Which Way Should I Wire This Breaker?

[Squidward]

GLOSO E69 Manual (T3) Reset Mid Range Mini Surface Mount Circuit Break

About this item 10-60A; 10-32 Thread Studs Mini Surface Mount GLOSO E69 Mini T3 Manual Reset Single Pole Thermal Circuit Breakers IP66 Ingress Protection & Ignition Protected Mini Surface Mount, Compact Design Manufacturer ‎GLOSO Brand ‎GLOSO Item Weight ‎1.9 ounces Package Dimensions 2.76 x...

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I'm wiring solar panels, and I added one of these breakers between the panels and the charge controller. I'm aware that it's just one of many clones of this breaker design.

One terminal is labelled "Batt Line" and the other "Aux Load". So conventional logic would mean the panels get connected to the Batt Line terminal, since they are supplying the power.

However, the panels aren't supplying THAT much power. And the idea here isn't to protect the batteries from the panels, it's to protect the panels from the batteries.

I can't even find any mention of whether these units are polarized, so maybe it doesn't matter?

 

[twistedtree]

It's hard to say if it matters, but if installed between panels and charge controlled, I'd connect the "battery" side to the panels, and the "aux/load" side to the charge controller.

Just be sure the breaker voltage rating is sufficient at 32V. It needs to be at least 1.25 times the panel's Voc rating. 32V might be too low.

 

[Fleming]

It doesn't matter because you don't really need a breaker between the panels and the controller. Solar panels are 'self-limiting' so as long as the wire is sized to handle a greater current than the panels can put out you don't need overcurrent protection. It's a good idea to put a disconnect switch in there, and the breaker can serve that purpose. More important is to insure the conductors between the controller and the battery are protected at the battery.

 

[jgwinks]

Even though the controller is connected to the batteries, there shouldn't be any backfeed from the controller to the panels. So the panels are the power source and connected to the Battery terminal on the breaker. And yes you don't really need the breaker, it's only use would be if you were to disconnect the controller from the batteries, you should disconnect the panels first.

 

[twistedtree]

It doesn't matter because you don't really need a breaker between the panels and the controller. Solar panels are 'self-limiting' so as long as the wire is sized to handle a greater current than the panels can put out you don't need overcurrent protection. It's a good idea to put a disconnect switch in there, and the breaker can serve that purpose. More important is to insure the conductors between the controller and the battery are protected at the battery.

Although the breaker isn't after required between panels and controller, I highly recommend some form of a disconnect. The first time you have to work on the system, you will be thankful that you have it.

Also be aware that there ARE configurations where fusing or breakers are required for the panels, so don't take it as a blanket rule that nothing is required between panels and controller.

 

[rslifkin]

A disconnect is handy, but turning off the battery side of the controller and placing a large piece of cardboard or similar over the panels (making sure no light hits the panels at all) works as well in a pinch.

 

[Greg QS]

Line is where the power is coming from ( solar panel)
Load is where it is going to in this case the solar charger/ batteries What you want to protect.

 

[CharlieJ]

OP: The breaker you posted is a knock off with no UL/SAE listing. It is a piece of safety gear that you are depending on to correctly operate when bad things try to occur. My professional opinion is that these do not belong on a boat that people sleep on.
Recommend a properly sized Blue Seas 187 Series circuit breaker. 187-Series - Blue Sea Systems

 

[BruceK]

This comes more from experience with regulators, they often have terminals for both a direct load to an appliance (like a fridge), and for the battery, that sounds similar to your breaker. But,it may be otherwise.