MPPT Sizing Calculator

ExSolar has been busy! Load shedding came like a unwanted visitor and surprised us all. While we had a tough time keeping up with the huge influx of solar enquiries, we got some more awesome sites finished and commissioned.
Thank you to all our customers for being so patient with us during that busy time.  
We know load shedding is bound to strike again, so be prepared before the demand skyrockets again, get a quote today and let's work with you to get load shedding ready! 

If you use VictronConnect, we have noticed some people assume you need an internet connection to update compatible products. To reassure those that have asked about this – it is not the case and here is why.
All firmware files are already bundled with the app, so as long as you have the latest version of the app – you have the latest firmware.
In other words, let’s assume you have not visited an installation for some time and that location does not have internet access on-site. As long as you ensure you have the latest version of the app whilst still in range of an internet connection, you can then go to site and if a product needs updating VictronConnect will tell you that. This applies to Wired and Bluetooth products (be they Smart tech built in or if using the VE.Direct Bluetooth Smart dongle).

• Here is the list of VictronConnect compatible products in the VictronConnect manual.
• All firmware files for all products, with changelogs, are available at Victron Professional
• VictronConnect App downloads
• Do keep your products up to date, as this ensures the latest fixes and features.

Firmware update exampleJust one example of the many products whose firmware can be updated with VictronConnect – in this instance using an iPhone XS Max over Bluetooth to a SmartSolar MPPT charge controller.

Note: if for some unlikely reason you have any issues updating your firmware using VictronConnect, it can usually be resolved by following the steps in the firmware update and troubleshooting section of the VictronConnect manual, or by contacting your distributor.

​Article courtesy of John Rushworth at Victron Energy 

Life used to be so simple; in a 12V battery system you took a ‘12V’ solar module, watched carefully that the maximum PV current would not exceed the charge controller maximum current and the system would work.
Unfortunately due to the fact, that with PWM controllers the PV module is not feeding the battery from its maximum power point (MPP), the system loses a lot of energy. In the following diagram you can see, the area of the MPP in blue  (Vmpp * Impp) is up to 30% larger than the PWM area (Vbatt * ~Isc) within the IV curve.

So, with the advent of the newer Victron Energy Blue Solar MPPTs, things changed for the better when compared to PWM solar charge controllers.

• If a specific yield is the goal, the 30% higher efficiency of the MPPT will reduce system costs, because the same energy can now be produced with a smaller PV generator.
• If the size of the solar module was already fixed, the yield is now higher in the same system when using an MPPT.

In both cases the user is a winner!
Sizing the system can be done electrically to see if the system is allowed and will not destroy any components, when looking at the yield to see how much energy it will produce. For now I will look at the first part, to find out what is possible on the electrical side.
By adding a DC/DC converter in the Blue Solar MPPT controller, the system also becomes more flexible when we look at the input voltage of the controller. The challenge now, is to match the PV modules to the controller, because we are not concentrating on only ‘12V’ or ‘24V’ modules anymore. Basically any module can now be used if it is within the input voltage range of the charge controller.
In fact we can now put modules in series as well as parallel, which will also increase the input power and flexibility. Thanks to the output power or current limiter, the output power will never exceed the maximum of the controller. This Blue Solar MPPT feature is unique and makes the charge controller even more interesting!
You can now for example add the same type of modules in parallel later without the need to change the MPPT charge controller. This reduces costs to a minimum, whilst still increasing the yield!
Also, I took the values for all our Blue Solar MPPT charge controllers and Blue Solar modules and combined them into a Spreadsheet. Now sizing a Blue Solar MPPT charge controller is easy!

