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Understanding Victron SmartSolar Synchronized Charging

Jan 11, 2014
7,494
Sabre 362 113 Fair Haven, NY
Second Star has 2 150 watt Solar PV panels independently controlled by 2 Victron 75/15, the PV panels charge 2 Group 31 FireFly batteries. The controllers connect to a positive busbar.

Both controllers show the panels to be functional with open circuit voltages up to ~27 v.

Both controllers are on the same network.

One panel (port) is producing electricity and charging the battery, yesterday it developed 550wh with a max current output of 107 w.

The other panel (starboard) has no output with ~27 voc. This panel needs drops off the network every night and is not visible with the Victron Connect app until it is rebooted.

Both devices indicate they are configured for VE Smart Networking and "is waiting for data." With an additional message: "Sychronised charging is active and charge data is being shared between same type of chargers on the network."

At the moment, the batteries are at 68% SOC with the Port Panel supplying ~2 amps at 13.27 v to the battery. (It is 9:30 am, so low output would be expected.)

Open circuit voltage on the Starboard panel is 27.21v with no output.

The manuals and Victron website have not be particularly helpful.

What am I missing here? Why is only one panel supplying current, when both appear to be producing capable of supplying power?

Thanks for any insight and solutions.
 

Bob S

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Sep 27, 2007
1,663
Beneteau 393 New Bedford, MA
What would happen if you throw a blanket on the port panel? Would the other panel take over and start feeding the batteries? I don't have an answer but will follow. How easy would it be to put them in series and run them through on controller ans see what the different output would be? I know your controllers would be too small for the load but my understanding is the MPPT controller would just dump the excess or limit it to 15a.
 
Jul 1, 2010
831
Seaward 25, Catalina 350 Erie, Pa
I would first make sure both controllers have the same battery charging parameters set in them. You could then try taking them off the network and see how the 2 controllers perform independently. Do both controllers show close to the same battery voltages?

Though it sounds like you could have a bad controller due to the network issues, I'd uninstall and reinstall the victron app, and reconfigure the controllers (and call victron) before I condemned it.
 
Last edited:
Jan 11, 2014
7,494
Sabre 362 113 Fair Haven, NY
What would happen if you throw a blanket on the port panel?
The port panel shuts off. No change with the starboard panel.

I would first make sure both controllers have the same battery charging parameters set in them.
The settings are the same on both units.

Do both controllers show close to the same battery voltages?
No, and both are different from the SG 200. P =12.48 v, S = 13.21v SG200 = 12.6
The SG 200 is probably the most accurate as it is connected directly to the battery. The controllers get there voltage sense from the connection to the bus bar.
 
May 17, 2004
3,276
Beneteau Oceanis 37 LE Havre de Grace
No, and both are different from the SG 200. P =12.48 v, S = 13.21v SG200 = 12.6
The SG 200 is probably the most accurate as it is connected directly to the battery. The controllers get there voltage sense from the connection to the bus bar.
That sounds weird. Why would the port controller show such a low voltage? When charging if there were any “voltage loss” it would make the more distant voltage sensor (the port controller on the bus bar) read higher, not lower.

Can you swap the controllers and see if the port panel still works properly, or if the starboard one starts to? That might help narrow down the problem to the panel vs the controller.
 
Jan 11, 2014
7,494
Sabre 362 113 Fair Haven, NY
That sounds weird. Why would the port controller show such a low voltage? When charging if there were any “voltage loss” it would make the more distant voltage sensor (the port controller on the bus bar) read higher, not lower.
This might have been because the Port Panel was covered by a blanket. This morning the Port controller is reading about .1v higher than the SG 200 which is a small difference that could be attributed to measurement error or rounding errors.

Both controllers attach to a small fuse panel which is attached to the bus bar, so voltage loss from one to the other should be negligible.

This morning once again, the Starboard controller needed to be reset because the app didn't recognize it. Once the panel was unplugged and plugged in again the app recognized the panel. Both controllers are in the Bulk mode, with the port panel producing about 6w (not bad for a few minutes after sunrise on a dew covered panel) and the starboard panel is not producing any current.

