SAMSUNG 45T vs. 40T: Power, Performance & Range Compared

2 days ago
3 min read

Which Cell Builds a Better High-Current eBike Battery?

When choosing a premium eBike battery, the cell you select matters just as much as the voltage, amp-hours, or BMS. Samsung’s high-performance 21700 line is widely used in performance e-mobility systems because of its reliability, thermal stability, and strong current output.

Two of the most popular options—especially for mid-to-high-power eBike builds—are the Samsung 45T and Samsung 40T.

Both are excellent. Both are proven. But they’re very different in how they deliver power, handle heat, and affect ride performance.

Here’s a grounded breakdown based on manufacturer specifications and known independent test behavior.

1. Cell Overview: 45T vs. 40T

Samsung 45T (INR21700-45T)

Capacity: ~4500 mAhContinuous Discharge: ~35A (up to ~45–50A with

temperature cut-off)

Voltage: 3.6V nominal

Profile: High-current performance with strong energy density and excellent thermal reliability

Samsung 40T (INR21700-40T)

Capacity: ~4000 mAhContinuous Discharge: ~30A

Voltage: 3.6V nominal

Profile: Earlier-generation high-drain cell known for stability, reliability, and predictable sag under heavy load

2. Spec Comparison Chart

FEATURE	Samsung 45T	Samsung 40T
Capacity (mAh)	~4500	~4000
Continuous Discharge	~35A	~30A
Max Rated Discharge	Up to ~50A (with temp cut)	~35A (with cooling)
Voltage Sag Under Load	Lower sag	Moderate sag
Heat Management	Excellent	Good but older chemistry
Ideal Use	Modern mid/high-power systems	Mid-power, general performance

3. Real-World Performance Differences

⚡ The 45T Delivers Stronger Acceleration and Torque

With higher allowable current and lower voltage sag, packs built with 45T cells deliver:

Faster throttle response
Stronger mid-range torque
Better climbing power
Higher sustained output for performance motors

In a 14S2P or 14S3P build, the difference is noticeable—especially on systems demanding 40A+.

🔋 The 45T Also Offers More Range

Even though the 45T is a “power cell,” it still packs 500 mAh more capacity than the 40T.

That’s:

~12–15% more watt-hours per cell
Better runtime on mid-power rides
The ability to build the same pack size with more usable energy

🌡️ Thermal Performance: Where the 45T Really Wins

The 45T handles heat better at high current.

It runs cooler under the same load
It maintains voltage better as temperature increases
It recovers faster after high-current bursts

The 40T is still a safe, stable cell—but it was designed several years prior and does not manage heat as efficiently.

4. When a Samsung 40T Pack Still Makes Sense

Even though the 45T is the better performance cell, the 40T is still a good match when:

You’re building a mid-power pack that draws under 30A
You want a stable, predictable cell at a slightly lower price
You’re designing for long cycle life at moderate discharge
Your customer rides at light/normal loads, not max output

The 40T remains one of the best budget-friendly 21700 cells for “everyday high-power” riding.

Conclusion

The Samsung 45T is the clear upgrade for riders who want maximum power, better heat handling, and improved range. Its modern chemistry delivers noticeably stronger acceleration and better sustained output for high-performance eBike systems.

The Samsung 40T still has its place—affordable, stable, reliable, and excellent for mid-power setups.

But if your build demands serious current, or your customers expect the best torque and throttle feel in the 21700 class, the Samsung 45T wins the matchup.