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Battery Charging & Maintenance

Here you will find basic information about charging and maintaining your new Shorai Lithium battery. Please take a moment to read the information below, this guide provides essential troubleshooting & safety information to ensure optimal performance and longevity of your battery.

Compatible Chargers

The use of a compatible charger can go a long way towards optimal performance and longevity of your Shorai battery. There are some definite "DOs" & "DON'Ts" when it comes to chargers, and we will try to help point you in the right direction.

• DO's
• If you currently own a Shorai BMS01 charger you may continue to use it. They are great chargers and work with both LFX and LFM models.
• Whenever possible, use a lithium-iron-phosphate (LiFePO4) charger to charge your battery. There are several options available, we like the Optimate Lithium chargers, they have a "unlock" function for the BMS.
• Lead-acid chargers are acceptable if they DO NOT have a "desulfation" (or similar) mode.
• Most "tender" style chargers are now available in "lithium" versions, they work well and do not have a desulfation mode.
• DONT’s
• Do not use any charger that has a "desulfation", "repair", "recondition", or "recover" mode that cannot be turned off. These modes are specifically for lead-acid batteries and will damage a lithium battery by spiking the voltage too high. 
• Do not use any LiPo (Lithium Polymer) or Li-Ion chemistry chargers as they will overcharge the battery and cause potential fire. 
• If you are unsure if your current charger is acceptable for use with a Shorai battery, contact us, we will be happy to help!
  

Non-Shorai Chargers

If using a lead acid style charger, DO NOT use it if it has an automatic "desulfation mode", "repair", "recondition", or "recovery" mode, which cannot be turned off. (nearly ALL Schumacher Lead-Acid chargers have these modes that cannot be turned off; therefore, we do not recommend the use of ANY Schumacher chargers. If you are unsure about your charger, please contact us.)  Lead acid charger/tenders can be used for regular maintenance charging and then be disconnected after the battery is fully charged.  DO NOT leave the lead acid charger connected to store the battery, because most will NOT maintain the proper voltage for lithium batteries.

 Charge Before Installation

 Shorai batteries are shipped at a low state of charge (SOC) due to shipping regulations. Properly charging before use will condition and break in the cells in a controlled manner to maximize performance and extend the batteries lifespan.   See the charge time reference sheet (at the bottom of this page) for estimates on the charging times.  Most Shorai battery models will fully charge in several hours from 30% SOC when using a typical charger.  For larger batteries like the 36 series or using a low output trickle charger may require 12 hours or more to fully charge. If your battery finished charging before the suggested time, don’t be alarmed, as dealers will occasionally perform maintenance for Shorai batteries and may pre-charge them to a certain level before shipping to the customer.

Before installation:

• Charge the battery for at least 6 Amp Hours (e.g., 6 hours with a 1A charger, 12 hours with a 0.5A charger).
• Ensure the battery is fully charged to maximize performance. 
  

 Battery Voltage & Charging

LiFePO4 batteries (like Shorai) have a unique discharge curve. They are virtually flat throughout 60% of the usable capacity of the battery. The voltage drop from 90% SOC to 30% SOC is less than 0.4v! What this means to you is that how quickly and easily your vehicle cranks at full charge will be the same when it is at 50% charge.

This leads us to a point to mention: When a LiFePO4 battery comes straight off the charger it will read ~14.4v. Within a few minutes the voltage will drop to ~13.4v. This voltage is known as its "resting voltage" and is perfectly normal. If you see the voltage at ~13.4v after you have charged your battery, don't worry, it is fully charged. (Please see the image at right)

BMS

Since May 2022, Shorai batteries feature an advanced internal Battery Management System (BMS) designed to protect against over-discharge. If the battery’s voltage drops too low (e.g., when the vehicle key is left on, or high parasitic draw), the BMS disconnects the main terminals to prevent damage. This is a protective measure, not a fault.

In this state:

• The battery may read zero volts (or near) at the main terminals, this is normal behavior when the BMS is "locked". 
• Charging with a "smart" battery charger may not work, as the charger will see zero volts and refuse to start.

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 at that time your battery is once again locked or you are reading very low voltage at the terminals, please contact us.
If you are unable to unlock your battery and perform a full charge after attempting the above processes, please contact us directly or complete the warranty claim form here -> Warranty Claim
Do not use Shorai BMS01 Charger STORE MODE for these new Shorai batteries with internal BMS.  The battery fully protects against overdischarge itself, and the Shorai internal BMS may conflict with the charger store mode.

Long Term Storage

If you need to store your vehicle for extended periods, it is best to "manually" store your battery. Because modern Shorai batteries include a BMS, there is no longer a need to leave the battery connected to a charger/tender indefinitely. If you have a vintage or off-road vehicle which has NO draw on the battery when 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 is off to support clock, computer, alarms, or other devices.  This draw will eventually drain the battery, which is damaging to the battery and could void your warranty.

To manually store your battery:

• Fully charge your battery at the beginning of the storage period.
• Every 3-6 weeks (depending upon an parasitic draw on the battery), measure the voltage at the terminals and compare to the chart above. 
• If the measured voltage is getting down to around 13.1v (40%) or less, recharge your battery and let it sit until it is time to measure again.
• You can expect longer storage if your battery is disconnected from the vehicle. You will still use the same process to manually store it, just a longer interim between charges. 

Some key points to remember about Storing your battery:

• Different bikes will have different parasitic draw rates on the battery. If your bike has an alarm system, it may have a higher "key off" draw on the battery. Some older bikes may have very little parasitic draw on the battery while some newer bikes may have significant key off draw.
• We can measure this draw using a multimeter and know approximately what the parastic draw is. Follow this link to learn how to check the key off draw on your battery -> Testing Parasitic Draw
• Storing in a cool, dry environment is always best.  Temperatures between 34F/1C and 90F/32C are acceptable, preferring towards cooler if possible. If you remove the battery from your bike, storing in a refrigerator is great!
• It is best to not leave the charger/tender connected to the battery indefinitely.
• If possible, disconnect the battery from the vehicle.

If you still have questions or require assitance, click here to email Shorai staff for comments or technical questions.

Battery Charge Times