Installing Victron solar panels, charge controller and battery monitor

[Cockers]

Morning all you intelligent Motorhome electricians out there,

i’m just about to start fitting some new solar panels 2 x 175w panels a Victron smart charge controller and a Victron smart battery monitor, I have 2 x 110amp batteries fitted.

Question is do I wire the system independently to the existing setup and leave the old 100w panel on the roof with all its connections and let it continue to feed charge to the batteries, not that they are very efficient. The reason I ask is I just unscrewed the EC 500 Sargent unit and found the charge controller attached to it and the split charger tucked in the hole as well. There is a mass of wiring in there and not sure what goes where. Not sure if I need to unplug anything and wire any of the new wiring to it. I can’t find a wiring diagram anywhere.

I was thinking I would run the solar panel cables to the charge controller then to the battery monitor and then continue to the batteries. I like installing things myself then you understand where everything is should you have problems in the future.
Advice greatly received
Thanks
Graham

 

[Pausim]

I know little about solar controllers but having 2 in the same system sounds like a possible conflict. If one sensed a higher voltage in the system from the other one would it not shut down?

I have installed a Victron BMV battery monitor and you would not be able to wire any positive solar feeds to it. The shunt monitors only the negative connections. Basically it needs to be the very last connection to the negative side of your battery bank and it will only work properly if all negative connections go through it.

 

[Jaws]

What is the Victron controller rated at ?
If it can handle the max possible amperage I would just parallel up all three panels and stick the feed in to the Vectron
The problem you may encounter is that one or other of the controllers is more efficient and it will push up the battery voltage that the other controllers 'sees', and it will think the batteries are charged and reduce the feed accordingly, thereby negating any extra you should get ( if you see what I mean )

 

[Cockers]

The Victron controller is the MPPT 100/30. Where do I disconnect the old solar panel, I was told if you link solar panels together the system sees the lowest wattage panel and thinks they are all the same. So maybe I just need to work out how to disconnect the solar part of the Sargent unit and leave the split charger as is

 

[Jaws]

The Victron controller is the MPPT 100/30. Where do I disconnect the old solar panel, I was told if you link solar panels together the system sees the lowest wattage panel and thinks they are all the same. So maybe I just need to work out how to disconnect the solar part of the Sargent unit and leave the split charger as is

If all three panels are wired together all that the controller will see is the cumulative amperage.. Not any single panel.. and the panels are not 'intelligent' so they will keep outputting no matter what.
The only thing on the back of a panel is a big diode to stop back feeding

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[DBK]

You can wire them all in parallel but only if the 100W panel has the same nominal voltage as the 175W panels. You can check this by counting the cells, if they have the same number you will be fine.

Alternatively, you could connect the 100W to a Victron 75/10 charger (about £80) and connect the two 175W panels in series to the 100/30 controller. Series connection is what Victron recommend for best efficiency and having two separate systems will reduce the effects of shading. Using a Victron 75/10 will avoid any issues of conflict as it will follow the same charging regime as the 100/30.

 

[Clarky]

If anyone needs a solar controller we have used one to dispose of.
It was replaced as part of our recent lithium upgrade as it doesn’t have a lithium setting.
It’s a Victron 75/15 and has been in use for just over 4 years.
£30 (£80-90 new) and prefer collection rather than faffing about with post.

Richard

 

[Leakylunar]

That’s the size I need for 175w panel, are they fit n forget? I was looking at the ones with built in blue tooth so I can see what’s going via my phone.