Our technicians at Battle Born Batteries have recently spoken with many customers who are seeing heat build-up at their fuse and fuse holder. If you’re noticing the same thing, it’s worth addressing, because fuses and fuse holders aren’t just “accessories.” They’re critical safety components that help protect both your system and your battery investment.
Below, we’ll explain what a fuse does, what fuse ratings actually mean, why some holders run hot in mobile power setups, and how to install everything correctly.
What Is a Fuse?
A fuse is an electrical safety device built around a conductive strip that’s designed to melt and separate if current becomes excessive.
Fuses are installed in series with the component(s) you want to protect. When a fuse blows (opens), it opens the entire circuit, stopping current flow through the protected components.
Because customer safety is our top priority, we recommend using high-quality fuses and fuse holders. Unfortunately, there are many cheap fuse holders out there that do not meet the ratings they claim.
High-quality fuses help keep you safe, and they also help protect your Battle Born Batteries. Batteries are an investment, and a properly chosen fuse is a cost-effective way to help protect that investment in the event of an overcurrent situation.
Why Some ANL Fuse Holders Overheat in Mobile Power Systems
Some customers have contacted us about fuse heat build-up, and these issues have been directly connected to lower-cost ANL fuses and fuse holders, often purchased through online retailers like Amazon.
These budget fuse holders commonly use:
A clear plastic base without plastics designed for heat
Very minimal metal, which limits their ability to act as a heat sink
While that style of holder may work well for car audio systems (because car audio equipment is not continuous current), it can run too hot in mobile power systems where sustained high-current loads are common.
In fact, some customers have used a heat gun and recorded 175°F to 200°F at the fuse and holder in their mobile power systems and have even seen melting!
Trying to save money on supporting components can sound great initially, but buying the wrong—or inefficient—fuse hardware can create a potential hazard in a lithium battery system.
The Better Option: High-Quality Fuses and Fuse Holders
When it comes to fuses, it’s worth investing in a higher-quality product.
We sell three fuse kits in our shop:
300 A Fuse Kit
400 A Fuse Kit
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500 A Fuse Kit
All three kits are $35.
These fuses cost more upfront than a traditional glass fuse because they’re ceramic and contain a significant amount of metal. Ceramic fuses are also more reliable and durable during high-current events because they contain sand, which helps extinguish arcs when the fuse blows.
Why fuse holder quality matters
Our recommended fuse holders contain a high amount of metal built into the base and special thermoplastics that will not melt, which act as a heat sink. That helps maintain a more consistent operating temperature at the fuse and cable under heavy loads.
Using a higher-quality fuse holder kept one customer’s temperature under 95°F while running an 1800-watt load for an extended period. This is a normal amount of heat.
Installation Matters: Assembly and Torque Are Not Optional
Even the best fuse and fuse holder can run hot (or fail to protect properly) if it’s assembled incorrectly.
Proper assembly of the fuse holder, cables, and fuse is necessary to protect your investment. The final step is making sure all hardware is properly installed and torqued.
Tip: Use the correct washer stack-up and ensure the cable lug and fuse contacts sit flat and secure before tightening.
Directions for Fuse Replacement
Remove cover
Remove nut, spring washer, and flat washer
Replace fuse
Replace (in order) the flat washer, spring washer, and nut
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Fastener torque:
5/16”-18: 144 in/lbs. [16.2 Nm]
3/8”-16: 180 in/lbs. [20.3 Nm]
M10 x 1.5: 180 in/lbs. [20.3 Nm]
Replace protective cover
Don’t Gamble on Cheap Fuses
Battle Born Batteries recommends you run, not walk, away from cheap fuses when top-quality fuses are relatively inexpensive. It’s a small price to pay to help protect your investment in Battle Born Batteries—and to keep everyone safe around your electrical system.
Also, Battle Born partner Nate Yarbrough from Explorist.life is a master at fuse installation. There are many blogs and diagrams like the one above on his website. For more in-depth reading, check out Nate’s blog called “What size fuses to use for a DIY camper electrical setup." He also has a very helpful fuse size calculator.
For questions on fuse sizing, install or other technical questions, please call Battle Born Batteries at (855)-292-2831 or email us at info@battlebornbatteries.com to speak with one of our sales technicians.
