One extra minute during installation to prevent a catastrophic battery failure

After 5 years in operation, we've seen all kinds of wild installation mistakes — but the most common issue by far involves the M5 terminal nuts.

Too often, the nuts are either left loose or worse, the plastic wire harness gets accidentally sandwiched between the copper busbar and terminal. These mistakes can lead to poor contact, overheating, or even thermal runaway. Unfortunately, some frustrated customers assume the product is defective and take their frustration to social media — sometimes with dramatic (and misleading) photos.

In this newsletter, we want to emphasize one simple idea:

Take one extra minute during installation. That minute can save your battery — and help protect small businesses like ours from unnecessary backlash.

Here’s what we recommend:

1. Make sure the copper busbar is fully seated and in direct contact with the terminal, no harness is caught in between.

2. Use a torque wrench to tighten the nuts to 3 ft-lbs for a secure, reliable connection.

We’ve included some real-life photos below showing what can go wrong when these steps are skipped. It’s a small detail that makes a big difference.

From our experience, some Prius ECUs with the proper software updates can detect this issue. However, others fail to recognize the voltage spikes entirely — offering no warning until the battery pack overheats and, in some cases, begins to smoke.

To prevent this, we’ve fully transitioned to the more robust Sodium-ion battery, which significantly reduces the risk of thermal events. That said, improper installation can still pose a safety risk to the vehicle and accelerate cell degradation, ultimately impacting product reliability and our company’s reputation.

We hope this message raises awareness of this common issue — and serves as a reminder of the importance of spending that one extra minute during installation. Thanks for reading, and thank you for helping us keep things safe and reliable — one install at a time.