First Solar Design, Feedback Please?

[sma92878]

Hello all,

I've learned so much from this forum, and from Will's book. I'm honestly still very anxious about putting together a solar system, but this is my first attempt based on what I've learned so far. My goal is to put together a system so I can power critical devices in my home in case of a long term power outage. I've used these little things to collect power data on my critical loads:

https://www.amazon.com/dp/B08CVSSVWP

They have worked really well and have given me my power draw of the loads I want to protect.

For the week, for my fridge, kettle to boil water, and a small counter top oven we use, we're just shy of 12kwh per week.

My design is as follows (also see attached image)

3000w 24v Growatt all in one inverter, solar charge controller
2 x 450w solar panels (which I will put in series, link here) - https://renogy.com/450-watt-monocrystalline-solar-panel/
6 x 12v 100ah battle born batteries, I selected these because my battery configuration was approved by the vendor, 2s3p for 24v / 300ah battery for a total of 7200ah

I'm still a little unsure of how to actually connect these parts together, but from talking to folks over at Battle born they recommended 2|0 cable sizes in between the batteries and to connect up to the inverter.

My max appliance load will be 1800w, though usually use from my counter top oven is about 600w

Several folks gave me input on the breaker size in between shore power and the batteries (thank you to this great community)
The only real thing I have to figure out is the fuses in between the solar panels and the Growatt.

I was wondering if my simple wiring diagram looks correct?

Kind regards, and thank you to everyone who's answered questions up to this point.

Kind regards and happy father's day!

 

[FilterGuy]

You should have a disconnect, but you really don't need fuses for a properly wired single string.

Fusing & Wire Sizing guidelines for solar panels

To get the paper, click on the orange'' button at the top of the screen. This resource is intended to help the user understand when they need to add Over Current Protection Devices (OCPDs - Fuses or Breakers) to the solar panel array and what...

diysolarforum.com

 

[sma92878]

You should have a disconnect, but you really don't need fuses for a properly wired single string.

Fusing & Wire Sizing guidelines for solar panels

To get the paper, click on the orange'' button at the top of the screen. This resource is intended to help the user understand when they need to add Over Current Protection Devices (OCPDs - Fuses or Breakers) to the solar panel array and what...

diysolarforum.com

Thank you for your feedback, would this be true is this setup was not connected to my home? I'm building a self contained unit that I will be able to use when power is lost. I simply will be able to charge the batteries by using shore power or via solar. Also would this be different then what I have labeled as my cut off switch in the diagram?

Kind regards

 

[FilterGuy]

Yes.... the proper wiring for the solar array does not change for a portable system.

 

[chess-equality]

6 x 12v 100ah battle born batteries, I selected these because my battery configuration was approved by the vendor, 2s3p for 24v / 300ah battery for a total of 7200ah

I'm also planning to create a 12v 2s2p configuration, did the vendor (Battle Born?) say any potential issues with 2s*p?

I'm a little concerned about here, though this is only 2s:

Uneven battery draw w new Growatt System

OK here goes...first post and new system. Setup: Cargo conversion RV system Growatt 3000 24v 2 x 200 solar panels in series 2 x SOK 12V 100AH batteries Problem: Batteries start with equal capacity (measured w meter). Balanced the batteries before initial install too, but overnight with...

diysolarforum.com

Neat diagram by the way

 

[sma92878]

I'm also planning to create a 12v 2s2p configuration, did the vendor (Battle Born?) say any potential issues with 2s*p?

I'm a little concerned about here, though this is only 2s:

Uneven battery draw w new Growatt System

OK here goes...first post and new system. Setup: Cargo conversion RV system Growatt 3000 24v 2 x 200 solar panels in series 2 x SOK 12V 100AH batteries Problem: Batteries start with equal capacity (measured w meter). Balanced the batteries before initial install too, but overnight with...

diysolarforum.com

Neat diagram by the way

I spoke to them about my configuration and they said it was supported, but please call them yourself, this is my first solar build. I believe it's one of the main reasons why they are more expensive, from watching Will's videos it doesn't seem like other battery manufactures actually support alternate configurations like this. I can also say their support has been outstanding.