Download: VE-MPPT-Calc.xlsx (744KB) – This configuration spreadsheet is compatible with MS Excel.
Now for the technical explanation, for those who would like to know some more details:
Exceeding the input voltage range will (as it did with the PWM controllers) damage the controller permanently. 
Of course we will also need to take a look at the minimum voltage, where the Blue Solar MPPT controller will start working. If you take a SPM50-12, the Open Circuit Voltage (Voc) is 22.2V and the maximum power voltage (Vmpp) is 18V at Standard Test Conditions (STC) which means 1.000W/m² irradiation, 25°C cell temperature and an Airmass of 1.5. If the cell temperature is higher or less than 25°C, this voltage reduces or increases due to the temperature coefficient, in this case -0.34%/°C (see Blue Solar module datasheet).
So if you take 3 modules SPM50-12 on a Blue Solar MPPT 150/70 in a 48V system on cold days say, -10°C (only looking at the voltage), you can start up charging:
The startup voltage is 48V + 7V (see MPPT 150/70 datasheet) = 55V The modules will produce 3 * ( 22.2V + (-0.34% of 22.2V * -35°C temperature difference)) = 74.5V 74.5V is higher than 55V -> that’s perfect
Also running in the MPP the system would work:  
The running voltage is 48V + 2V (see MPPT 150/70 datasheet) = 50V The modules will produce 3 * ( 18V + (-0.34% of 22.2V * -35°C temperature difference)) = 61.9V 61.9V is higher than 50V -> that’s perfect
Doing the same thing, when the modules get warm during the day, in this case 70°C you can see what happens:
The startup voltage is still 48V + 7V (see MPPT 150/70 datasheet) = 55V The modules will produce 3 * ( 22.2V + (-0.34% of 22.2V * 45°C temperature difference)) = 56.4V 56.4V is higher than 55V -> that would work
But now in the MPP the module voltage is lower than the minimum:
The running voltage is 48V + 2V (see MPPT 150/70 datasheet) = 50V The modules will produce 3 * ( 18V + (-0.34% of 22.2V * 45°C temperature difference)) = 43.8V 43.8V is lower than 50V -> this is not enough!
The high DC/DC conversion efficiency (97.5% at 48V) will result in following output maximum charging current (@ -10°C) of 61.9V Vmpp* 2.74A Impp / 48V Battery voltage * 0.975 Efficiency = 3.45A This is far below the maximum of 70A, so it will be all used to charge the battery.
Increasing the number of modules per string to 6 in series and making 10 strings in parallel gives the following result at -10°C:

Now at high temperatures such as a 70°C cell temperature the system will work just fine! Taking this example in the Spreadsheet you can now  increase the number of strings in parallel and you will see, if starting at 11 strings, that the controller will start to reduce power. The big advantage in doing this is that you will now produce the maximum controller output at a lower irradiation. As module prices decrease, this is an effective option.
Please note, that you can use ‘preconfigured’ minimum and maximum temperatures. I’ve also given some installation examples, at the bottom of the spreadsheet, with their anticipated module temperatures for various types of installations.
Oversizing a PV arrayOversizing a PV array is installing more peak power (Wp) than the maximum charge power of the chosen MPPT charge controller. A common reason to oversize is to cater for winter time.
How to determine by how much you can oversize a PV array? This can be done with help from the spreadsheet tool. Here though is the manual explanation of how it is done.
There are two limits, when determining the maximum array size that can be connected to an MPPT:

1. The Maximum PV open circuit voltage (Voc at STC)
2. The Maximum PV short circuit current (Isc at STC)

Both values are specified in the datasheets of all our MPPT Solar Charge Controllers. Those two ratings of the PV array must not exceed these MPPT limits.
Note that these two maximum ratings must not be multiplied to determine the maximum installable peak power. Instead, each of them needs to checked by itself:

Determining the maximum PV open circuit voltageFirst look at the datasheets of the solar panels to see what their maximum open circuit voltage is. Then multiply that by the number of panels that are in series in the array. The result of the multiplication must not be higher than the Maximum PV open circuit voltage as listed on the MPPT Datasheet. Make sure to take into account the coldest expected temperature. The colder it is, the higher the open circuit voltage on a PV array will be.

Determining the maximum PV short circuit currentGet the maximum PV short circuit current from the PV Panel datasheet. Multiply by the number of panels in parallel in the array. Having more panels in series does not change the number.
The result of the calculation may not exceed the Max PV short circuit current as specified in the MPPT Datasheet.
Good luck and enjoy sizing the BlueSolar MPPT Charge Controller!


Article courtesy of Victron Energy 

Victron Energy have released version 2.23 of Venus OS – the software which is at the heart of the Color Control GX, Venus GX, Octo GX and the CANvu GX. A nice page outlining those products and comparing them is available here. They have also released VE.Bus version 455, for the MultiGrid and MultiPlus-II inverter/charger models.
Included in this update are various improvements; including that the user interface will not show details of VE.Bus Error 11.

VE.Bus Error 11
This error only applies to the MultiGrid and MultiPlus-II models: the inverter/chargers with a dual backfeed relay. For ESS systems, a grid-code is selected in VEConfigure, and then as part of grid-code compliance; the device verifies that its internal relays and measurement circuitry functions properly. When this test fails; Error 11 shows. Quite often, the error can be tracked down to an installation error (swapped Phase and Neutral wiring for example), but there were also some software issues; and the details of Error 11 not being visible was not helping. Today we are taking care of all that. A short list of related firmware releases:

1. VE.Bus firmware 454 – February 8th – Adds detailed Error 11 reporting.
2. Venus OS v2.23 – today – Adds detailed Error 11 reporting.
3. VE.Bus firmware 455 – today – Fix false Error 11 of the type “AC0/AC1 mismatch” and “UMains error”.

