Please help me configure my first Solar setup...

[Firesky567]

Hi, I just joined the site today and I am looking for some advice.
This is my first setup and also my first time posting here.
I am planning to use the following components to run my cabin off grid.

- 4x 270W PV Panels in 2S2P https://static.trinasolar.com/sites/default/files/Datasheet-PD05.08D.pdf
- 4mm Solar UV Proof cable / 2x Branch Connectors / MC4 between strings
- Victron Smart Solar 100/50 MPPT
- Victron Smart Shunt 500A
- 24V/100Ah LiFePo4 Battery (+Victron Temp Probe + 7w Heat mat + Inkbird Temp Controller)
- Victron PSW Inverter 1500w

Wiring to a 230V AC 6A Breaker in Consumer Unit to provide power to 13A sockets.

My question is how best to fuse the setup?

I have read that I need not fuse between the 2 strings of panels as they won't generate enough current to damage the cable I'm installing.
I know I need something between the MPPT and Battery, and something between the Battery and the inverter but what is best?

Are DIN Rail mounted DC breakers, in one consumer unit best to keep everything tidy?
Or is this unsafe/unwieldly and should I use inline breakers, albeit more expensive, and I have read bad reviews about them.
Plus they only interrupt + not both +&-.

Many thanks in advance for any help / suggestions. It's more valuable than you know.
I have some formal electrical training but this is all still new to me.

Peace

 

[12VoltInstalls]

This thread HERE should refine your thoughts- and there’s other threads similar where scads of people have started out as you have.

 

[Firesky567]

This thread HERE should refine your thoughts- and there’s other threads similar where scads of people have started out as you have.

Tyvm much appreciated. Was hoping for someone to point out where in particular I need to redefine and I already went over that link. Doesn't seem to be much consensus on what breaker is best for which job.

 

[12VoltInstalls]

Doesn't seem to be much consensus on what breaker is best for which job.

There is a consensus, but some people are at different opinions.

The idea of the link wasn’t finding specific recommendations but rather to get you some context on what and how things are done.

 

[MisterSandals]

Many thanks in advance for any help / suggestions.

You need to provide volts, amps and wire length for anybody to calculate wire and fuse size. If you break this down for each area, it will be easier for someone to help you DIY. As stated, its pretty close to "do everything for me".

 

[Firesky567]

You need to provide volts, amps and wire length for anybody to calculate wire and fuse size. If you break this down for each area, it will be easier for someone to help you DIY. As stated, its pretty close to "do everything for me".

2S2P Array is going to provide 57V @ 20A (On paper)
4mm copper - solar rated cable (between PV Array & 100/50 MPPT) @ about 2m if that (not installed yet)

I believe I need 4AWG cable & the appropriate size lugs for the 24V battery (2 runs - To Inverter & From MPPT / Shunt)

I'm starting to think I don't need fuses at all; DC Breakers in a consumer unit ought to do it nicely afaik.
Is this a commonly used solution or is there something better I should be looking at?

Seems the right way to go about it, as DIN Breakers are a reliable manual disconnect, and also a reliable reusable fuse
Please correct me if I'm mistaken

 

[MisterSandals]

2S2P Array is going to provide 57V @ 20A (On paper)
4mm copper - solar rated cable (between PV Array & 100/50 MPPT) @ about 2m if that (not installed yet)

Lets start here. I am using this tool to stay below 3% voltage drop:

Voltage Drop Calculator

This free voltage drop calculator estimates the voltage drop of an electrical circuit based on the wire size, distance, and anticipated load current.

www.calculator.net

Looks like 14Awg is sufficient, it does not go to smaller gauges but 1.3% loss is respectable. Using 10Awg solar wire (uv protected would be a good choice too).

 

[MisterSandals]

- 24V/100Ah LiFePo4 Battery (+Victron Temp Probe + 7w Heat mat + Inkbird Temp Controller)
- Victron PSW Inverter 1500w

for LiFePO4, folks recommend a Class T fuse at the battery.

1500W inverter, assuming 20 low V shutoff:
1500W / 20V / .85 efficiency x 1.25 headroom = 110A. Use 125A fuse/breaker.

 

[Firesky567]

Thankyou for the information; very helpful stuff.

 

[Firesky567]

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