When pushing a high C (real C Rating) LiPo to its limits, the RC ESC connector can quietly limit your setup’s true potential. I ran back-to-back tests comparing EC5 connectors against AS150 connectors to see how much connector resistance, heat buildup, and efficiency differ under load.
Both setups used identical 5200 mAh LiPo packs, and internal resistance was measured at about 1.43 mΩ per cell—meaning the connectors didn’t affect balance tap readings. However, once current started flowing under heavy discharge, the results shifted noticeably.
Heat and Efficiency Differences Under Load
During full-throttle testing, EC5 connectors reached 67–72°C, while the AS150 connectors stayed significantly cooler. In tests after the video was recorded, temperatures on the connectors were measuring more than 90°C! That difference in temperature directly affected the system’s performance. The cooler AS150 connectors allowed the battery to maintain higher voltage during discharge, leading to increased power output and improved overall efficiency.
While the peak current difference was modest, the real benefit came from reduced thermal stress. Lower connector temperatures help maintain efficiency, reduce power loss, and extend the life of both the battery and ESC.
EC5 vs AS150 Performance Comparison
| Metric | EC5 Connector | AS150 Connector |
|---|---|---|
| Average Cell Resistance | 1.43 mΩ | 1.43 mΩ |
| Connector Temperature (°C) | >90°C | <50°C |
| Voltage Stability Under Load | Moderate sag | Improved performance |
| Energy per Cell (Wh) | Slightly lower | Slightly higher |
| Efficiency | Poor | Good |
| Notes | Heat travels through wire to LiPo | Easily makes series connection |
| Connector Size / Ease of Use | Compact, tighter fit | Larger, independent fit |
Final Thoughts
When pushing high-C LiPo packs to their limits, even small resistance points can make a big difference. The test results showed that the AS150 connectors not only reduced temperature buildup but also improved overall efficiency compared to EC5s.
For speed runs, use a low-resistance connector like the AS150 or better to keep temperatures down and maintain peak performance. If top speed isn’t a priority, a setup that stays less than 60°C is sufficient for safe, reliable operation.
If you’d like full access to the raw data and comparison sheets from my battery tests, consider joining my Patreon community. Tier 1 members get access to the same RC LiPo calculator used in these reviews.