Solar charge controller to fuse block?

[Debbies]

Hi all,
I m wondering if a solar charge contoller can go directly to a fuse block, rather than the battery?

Thanks!

 

[45North]

Why would you want to?

 

[Dzl]

Is the right hand illustration essentially what you are imagining? Or are you talking about a situation where there would be no battery, or a situation where the fuse block would be wired to the SCC's load output?

 

[willo]

I just did this but with a dedicated fuse block - I have three controllers on my boat, each called for a 25a fuse.
That will feed into a battery protect that the BMS controls as a charging disable override.

 

[John Frum]

This is a fuse block

This fuse block is... a positive busbar with a feeder lug and 12 fused branchs.
It also has a negative busbar with a feeder lug and 12 returns.
Each branch circuit can be fused up to 30 amps which means 24 service amps.

It would be easy to make a nice little system using this fuse block as the core.
At 24 volts nominal 2 branch circuits would easily power a 600 watt inverter.
600 ac watts / .85 conversion factor / 20 volts low cutoff = 35.294117647 service amps
35.294117647 service amps / 2 circuits = 17.647058824 per circuit.

 

[Debbies]

Is the right hand illustration essentially what you are imagining? Or are you talking about a situation where there would be no battery, or a situation where the fuse block would be wired to the SCC's load output?

View attachment 82862

Yes, the right one is what I would like to do.

 

[Bud Martin]

Don't you need the fuse on the output terminal of the SCC if you have short circuit down the line?
and fuse at the battery terminal?

 

[John Frum]

Don't you need the fuse on the output terminal of the SCC if you have short circuit down the line?
and fuse at the battery terminal?

The solar charge controller can be connected to a branch circuit if its under 24 amps.
Or 2 branches for 48 amps.

 

[Bud Martin]

The solar charge controller can be connected to a branch circuit if its under 24 amps.
Or 2 branches for 48 amps.

Without the fuse to protect the two wires from SCC if the ends of the wires that go to the bus bar on the fuse block shorted together?

 

[John Frum]

Without the fuse to protect the two wires from SCC if the ends of the wires that go to the bus bar on the fuse block shorted together?

The branch circuits are fused.
Like this.

legend {
    {} { functional block }
    nnn|NNN| { fused busbar position where nnn is the wire guage and NNN is the fuse rating in amps }
    nnn|UUU| { un-fused busbar position where nnn is the wire guage }
    <-> { bi-directional current flow }
    -> { uni-directional current flow }
    <- { uni-directional current flow }
}
fuse_block {
    positive {
        feeder {
            006|UUU|<->100A_fuse<->battery.positive
        }
        branches {
            010|030|->inverter.positive
            010|030|->inverter.positive
            010|030|<-solar_charge_controller.positive
            010|030|<-solar_charge_controller.positive
        }
    }
    negative {
        feeder {
            006|UUU|<->battery.negative
        }
        branches {
            010|UUU|<-inverter.negative
            010|UUU|<-inverter.negative
            010|UUU|->solar_charge_controller.negative
            010|UUU|->solar_charge_controller.negative
        }
    }
}

 

[Bud Martin]

I know that the branch circuits are fused for each branch to protect each branch, but you have two wires from SCC that are connected to the positive and negative bus bars of the fuse block, so what is protecting the SCC wires if those two wires of SCC shorted together? Same for the battery since the two battery wires are also connected to the bus bars.

 

[John Frum]

I know that the branch circuits are fused for each branch to protect each branch, but you have two wires from SCC that are connected to the positive and negative bus bars of the fuse block, so what is protecting the SCC wires if those two wires of SCC shorted together?

10 awg wire with 105c insulation is rated for 60 amps in open air.
Since we specced an scc with a max ampacity of 48 volts the current will flow and nothing exciting will happen.
This is conceptually the same as running a victron multiplus off of a lynx distributor.

Lynx Distributor - Victron Energy

Monitor the status of each fuse and see its condition with a LED on the front of the Lynx Distributor. Find a Victron Energy dealer near you.

www.victronenergy.com

It makes sense to have the fuses at the start of the branchs for fault isolation.

Same for the battery since the two battery wires are also connected to the bus bars.

The battery is connected by a single pair of wires to the feeders and is fused as close as possible to the battery positive.
I'm not really seeing the problem.

 

[time2roll]

Fuse block is fine. However the more distance to the battery could reduce charging efficiency. Also most controllers like to be powered by a battery at all times.... don't forget to disconnect the panels before battery service.

 

[John Frum]

@Debbies my apologies if your eyes have glazed over.

 

[Debbies]

Why would you want

@Debbies my apologies if your eyes have glazed over.

Lol. I'm good. Thanks for all the info. Much appreciated.

 

[John Frum]

This is also a fuse block with much greater ampacity.

Littelfuse 880089 LX Series Power Distribution Module | Waytek

Littelfuse 880089 LX Series Power Distribution Module, 4 MIDI Fuse Block, 60V, Max 600A, IP59K is in stock and ready to ship. Order today!

www.waytekwire.com

 

[12VoltInstalls]

like to be powered by a battery at all times.... don't forget to disconnect the panels before battery service.

That’s the only possible practical issue!

battery is connected by a single pair of wires to the feeders and is fused as close as possible to the battery positive.
I'm not really seeing the problem

like in my setup: I have <6” between SCC and 63A breaker, unfused 6ga. There’s a fuse in SCC- the short 6ga wires aren’t really unprotected. At some point you have to get power someplace

 

[Bluedog225]

It’s a good way to put a quick disconnect on your panels if you have a small system.

 

[Zil]

Don't you need the fuse on the output terminal of the SCC if you have short circuit down the line?
and fuse at the battery terminal?

No. The wire or cable from the SCC should be of the right awg to carry all the current from the cc. That cable can not handle all the current from the battery. The circuit between the SCC and battery must be fused at the battery end. The SCC is considered a Limited Supply. The battery is not a Limited Supply.

 

[time2roll]

No. The wire or cable from the SCC should be of the right awg to carry all the current from the cc. That cable can not handle all the current from the battery. The circuit between the SCC and battery must be fused at the battery end. The SCC is considered a Limited Supply. The battery is not a Limited Supply.

Yes and if connected to a fuse block branch connection, the fuse to protect the wire from battery power is already in place.
Should also be a main battery fuse/breaker. Verify the ratings.