USA-Made Lithium Battery Review – SFK 300 Amp Hours

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In this part one video, my first look and a quick test of an interesting 12V 300Ah lithium battery from a company called SFK (SunFunKits). Don’t let the funny name fool you. This is a sweet looking, well-put-together battery made in the USA. It has more features than I’ve ever encountered in all my battery reviews.

I’m sure any DIY geek will love this battery, but it’s also easy to use for anyone. Both the user manual and app are top-notch, very informative. Stay tuned for more videos coming in the future as I use and test out this cool new battery.

(Part 1 – Introduction)  SFK 300Ah Battery Review

FEATURES

  • 4.0 kilowatt hours of reliable lithium power, replaces up to 6 lead acid / agm batteries (100ah) and is designed to be discharged to 100% of available capacity without harm to the battery.
  • Up to 2.4 kilowatts of peak power, and 1500 watts of continuous power.
  • GEN 2 I/O Switch allows bluetooth to be turned on/off, full active balancer control, and a simplified heating control system.
  • Expected cycle life of 2000-3000 cycles at 80% DOD, and up to 5000 cycles at 50% DOD, 10-15 year usage life.
  • Fully compatible with existing 12v infrastructure including standard 12v lead acid/agm battery chargers, trickle chargers and high voltage DC systems up to 48v (when linked in series with 4 batteries).
  • Built-in cell heaters to allow for low temperature charging, temperature to activate heaters can be set inside the app.
  • Smart phone/device compatible with Bluetooth monitoring/configurable app. Available for IOS/Android.
  • Can be linked in series up to 48v (4 batteries in series) as well as up to 4 in parallel with a combined output of 3.0 KW continuous.
  • Automatic low/high temperature and low/high voltage cut-off to stop battery damage from occurring.
  • Automatic short circuit prevention as well as over charge and over discharge prevention.

Pt. 2 – App Features & Capacity Benchmark Test

In part two of my SFK 300Ah lithium battery review, we look at its companion app in-depth. The battery app is so full-featured that it demands its own video. One of the coolest features is built-in cell capacity benchmarking. So, I gave that a test with a 600-watt space heater load. Then, I uploaded the results to the SFK website so they could be viewed.

Part 3 Teardown – SFK 300Ah Review

In part three of my review, I disassemble the HP-SFK300 battery and give you a close-up look at the build quality, BMS board (Battery Management System), Heating Pads, and Prismatic Lithium (LiFePO4) cells. The cells turn out to be EVE Model LF304-V2. Overall, I’m happy with the construction, attention to detail,  ease of disassembly, and case design. It’s an extremely DIY-friendly battery.

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Longer Term Review Update

Self-Heating  Low Temperature Test

With overnight lows in the low 20s Fahrenheit, I tested the low-temperature charging feature in an SFK (SunFunKits) battery I have been reviewing. The model HP-SFK300 battery includes a self-heating feature using thin silicone heating pads sandwiched between the lithium cells. Self-heating can be turned on manually via a button on top or automatically when a charge voltage is applied.

The SFK app includes a setting to adjust the self-heating temperature cut-off point. In my test, the battery self-heating function performed flawlessly. It took about 13 minutes to reach a temperature above freezing, allowing charging to begin.

Firmware Update – New Features!

In this video, I update the firmware on my SFK-300HP lithium battery using a Windows laptop. The new firmware introduces additional features to the SFK app, including control over self-heating functionality and high/low state of charger percentage settings. The firmware can also be upgraded via most Android phones and tablets. See this video.

Final Review Update – Good & Bad News to Report

In this video, a final update on the SFK battery I’ve used since early 2024. Overall, this battery has performed well, and I’m happy with it. However, I have had a very negative report about the company from a fellow RVer. I thought it was worth sharing. At the end of the video, I perform another benchmark capacity test to compare with my original test taken in Feb 2024.

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