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Battery Charging


Many common Tech and Usage questions are already answered within our site. Please see the FAQ,Specifications and Install Guides before submitting tech questions via our online contact form!

Click here to email Shorai staff for comments or technical questions after visiting the FAQ / Specs links above.


Battery Charging

Before installing your new LFX battery it is important to fully charge the battery.  As delivered the battery is capacity is less than 100%.   Properly charging the battery 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 for estimates on the charging times.  Most Shorai LFX battery models will fully charge in 1-2 hours from 30% SOC when using a typical charger with a 2A rate.  For larger batteries like the LFX36 and using a low output trickle charger with 0.75A rate, may require up to 12 hours to fully charge.


If using a lead acid style charger, do NOT use if it has an automatic "desulfation mode", "repair", "recondition", or "recovery" mode, which cannot be turned off.  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.  IMPORTANT- if the LFX battery is deeply discharged below 12.86V only a lithium charger with cell balancing can be used to recover the battery.  The Shorai BMS01 charger or the Hyperion EOS 720 chargers are the suggested balance type chargers.


When a Shorai LFX battery is fully charged it will measure a peak voltage of ~14.4V.   Floating the LFX battery voltage at 14.6-14.8V for 24 hours can help to improve capacity and slow the self-discharge rate.   If the batteries self-discharge rate is bench tested for 24hour out of the vehicle and the battery voltage drops below 13.3V, the battery may need additional cell balancing and charge time.


If the battery is left on a shelf for several months it is normal to see the voltage drop to the nominal voltage of 13.2V.  If the battery is fully charged to 14.4V and placed on the shelf it can sit for up to 1 year before charging is required.


It is important to note that battery voltage will drop more quickly when connected to a vehicle due to the electrical systems parasitic draw.   Most vehicles draw less than 2mA with the key off, but some discharge the battery with up to 350mA.   For batteries that are left in bikes that will sit for long periods between rides, it is important to charge the battery if the resting voltage drops to 13.1V.   The general rule of thumb is to charge the bike if it sits for more than 1 month.   Some vehicles with high key off draw will discharge the battery to 13.1V in only a few days while other bikes with low key off draw can sit for several months before needing to charge.


Battery Charge Times

    Charger Current Rate (Amps)
    0.75 2 4 6
Item   Starting State of Charge Starting State of Charge Starting State of Charge Starting State of Charge
    30% SOC 30% SOC 30% SOC 30% SOC
Battery Model Capacity (Ah) Charge time (hours) Charge time (hours) Charge time (hours) Charge time (hours)
LFX07L2-BS12 2 1.9 0.7 0.4 0.2
LFX09A2-BS12 3 2.8 1.1 0.5 0.4
LFX09L2-BS12 3 2.8 1.1 0.5 0.4
LFX12A1-BS12 3.5 3.3 1.2 0.6 0.4
LFX14A1-BS12 4.5 4.2 1.6 0.8 0.5
LFX14A2-BS12 4 3.7 1.4 0.7 0.5
LFX14A4-BS12 4.5 4.2 1.6 0.8 0.5
LFX14A5-BS12 4.5 4.2 1.6 0.8 0.5
LFX14L2-BS12 4 3.7 1.4 0.7 0.5
LFX14L5-BS12 4.5 4.2 1.6 0.8 0.5
LFX18A1-BS12 6 5.6 2.1 1.1 0.7
LFX18A2-BS06 6 5.6 2.1 1.1 0.7
LFX18L1-BS12 6 5.6 2.1 1.1 0.7
LFX18L2-BS06 6 5.6 2.1 1.1 0.7
LFX19A4-BS12 6.4 6.0 2.2 1.1 0.7
LFX21A6-BS12 7 6.5 2.5 1.2 0.8
LFX21L6-BS12 7 6.5 2.5 1.2 0.8
LFX24A3-BS12 8 7.5 2.8 1.4 0.9
LFX24L3-BS12 8 7.5 2.8 1.4 0.9
LFX27A3-BS12 9 8.4 3.2 1.6 1.1
LFX27L3-BS12 9 8.4 3.2 1.6 1.1
LFX36A3-BS12 12 11.2 4.2 2.1 1.4
LFX36L3-BS12 12 11.2 4.2 2.1 1.4
Note- the actual charge times will vary depending on the chargers duty cycle, and will be longer if the RMS current is less than the calculated value.