Hello everyone,

I have a question about setting up my solar panels with an MPPT inverter. I have 4 solar panels and I want to add 4 more, each with a voltage of 45V. I’m trying to figure out whether it’s better to connect all 8 panels in a single series or to split them into two groups of 4 panels each, connecting each group to separate MPPT inputs on the inverter.

Could anyone share their experiences or recommendations on which configuration would provide better performance and efficiency? Thank you in advance for your help!

This way, you can engage with the community and get insights based on others’ experiences.

If they are all going to face the same direction and if your inverter allows the voltage then I would put them all in one series string onto 1 mppt as that should bring your voltage close to or on the sweet spot for most inverters that allow high voltages.

If you share your inverter specs then the community will more accurately be able to suggest/advise you :)

Edited July 10, 20251 yr by WannabeSolarSparky

@WannabeSolarSparky gave a good reply. When having only 4 per MPPT you might find at times the voltage is too low to start the MPPT. Think of heavy cloud or just a small patch of shade.

On 2025/07/10 at 2:14 PM, esmail-kassir said:

Hello everyone,

I have a question about setting up my solar panels with an MPPT inverter. I have 4 solar panels and I want to add 4 more, each with a voltage of 45V. I’m trying to figure out whether it’s better to connect all 8 panels in a single series or to split them into two groups of 4 panels each, connecting each group to separate MPPT inputs on the inverter.

Could anyone share their experiences or recommendations on which configuration would provide better performance and efficiency? Thank you in advance for your help!

This way, you can engage with the community and get insights based on others’ experiences.

I agree with the others but If you have any trees near you I would puth 4 on each. Any shading would only affect the 1 mppt input and not the other, series sucks when it comes to shading. But if there is no trees or potential shading then add them all on 1 input. I do think 4 is enough though, that is close to 200V with just 4, Most mppts come on with half of that.

My inverter MPPT range is 60-450

I have a shading between 08:00-09;00) and (16:00-18-00)

The new extra 4 panels will be 1 year newer than the old 4 ones

So I am confused if the sweet spot is more important or the optimized performance for 2 mppts

Here's my take...

• If the MPPT does not start up due to low voltage as a result of clouds, then you have zero PV input until the light intensity increases to above the threshold.

• Even just a bit of shading on one or two panels can reduce the power of the string by 50%, or even worse, even on good sunshine days.

• Solar panels are relatively cheap.

I would add (say) two panels of the same make & output to the existing four to take you safely above the startup voltage of the MPPT. This will also result in earlier startup, and give you more "legroom" when it's cloudy.

I would then add a second string (of higher power rating if you like) of 5 panels to the second MPPT if you have roof space to accommodate them.

For the price of two or three additional panels (R2500 - R4500...) you will then have addressed both the voltage "sweet spot" and (to some extent) your early morning & late afternoon shading.

If this is not an option, then I would just add all eight panels on the same MPPT.

On 2025/07/10 at 2:14 PM, esmail-kassir said:

I have a question about setting up my solar panels with an MPPT inverter.

We need more information on your setup? Inverter make and model?

On 2025/07/10 at 2:14 PM, esmail-kassir said:

I have 4 solar panels and I want to add 4 more, each with a voltage of 45V.

What is your solar panel(s) spesifications? Make and model? The 45v is it Voc or Vmp? What orientation is existing 4 panels and the 4 new panel(s) planned orientation.

By supplying the above information it will be clear if you will be on the border of mppt starup voltage.

3 hours ago, esmail-kassir said:

So I am confused if the sweet spot is more important or the optimized performance for 2 mppts

It is not more effiecient running 2 mppt's at a lower voltage than running 1 mppt at a higher voltage as the latter produces less current at a higher voltage(mpp) and is therefore more efficient with less I²R losses especially in longer solar cable runs.

3 hours ago, esmail-kassir said:

I have a shading between 08:00-09;00) and (16:00-18-00)

The concept of “peak sun hours” (PSH) is more useful than simply counting daylight hours. Daily kWh = Total panel kW × Average PSH. Example: 5 kW solar × 5.5 PSH (summer) = 27.5 kWh/day ,5 kW solar × 3.5 PSH (winter) = 17.5 kWh/day. Maybe you already supplied the information on a different thread not sure.

14 hours ago, TaliaB said:

It is not more effiecient running 2 mppt's at a lower voltage than running 1 mppt at a higher voltage

that's the answer I am looking for , but what if the panels in different angles , can that make them more efficient than 1 group facing one way

3 hours ago, esmail-kassir said:

that's the answer I am looking for , but what if the panels in different angles , can that make them more efficient than 1 group facing one way

Maybe more effective, but not more efficient.

To really get to the bottom of this, can you state the make and model for the inverter as well as for the panels. And then also a sketch or a Google Map satellite image of the house, showing where the panels are now, and where you intend to put the panels, and where you are likely to get shading. Without that it's hard to give you much more than generalisations.