Kelly Controller Battery & Smart BMS Selection Guide
Kelly Controller Battery Sizing Guide
Set Max Battery Current below your BMS continuous rating, not equal to it. In this guide 84V means the full charge voltage of a 72V nominal pack, not a separate pack voltage.
Quick answer: Tell us your Kelly model and its max voltage label first. Set Max Battery Current so the product stays below BMS continuous, with headroom. 84V here is 72V nominal pack full charge.
Kelly Controller Model vs. Battery BMS Specification Matrix
Kelly KLS7218S
- Target Applications1000W-2000W DIY / E-Bikes
- Max Controller DC Draw80A DC
- Required BMS Rating80A - 100A Continuous
- Recommended CellSamsung 50G / 50S
- Main ConnectorXT90-S Anti-Spark, QS8 For 100A Class
Kelly KLS7230N / 7230S
- Target Applications3000W Hubs / E-Karts
- Max Controller DC Draw120A DC
- Required BMS Rating120A - 150A Continuous
- Recommended CellSamsung 50S, High Power
- Main ConnectorQS8 Anti-Spark
Kelly KLS7245N / KLS72701
- Target ApplicationsQS205 V3 / Custom Motos
- Max Controller DC Draw180A DC
- Required BMS Rating180A - 200A Continuous
- Recommended CellSamsung 50S Extreme
- Main ConnectorQS8 / QS10 Anti-Spark
Kelly KLS8080H / KLS8080I
- Target Applications20kW+ Extreme E-Motos
- Max Controller DC Draw250A DC Limit
- Required BMS Rating250A Continuous, Set Below 250A
- Recommended CellSamsung 50S Extreme
- Main ConnectorQS10 / Heavy Copper Lugs
Recommended Battery Configurations for Kelly Setups
72V 30Ah / 35Ah, 120A-150A BMS
Samsung 50G or 50S cells. For Kelly KLS7218S at 80A DC and KLS7230N at 120A DC, set Max Battery Current below BMS. 7230N needs 150A class for headroom, not 120A exactly. Check tray dimensions first.
72V 40Ah / 50Ah, 180A-200A BMS
Samsung 50S cells. For Kelly KLS7245N and KLS72701 controllers. Less sag than smaller Ah at the same current. Set Max Battery Current below BMS, check P count for 40Ah tier.
72V Nominal, 84V Full, 250A BMS
Steel armor casing with 250A Smart Bluetooth BMS. 72V nominal pack, 84V full charge, for Kelly KLS8080H / KLS8080I extreme race applications. Set Max Battery Current below 250A.
Kelly Software Settings: Max Battery Current %
Set battery current first, motor current is phase current, not battery current.
- Max Battery Current %: Set this percentage so that controller current times battery current % stays below your BMS continuous rating, with headroom, not equal to it.
- Max Motor Current %: Controls phase current and low-speed torque. Battery current % is the limit that protects the BMS, set battery % first.
- Low Voltage Cutoff (LVP): Set LVP to 60.0V for 72V 20S packs. This matches BOOANT 72V cutoff at 60.0V, do not set LVP below BMS cutoff.
Regen Braking & Anti-Spark Plug Standards
Regen must stay below BMS charge limit, not discharge limit. Check BMS charge spec first.
- Regen Current %: Limit regen in Kelly software to 20 percent to 30 percent as a starting point, and check that the resulting regen current stays below BMS charge limit on a full pack.
- Anti-Spark Plug: QS8 up to 180A class, QS10 or copper lugs for 250A class. QS8 alone is not enough for 250A. High capacitor capacitance causes severe arcing without pre-charge protection.
- Smart App Telemetry: Check cell voltages and BMS MOSFET temperatures in real time.
Frequently Asked Questions
Q: Why does my Kelly controller show a flashing Red Error Light during hard acceleration?
A: Usually LVP trip from voltage sag, or over-current trip when BMS cuts power. Check sag, check Max Battery Current % setting, and check that the product stays below BMS continuous.
Q: How do I set the Max Battery Current % in the Kelly Configuration Tool?
A: Divide BMS continuous rating by controller peak DC rating, then set below that result. For example, 150A BMS with a 200A controller gives 75 percent exactly, so set below 75 percent, for example 70 percent, for headroom. Do not run at BMS limit continuously.
Q: Can I use an 84V pack with a Kelly KLS7230N controller?
A: Yes, if 84V means the full charge voltage of a 72V nominal 20S pack, and your KLS72 HVP label is above 84V, check your exact model label first. 84V here is not a separate pack voltage, and there is no 24S pack in this guide. Do not use a pack whose full charge exceeds controller HVP.
