Question about Victron Controllers

AnOldUR · August 2021

Two questions that I'm having trouble searching for answers to. I have factory solar on my 320S with the SmartSolar MPPT 75|10 controller. I purchased a Renogy 100W suitcase without a controller and plan to use a Victron controller in the tongue box next to the batteries. First question is, should I use another 75|10 or are there advantages to going bigger? Second, there's a Victron BlueSolar controller that a little cheaper. I thought they were all Bluetooth capable, but the description says, "Remotely control and monitor the extensive features of your BlueSolar MPPT charger by attaching a Bluetooth dongle ...". Am I right in assuming that it would be better to buy the SmartSolar version for using the Victron app to pair the two controllers? Thanks!

Dutch061 · August 2021

Unless you plan to add additional watts to your solar suitcase, the 75/10 is sufficient.

If it were me, I would use the Bluetooth version so they can be networked. You can network up to 10 Victron Bluetooth controllers together, they will automatically assign the master if I remember correctly.

Brad

CrabTab · August 2021

@AnOldUR I frequently get more than 5Amps of output from each Renogy Eclipse 100W panel (I have two) using an MPPT controller. The MPPT will push down the voltage, upping the amperage when in bulk charging mode. If you think you'd ever want to add a second suitcase panel, a bigger controller may be a wise investment now. Otherwise the 10Amp unit would be more economical and work fine.
The SmartSolar was the way I went. I believe when you add the Bluetooth dongle to the BlueSolar it becomes more expensive than the Smartsolar, plus you have two components to mount.

RMo · August 2021

From what I’ve read, the only difference between BlueSolar and SmartSolar is that Blue Solar lacks integrated Bluetooth so you have to buy a separate dongle to connect to your phone app.

AnOldUR · August 2021

CrabTab said:

If you think you'd ever want to add a second suitcase panel, a bigger controller may be a wise investment now.

So, there's no problem networking a 75|10 with a bigger controller? If at some point I decide to go with an additional suitcase or a larger one, would you suggest a 75|15 or 100|15 ? Or go even bigger to cover all bases? Thanks for all the replies!

edit to add side story:
I ordered a "used, like new" Eclipse like yours from Amazon but they sent me the older model. Had to send it back.

CrabTab · August 2021

@AnOldUR

OK, this'll be a longish answer. I apologize in advance for anything I type that you already know...

Firstly, I don't have experience networking multiple controllers. I route all of my panels through a 100V/20A Victron Smartshunt mounted in my tub, rooftop and suitcases. I know others have written about successful App networking on the forum and would defer to what they say.

In setting up my solar charging I hooked up everything in parallel, so each new panel adds amperage capacity. If I had added panels in series, the voltages would add. I wasn't worried too much about the voltage capacity of the charge controller as all my panels are rated around 20VDC max output. Since they are in parallel, the line voltage is about that no matter how many panels I add.

The voltage specs on all of my panels(4) are about the same and they are are each100W. The two rooftop panels are flexible HQST brand. The two suitcases are Renogy Eclipse. I will point out that some of the wiring components that I ordered from HQST came in Renogy labeled boxes (draw your own conclusion).

My early experience with my first Renogy Eclipse and it's factory mounted PWM controller, wired into the tub never had an amperage output over 4.5A (through a full camping season in 2019). Using that data, I chose the 20Amp Victron, thinking that at full tilt I would be skirting the capacity (4.5A x 4panels = 18A) should I ever have all 4 panels connected in full sun. After installing the rooftop panels and the Victron MPPT this spring, I quickly saw that he MPPT could and would alter the input voltage to maximize the amperage while bulk charging. I was frequently getting 11A of charge current (from 200W of rooftop panels) while in bulk mode. When I tested my two suitcases (also a combined 200W) I saw the same thing out the the Victron and the MPPT that is in my Goal Zero power unit.

Knowing the capability of these MPPT charge controllers, in hindsight I would have purchased something larger than a 20A controller for the T@B. As it is, I'll only use the suitcases on the T@B when the sun isn't hitting the rooftop panels (i.e. when the back of the trailer is in the shade). I have concern about overloading the 20A Smartshunt with all my panels working in full sun. That is why I made the recommendation that I did about the size of controller.

Sorry this was so long...

AnOldUR · August 2021

CrabTab said:

Sorry this was so long...

No apology necessary. I for one need all the information I can get to wrap my head around this. Very helpfully information.

