System design

[RJBubbs]

Hi, I want to design a system to understand which cable sizes I need.
I will have a growatt spf 5000es with 4 550w panels with a voc of 50.
The batteries will be 4 x 12v 100ah litime batteries.
Let's assume the panel array will be between 10-20 meters from the growatt and batteries.
What size of wires I'll need between the batteries themselves, batteries to inverter
Between the panels themselves to the inverter.
Also are fuses necessary?
Thank you

 

[Dave in AZ]

Hi, I want to design a system to understand which cable sizes I need.
I will have a growatt spf 5000es with 4 550w panels with a voc of 50.
The batteries will be 4 x 12v 100ah litime batteries.
Let's assume the panel array will be between 10-20 meters from the growatt and batteries.
What size of wires I'll need between the batteries themselves, batteries to inverter
Between the panels themselves to the inverter.
Also are fuses necessary?
Thank you

The guy who built this forum, Will Prowse, has a whole series of.videos to teach you these exact basics, so you're not buying or deciding on equipment without even knowing how to size a cable or fuse... I recommend you take 30 min and read this starter 12v design with fuses all shown, its basics apply to 48v designs too. Then watch his beginner solar series. I could look up your answers on a chart in 15 seconds, but the fact you don't know how yet you're already decided on an inverter is worrisome... I would rather teach you to fish here, than give you a fish. 20 to 30 min of your life for a few basics, you'll be glad

RV Solar Power Blue Prints

Building a vehicle mounted solar power system? Let me help.

www.mobile-solarpower.com

Solar Power for First Timers

If you are a complete beginner and would like to learn more about solar, kick back and watch the videos below:

www.mobile-solarpower.com

Part 1: Choosing the Correct Wire Size for a DC Circuit - Blue Sea Systems

Engineering high quality marine electrical components for safety, reliability and performance

www.bluesea.com

 

[RJBubbs]

Thank you very much.
I have looked a hit about all in one's and I thought the growatt will suit my needs as well be able to be scaleable.
what other inverters/ all in one's you would recommend?

The guy who built this forum, Will Prowse, has a whole series of.videos to teach you these exact basics, so you're not buying or deciding on equipment without even knowing how to size a cable or fuse... I recommend you take 30 min and read this starter 12v design with fuses all shown, its basics apply to 48v designs too. Then watch his beginner solar series. I could look up your answers on a chart in 15 seconds, but the fact you don't know how yet you're already decided on an inverter is worrisome... I would rather teach you to fish here, than give you a fish. 20 to 30 min of your life for a few basics, you'll be glad

RV Solar Power Blue Prints

Building a vehicle mounted solar power system? Let me help.

www.mobile-solarpower.com

Solar Power for First Timers

If you are a complete beginner and would like to learn more about solar, kick back and watch the videos below:

www.mobile-solarpower.com

Part 1: Choosing the Correct Wire Size for a DC Circuit - Blue Sea Systems

Engineering high quality marine electrical components for safety, reliability and performance

www.bluesea.com

 

[MisterSandals]

I have looked a hit about all in one's and I thought the growatt will suit my needs as well be able to be scaleable.
what other inverters/ all in one's you would recommend?

You need to supply your system requirements in order for someone to be able to recommend a solution.

What are your power needs? What are your power storage needs? Do you have grid power?
Are you looking to reduce your grid electricity costs or have a backup, or ??

 

[RJBubbs]

You need to supply your system requirements in order for someone to be able to recommend a solution.

What are your power needs? What are your power storage needs? Do you have grid power?
Are you looking to reduce your grid electricity costs or have a backup, or ??

I want to have a back up system, maybe something like a charging station and a system that would be able to operate loads up to 3000-4000w, that's why I thought the growatt 5000es would be enough for the start at least.
I'm in portugal so there's plenty of sunshine.
I have grid power but I want this system as a separate off grid system.
Thanks for your response

 

[MisterSandals]

a system that would be able to operate loads up to 3000-4000w

4x100Ahx12.8V = 5120wh

5120wh / 3500W = 1.46h runtime from battery.

5120Wh / 5h solar = 1024W solar panels to fully charge from empty in a day.

thought the growatt 5000es would be enough

i have no experience with this unit.

A search would reveal a lot of discussions I am sure.

 

[hwy17]

be 4 x 12v 100ah litime batteries

Did you already buy these.

 

[RJBubbs]

4x100Ahx12.8V = 5120wh

5120wh / 3500W = 1.46h runtime from battery.

5120Wh / 5h solar = 1024W solar panels to fully charge from empty in a day.

i have no experience with this unit.

A search would reveal a lot of discussions I am sure.

Is there a difference between 4x12 v
To one 48v battery?

 

[RJBubbs]

Did you already buy these.

Yes, I already own them

 

[MisterSandals]

Is there a difference between 4x12 v
To one 48v battery?

The main difference is that each battery has its own BMS.
Both 4x12V vs 1x48V have 16 cells connected in series.

What does the battery maker say about 4 of their batteries in series?

I've never put 4 12V batteries in series so cannot add anything experience-wise. I do have a couple 16S batteries that i made out of big LiFePO4 cells and this is tricky enough.

 

[hwy17]

Yes, I already own them

So there is a downside to putting 12v batteries in series, they cannot stay balanced on their own in series. Each battery can balance itself internally, but the whole batteries will get out of balance compared to each other.

You will need to either use a 12v/48v balancer, or periodically break up the bank and fully charge each one individually or all of them in parallel. If you choose this manual balancing method, the frequency will depend on luck with how well matched they are. They could need it every two weeks, or every 6 months, or anywhere in between.

 

[RJBubbs]

The main difference is that each battery has its own BMS.
Both 4x12V vs 1x48V have 16 cells connected in series.

What does the battery maker say about 4 of their batteries in series?

I've never put 4 12V batteries in series so cannot add anything experience-wise. I do have a couple 16S batteries that i made out of big LiFePO4 cells and this is tricky enough.

Thank you for the reply, I will have to check about being connected in series but I'm pretty sure they can be connected in series.