question

marvin2812 avatar image
marvin2812 asked

Smart Solar 100/30 MPPT PV Voltage frozen after some time in float mode

b61de3d9-cdb5-437c-8275-f180441cd694.jpegHi Victron Experts,

i have a question regarding my Victron Smart Solar 100/30. I used the MPPT controller for a year now with an AGM Battery. Everything worked fine, now i bought a Victron LiFePo4 Battery (200Ah) and strange things happen from time to time. The MPPT Voltage seems to be frozen at a certain value after some time the device has entered the float mode. In the screenshot below, you can see the PV voltage of about 15V instead of usually 17-18V or higher when the power is not needed and the battery is full.

So i am wondering why the MPPT is using such a low voltage now, this never happened when the device was connected to the AGM battery previously. Also you can see, the 10 minute MPPT adjustments are not made anymore while the device uses 15V PV for the MPPT. After disabling and enabling the charger in the battery settings of the smart solar, the mppt goes to around 18V PV again and does the 10 minute mppt adjustments. That workaround does just help one time, tomorrow the same will happen after some time in float mode.

Do you have an explanation for this behavior or am i doing something wrong?

I have 2x 120W modules, parallel connected to the MPPT, charge mode is set to predefined lifepo with manual adjusted absorption time. Absorption voltage 14,2v float voltage 13,5v

Module Data (WS120SPS-L)
Umpp 19,2v
Impp 6,25a
Uoc 21,8v
Isc 6,84a

Thanks for your help !

BR
Marvin
MPPT Controllers
b61de3d9-cdb5-437c-8275-f180441cd694.jpeg (131.2 KiB)
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
kevgermany avatar image
kevgermany answered ·

Looks as if the panels are delivering too low a voltage. The MPPT doesn't really control panel voltage. Did you get them covered in Kalahari dust last week? Had to clean mine.

3 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.

Stefanie (Victron Energy Staff) avatar image Stefanie (Victron Energy Staff) ♦♦ commented ·

Wasn't that dust from the Sahara? Mine are still covered in dust, hoping for a self clean with the next rain ;-)

@Marvin2812

I've a new PV module on my balcony, which shows a similar behaviour, but independent of charge state. The reason for this is shading. I'm using a half cell module and when certain parts of the module is covered from shade, it kind of switches to a lower voltage mode and ensures still a pretty good output, which I never would get with a standard module.

img-4990.png


0 Likes 0 ·
img-4990.png (641.3 KiB)
marvin2812 avatar image marvin2812 Stefanie (Victron Energy Staff) ♦♦ commented ·

Thanks to both of you for your feedback, thats a good point. I have cleaned the modules after the dust but shade is a good point. I have installed 2 modules, 1 horizontally 1 vertically, at the time when the MPPT operates with low voltage, the horizontally module is almost not covered by sunlight because of the low angle of the sun in the afternoon. I‘ll see how it goes in the future. I was just wondering if there is something wrong with my smart solar mppt because the voltage seems to be frozen more or less but as Stefanie shows, it seems to be normal then. Next time when it happens i‘ll disconnect one module to see what happens then. I‘ll share the outcome here then.

0 Likes 0 ·
kevgermany avatar image kevgermany ♦♦ Stefanie (Victron Energy Staff) ♦♦ commented ·
Sorry, yes Sahara.
0 Likes 0 ·