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.
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.
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.
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
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.
Our recommended fuse holders contain a high amount of metal built into the base and special thermo plastics that will not melt, which acts 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.
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.
Remove cover
Remove nut, spring washer, and flat washer
Replace fuse
Replace (in order) flat washer, spring washer, and nut
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
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 [email protected] to speak with one of our sales technicians.
We know that building or upgrading an electrical system can be overwhelming, so we’re here to help. Our Reno, Nevada-based sales and customer service team is standing by at (855) 292-2831 to take your questions!
Also, join us on Facebook, Instagram, and YouTube to learn more about how lithium battery systems can power your lifestyle, see how others have built their systems, and gain the confidence to get out there and stay out there.
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6 thoughts on “Why Some Fuses and Fuse Holders Get Hot (and How to Prevent It)”
I have two Battleborne 100AH batteries in a new Outdoors RV trailer. My selling dealership modified the trailer wiring to allow installation of the batteries inside the coach. I strongly suspect the system uses the OEM fuses, but I do not know that.
Should I be concerned about the installation?
I don’t know what this OEM installation uses, but my previous trailer used auto reset breakers instead of fuses.
Hi John, thanks for reaching out! They should have properly sized the fuses, but we suggest giving the manufacturer a call to verify the size breakers that they used in their specific rig.
I just purchased 4 battle born 100 AH batteries as part of a system to charge my Tesla model 3 as I live off grid and want a dedicated system. I have four 300 watt solar panels 24 volts fed into a 50 amp MPPT charge controller and will use a 5000 watt inverter outputting 220 volts. Question: what fuse set should I buy? And do I put one each between panels and Mppt, Mppt and batteries, and Batteries and inverter?
Is the 300 amp fuse what I should use.
Hi Steve, thanks for reaching out. It sounds like a great system to have! You can place a 60 amp fuse on the positive side between the solar panel and controller and also between controller and battery bank. If you could please give our technical sales team a call at 855-292-2831 they can answer the inverter part of your question. Thanks again and have a great rest of your morning!
Hey there; I have a SINGLE 100Ah Battle born battery.
What size Fuse should I use on the positive terminal? (Max 1 ft RED 0 Gauge OFC cables all the way) (That handle the loads)? Will a 300A fuse be too large?
Note: I am NOT yet planning a solar setup for this
Here’s my setup:
I use this battery with the following equipment:
1) the output of this battery is in parallel with a supercap to drive 3 stereo amps; one of them being a 1200/1v3 JL Audio ( a 1200W RMS Amp)
2) It is charged with a BCDC1250D RedArch via the car’s alternator
3) Victron BM Blue Tooth shunt
4) I ALSO plan to have to have a separate (land wired) 4.5A Lithium Battery trickle charger
Hi David! For a system with a single 100Ah battery, we wouldn’t recommend using a fuse large than 150A.