DIY Solar Equipment Protection

[PeterInSa]

I read somewhere that fuses/circuit breakers should be included in a Solar Home Install:

In my proposed install, this would include:

Between the solar Panels and the Controller, see below for Fuses/Circuit Breaker/Lightening protection

Between the Controller and the Batteries see below for a 60amp circuit breaker example. ( Really necessary? see comment below and BMS)

Between the Batteries and the 3000watt Inverter with a 250Amp Circuit Breaker ….. For Battery Protection. Is this 250Amp Circuit Breaker really necessary since the Renogy Battery has Short Circuit protection?. ie:

Reliable BMS System
The state-of-the-art battery management system (BMS) with high-performance dual-processors provides short circuit, over charging and over-temperature protection while maintaining a balanced voltage across all cells.

Entry Protection

12v Circuit Breaker

Appreciate comments
Thanks

Peter

[lsemmens]

If it's grid connected then there MUST be an isolator that automatically disconnects the array from the grid! Beyond that, you must wait for some experts in this field to pop in. Given the fact that 240v can be lethal, there is a good reason why installers must be licensed and KNOW WHAT THEY ARE DOING. Not a job for a handiman.

[PeterInSa]

This is NOT a Grid Connect setup.
I have installed Solar Systems in our Caravan and our Sprinter Campervan so have some experience in this area, as well as an electrical an electronic background in my previous working life. This system for a family member is larger than my 2 previous installs and involves lithium Batteries and I am in the investigation/planning phase.

[lsemmens]

Fair enough. You will still have to wait for someone with more experience than I. Sorry 'bout that.

[Uncle Fester]

I read somewhere that fuses/circuit breakers should be included in a Solar Home Install:

In my proposed install, this would include:

Between the solar Panels and the Controller, see below for Fuses/Circuit Breaker/Lightening protection

Between the Controller and the Batteries see below for a 60amp circuit breaker example. ( Really necessary? see comment below and BMS)

Between the Batteries and the 3000watt Inverter with a 250Amp Circuit Breaker ….. For Battery Protection. Is this 250Amp Circuit Breaker really necessary since the Renogy Battery has Short Circuit protection?. ie:

Reliable BMS System
The state-of-the-art battery management system (BMS) with high-performance dual-processors provides short circuit, over charging and over-temperature protection while maintaining a balanced voltage across all cells.

Entry Protection

12v Circuit Breaker

Appreciate comments
Thanks

Peter

The breaker between panels and the charge controller is the most critical as it has to switch high voltage DC and using the wrong type of breaker has been the cause of many fires.
For that one I would skip Ebay and go to a trusted local electrical supplier that sells PV rated components.

For the 12V side I don't have an issue with your second link although the price seems a tad low for reliable quality.
I use this type myself. They have rotary switching contacts that shouldn't weld themselves together over the DC arc when the circuit breaks.

Even if you have trust in your BMS and inverter protection, which you shouldn't, those breakers provide the convenience of disconnection for service/modification or just piece of mind when being away from the premisses for a longer period.

I also disconnect the PV panels on my off grid-system when I am away from house for more than 2 days, I also have grid power.
The off-grid is to charge my EV, but my IP security cams are also running on that battery bank incase intruders think they would be smart by turning off power in the meter box. The battery bank can comfortably run those for a month.

Related to this I would like to share an experience I had only fairly recently with my solar panels.
I suddenly noticed one panel looked like it was made out of crystal or something.
On closer inspection the tempered glass had shattered through out the whole surface of the panel.
I removed the panel and saw traces of arcing on one cell and black burn spots on the back with strong smell of burnt plastic. Luckily it didn't catch fire, I assume flame retardant backing foil is used.
On closer inspection it appears that two spots very close together in the glass looked like the source of impact.
However a faulty or cracked cell could have formed heat spots and cracked the glass but those two spots did not correspond with the location of the burn spots on the rear.

To this day it is a mystery what exactly happened here but confirms my desire to disconnect the PV panels when I am away for longer.