Solar panels should each have their own controller?

[RupertW]

I’ve got 2 controllers - I introduced the second one after 4 years as a backup as we were planning a long trip and I wanted redundancy. I use the second one from two panels which are a different manufacturer and power to the others in parallel, and which typically are more vertical dodgers than useful power but can be raised to horizontal if we are at anchor.

I think it makes sense for different panel types and for redundancy but have seen a set up with 6 controllers which I thought was bonkers as all are way under their maximum specs even in full sunlight.

 

[noelex]

Technically… Mine are 18.4v but yeah, that’s hair splitting

What panels are they?

The open circuit voltage (Voc) is very unlikely to be this low. You are probably referring to the maximum power point voltage (Vmp). Typical 12V panels have a Voc of around 21-23V and a Vmp of around 17.5-19.5V.

Before start-up, the solar panels are not connected to the batteries, so it is the open circuit voltage that determines the start-up. This needs to be 5V above the battery voltage as Paul mentioned. Once the solar controller connects to the batteries, the solar panel voltage needs to be 1V above the battery voltage for the charging to continue. This is where the Vmp is relevant.

 

[Chiara’s slave]

What panels are they?

The open circuit voltage (Voc) is very unlikely to be this low. You are probably referring to the maximum power point voltage (Vmp). Typical 12V panels have a Voc of around 21-23V and a Vmp of around 17.5-19.5V.

Before start-up, the solar panels are not connected to the batteries, so it is the open circuit voltage that determines the start-up. This needs to be 5V above the battery voltage. Once the solar controller connects to the batteries, the solar panel voltage needs to be 1V above the battery voltage for the charging to continue. This is where the Vmp is relevant.

Make? Fleabay. OCV 18.4v MPPV 17.8v it says in the booklet. Bullsh1t? Very possible, but thats what it says.

 

[noelex]

Make? Fleabay. OCV 18.4v MPPV 17.8v it says in the booklet. Bullsh1t? Very possible, but thats what it says.

If that open circuit voltage is correct, it would not work well with Victron, or most other MPPT controllers) unless you joined two or more panels in series, but it is likely to be a mistake as you surmised. There is typically around a 3-5V difference between Voc and Vmp, not the 0.6V reported

 

[Chiara’s slave]

If that open circuit voltage is correct, it would not work well with Victron, or most other MPPT controllers) unless you joined two or more panels in series, but it is likely to be a mistake as you surmised. There is typically around a 3-5V difference between Voc and Vmp, not the 0.6V reported

I have 2 different power panels, a 60w and a 100w, both on separate mppt controllers. As I never have to think about whether my battery is charged, I guess it works, and the supplied numbers mean nothing.

 

[Refueler]

I have 2 different power panels, a 60w and a 100w, both on separate mppt controllers. As I never have to think about whether my battery is charged, I guess it works, and the supplied numbers mean nothing.

KISS !!

Love it !