Fuse for 60watt 24v panel

[DaveBad]

I'm looking for some help to determine what size fuse I should have between the panel and the solar controller.

My panel:

• Dimension: 25.20*20.87*1.18 inches
• Weight: 8.98 lbs
• Max Power Output(W): 60W
• Voltage MPP Vmp(V): 34.74V
• Current MPP Imp(A): 1.73A
• Voltage Open Circuit Voc(V): 40.07V
• Short Circuit Current Isc(A): 1.83A

SC:
Victron Energy SmartSolar MPPT 75-Volt 10 amp

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Thanks, Dave

 

[seneysolar]

Single panel?
Wire size?

I probably wouldn't go smaller than 5A to avoid an nuisance fuse blows.

 

[JWLV]

If I was doing this, I wouldn't bother with a fuse. The amount of power we're looking at here is like a USB C plug. And you don't see fuses on USB C cables.

 

[DaveBad]

Single Panel - (Newpowa panel)
Wire size - I'm not sure if the 30" leads are 14 or 12 gauge. Lots of writing on them. There is a 1x2.5mm dimension on them.

 

[seneysolar]

Single Panel - (Newpowa panel)
Wire size - I'm not sure if the 30" leads are 14 or 12 gauge. Lots of writing on them. There is a 1x2.5mm dimension on them.

5A should suffice

 

[LakeHouse]

Single Panel - (Newpowa panel)
Wire size - I'm not sure if the 30" leads are 14 or 12 gauge. Lots of writing on them. There is a 1x2.5mm dimension on them.

You don’t need a fuse for a single panel going to a charge controller.
Fuses protect from overcurrent, but you have no possible source for current other than the panel, and it’s short circuit current is only 1.83 Amps, which won’t hurt the panel, or the wire, or the SCC.

 

[seneysolar]

You don’t need a fuse for a single panel going to a charge controller.
Fuses protect from overcurrent, but you have no possible source for current other than the panel, and it’s short circuit current is only 1.83 Amps, which won’t hurt the panel, or the wire, or the SCC.

Assuming everything works correctly, sure, it will never overload.

Fuses are for when things dont work correctly. On the victron community forum, there is talk of diodes failing in the charge controllers and backfeeding panels. Its not the solar panel id worry about its the battery potential in that scenario.

Given the cost of a small fuse holder, why not fuse it?

The manual says to fuse it

 

[MattiFin]

Assuming everything works correctly, sure, it will never overload.

Fuses are for when things dont work correctly. On the victron community forum, there is talk of diodes failing in the charge controllers and backfeeding panels. Its not the solar panel id worry about its the battery potential in that scenario.

Given the cost of a small fuse holder, why not fuse it?

The manual says to fuse it
View attachment 194910

Battery voltage is below the panel voltage so there won’t be any backfeeding even if you replace the solar controller with half inch bolt.

 

[seneysolar]

Im surprised at the pushback to install a fuse. Does anyone have a reason to not install one other than to save 5 bucks?

 

[DaveBad]

I have a bunch of fuse holders and a ton of different fuse sizes. Just kinda wanted to know as far as a fuse, how big is to big and how small is to small. No worries on $. If none is needed that's fine too. I'm setting up a security camera in a remote location. I do appreciate everyone's input.

Thanks, Dave

 

[zanydroid]

Very few people install fuses on permanent roof installs unless required (EG more than two in parallel). It's an extra failure point. And on a big person system with decent voltage and current you need to do due diligence on the quality, and they cost more than $5.

Electrical code is OK with this (and presumably the failure mode of SCC going nuts and full sending into the solar panel is either considered low or protected by UL product requirements)

 

[LakeHouse]

Im surprised at the pushback to install a fuse. Does anyone have a reason to not install one other than to save 5 bucks?

I don't see any pushback on installing a fuse.
@JWLV said they wouldn't bother with a fuse, and I said a single panel didn't need to be fused, and I gave reasons why. Two panels in parallel don't need to be fused either, and for the same reasons. People come here for information, and the information that a fuse is not necessary seems like it might be relevant for the OP.
As for benefits, eliminating a fuse eliminates a failure point in the circuit, at least one connection (probably two) and associated resistance, and saves a few bucks. Is that worth it? Up to the OP. No one told him that he shouldn't put a fuse in.

As for the battery backfeeding: the connection between the SCC and the battery absolutely must be fused.