Expansion on Solar Panel and Battery ???

[pjvon]

I am researching the planning of my solar expansion. I am pretty new to to solar so I have a couple of questions about expansion. I currently have 12V panels, 4 in series, 8 in parallel on my 48V inverter and the batteries are 12V, 4 in series. I will be expanding my panels and batteries in the future but wanted to know if they also need to be 12V or can they be a larger voltage as long as they are put in a 48V series?

 

[MichaelK]

Only the terminal voltage needs to be close, within 5%. Let's say your four panels put out 18.0V, so four in series equals 18 X 4 = 72V. Two 72-cell grid-tie panels typically put out ~36V each, so two in series would be 36V + 36V = 72V.

The batteries are somewhat different. What kind of batteries do you have now, and how old are they? You can double battery capacity by adding a second parallel string, but batteries need to be matched in terms of chemistry, Ah, and age. If the batteries are no more than a year old, and you can get exactly the same brand/Ah rating, then pairing won't be too problematic.

What you do NOT want to do is pair a brand-new battery string with one that's 5 years old, or pair a 250Ah string with a 100Ah string, or a 100Ah lead-acid string with a 100Ah Li string.

 

[MisterSandals]

researching the planning of my solar expansion

Just out of curiosity, what is your existing charge controller? Are you planning on getting a different charge controller as part of your solar expansion?

 

[Bud Martin]

Just out of curiosity, what is your existing charge controller? Are you planning on getting a different charge controller as part of your solar expansion?

+1.

 

[pjvon]

Only the terminal voltage needs to be close, within 5%. Let's say your four panels put out 18.0V, so four in series equals 18 X 4 = 72V. Two 72-cell grid-tie panels typically put out ~36V each, so two in series would be 36V + 36V = 72V.

The batteries are somewhat different. What kind of batteries do you have now, and how old are they? You can double battery capacity by adding a second parallel string, but batteries need to be matched in terms of chemistry, Ah, and age. If the batteries are no more than a year old, and you can get exactly the same brand/Ah rating, then pairing won't be too problematic.

What you do NOT want to do is pair a brand-new battery string with one that's 5 years old, or pair a 250Ah string with a 100Ah string, or a 100Ah lead-acid string with a 100Ah Li string.

Thank you!

 

[pjvon]

Just out of curiosity, what is your existing charge controller? Are you planning on getting a different charge controller as part of your solar expansion?

Not changing, I have Mpp solar all in one 3048lv-mk.