question

ldoctor1 avatar image
ldoctor1 asked

Why does my SmartSolar 100/20 MPPT appear to be limiting the watts I am getting from my system?

I have a 300 Watt solar setup with a 48V battery that I am trying to use the SmartSolar 100/20 MPPT to charge. The setup is designed to have a high enough voltage to charge the 48V battery, around 52-55V, but it appears that the MPPT is stepping down the watts coming off of the panels. When I directly connect the solar panels to the input of the battery, the watt meter reads about 180W coming in. It has read as high as 215W with ideal conditions. However, when I feed the power from the panels through my MPPT, it only reads about 110W. I don't make any changes to the setup except for adding the MPPT. Is there a setting that I have wrong somewhere in the Victron app? Or is this supposed to happen? If anyone knows where the 70 or so watts that I appear to be losing are going I would appreciate the help!

Thanks,

Liam

charge current limitlow power
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

1 Answer
klim8skeptic avatar image
klim8skeptic answered ·

With your 48v battery you will need an array Vmp of about 60 volts.

What is your arrray specs?

5 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

ldoctor1 avatar image ldoctor1 commented ·

@klim8skeptic Each panel has a Voc of 22.5V and a Vmp of of 18.9V, so the array total is a Voc of 67.5V and a Vmp of 56.7V.

0 Likes 0 ·
klim8skeptic avatar image klim8skeptic ♦ ldoctor1 commented ·
What is the array voltage when the battery is being charged?

Panel temperature?

0 Likes 0 ·
ldoctor1 avatar image ldoctor1 klim8skeptic ♦ commented ·
Array voltage is around 53.5V it appears. Panel temp reads at about 80 F.
0 Likes 0 ·
klim8skeptic avatar image klim8skeptic ♦ ldoctor1 commented ·

Your Vmp is not high enough.


As the battery voltage increases, the array input voltage also increases. Once the input voltage increases above Vmp (@ temp) the available current reduces.

You need a higher Vmp array.

Victron online MPPT calculator.

0 Likes 0 ·
ldoctor1 avatar image ldoctor1 klim8skeptic ♦ commented ·
Ok, thank you! I will throw another panel on there and see if that fixes it.
0 Likes 0 ·

Related Resources

Additional resources still need to be added for this topic