Battery voltage readings on the app differ for each panel. Stbrd = 14.29v, Port 13.36, and SG 13.0.

At this point I think there are two possible explanations: 1) there is some setting on the controller that I missed or set wrong or 2) the controller is faulty. A third possibility is the boat gremlins have found yet another (un)amusing way to torment me. :huh:
 
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HMT2

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Mar 20, 2014
880
Hunter 31 828 Shoreacres, TX
The controllers connect to a positive busbar.
I’m no expert. Most everything i have read indicates the controller should be connected directly to the battery. Have you tried doing that?
 
Jan 11, 2014
7,494
Sabre 362 113 Fair Haven, NY
I’m no expert. Most everything i have read indicates the controller should be connected directly to the battery. Have you tried doing that?
No I haven't and won't. The total number of connections to a battery terminal should not exceed 4. Adding 2 controllers would exceed this limit. The bus bar works fine for one panel, the issue is one controller is not functioning properly.

On the positive battery terminal are the main cable to the bus bar, a jumper cable from the paralleled battery, and 2 voltage sense/supply wires for the battery monitoring system. Functionally, the bus bar is simply a big terminal for the battery.
 
May 17, 2004
3,276
Beneteau Oceanis 37 LE Havre de Grace
Battery voltage readings on the app differ for each panel. Stbrd = 14.29v, Port 13.36, and SG 13.0
That makes more sense than when the blanket was on the port panel. Still, why would the starboard panel be reading between OCV and actual battery voltage?

My suspicions are:

1) There’s a bad connection between the stbd controller and fuse panel, preventing it from pushing much current into the bus. If that connection gets flakey overnight maybe it affects the power to the controller and disrupts its networking.

or 2) A fault in that controller that’s either preventing it from outputting, or just preventing it from registering the current that it is pushing. If you cover both panels long enough to let the battery voltage sag, then only uncover the stbd panel, does the SG read voltage increase? If so I’d suspect that the panel and controller are outputting fine but it’s not reading the output.
 
Jul 1, 2010
831
Seaward 25, Catalina 350 Erie, Pa
FWIW, I also have 2 Victron networked together on our boat, and had a discrepancy between them concerning battery voltage this spring when I started things up. In our case cleaning up the mini fuses I have in series with each of them fixed it.
 

Bob S

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Sep 27, 2007
1,663
Beneteau 393 New Bedford, MA
Interesting. Dave, is this the first season for your set up? Was it working properly earlier this year? I am all set up and rewired for adding flexible panels to a Bimini. Unfortunately my canvas shop got shut down (Covid) and then the owner broke his shoulder so I've been waiting over a year for the new Bimini.
 
Jan 18, 2016
595
Catalina 387 Dana Point
I’m no expert. Most everything i have read indicates the controller should be connected directly to the battery. Have you tried doing that?
What would be the rationale? Voltage drop? Most boats 30' and up have a pretty seriously large conductors from the battery to the busbar/switch/panel/etc... And it most definitely shouldn't be connected "directly" to the battery, there needs to be an overcurrent device to protect the wiring to the controller(s), ampacity determined by the wire size that's running to the controller. And that wire isn't likely larger than 10 gauge because that barely fits into the controller's terminals.


Swapping port/stbd is a good idea. It would be pretty definitive on if the controller is bad.

I assume Dave (dlochner) has taken a voltmeter and measured the voltage on the battery side setscrews going to each controller? Even with no solar they should both read battery voltage. Of course, with no load, a poor connection may not show by just measuring voltage. You could force some current to flow from the battery to the controller by attaching a load (<15A) to the "Load" terminals of the controller and forcing them on with the app. The inverse is also possible, have enough load/battery charge need during the day so that current is flowing from the controller - but battery V should be the same in all cases.