 

[sma92878]

Yes.... the proper wiring for the solar array does not change for a portable system.

Can you say a little more about where the cutoff switch / disconnect should be? I currently am planning on in between the battery bank and the solar charge controller / inverter. Should there be another one some where?

Kind regards

 

[iamrich]

Can you say a little more about where the cutoff switch / disconnect should be? I currently am planning on in between the battery bank and the solar charge controller / inverter. Should there be another one some where?

You should have a cut off between the battery and the inverter and between the solar panel(s) and the controller. You don't technically need either to get the system up and running, but you want a way to quickly and safely disconnect any source of power. Image your solar panels are doing something you don't want, do you really want to be looking for your MC4 disconnect tool to break the circuit? Image your battery goes haywire, do you really want to be looking for a wrench to disconnect the bolts?

 

[FilterGuy]

I spoke to them about my configuration and they said it was supported, but please call them yourself, this is my first solar build. I believe it's one of the main reasons why they are more expensive, from watching Will's videos it doesn't seem like other battery manufactures actually support alternate configurations like this. I can also say their support has been outstanding.

For 2P2S, this wiring will keep things balanced.

 

[sma92878]

You should have a cut off between the battery and the inverter and between the solar panel(s) and the controller. You don't technically need either to get the system up and running, but you want a way to quickly and safely disconnect any source of power. Image your solar panels are doing something you don't want, do you really want to be looking for your MC4 disconnect tool to break the circuit? Image your battery goes haywire, do you really want to be looking for a wrench to disconnect the bolts?

Oh interesting I've never seen a diagram with a cut off between the panels and the solar charge controller. I did a quick search on Amazon for:

"solar charge controller cut off switch"

Do you have link to what you're referring to, or will a standard cut off switch work? Something like:

https://www.amazon.com/AWBLIN-Disconnect-Isolator-Vehicles-Application/dp/B094JTVLX4/

thank you for the guidance and kind regards.

 

[iamrich]

I am suddenly feeling like this is an RV/Mobile installation? Something like this:

How to Wire a Solar Disconnect for a DIY Camper Electrical System

In this blog post, I am going to teach you how to wire a solar array disconnect, why you need one, and which one to use when installing a solar array into your camper electrical system.

www.explorist.life

 

[sma92878]

I am suddenly feeling like this is an RV/Mobile installation? Something like this:

How to Wire a Solar Disconnect for a DIY Camper Electrical System

In this blog post, I am going to teach you how to wire a solar array disconnect, why you need one, and which one to use when installing a solar array into your camper electrical system.

www.explorist.life

This is actually to create a solar powered generator in the case of prolonged power outages, but my all in one SCC / Inverter can also charge off shore power.

 

[sma92878]

I'm also planning to create a 12v 2s2p configuration, did the vendor (Battle Born?) say any potential issues with 2s*p?

I'm a little concerned about here, though this is only 2s:

Uneven battery draw w new Growatt System

OK here goes...first post and new system. Setup: Cargo conversion RV system Growatt 3000 24v 2 x 200 solar panels in series 2 x SOK 12V 100AH batteries Problem: Batteries start with equal capacity (measured w meter). Balanced the batteries before initial install too, but overnight with...

diysolarforum.com

Neat diagram by the way

I remembered your question, here is an image on the wiring design that Battle Born sent me.

 

[FilterGuy]

I remembered your question, here is an image on the wiring design that Battle Born sent me.

Battle Born is showing a serial-first connection for the batteries



In my earlier post, I showed parallel first. Either way works fine, but since BB is saying serial first.... that is what you should do.

A few notes:

1) Make sure the batteries are all charged to 100% before you hook them up.
2) The wires for the two serial connections should be the same length.
3) The Wires for the two parallel connections should be the same length
4) Notice that the main negative and the main positive are diagonal from each other.