One more thing came up during my research. I read that to charge two batteries more evenly I should connect all the positive leads to one battery and all the negative to the other. Then add parallel jumpers between the two positives and the two negatives.

Is this a good idea? I’m having a hard time seeing how this differs from having all the connections on the first battery and running parallel wires to the second. Can anyone explain if/how this works?

CrabTab · August 2021

@AnOldUR The simplest explanation I could give is "Electrons are lazy'.
The first method your mention is the correct way to charge.
If you hook up everything to the first battery and just add jumpers to the second battery, the resistance (further distance to travel) in the circuit will have more of the electricity flowing in and out of the first battery. The first battery will go through deeper charge/discharge cycles and wear out quicker.
Having the positive and negative leads on opposite batteries in the bank will make the electrons flow more evenly between them since the circuit routes directly through both batteries.

ChrisFix · August 2021

AnOldUR said:

Then add parallel jumpers between the two positives and the two negatives.

Is this a good idea? I’m having a hard time wrapping my seeing how this differs from having all the connections on the first battery and running parallel wires to the second. Can anyone explain if/how this works?

I don't know what type of batteries you have, but what you have described above is how to connect two batteries in 'parallel', which will maintain the voltage of both batteries (if they are both 12V, then combined in parallel, the combined battery is still 12V). The amperage of the combined battery will be doubled in this configuration.

If you have two 6V batteries, you'd want to combine them in series, which doubles the battery voltage, but the combined batteries amperage will be at the level of one battery. Series would require connecting the positive terminal of one battery to the negative terminal of the other battery. The other positive and negative terminals are where you attach all the loads.

AnOldUR · August 2021

CrabTab said:

@AnOldUR The simplest explanation I could give is "Electrons are lazy'.

I like simple. And the logic behind the explanation makes sense. Thanks!

The replacement SmartSolar MPPT 75|15 came today (sent back a BlueSolar non-Bluetooth purchased by mistake). I got the new battery and controller wired and it appears to be working. I say "appears" because I ran out of time and have not yet connected my solar suitcase. It's wired to the port, but I'll have to wait until the sun's up tomorrow to check that end of the system. Networking the two controllers went smoothly, but I'm not yet sure what to expect.

I read that when using two batteries they should be the same age. The first Vmaxtanks VMAXSLR125 AGM was installed about a month ago and was used on a 10 day mostly dry camping trip. I'm hoping that they are close enough that the age difference won't be a problem. I'll remain hooked up to shore power over night to top off both and then test my new capacity. The first Vmax made a huge difference compared to the original battery that came with my new to me 2020 320S. Expecting the solar suitcase and second battery to be all I'll need.

Edit to add the second picture. Found a shelf for over the batteries that perfectly fit the supports in my tongue box.

Image: https://us.v-cdn.net/5021717/uploads/editor/d3/p4sdwt5micy0.jpg

Image: https://us.v-cdn.net/5021717/uploads/editor/8v/0q9zvlfy57hv.jpg

CrabTab · August 2021

Well done @AnOldUR! Tag, you're it (explain it all to the next person)!

Tundra57 · August 2021

I have original bluetooth smart solar and factory solar panel. I added two 100w renogy suitcases. I added a connector on the tab along with another smart solar in the tab, output wired to the battery via a suitable fuse. I chose the smart solar unit by chosing it for max voltage out of the two renogy panels in series (2 x max voltage per panel) and current 2 x max current from a panel. This way you are set if the external panels are in series or parallel. (There is a big discussion about this on this site).

At first i just had both the controllers un networked. They did not share load evenly and would get confused about which mode to be in. I called a victron dealer and their tech guy suggested buying the BMV power monitor which sets up a blutooth network and allows the controllers to talk to each other so they share better and stay in the same charging mode.

Works good for me. I have had this stup for over a year and it works fine.

BTW, the controller fitted by nucamp is actually a bit small for the panel fitted. I did the calculations and contacted them. If the panel got close to full output (although unlikely) the 75/10 provided would be close to maxed out. Nucamp sent me a 75/15 to replace it

The BMV power monitor is very useful to monitor load and usage. I am very happy with the result.

I have also added two more sealed lead acid golf cart batteries so i have a total of 400 AH plus. It was not an easy job and i would not do it again. Lithium batteries are smaller and lighter. But at the time my lead acid batteries were new and I couldn't afford the $1,000 + for Lithium. When they die (its been 2 years and they are still holding up) ill probably swap them for lithium, paid for from my RV fund.