I have the exact same Victron controllers, fed with 200W solar each. They both agree on battery voltage. The network thing works well, as in bulk they tend to both be putting out 8+ amps in pretty decent sun. Of course they're different depending on which way the boat is pointed, but they do stay in bulk/absorb/float together. Neither controller comes out of float when the fridge comes on. The networked display of wattage is correct. If you don't find a problem in the wiring to the stbd controller I'd concur it's a bad controller.
 
Jan 11, 2014
7,494
Sabre 362 113 Fair Haven, NY
Problem solved. Contacted Victron support who referred me to the dealer I bought it from.

Apparently this is a common issue and is caused by inadequate current from the battery to the controller. The controller will operate with power from the PV, however when the sun goes down, the controller shuts off. The problem was caused by a poor connection in the wire from the controller to the bus bar. After several hours of boat yoga to replace the wire, the panel is working as expected.

The first question Tech Support asked was about the fusing, about six months ago a shipment of off-brand cheap circuit breakers arrived in the country that trip too easily. I didn't have one of those.

At 8:45 the PVs are providing about 50w of power to the batteries. I'm a happy sailor this morning. Now off to tend to more tasks while waiting the waters to recede so we can escape Lake Ontario.
 
May 17, 2004
3,276
Beneteau Oceanis 37 LE Havre de Grace
My suspicions are:

1) There’s a bad connection between the stbd controller and fuse panel, preventing it from pushing much current into the bus. If that connection gets flakey overnight maybe it affects the power to the controller and disrupts its networking.
The problem was caused by a poor connection in the wire from the controller to the bus bar.
Not to pat myself on the back too hard, but that wasn’t a bad guess.

Glad you got it working!
 
Jan 11, 2014
7,494
Sabre 362 113 Fair Haven, NY
Not to pat myself on the back too hard, but that wasn’t a bad guess.

Glad you got it working!
To be honest, I was trying avoid changing the wire until all options were explored. To access the the controller it was necessary to empty a locker, remove a floor panel, hang upside down in an exaggerated downward dog position while unscrewing wires that have carefully installed on the panel which was mounted on a bulkhead. Not to mention chasing small screws that were reluctant to return home on the fuse box.

In the end I had to lower myself down into the locker and sit on 232 amp hours of battery in order to reach the devices. Fortunately I had replaced the 4 6v GCs with 2 Group 31 FireFlys so there was some room and the batteries did not have to be removed.

The PVs are now happily recharging the batteries with about 100 watts at 10 am. I'll be interested in seeing what they produce later in the day. With decent sun we should get about 1 KWH a day.

Thanks to everyone's suggestions.

Now, does anyone have an idea on how to get the Oswego River current to drop so the canal can open again and we can escape Lake Ontario. Its been closed for 10 days. And it doesn't look good for the next few days. :(
 
Feb 26, 2004
21,710
Catalina 34 224 Maple Bay, BC, Canada
Now, does anyone have an idea on how to get the Oswego River current to drop so the canal can open again...
Dave, isn't there a plug somewhere to pull? :)
Glad to hear you fixed your issue with the controllers. Sometimes it's worth a few extra feet of wire to put stuff where you can work on it. I've messed that up myself too often...
 
Jul 1, 2010
831
Seaward 25, Catalina 350 Erie, Pa
You need to stop the rain storms. Can you please do it before we head back down toward our Lake Erie home port. Currently in Lake Michigan where life is quite good. Hate heading down Lake Erie during tstorm season.
 
Jan 11, 2014
7,494
Sabre 362 113 Fair Haven, NY
You need to stop the rain storms. Can you please do it before we head back down toward our Lake Erie home port. Currently in Lake Michigan where life is quite good. Hate heading down Lake Erie during tstorm season.
You're lucky, no locks between Lake Michigan and Erie.

After a rather dry winter and spring, by the end of the month we'll be back to about average precipitation levels. The problem is caught back up to normal in 2 weeks with 5-7 inches of rain in the first 2 weeks of July. The drainage area is huge at 5,070 square miles and the gradients on the rivers feeding the Oswego river is very flat. The drop in elevation is between 10 and 20 feet over 50+ miles.