Should I upgrade to a 48 volt system? advantages?

[WYtreasure]

I am currently putting together my system and learning as I go, I'm curious of the advantages of a 48V system over a 24V.
I read somewhere you can use smaller wire, but which wire is this referencing? I did not see that info needed on a wire sizing calculator
for my wire from panels to Charge controller? can you run smaller wire there with 48V, that would save $$$

I currently have 12, 440 watt panels (5,280 watts total)
I have 2 Midnight 150 charge controllers
I currently have 24 lithium cells, to make 3, 24V batteries, each consisting of 8 cells.

I am considering buying another 8 cells, to make a total of 2, 48V batteries. and I need to decide this before I order my inverter.

suggestions? input, is it worth it?

FYI I barely know enough to discuss the subject, but am learning.

I am attempting to put together a 2000 to 3000 watt array with 24 or 48 volt batteries and intend to use the MidNite Classic 150.
I like the capacity of the Classic 150 at 48 volts. 24 volts would limit the system, and require much larger wire for my long run to the controller.

But you may want to make sure you can find the proper inverter, Watts & Volts, before you base your system voltage on the cost of wire. It doesn't sound like finding the proper inverter will be an issue though.

 

[MichaelK]

I am attempting to put together a 2000 to 3000 watt array with 24 or 48 volt batteries and intend to use the MidNite Classic 150.
I like the capacity of the Classic 150 at 48 volts. 24 volts would limit the system, and require much larger wire for my long run to the controller.

This becomes a simple math problem. If you want to install 3000W of solar, then 3000W/25V charging = 120A, which substantially exceeds the capacity of a single Midnight 150. Even pro-rating that number down to 85%, that's still 102A.

So, going with 48V the two numbers are 60A and 51A respectively, which the MN150 will easily handle.

 

[Bluedog225]

Another consideration, I believe DC arc is not an issue below 80V. Might want to double check that number though.

 

[12VoltInstalls]

24 volts would limit the system, and require much larger wire for my long run to the controller.

Do you mean your charge controller is a long way to the batteries?
Why not put the controller close to the batteries and wire the panels so voltage is higher and solve the problem? Panel output voltage doesn’t have to match the batteries.
Unless I misunderstood you.

 

[wholybee]

Some very basic understanding of the math is in order: Watts = Volts * Amps

Now with that. You said you will have a 3000W inverter. Solve for Amps.
12 Volt system = 250A
24 Volt system = 125A
48 Volt system = 62.5A

That is for the Battery Cables to the Inverter. The "Limit" spoken of before isn't a hard rule. You can buy giant battery cables for a 12V system, and they make 3000W inverters for 12V. But unless they are very short (they very well might be as inverters are often right next to the battery) then you might run in to some issues with Voltage drop. Do you know what appliances you will be using, and have you added up the required wattage?

The same principle applies to the wire for the panels. For simplicity, take an example of 4 100W panels, each with a voltage of 20V. You can wire them in parallel for 20V, series-parallel for 40V, or series for 80V. In all cases, there is still a total of 400W. Again, solve for Amps.
20V = 20A
40V = 10A
80V = 5A
You will nominally get the same wattage from the panels and charge at the same rate, but the series configuration requires much smaller wire.

 

[Deleted member 1888]

My max power usage out of the 3,000 watt inverter will be about 2,400 watts if I run everything at the same time with the big pull being the 1,500 watt air fryer

Look at it this way, if you ever think you will need more than 3000w then go 48v. If you know for a FACT you will NEVER use more than 2400w then go 24v. You can get more than 3000w at 24v but it will cost more than just going 48v. If you go 48v you can always add more panels later, you can even add more controllers to the same system.

 

[MrM1]

This becomes a simple math problem. If you want to install 3000W of solar, then 3000W/25V charging = 120A, which substantially exceeds the capacity of a single Midnight 150. Even pro-rating that number down to 85%, that's still 102A.

So, going with 48V the two numbers are 60A and 51A respectively, which the MN150 will easily handle.

With the classic you can over panel it as long as you do not exceed 150 VOC, and in 24v mode it will clip everything above about 2600 watts. I am about to install a 5200 watt array on a single classic at 24v. Midnite Solar has said it is not a problem and will aid in getting more production in the morning / evenings and on cloudy days. The Classic will just clip the excess power once it exceeds what the classic can use

A classic at 12v can do 96 amps charging. Can do 92amps at 24v and 86amps at 48v.

Another feature exclusive to Classics is Midnite's HyperVOC feature. Allows you to actually go over 150 VOC without smoking the SCC. If can actually take (but not use) 198v dc using a 48v system.

 

[WYtreasure]

Do you mean your charge controller is a long way to the batteries?
Why not put the controller close to the batteries and wire the panels so voltage is higher and solve the problem? Panel output voltage doesn’t have to match the batteries.
Unless I misunderstood you.

My array will be located 55' from the controller for numerous reasons; starting with the boss lady says so, and ending with it really needs to be that way. I think.

The 48 volts was pure coincidence, referring to combiner box output and batteries. But thanks for the Volts advice.

Don't want to hijack this thread, my stuff is here:
A simple build, or so I thought; 12 panels, MidNite combiner & Classic 150, 2 LiFePo4 200Ah, Inverter …

 

[Stewfish]

I am currently putting together my system and learning as I go, I'm curious of the advantages of a 48V system over a 24V.
I read somewhere you can use smaller wire, but which wire is this referencing? I did not see that info needed on a wire sizing calculator
for my wire from panels to Charge controller? can you run smaller wire there with 48V, that would save $$$

I currently have 12, 440 watt panels (5,280 watts total)
I have 2 Midnight 150 charge controllers
I currently have 24 lithium cells, to make 3, 24V batteries, each consisting of 8 cells.

I am considering buying another 8 cells, to make a total of 2, 48V batteries. and I need to decide this before I order my inverter.

suggestions? input, is it worth it?

48v =
16 cells in series = larger battery with less BMSs
48v = smaller wire and longer wire runs
48v = larger amount of panels input (watts and volts)
MPP LV 6548 does 250v in 8000w max in