Fuses/breakers with higher current for MPPT CC?

[sunrise]

Hello,
I came across this article
https://www.doityourselfrv.com/solar-install-5/

I placed a 40-amp DC breaker on the positive lead inline between the charger and the batteries to prevent overflow of current and protect the batteries. I chose a breaker with a 10-amp higher current tolerance than the controller, which will allow the Victron charger to operate at full capacity but trip if there is a problem.

Is this a good practice? I mean if the CC is rated 30A, then 35A could potentially harm it, and Solar CC rarely reach full capacity due to the PV operating conditions anyway. Does Victron have over current protection?

Thanks!

 

[snoobler]

Probably worth watching some of Will's videos and blueprints. Common practice.

Fuses/breakers are there to prevent the WIRE from being overloaded. The CC is the SOURCE of the current, so if it goes over-current, then it's malfunctioning, and other stuff should be protected from IT.

1.25X current is desired, so 40A is reasonable.

The danger is in buying cheap components from ebay or Amazon. Often the Chinese made stuff is poor quality, and the breakers can't support their rated current.

 

[sunrise]

Probably worth watching some of Will's videos and blueprints. Common practice.

Fuses/breakers are there to prevent the WIRE from being overloaded. The CC is the SOURCE of the current, so if it goes over-current, then it's malfunctioning, and other stuff should be protected from IT.

1.25X current is desired, so 40A is reasonable.

The danger is in buying cheap components from ebay or Amazon. Often the Chinese made stuff is poor quality, and the breakers can't support their rated current.

Thanks a lot, I watched whole bunch of Will's videos and read some blueprints but overlooked this detail.
What source would you purchase breaker/fuse from?

 

[HRTKD]

Blue Sea Systems circuit breakers are very popular around here.

 

[MrNatural22]

I have a 50a breaker on a 40a CC in-line from the CC to the batteries for protection.
Snoobler is right on the formula.
40a x 1.25= 50a ?
I made a small wooden block with two holes to cover the CB terminals