Winter-ready Power
built For the Cold
NOW AVAILABLE >>> AMPACE JP50 SUPER POWER!
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Minimal capacity loss at sub-zero temps
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Ultra-power cell formula, No voltage sag
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Pure copper busbars, Least resistance
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Proven deep cold performance data
COMPARE CELLS
NEW ADDITION: Ampace JP50 - compared to the Reliance RS50 and Molicel P50B. More information to come, contact us today!
#1 KING OF COLD WEATHER POWER
Molicel P45B
Exceptional cold-weather cell; maintains strong usable capacity at deep-cold temps; very low voltage sag.
#2 HIGH ENERGY PERFORMER
Molicel P50B
High energy + high power with cold-optimized electrolyte; excellent voltage stability as temps drop.
#3 ALL WEATHER HIGH POWER
RELIANCE RS50
Powerful all-weather performer; designed for stable output in colder regions; high current capability.
#4 LOW-IR, HIGH POWER, MID-WINTER
AMPACE JP40
Extremely low internal resistance (tabless design); performs well under load in cool/cold conditions.
#5 IMPROVED COLD TEMP OPTIMIZED
AMPACE JP50
Higher-output design with improved voltage stability over typical high-power cells. Performs better in the cold than many legacy 50A-class cells. Still slightly more sensitive to extreme cold than P45B / RS50. Best for: Riders who want more power while retaining winter usability.
OVERALL RATINGS
Explore
BUILT FOR THE COLD. BECAUSE WINTER SHOULDN'T SLOW YOU DOWN.
CHARGE SAFELY
AVOID THE DANGERS OF CHARGING A COLD eBIKE LI-ION BATTERY & FOLLOW OUR GUIDE TO WINTER BIKE MAINTENANCE.
Molicel P45B
Evidence-Based Advantages
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Verified reseller data: >3.51 Ah delivered at –30°C (≈78% of rated capacity).
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Documented low impedance and extremely low voltage sag under cold loads.
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Independent testers consistently praise Molicel for “designed-for-cold” engineering (SEI stability + electrolyte formulation).
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Known for exceptional thermal performance, minimizing IR spike in cold conditions.
Bottom Line:
The only 21700 cell with public, quantified deep-cold performance data. Unmatched for below-freezing riding.
Molicel P50B
Evidence-Based Advantages
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Molicel’s official materials highlight a low-temperature electrolyte blend.
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Published performance data: 238 W output at –10°C with stable voltage.
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DCIR ~12.8 mΩ.
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About:Energy testing indicates better thermal stability than P45B at heavy loads in normal temps.
Bottom Line:
Nearly tied with P45B, but lacking a public “Ah @ –30°C” datapoint. Still an elite winter cell with more Wh.
Reliance Rs50
Evidence-Based Advantages
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Manufacturer literature + industry channels cite –40°C discharge capability.
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Community testing: “Designed to have less performance drop in cold regions” (Reddit battery builders).
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70 A high-current rating with excellent runtime-to-weight ratio.
Limitations
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Mooch’s early commentary: Molicel still superior for cold-weather and cycle life.
Bottom Line:
Fantastic all-weather choice, and likely strong in cold—but with less independently verified sub-zero data than Molicel.
Ampace JP40
Evidence-Based Advantages
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Datasheet discharge rating: –20°C to 60°C.
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Tabless design → extremely low DCIR (~5.4 mΩ), which mechanically helps cold-weather performance (less sag).
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Strong high-load runtime (beats P50B by a few percent at 25°C in some tests).
Limitations
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No public cold-temperature discharge curves.
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High performance proven at 25°C, not at –10°C or below.
Bottom Line:
A very strong all-weather power cell, but least validated for deep-winter usage. Great for cold-ish weather, not proven for Arctic-level conditions.