One last issue with my solar install:The controller manual says the fuse needs to be no more than six inches from the battery terminal. That would locate it inside the battery box under the steps.Is it safe to have a fuse in the same general area where hydrogen gas might accumulate? Yes, the box is vented but hydrogen is tricky stuff. The closest I can locate the fuse outside the compartment is about 36 inches from the battery. Better yet, I would like to locate the fuse about five inches from the controller. The overall run from the battery to the controller is 60 inches.But, I go back to my original question: is it unsafe to have the fuse in the battery compartment? My fuse holder is one of those sealed ANL monsters.

The battery compartment should be ventilated even under the step. Many rigs have relays, circuit breakers or fuses in that area.

enblethen wrote:The battery compartment should be ventilated even under the step. Many rigs have relays, circuit breakers or fuses in that area.Oh, yeah - it's totally vented. I just wasn't sure if having the fuse basically sitting on the battery is such a good idea. It's a very enclosed space.

I can't see how it makes any difference where the fuse is. If the wire is carrying enough amps to blow it, it's going to be carrying that amperage its entire length.

Any wire between the fuse and the battery is not protected. The reason for the fuse is to protect the wire if it get shorted to ground. Yes it is safe to have the fuse in the batt. compartment. You should also have a fuse or disconnect switch between the solar panels and the controller.

2oldman wrote:I can't see how it makes any difference where the fuse is. If the wire is carrying enough amps to blow it, it's going to be carrying that amperage its entire length.Well, see, that was my thinking as well. Amps are amps, right? But, in addition to the Renogy manual I have heard that fuses should be as close to the load as possible. I have no idea.

fuse in the battery compartment? | Good Sam Community

22 Replies

Ductape
Explorer
Mar 04, 2016
windviewer wrote:
I plan on using the battery terminal fuse commonly found on boats.

See
BLUE SEA 5191 MRBF FUSE BLOCK 30-300AMP

Example from Binnacle.ca

There is also a version holding two fuses, which I used. Large fuse for house load wiring. Smaller fuse for smaller wiring to solar.
time2roll
Nomad
Mar 04, 2016
I agree fuse should be close to the source of power that exceeds the wire ampacity.
kellertx5er
Explorer
Mar 04, 2016
Dusty R wrote:
Fuse location depends on what it is protecting.
In this case it is protecting the wire.
In other cases it could be protecting a motor, so then you want the fuse close to the motor, which could be at the end of a wire a long ways from the source, battery or main panel. So here you would have 2 fuses, one at the panel and the other at the motor.

Dusty

The second fuse in your example is unnecessary. A single fuse at the source (panel) will protect the motor EXACTLY the same as one near the motor, and also protect the wire.
westend
Explorer
Mar 04, 2016
I used one of these AMG fuses on each (+) phase lead from my battery banks. The fuse is inside a sealed, vented battery box and is surviving well. I have the same style fuses on distribution buses for converter, controller, and inverter. They are easy to install as they accommodate a 5/16 fastener, the same size as typical battery terminals.
Dusty_R
Explorer
Mar 03, 2016
Fuse location depends on what it is protecting.
In this case it is protecting the wire.
In other cases it could be protecting a motor, so then you want the fuse close to the motor, which could be at the end of a wire a long ways from the source, battery or main panel. So here you would have 2 fuses, one at the panel and the other at the motor.

Dusty
RJsfishin
Explorer
Mar 03, 2016
2oldman wrote:
Ed_Gee wrote:
Your lack of understanding electricity shows.
You should see my lack of fuses.

You are not fuse poor?
Neither am I !
I put fuses (or CB) where there is a potential for shorting.
And that ain't very many places.
I have no fuses in my solar circuits. But I don't question my installation ability either.
2oldman
Explorer II
Mar 02, 2016
Ed_Gee wrote:
Your lack of understanding electricity shows.
You should see my lack of fuses.
Almot
Explorer III
Mar 02, 2016
DrewE wrote:
Fuses and circuit breakers generally should be as close to the source of power as practical when the source is capable of supplying a greater current than the circuit can safely carry.

Which would be the case of a battery only. All other fuses and breakers in solar circuitry can be installed at any length.
Got_Dirt_
Explorer
Mar 02, 2016
+1 on the Blue Sea 5191. Got mine from Genuinedealz.com

Good prices and free shipping. For all your wiring needs.
time2roll
Nomad
Mar 02, 2016
Long wire is fine as long as it is in plain view and protected.
Otherwise put the fuse in with the battery.

Not explosion proof but I would have no worries about this one: