EcoWorthy Cubix Pro: Cold & Hot Charging Fixes Tested

I recently revisited the EcoWorthy Cubix 100 Pro battery to test out a crucial firmware update. The big takeaway? EcoWorthy listened to feedback and delivered a fix that makes this battery significantly more reliable, especially in extreme temperatures.

What I Built

My setup for testing the EcoWorthy Cubix 100 Pro was straightforward but effective. I connected the 51.2V, 100Ah battery to my EG4 12000XP inverter/charger, which I configured to push 100 amps for charging. To accurately monitor the current and temperature, I used a Victron SmartShunt and the EcoWorthy Bluetooth app.

The initial concern, highlighted by fellow tester Will Prowse, was that the previous firmware caused the battery to repeatedly connect and disconnect when attempting to charge at 100A in sub-freezing temperatures (around 13°F or -10°C). This was problematic because the battery is advertised to charge down to -4°F. EcoWorthy took this feedback seriously, and I was eager to see if their firmware update (version 14.7.2) had resolved the issue. For my tests, I used a can of coolant spray to drastically lower the temperature of the internal sensors and a heat gun to raise them, allowing me to observe the battery's thermal protection mechanisms.

Why It Works

The core of the previous cold-weather charging issue was a software oversight, not a hardware limitation. Will Prowse's initial teardown revealed that the Cubix 100 Pro actually contains an inductor, which is a key component for a converter circuit that can regulate current. This meant the hardware was capable of throttling the charge current, but the software wasn't utilizing it correctly when temperatures dropped.

The new firmware addresses this by implementing proper current throttling. Instead of repeatedly disconnecting, the battery's Battery Management System (BMS) now intelligently reduces the charge current when cell temperatures approach freezing. This prevents damage to the LiFePO4 cells, as charging these batteries below 0°C (32°F) at high currents can cause lithium plating, which degrades performance and safety. Furthermore, at extremely low temperatures (below -20°C or -4°F), the battery completely shuts down charging and discharging to prevent any potential damage. This proactive thermal management, coupled with the battery's special low-temperature electrolyte, makes it uniquely capable among many LiFePO4 options.

Parts & Specs

• Battery: EcoWorthy Cubix 100 Pro (51.2V, 100Ah LiFePO4)
• Charger/Inverter: EG4 12000XP
• Monitoring: Victron SmartShunt, EcoWorthy Bluetooth App
• Firmware Version Tested: 14.7.2 (latest)
• Temperature Manipulation: Coolant spray, heat gun

Math & Run-Time Numbers

During my tests, I observed the following key temperature thresholds and current behaviors:

• Initial Charge: The EG4 12000XP consistently pushed around 96-98 amps into the battery when temperatures were normal.
• Cold Charging (Throttling): As I cooled a temperature sensor, the battery's current throttled down to about 9-10 amps once the minimum internal temperature reached 0°C (32°F). This sustained a slow charge.
• Extreme Cold Shutdown: When the temperature dropped below -20°C (-4°F), the battery's BMS triggered a complete shutdown, halting both charging and discharging. The app displayed "Discharge low temperature protection" alarms.
• Cold Recovery: As the temperature naturally rose above -20°C, the battery resumed charging at the throttled 9-10 amps. Once it warmed past 0°C, it returned to its full 96-98 amp charge rate.
• High Temperature Shutdown: Using a heat gun, I raised a sensor's temperature. The battery initiated a complete charging shutdown at approximately 60°C (140°F). The app showed "Charging over temperature protection" alarms.
• High Temperature Recovery: As the temperature cooled, the battery resumed charging at a reduced rate of about 26 amps around 49°C (120°F). It then returned to full 96-98 amp charging once the temperature dropped further to about 44°C (111°F).

These tests confirm the new firmware effectively manages charging and discharging across a wide temperature range.

Pros & Cons

Pros:

• Responsive Manufacturer: EcoWorthy quickly addressed critical feedback and released a firmware fix. This boosts confidence in their commitment to product improvement.
• Effective Thermal Management: The battery now intelligently throttles charge current at low temperatures and completely shuts down at extreme highs/lows, preventing cell damage.
• Unique Cold-Weather Capability: The ability to charge (albeit at a reduced rate) down to -20°C is highly unusual for a non-heated LiFePO4 battery and a significant advantage for cold environments.
• Safety Features: The video briefly mentions dual fire extinguishers on the lid and other safety measures, contributing to overall peace of mind.

Cons:

• Initial Firmware Issues: The original firmware had a critical flaw regarding cold-weather charging, which required a user update.
• Reduced Current in Cold: While it can charge below freezing, it's at a significantly reduced current, which might not meet high-demand charging needs in very cold conditions.

When To Use This vs. Alternatives

The EcoWorthy Cubix 100 Pro, with its updated firmware, is an excellent choice for DIY solar enthusiasts and homeowners looking for robust energy storage, especially in regions that experience cold winters. Its unique ability to charge below freezing (down to -20°C) without external heaters makes it stand out from most standard LiFePO4 batteries on the market. If you have an unheated garage, shed, or off-grid cabin where temperatures might drop below 0°C, this battery offers a significant advantage by continuing to accept a charge when others would simply shut down or require power-hungry heaters.

However, if you require maximum charging current in consistently sub-freezing conditions, or if your environment regularly drops below -20°C, you might still consider a battery with integrated heating or ensure your charging setup can accommodate the reduced current. For most residential and recreational applications in varied climates, though, the Cubix 100 Pro now offers a compelling blend of safety, reliability, and unique cold-weather performance.

Bottom Line

The EcoWorthy Cubix 100 Pro has truly unlocked its potential with the latest firmware update. The manufacturer's responsiveness to feedback and the successful implementation of intelligent thermal management for both cold and hot conditions are commendable. This battery is now a very solid contender for anyone seeking a safe, reliable, and uniquely capable LiFePO4 solution, particularly for environments where temperatures can fluctuate wildly.

Final Wrap-Up

I hope this deep get into the EcoWorthy Cubix 100 Pro's firmware update and performance tests was useful. If you found this information helpful, please consider subscribing to the channel for more hands-on reviews and DIY solar insights. Don't hesitate to ask any questions in the comments below, and check out my gear page for links to everything mentioned in this video!