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midwest-van-man avatar image
midwest-van-man asked

Are Fuses or Breakers Necessary Between Battery and Lynx Distributor?

In my set-up the 4/0AWG wires that connect the batteries to the [Battery Bank] Lynx Distributor do not feature fuses. There are fuses internal to the Lynx Distributor, but the wires are effectively unprotected until they reach the Lynx Distributor.

Of course, I’ll keep those runs as short as possible (less than two feet long per wire/conductor) but it still seems weird to me to have a wire run unprotected.


Should I have an MRBF, or similar, fuse directly on the battery terminals?

Should I be using a different fuse or circuit breaker to protect the wires between the batteries and the Lynx Distributor, or is the system safe as it's currently designed?


The wiring schematic in the Lynx Smart BMS doesn't show any fuses in that location.

The example schematic on the Victron Support site doesn't show any fuses here (https://www.victronenergy.com/upload/documents/MultiPlus-II-3KW-230VAC-12VDC-600Ah-Li-Lynx-Smart-BMS-&-distributors-Cerbo-GX-touch-generator-MPPT-Orion-Tr-Smarts.pdf).

On the other hand, this post (https://community.victronenergy.com/questions/108271/mega-fuse-arcing-dangers-lynx-distributor-li-batte.html) on the community makes me think I will need protection, if what that discussion says about Lithium batteries arcing past MEGA fuses is correct.

Lithium Batterybatteryfuseslynx distributor
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hjohnson avatar image hjohnson commented ·

AYBC and the European counterpart generally require fuses to be within 8 inches of the power source, aka the battery. The idea is to protect the cable should it wear through, chafe, or otherwise short out.

I have a DIY battery using a REC ABMS, and I have a 6” positive lead (actually two of them, since it’s a 2p4s configuration) that goes into a 400A Class T. That’s the “oh crap” fuse that should blow if I do something really stupid.

In your situation, it would be worthwhile to investigate whether running MBRF fuses on each of the batteries, and then just going to a Power In rather than a Distributor, would make more sense.

But yes, the key is that you want the fuses as close as possible to the battery, since it’s there to protect the wire leaving the battery.

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kkesp avatar image
kkesp answered ·

The Lynx Distributer is the fuse holder. There are 4 connections for batteries and 4 fuse locations. No fuse is need before that.


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himehran2000 avatar image
himehran2000 answered ·

in that case why are there Lynx power in with fuse option on IP 20 model?


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chrigu avatar image chrigu commented ·

The lynx power-in is not meant to be fitted with fuses. But its the exact same body as the distributor, so all you need, to be able to add fuses to a power-in, are up to four screws. Split the lower body shell, add the screws, put it back together.

The main difference at this point will then be the missing PCB that detects a blown fuse.

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Fuses & fuse holders Product Page.


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Lynx Power In product page

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