Not sure about Solar read out on Victron

[Makr0]

Hey All

My new boat came with a 400 w solar array Victron Smart Solar MPPT 100 | 30

The previous owner enjoyed doing DIY electrical, that for the most part seems sound but is ugly. In one note I found he talks about rewiring the solar panels.

I've not paid this much attention but today looking at the readouts from the smart solar the voltage looks off.

Solar voltage is reading ~37v... my hunch is he's paired the panels to increase voltage due to the cable distance from the battery.

Is this normal practice?

[Sailmonkey]

That’s perfect.

The mppt controller is designed to take higher voltage and step it down to always have a higher potential than the battery. When the voltage is reduced the current is raised.

This is a good thing.

[RaymondR]

Originally Posted by Sailmonkey

That’s perfect.

The mppt controller is designed to take higher voltage and step it down to always have a higher potential than the battery. When the voltage is reduced the current is raised.

This is a good thing.

The Victron MPPT solar controller will not work very well if you try to feed it with a nominal 12V from the panels.

[Zzmeyer]

He has apparently wired the panels in series. Easy to check if you can see the wiring between panels. If the positive comes off one panel and the negative off the other it is series which combines the voltage of the panels. Panels typically put out 18 or more volts and as said the charge controller adjusts down to the charge voltage.

[RaymondR]

"Victron Smart Solar MPPT 100 | 30"

What the 100/30 numbers mean is that the maximum input voltage to the controller from the panels is 100 volts and the maximum output to the battery is 30 amps.

Consequently, to minimize the power losses between the panels and the controller you can wire up the panels in series until their maximum output voltage is 100 volts.

[Makr0]

Very Cool. This all make perfect sense now!

[Zzmeyer]

Originally Posted by RaymondR

"Victron Smart Solar MPPT 100 | 30"

What the 100/30 numbers mean is that the maximum input voltage to the controller from the panels is 100 volts and the maximum output to the battery is 30 amps.

Consequently, to minimize the power losses between the panels and the controller you can wire up the panels in series until their maximum output voltage is 100 volts.

Raymond is correct, but make sure you don't assume the panels are 12 volts. A typical open circuit voltage is more than 20 volts, so wiring in series needs to be limited to the number of panels times a much higher number than 12 volts.

[Nicholson58]

Originally Posted by Zzmeyer

He has apparently wired the panels in series. Easy to check if you can see the wiring between panels. If the positive comes off one panel and the negative off the other it is series which combines the voltage of the panels. Panels typically put out 18 or more volts and as said the charge controller adjusts down to the charge voltage.

Not necessarily true. We have three panels in parallel, 54 volts open circuit feeding our MPPT controller. The PO May have use high VOC panels. That’s good.

It’s easy to research the makers specifications on line.

[Zzmeyer]

Originally Posted by Nicholson58

Not necessarily true. We have three panels in parallel, 54 volts open circuit feeding our MPPT controller. The PO May have use high VOC panels. That’s good.

It’s easy to research the makers specifications on line.

You're absolutely correct, both points. Checking the specs will tell him the answer.

[Zzmeyer]

Originally Posted by RaymondR

"Victron Smart Solar MPPT 100 | 30"

What the 100/30 numbers mean is that the maximum input voltage to the controller from the panels is 100 volts and the maximum output to the battery is 30 amps.

Consequently, to minimize the power losses between the panels and the controller you can wire up the panels in series until their maximum output voltage is 100 volts.

Raymond is correct, but make sure you don't assume the panels are 12 volts. A typical open circuit voltage is more than 20 volts, so wiring in series needs to be limited to the number of panels times a much higher number than 12 volts.

[sailcrazy]

Following. We are using a Victron Controller for our solar as well.....but our 4 panels are in parallel! Maybe that's part of the reason for our very limited solar output-I had always just written it off to fixed (horizontal) panels that are also old.

[RaymondR]

Originally Posted by sailcrazy

Following. We are using a Victron Controller for our solar as well.....but our 4 panels are in parallel! Maybe that's part of the reason for our very limited solar output-I had always just written it off to fixed (horizontal) panels that are also old.

Did the same myself and was baffled as to why my LiPo was not charging until I pondered a while on the "Trends" page of the Victron Connect app and noticed that the "Panel Voltage" would cycle to below the battery plus five volts threshold and switch the amps off. I rewired the panels for nominal 24 volts and it fixed the problem.

I now have a strange arrangement whereby 300 watts of panels are connected in series with about 700 watts which supply 12 volts to both the series connection for 24 volts and also the 12 volt regulator for the Lead acid bank.

[noelex 77]

Originally Posted by Makr0

Hey All

My new boat came with a 400 w solar array Victron Smart Solar MPPT 100 | 30

The previous owner enjoyed doing DIY electrical, that for the most part seems sound but is ugly. In one note I found he talks about rewiring the solar panels.

I've not paid this much attention but today looking at the readouts from the smart solar the voltage looks off.

Solar voltage is reading ~37v... my hunch is he's paired the panels to increase voltage due to the cable distance from the battery.

Is this normal practice?

What are the specifications for your solar panels ?

[Wilyum]

Originally Posted by sailcrazy

Following. We are using a Victron Controller for our solar as well.....but our 4 panels are in parallel! Maybe that's part of the reason for our very limited solar output-I had always just written it off to fixed (horizontal) panels that are also old.

You have 4 panels in parallel, going to only 1 controller? How many watts each?