AnOldUR · August 2021

Tundra57 said:

I called a victron dealer and their tech guy suggested buying the BMV power monitor which sets up a blutooth network and allows the controllers to talk to each other so they share better and stay in the same charging mode.

I thought that the BlueSolar lacked integrated Bluetooth. When I returned the BlueSolar and replaced it with a SmartSolar I thought I was ready to network. During the setup I did what I believed was networking the two SmartSolar controllers. Is a BMV power monitor still necessary? How would I know if the two SmartSolar controllers are sharing the load?

edit to add:
Found a link and video that says, “ Connect either a BMV battery monitor, a SmartShunt, or the new Smart Battery Sense, to a Solar Charger.” The Smart Battery Sense looks to be the way to go.

Is there a bottom to this rabbit hole?

Sharon_is_SAM · August 2021

@AnOldUR - here is a link that says you do NOT need a BMV or SBS to network 2 SmartSolar controllers. The rabbit hole is as deep as you want it to be😉

https://community.victronenergy.com/questions/64684/syncing-two-different-mppt-smartsolar-controllers.html

AnOldUR · August 2021

Sharon_is_SAM said:

The rabbit hole is as deep as you want it to be 😉

Thanks for the link. From what I got from reading posts by you and others, that's what I thought going into this project. Even though it's not necessary I plan to install the Smart Battery Sense. At $40 for the longer range model, it seems to be a good value compared to a BMV. The improved efficiency and battery life from the Victron quote below should make up for that cost.

"Smart Battery Sense is a wireless battery voltage and temperature sensor for Victron MPPT Solar Chargers. With voltage and temperature sense in place, batteries will be better charged; improving charging-efficiency and prolonging battery life."

Denny16 · August 2021

Great, good to know. Thanks for the update.
cheers

AnOldUR · August 2021

My Solar Battery Sense, MPPT 75|10 and MPPT 75|15 are in place and networked. I'm running a test to see if it can keep up with demand. Shore power is disconnected. Solar suitcase is in place supplementing the rooftop panel. Fan is on high and a terribly inefficient (over a 5A draw) Igloo absorption cooler running. I'm looking for a drop in the battery voltage.

Here's what the Victron app is reporting. The network symbol is shown on all three when scrolled up. Does it look right? Right now, only the 75|15 is reporting "Network total power", but sometimes neither has that listed. Why does that total not include the wattage from both?

Image: https://us.v-cdn.net/5021717/uploads/editor/mc/81wdpehtcl13.jpg

Image: https://us.v-cdn.net/5021717/uploads/editor/jm/st84smuklmcu.jpg

Image: https://us.v-cdn.net/5021717/uploads/editor/3w/c8o0r4ca8ry1.jpg

Image: https://us.v-cdn.net/5021717/uploads/editor/5z/skueqa777e8r.jpg

Denny16 · August 2021

Looking good @AnOldUR, similar results to what I get, roof solar at around 50% and portable solar putting out more, as it is in direct sun, whilst rooftop is indirect.
cheers

AnOldUR · August 2021

@Denny16 ... Thanks for the feedback. Good to have conformation that I got it right. The only thing I'm still confused about is why I sometimes get a "Network total power" and why it only reflects the output from the panel it's showing results for instead of an actual total of both?

AnOldUR · August 2021

CrabTab said:

@AnOldUR The simplest explanation I could give is "Electrons are lazy'.

Third time is the charm? For the first wiring of my Victron Solar Battery Sense I simply connected the lugs to one of my two battery system. Thinking about the quote above, the next day I moved the negative lug over to the other battery where all the other negative wires were connected. Then this morning, thinking again about the lazy electrons, I moved both of the Solar Battery Sense wires to the opposite side of the batteries that only had the parallel jumper wires attached. Is there a winner somewhere in my confusion?

Denny16 · August 2021

@AnOldUR, You need all the negative connections on one battery, and all the positive wires on the second battery. The only connection between the two batteries is the jumper wire (for series battery setup) or two jumper wires, one positive to positive and the second negative to negative to negative. This includes solar connections, MPPT voltage monitor and the Battery Sense unit.
cheers

AnOldUR · August 2021

Denny16 said:You need all the negative connections on one battery, and all the positive wires on the second battery.

This is how my two battery bank is wired. The exception is the Battery Sense which is connected to the opposite side of each battery. My logic was that the sensor would get less interference from the other connections and give a more accurate reporting of the state of charge. This could very well be misguided?

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