Fuse or DC Breakers for an RV solar setup?

[sawmonandnatalie]

Hi all,

We are planning to set up a 400W solar setup with 12v battery bank. In our system do you recommend using fuses or dc breakers between

1. Solar panels array and MPPT charge controller
2. MPPT charge controller and battery bank
3. MPPT charge controller and load
4. Battery bank to fuse box
5. other possible places

What are the pros and cons of using dc breakers vs fuses? Is it about fast response time/sensibility?

 

[Dzl]

Some of this is situational, some of it is personal preference. It would be helpful to see a simple diagram of what you will be doing?

For the main battery bank overcurrent protection (OCP) A fuse--specifically a fuse with a high Interrupt Capacity (AIC)--is more appropriate. In simple terms a fuse with high AIC is fuse that can protect against a really high current short, and a lithium battery can produce a lot of current. Class T is the most recommended choice for main battery protection.

Beyond this, the answers to your other questions are somewhat context based or personal preference (fuses are often cheaper and simpler, breakers have the added convenience as doubling as a switch (for occasional use)). Sketch out your design and you can get more specific feedback.

 

[HRTKD]

The general design pattern that I've seen, and I'm using, is to put DC 2-pole breakers between the solar panels and solar charge controller, and then another DC breaker between the solar charge controller and the positive common bus bar.

As Dzl said above, Class T fuse immediately downstream of the battery. Some are using lesser expensive fuses in place of the Class T, but I haven't seen DC breakers used in that position, at least not enough to mention.

 

[GSXR1000]

I would put a circuit breaker betwen charge controller and solar. fuses everywhere else..
if you but the $20 on Amazon they suck.. I have a 20 amp one that I have pulled 100a thru continuously.... and my 40, 60, 80 amps one trip way early

 

[brooke_heaton]

@GSXR1000 do you have a recommendation on a solid 20amp breaker that works well?

 

[GSXR1000]

@GSXR1000 do you have a recommendation on a solid 20amp breaker that works well?

I found all breakers suck... (I would guess you could get $80+ ones and would work.. I just went with fuses