Fuse Between Charge Controller and Solar Panel

[Capt Y Knot]

Hello, I'm working on a small solar system for a 30' sailboat. I have used Will's book and have purchased many of the components base on the books recommendations.

Components on hand ready for assembly:

50 Watt Monocrystalline rigid solar panel, Epever 20 AMP Charge Controller, Bussmann 25 AMP Circuit Breaker, two 12 volt 100 AMP DC Deep Cycle Flood Acid Batteries with MRBF Terminal 300 AMP fuses, 10 AWG and 8 AWG wire.

I plan to put the Bussmann 25 AMP Circuit Breaker between the battery bank and the charge controller. I plan to wire only one battery (the house battery) to the solar system.

Question: Do I need to fuse the wire from the charge controller to the solar panel? Thank you! All good advice is welcomed.

 

[Off Grid Circuits]

It's good practice. It protects the charge controller and mostly acts as a circuit cut off for maintenance. Solar panels will arc when disconnected under a load. Use a small breaker roughly 10% higher than the total ISC input from the panels. The bussmann series are fine for this.

 

[gnubie]

Make sure the breaker voltage rating is greater than the VoC of the solar array. If just one panel, the VoC is shown on the specs label on the back of the panel.

 

[Ped]

Like said its really for maint. I once destroyed a cheap PWM by unhooking the battery and leaving the panels. I did that knowing they say not but I routinely do it to my old epever and renogy rover without harm so I figured it would be ok. It took a split second and fried.

But I still do it to my rover on a reg basis for hours at a time and at max current. YMMV

 

[Justin Laureltec]

50 Watt Monocrystalline rigid solar panel, Epever 20 AMP Charge Controller, Bussmann 25 AMP Circuit Breaker, two 12 volt 100 AMP DC Deep Cycle Flood Acid Batteries with MRBF Terminal 300 AMP fuses, 10 AWG and 8 AWG wire.

I plan to put the Bussmann 25 AMP Circuit Breaker between the battery bank and the charge controller. I plan to wire only one battery (the house battery) to the solar system.

Question: Do I need to fuse the wire from the charge controller to the solar panel? Thank you! All good advice is welcomed.

The Bussman breakers are only rated to 48vDC, but for that small of a panel I'm sure the VOC doesn't go over that... on the off chance that the VOC rating (sticker on the back of the panel) is higher than 48vDC, you can use a MidNite Solar DIN-Mount Breaker like the MNEPV30 - the MidNite Solar breakers are rated to 150vDC, so they'll cover even a decently-sized PV array output. If you do go with one of those, you'll also need the enclosure for it, which will be the MidNite Solar BabyBox.