Victron Battery Monitor & Solar Controller - installed in wrong order - Resolved

valkraider

I spent a good few days boondocking in my 360CS a location with a perfect east/west campsite and sunny clear skies with no shade on my panels, and I got really good solar - mid 230s wattage for a long part of the day.

But the Victron Battery monitor only ever showed battery drain, it just kept showing power being consumed and never any going back in. Even though the solar is producing well.

When I plugged in to shore power, the Battery monitor does show battery charging - power going into the battery.

So it clearly will detect both directions.

I thought I had found a solution: using the phone apps, I set both of them up with a local "network" and they should be talking to each other. The Solar charge controller does say that it should get battery info from the battery monitor - but the battery monitor does not get any info from the solar controller.

Looking at my wiring in the 260CS "battery in the drawer": the Victron solar controller is wired directly to the battery. (Both fuses were good, and the positive wire from the controller was warm - indicating its doing the work...)

This makes the "state of charge" numbers in the battery monitor useless because it has no knowledge of the solar charging.

Everything below this point is me guessing just based on my observations. This is not any official design, wiring diagram, or owners manual - and I certainly am not an electrician. 

I am wondering if they are installed in the wrong "order" kind of?

It seems like maybe they are set up like this:

Should the battery monitor be closest to the battery, and the solar controller be upstream of that - so that the battery monitor is aware of power coming in from the solar controller?

I am not well informed about this at all, but to me (un)common sense says it should be set up kind of like this if we wanted the battery monitor to have good actual charge and consumption numbers:

In any event - we had plenty of juice for the few days, I just have no way to use the info from the battery monitor effectively...

Grumpy_G

You are correct but your drawings are too simplistic to make sense as there are positive and negative wires. The battery monitor sits on the negative side of the battery between the battery and everything else. So the negative side of the solar charger should not go directly to the battery but to the other side of the battery monitor shunt. 

valkraider

I will look around the wiring and see where they put the battery monitor.

Yeah, my professional highly technical diagrams were built for speed, not finesse.

Thank you for the info - I will see what I come up with!

pthomas745

What we need to see, if you can: your settings pages for the shunt and the  solar controller.  And, show us a picture of the shunt and the wiring to the battery.  It just may be something really simple that needs to be adjusted.  

Gomers2

Another way to say it: the ONLY wire attached to the neg side of the battery should go directly to the neg terminal of the Smartshunt. I suspect you have some additional wires on that neg side of the shunt and or on the battery (from your solar controller). Move those to the system side of the shunt and you will see your state of change increase, not just decrease. You will need to recalibrate the state of charge by having the system auto sync or setting it to 100 when you know it's full. The shunt is not counting the current flow from the panel controller because it's not going through the shunt, but past it.  My unit was delivered with this erroneous set up.

valkraider

Yeah, that looks like the problem for me.

( FWIW: this is the "rebuilt" or "reconfigured" battery drawer of my 350CS - different than when they originally delivered it literally all on a drawer - including the battery...)



You can see the solar negative goes directly to the battery.

I will move it. 

Any suggestions for doing so safely?

I would think I pull the fuse on the charge side of the solar, to make sure no current is coming in. The 12v switch in the house is off, and I am not plugged in to shore power.

Since this is on the negative side of the battery I think I would be OK disconnecting and moving them - since you always disconnect negative first and reconnect it last...

Also - here are my settings just in case anyone sees any that look out of whack. I will search for some manuals as I want to understand what they mean in some of these settings .

Solar:
     



Battery:
    

Thanks!

pthomas745

Yes, that "solar negative" should be moved to the shunt like the picture that Gomers provided.

Your shunt needs some adjusting.  Your "charged voltage" should be moved up to 14.2.  The "discharge floor" is what the shunt uses to determine the "time remaining" display, should be set to zero.  

Here is a Battleborn page about this sort of setting.

https://battlebornbatteries.com/blogs/articles/configure-victron-bmv-700-bluetooth-dongle

Grumpy_G

Any suggestions for doing so safely?

I would think I pull the fuse on the charge side of the solar, to make sure no current is coming in. The 12v switch in the house is off, and I am not plugged in to shore power. 

Not being plugged in is the most important step so there is no unexpected power from the converter when the battery terminal is disconnected. It's only 12V so no danger of electrocution. 

Horigan

@valkraider Given that you have an LiFePO4 battery, you can update the Discharge Floor to 10%.  The current 50% value is for a lead acid/AGM battery.

valkraider

For the record too - these settings & wiring config are the way they were set on delivery.

I guess it’s too much to hope that people who build what are now realistically very expensive campers - would set these things up right for their customers.

Not everyone is as interested in the details as those of us on this forum. How many people just have these wrong forever? 

:(

pthomas745

You would be quite amazed at how many trailers come from dealers or the factory with absolutely wrong Victron setups. Which is the reason that in almost every thread about "Victron", the request usually is made to show us your "Settings Pages". Like we did here.  The owners with the Multiplus devices/apps have all sorts of issues trying to get things straight.  

And, you are correct: there are probably many trailers out there with the wrong settings.

Grumpy_G

Most solar charge controllers come with "AGM" as the factory setting because it is the safe option with the least aggressive charging curve. Maybe a good non-chain dealership will check it before delivery but it's pretty much on the buyer to verify the settings. A friend of mine had an Outdoors RV trailer with plenty of solar on the roof and his dual calcium lead acid batteries were done after a year and a half because the AGM absorption voltage is lower and the batteries never got properly equalized.

valkraider

OK, I fixed the wiring - moved the solar negative to the negative post on the battery shunt. Now the only thing connected to the battery negative is the shunt.

I rolled the trailer out into the sunshine and tested - everything is working as expected now, I can see energy moving both directions with solar.

Thank you all for the help!

Noteworthy: the solar negative wire had a connector that was too small for the shunt post, so I had to replace it. The shunt post is 10mm ( 3/8in ).