Motorcycle batteries generally need to be lightweight and compact in order to fit within the tight confines of a bike. Most motorcycle manufacturers will use a battery just big enough to meet the cold cranking amps required for the starter to turn the motor over. Any bigger, the weight and size of the battery is overkill. Any smaller and the battery will not have enough power to fire the bike's engine. The issue is that if the battery voltage is a bit low there may be insufficient power to start the bike. Often your lights will work, but the starter will not crank quickly enough to start the engine.
You should check the battery voltage with a voltmeter if you think that it is low or dead. You can pick a voltmeter up for under $20 at many retail spots that will do enough to get you by. If you are showing voltage on the battery with the bike off of under 12 volts that is most likely the reason your bike is not starting. If you have 12.7 volts at the battery there is a different issue with your bike.
The correct fix for a low battery voltage situation is to hook the battery up to a battery charger. Sounds simple right? STOP. There are a few important points to be sure on before you proceed.
Is your battery a conventional acid battery, sealed gel type, lithium ion?
The reason this is important is that certain battery types will charge properly, without damage, using certain battery chargers. Generally conventional acid type batteries will charge with a conventional charger whether it be transformer type or inverter controlled. However, most sealed gel type batteries require the use of a digitally controlled charger. Lithium ion battery manufacturers may recommend that you use a specific type of charger,and will generally recommend to not use lead/acid type chargers or desulfating chargers.
The best thing to do is to purchase a charger that is designed specifically for your battery type. Battery charger manufacturers should list the types of batteries that they can safely charge, or check with the manufacturer before your purchase it. If you invested in a lithium ion battery get yourself a charger for LIFEPO4 batteries.
If your battery has removable caps for each cell it is a conventional battery.
If there is a seal strip that reads "do not open" your battery is a sealed type battery.
If your battery is lithium ion it should indicate that on the battery case.
At what amperage should I charge my battery?
The amperage at which you charge a battery effects the life of the battery, and over-charging can be dangerous. Each battery should have a decal showing the recommended charging rate in amps. We recommend that you charge your motorcycle battery on the lowest setting of the charger to prolong battery life. Many chargers will offer 2 amp, 4 amp, 6 amp settings, so the lowest is usually best. The charger should come with instruction on what setting to use for each type of battery, so we suggest that you read up.
For how long do I charge my battery?
Do not overcharge your battery. Many of the latest digital chargers will charge your battery to a specific voltage and then reduce to a "maintenance" amperage, and let you know that the battery charging is complete. However, if you use a transformer type charger it is easy to forget that you were charging the battery and you will damage the battery, start a fire, burn your garage down, etc. We suggest to purchase a digital charger and save yourself the headache. Your battery is completely charged when the voltage is 12.7 volts for a conventional or sealed battery, 13.3 volts for a lithium ion battery, or at the voltage otherwise listed by the battery manufacturer.
Why is my battery dead or low?
There are many reasons for a battery to have low voltage. The battery may be past its usable life, the battery may not be charging properly on the motorcycle, or there may be a parasitic draw on the motorcycle. If you haven't ridden your bike in an extended period of time, chances are that the battery has just discharged over time. Lithium ion batteries tend to not discharge like conventional and sealed batteries over time, giving them an advantage. Additionally you may have a parasitic draw on the bike, so it's best to rule out the battery itself first. If you are riding the bike frequently and the battery is dead, then your battery may be past its usable life or you may have a charging system issue on the bike. Check out our article for testing your charging system for more information.
Charge your battery
It is preferred that you disconnect the battery completely from the motorcycle to charge it, but that is not always the ideal situation. We suggest this at spikes in amperage while charging can damage the delicate ECM's and ignitions on today's motorcycles.
Load test your battery
When you battery is showing surface voltage of 12.7 for a conventional battery it is time to load test that battery. A load test will determine if the battery can provide enough amperage to start your bike. A battery past its usable life will fail the load test. Load test tools are available in may retail stores. We do not recommend a load test on a lithium ion battery.
Install your battery
Properly re-install the battery. Check out our article on properly installing your battery for more information on this step.
Start your bike!
You should be able to quickly fire your motorcycle's engine at this point. It is always suggested that you push your starter button in 5-6 seconds maximum lengths of time. Excessively cranking your motorcycle's starter will damage the battery and starter. Multiple 5-6 second attempts is much more effective than long crank attempts.
Check your charging system
We suggest that you check your motorcycle's charging system for proper battery charging while the bike is running. Check out our article on checking your battery charging system for more information on this step.
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