Solar install - fuses between solar controller and batteries

[Winchweight]

Hi,

Should I fit in line fuses between the solar controller and the batteries and if so at which end, by which I mean at the battery end or the controller end? What would be a sensible rating?

[Winchweight]

Anyone installed fuses inline?

[max and caddy]

Dunno...I would suggest at the battery end as that's always full of damaging amps....but I'm no expert on solar panels...ask a solar guru?

[MGP]

I was always tought that the fuse is there to protect the wire, with that in mind the fuse should always be as close to the power source as possible.
As you are running the wire between a charge controller (source) and the battery (source) the wire should be fused both ends unless the charge controller has short circuit protection in which case there is no need for a fuse that end.
In this instance the fuse should be rated above the maximum rating for the charge controller but the most important thing is that the fuse is rated less than the maximum current rating of the cable.

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[scottbott]

have not in my van,never even thought about doing that,now you have me worried!,been connected for three years no problems so far

[carthago ian]

I have looked at my set up , the charge control panel has a fuse built in to it ; the wiring to the batteries from panel is not fused ,the only fused circuits are the in the original set up ,light, fridge & 12v supply ... Not too sure what protection a fuse would give me on the wiring to the batteries from panel ,my thoughts being an fault or overload would be covered by local circuit protection...

[Winchweight]

True enough. Thanks for the answers guys.

[CovKid]

Indeed. And as many fit cheaper controllers, you'd need to ascertain exactly what any internal fuse is actually protecting. Often they're just car fuses soldered directly to the circuit board (not easily replaceable) and may merely be protecting controller, (ie overvoltage from panel) not the battery. The circuit board itself should be sensing current/voltage and protecting the battery - thats its job (we hope). No harm in a fuse I suppose, but it shouldn't be needed.

[Winchweight]

No harm in a fuse I suppose, but it shouldn't be needed.

Agreed, but I'm tempted to fit some anyway.

[MGP]

You may have installed the wire from the panel to the battery but unless you have installed a diode near the battery, in the event of the wiring chafing through and shorting out the current in the battery will happily flow down the wire, all the hundreds of amps the battery is capable of delivering at once down what I would assume is around a 20a cable, it not going to end well.

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[Winchweight]

Fair point. I have used 27a cable and planned on fitting either a 25a or 30a fuse in each (to starter batt and to leisure batt..

But you mention a diode? I'm not familiar with these except as small leccy components. Do,you have a link to what I need please?

[CovKid]

A diode allows current in one direction only.

[Winchweight]

Sorry chap, thanks for that but I wasn't clear in explaining my confusion. I understand the role of a diode but I'm only familiar with the little electrical component, usually about 5w and low volts. I don't know what to look for in this instance! i.e. for a diode capable of 12v and high amps / watts.

[marlinowner]

Fuse is better than a diode, you can see when it's done it's job.

[Winchweight]

Fuse is better than a diode, you can see when it's done it's job.

Fair point. Also I understand what to do with fuses.