1. If the vehicle charging system is not working properly the battery may be discharged while riding.  Using a volt meter check that the charging system output voltage is  between 13.1V and 14.8V throughout the typical rev range.  At 2000 rpm there should be a minimum reading of 13.8V.   Please see this video on how to test your charging system.

2. If the bike sits for long periods of time it can drain the battery due to the load created by vehicle systems such as: clock, computer, or alarm systems.  Make sure that no accessories have been installed which draw constant power during key off. Some GPS navigation will draw power even with Key Off. Most alarm systems typically draw current when the key is off. If your vehicle has accessories such as onboard GPS navigation or an alarm system, be aware that these vehicles  may need to be put on a frequent "routine manual charge" maintenance schedule (see "long term storage" section on the battery charging page).  Please see this video on how to test parasitic current draw.

Shorai Batteries produced since mid 2022 contain the Shorai Sentry BMS System.  If battery voltage falls too low, the main terminals are electronically disconnected (locked) to prevent a damaging "too deep" discharge. If your Shorai battery is equipped with the Sentry BMS, either of the two scenarios above can cause the BMS to engage (lock) the terminals of your battery. In this case checking the voltage at the main terminals will show zero volts. Attempting to charge with a "smart" battery charger may not work, as the charger will see zero volts and refuse to start. Please note, this is an indication of a problem, not a fault in the battery. 

If you have determined that the BMS has been locked due to either condition above, the BMS can be unlocked (reset) in several ways:

• Use the Shorai BMS01 Charger in CHARGE MODE (not store mode). The BMS01 LEDs will alternate between yellow and green for a period while the charger re-conditions the battery. The charger will automatically switch to full 2a charge mode and only the green LED will flash. When the charge is completed, the charger will turn off OR both green and yellow LEDs will go solid ON to indicate the charger is now in READY mode. 
• Using a DC power source, apply a low current "jump" of less than 1 amp of 12V~15V to the main terminals for no more than 5 minutes. Disconnect the power supply and test the voltage at the terminals. If it is reading a steady voltage greater than 12.2v you may connect your lithium appropriate battery charger and recharge the battery fully. 
• A "jump" from one 12V battery to the Shorai battery for no more than 30 seconds (best to use another motorcycle battery rather than a car battery). Disconnect the jump battery and test the voltage at the terminals, if it is reading a steady voltage greater than 12.2v you may connect your lithium appropriate battery charger and recharge the battery fully. 
• Use an old 12v "dumb" charger. If charger output is more than 2A only, use it to unlock the BMS, (until measured voltage is above 12.2v) then shift to an appropriate charger for LiFePO4 Lithium.
• Use a charger with a BMS recovery function such as the Optimate Lithium 4S TM-471.

If you ride twice a month or more, there is usually no need to ever charge for most motorcycles. If you have a vintage or off-road vehicle which has NO draw on the battery when the key is OFF, then you should only need to recharge your Shorai™ battery every few months.  However, most modern street bikes have a drain on the battery even when the key is off to support a clock, computer, alarms, GPS nav, or other devices.  This draw will eventually drain the battery, which is damaging to the battery and could void your warranty so we recommend a routine charging schedule to top off the battery when not riding. 

If you are NOT riding for an extended time (seasonal storage), we suggest setting up a "manual storage" routine as outlined in our Battery Charging page under the "Long Term Storage" section.

 

Shorai Batteries produced since mid 2022 contain the Shorai Sentry BMS System.  If battery voltage falls too low, the main terminals are electronically disconnected to prevent a damaging "too deep" discharge. In this case checking the voltage at the main terminals will show zero volts. Attempting to charge with a "smart" battery charger may not work, as the charger will see zero volts and refuse to start. Please note, this is an indication of a problem, not a fault in the battery. 

1.   If you have been using the vehicle recently and this has happened, and you did not drain the battery by leaving the ignition key on, etc, then it may indicate:

• Your charging system is not operating properly, OR
• The battery has an internal problem such as one weak cell.

Using a volt meter check that the vehicle charging system output voltage is  between 13.1V and 14.8V throughout the typical rev range.  At 2000 rpm there should be a minimum reading of 13.8V.   See the video on how to test your charging system HERE.  If the charging system tests good, then submit a warranty request for further support.

2.  If you have NOT been using the vehicle recently and you have NOT maintained the battery with a charger, then it is most likely the battery has correctly locked the terminals to prevent over discharge.

