  With all of the different items and components in an electrical system, finding a ground issue is going to be a frustrating experience.

There is a parasitic draw on the battery

Just like the parasites in the real world, a parasitic draw on your battery will suck your battery dry. Except in this case, the parasite might be any of your accessories that drawing low levels of current from your battery until its dead.

The accessories that are stealing power can be anything from the stock accessories your motorcycle came with to aftermarket items like GPS power supplies anything extra on your bike that uses power.

If you have your motorcycle plugged into a tender when your not riding it, you may not notice the extra power draw as long as the tender is keeping up. And of course if it doesn’t your battery is going to get drained overtime.

A way to perform a quick check is to get a multimeter and remove the negative cable to the battery terminal. With the key off, place the multimeter in the amps mode and place a lead between the terminal and the cable.

Generally, the reading should be zero, but if the draw is over an amp your going to need to take a closer look at what’s going on in the system.

motorcycle battery

Vibration and heat

Even with proper care and feeding of your motorcycle battery, some batteries have a difficult time with excessive heat and vibration.

If your battery is located in an area on the motorcycle where is can be subject more heat than usual, you may want to consider wrapping it in thermo heat shield to keep it protected. In fact, if you live in an area where there is considerable heat all the time (like the desert southwest for example) you might want to shield your battery.

The damage with heat and vibration occurs to the internal components of the battery. Once the internal components of the battery have suffered damage, the life span of the battery is reduced.

The battery is in weak condition

Sometimes your battery is just in a weak condition. It’s either been damaged by heat and vibration, or it’s been drained (at least once).

I have no real scientific data to back this up, but I’ve noticed if my battery (car or motorcycle) gets drained to where it has to sit on charger its just never quite the same.

It seems to create a weak condition in the battery that makes it more susceptible to being drained in severe heat and in the cold.

A weak battery in my motorcycle almost left me stranded at the Grand Canyon on one occasion. We woke up to a chilly morning and I went out to start my motorcycle. It cranked over twice, then I heard the dreaded clicks!

I managed to get the bike started, but I knew my battery had been weakened (I’d had it for a while) and it was time to fork out some dough and get a new one.

Your motorcycle battery is just done

This goes hand in hand with your battery being in a weak condition. Sometimes your battery is old and tired. It’s just plain done, and no amount of hooking it up to any machine will bring it back to life.

Batteries are usually hard to get to so we put it off for as long as possible. It’s a bit up in the air as to exactly how long a motorcycle battery will last, but if you got a good 2 – 3 years out of it, you’re doing pretty good.

gl1800 motorcycle battery

Motorcycle Battery maintenance tips

With a little TLC, you can extend the life of your motorcycle battery. It only takes a tiny bit of maintenance once a month or so to keep it running well.

Use a battery tender – Ideally, you want to keep your motorcycle battery at 100% all the time. The best way to do that is keep your battery hooked up to a battery maintainer or tender when you’re not using it. Don’t worry about over charging your battery… A good tender will keep your battery full without damaging it through overcharging.

Check Electrolyte levels – Make sure the liquid level in your battery is at the proper level and hasn’t dried out. Use distilled water, wear gloves and eye protection. Watch for fumes. Do NOT use tap water.

Clean the top of the battery – Keep the top of the battery clean and wipe off grime. If you start to see corrosion around the terminals, this could be an indicator that the battery is leaking.

Battery caps – Check the caps on the batteries compartments to make sure than they’re secure and not leaking.

Remove the battery – If you don’t plan on riding your motorcycle for a long period of time, consider removing the battery from the bike.

Make sure that when you store the battery that it’s in a place warmer than 32 degrees and not sitting directly on a concrete floor. Check the batteries instruction manual if you still have it.

Basic Tools You Need

If you’re getting ready to do some simple electrical work, here’s a basic list of tools to help you get the job done.

astro digital multimeter

AstroAI Digital Multimeter

Klein Tools Wire Cutter/Stripper

Wirefly 270 piece heat shrink connector kit

Need a basic toolkit? This motorcycle toolkit is the one I carry on my motorcycle.

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