The BMS can be unlocked (reset) in several ways:

• Use the Shorai BMS01 Charger in CHARGE MODE (not store mode). The BMS01 LEDs will alternate between yellow and green for a period while the charger re-conditions the battery. The charger will automatically switch to full 2a charge mode and only the green LED will flash. When the charge is completed, the charger will turn off OR both green and yellow LEDs will go solid ON to indicate the charger is now in READY mode. 
• Using a DC power source, apply a low current "jump" of less than 1 amp of 12V~15V to the main terminals for no more than 5 minutes. Disconnect the power supply and test the voltage at the terminals. If it is reading a steady voltage greater than 12.2v you may connect your lithium appropriate battery charger and recharge the battery fully. 
• A "jump" from one 12V battery to the Shorai battery for no more than 30 seconds (best to use another motorcycle battery rather than a car battery). Disconnect the jump battery and test the voltage at the terminals, if it is reading a steady voltage greater than 12.2v you may connect your lithium appropriate battery charger and recharge the battery fully. 
• Use an old 12v "dumb" charger. If charger output is more than 2A only, use it to unlock the BMS, (until measured voltage is above 12.2v) then shift to an appropriate charger for LiFePO4 Lithium.
• Use a charger with a BMS recovery function such as the Optimate Lithium 4S TM-471.

Please Note! Whenever possible after unlocking the BMS, allow 24hrs for the battery to rest.

If you are unable to unlock your battery and peform a full charge after attempting the above processes, please contact us directly or complete the warranty claim form.

If you ride twice a month or more, there is usually no need to ever charge for most motorcycles. If you have a vintage or off-road vehicle which has NO draw on the battery when the key is OFF, then you should only need to recharge your Shorai™ battery every few months.  However, most modern street bikes have a drain on the battery even when key the is off to support a clock, computer, alarms, or other devices.  This draw will eventually drain the battery, which is damaging to the battery and could void your warranty so we recommend a routine charging schedule to top off the battery when not riding. 

If you are NOT riding for an extended time (seasonal storage), we suggest setting up a "manual storage" routine as outlined in our Battery Charging page under the Long Term Storage section.
 

 

If after charging your Shorai battery you notice that the voltage has dropped, do not be alarmed. This is a normal condition of Lithium Iron Phosphate (LiFePO4) batteries. 

When a Lithium Iron Phospate (LiFePO4) battery is charged (using the correct LiFePO4 charger), as soon as the charge cycle completes, the voltage measured at the terminals will read ~14.4v (7.2v for a 6v battery). Within a few minutes (around 10) the battery voltage will settle to a "resting state" voltage of ~13.4v (6.6v for a 6v battery).  The voltage between 13.4v and 14.4v is less than 5% of the overall capacity of the battery. 

The discharge curve of Lithium Iron Phosphate batteries is very flat. This means that the majority of the capacity, and power of the battery is all within ~13.1v and ~13.4v. That flat discharge curve is why Shorai and many other powersports battery brands use LiFePO4 cells, there is very little difference in that great cranking power and speed that you get when the battery is fully charged versus when it is down to 30% capacity remaining. See the two images below of the discharge curve and a handy voltage to percentage of charge chart. 

If after charging your battery and you measure the voltage but it is dropping further than to its normal resting state voltage of ~13.4v, you may have an issue with a cell. 

When a LiFePO4 battery has an issue with a cell, the bad cell will not be able to retain voltage or capacity. You will see this by the overall voltage of the battery dropping significantly. Shorai batteries without a BMS can have very low voltage (~9v) if one cell has failed. 

On the other hand, if your Shorai battery has a BMS and a cell has developed a problem, the BMS will disconnect (lock) the terminals and you will read 0.0v (or very low voltage). If you attempt to unlock the BMS and recharge the battery but the voltage continues to drop or the BMS locks again after 24 hours please contact us by completing the warranty request form. 

Please note that we quality check all batteries prior to shipping to our customers or to dealers. It is rare for a cell to develop an issue. However, repeated overdischarging, storing in an overdischarged state, over current charging (exceeding the suggested charge rate shown on label of the battery), over charging (above 14.4v for a 12v battery or above 7.2v for a 6v battery), and other scenarios, can have adverse effects on the health of a lithium cell. In addition, use of an incorrect charger as defined in the battery charging page can also cause issues.

NEVER charge your Shorai battery from an overdischarge state using a high current charger or a jump box. Use of a high current charger or jump box on a deeply discharged Shorai battery will void the warranty and potentially cause fire. 

Shorai Batteries produced since mid 2022 are equipped with the Shorai Sentry BMS System.  

So how do you know if YOUR Shorai battery has a BMS?

• If the model number of your battery starts with LFM - your battery is equipped with a BMS.
• If there is a Red dot on the bottom right corner of the main label on the front of the battery - your battery is equipped with a BMS.
• If there is a Green, Black, or Orange dot on the bottom right corner of the main label - your battery does NOT have a BMS.

So what if there is NO dot on the front label and your battery is NOT an LFM model? If your battery doesn't have a dot on the front label and it is an LFX model, you can still determine if it has a BMS or not but you will need our assistance. You may use the Contact Us link to send us an email. Please include the model number of your Shorai battery. You will also need to include a photo of the bottom of your battery. Be sure that the photo is clear and zoomed in (or cropped) enough to be able to clearly read the two white labels on the bottom of your battery.