Conclusion: if you have a VE.Bus Error 11 and have already double-checked the wiring, then update all to the firmware released today; which is likely to solve the issue. And if it doesn’t – then at least you will have far more information to help you resolve it.

Full changelog
General:

• Fix that changing the date & time did not work properly for off-grid systems: changes to the date and time were only stored to the device when being rebooted from within the menus (which nobody ever does). Power cycling a unit would make it jump back to the previous date & time. This is now fixed. Note that only installations without internet were affected: with internet, the date and time are set automatically; as well as stored properly. This bug has always been in the system, since the first release.
• Update Eastern Europe time zones; fixes issues with Romania and other countries
• Add a low-cell voltage warning and alarm for Lynx Ion BMS systems. Note that this warning and alarm is only available for systems with a Lynx Ion BMS. Not for the (discontinued) Lynx Ion + Shunt models; and also not for any other (CAN-bus connected) battery types. How does it work? It will first issue a warning; and that will change to an alarm once the voltage is so low that the system has disabled the ‘allow-to-discharge’ signal; which shuts down any connected inverters and other loads.
• Fix internet connection issues for a small number of systems; by lowering the MTU to 1450. If affected you typically see that logging data to the VRM works, but Remote Console does not work; and Remote VEConfigure and Remote Firmware Update work partially: scanning typically works; but anything using full packet sizes; such as uploading a firmware file; or transferring the VEConfigure file; does not work and returns error 1300. More information here: https://community.victronenergy.com/questions/3608/how-to-solve-error-1300-on-remote-ve-configure.html
• Fix VE.Bus Low Battery, Overload and Temperature warnings and alarms showing up twice in the menu and notifications (bug was introduced in v2.18)
• Fix vup-error-9 on VRM Remote Firmware system. The error in itself was harmless; but raising questions.
• Debounce VE.Bus warnings: warnings now stay valid for at least 20 seconds in order to reduce the number of warning -> ok -> warning changes; notifications and VRM emails.
• Add the names of various new VE.Bus inverter/chargers

ESS:

• Fix bug in Scheduled charging that failed to make optimal use of the PV when in the scheduled charging window.
• When Active AC input is a generator, enable the Fronius zero-feedin limiter. Thanks to Simon Hackett for reporting.
• For systems with CAN-bus BMS batteries, MPPT Solar Chargers, and DVCC enabled, the use of PV power in systems with a relatively small batteries has been improved. An example to illustrate it: lets say the battery indicates a discharge limit of 25A. And at the same time, there is 40A of solar available from the solar charger. In the old situation; the maximum draw from the DC bus would be 25A = 1250 W. Net result for the battery would be that it was being charged with 40 – 25 = 15 Ampere. With v2.23 installed, it will allow up to 65 A draw from the DC: 25A from the battery, and 40A from the solar charger.

Venus GX:

• Improve flexibility of the multiplier setting for the pulse counter; the spinbox has been replaced with a normal edit box where a number can be entered now; with up to 6 decimal places. (thank you Greg for helping with this)

ModbusTCP:

• Make battery relay writeable, i.e. Lynx Shunt (thanks Shane)
• Add registers related to charge current and temperature alarms.
• Add register for LowCellVoltage alarm & warning sent by the Lynx BMS
• Add register for Battery Temperature on VE.Bus devices.
• Add register for VE.Bus system reset; same function as in the inverter/charger menu in the Device List.

And then there are a few more improvements, enhancing system stability and robustness.
For those who were hoping to find the Marine MFD chartplotter integration, as explained here in a blog, I have to disappoint you, it’s not ready yet; so not in this release. We can report good progress on that project though; and I still expect to release it at the end of this quarter for Navico and Garmin. As mentioned during the announcement, Raymarine will follow a bit later.

How to update?
You can find information about how to install the new version of Venus OS here. For the full changelog, visit Victron Professional.

​Article courtesy of Matthjis Vader at Victron Energy 

ExSolar Solar Solutions just completed another 6.6kW solar system complete with a Victron Backup Battery System for our lovely clients in Caledon. Here's what they had to say... 
We totally love the new system!  Thank you for doing this in such a sort time, we are already recommending your services to anyone and everyone. Also, a big thank you to you and your team for a job well done.  The guys up on the roof had to deal with extreme heat on both days, as well as a very steep angle to work with and they never faltered.  Please pass our thanks on. You have a really awesome, hard working team.   

We recently released a firmware update for our SmartSolar Chargers. This fix is especially important for all 150V and 250V SmartSolar Charger models. The BlueSolar Charger range is not affected.
The new v1.37 firmware fixes a problem that can, in certain cases, cause the device to fail.
If you notice that your Solar Charger is no longer charging the batteries; or, in the case of larger models, it is behaving erratically – then the hardware has already failed and the unit will need to be replaced, as by that stage it will be too late to apply the firmware fix.
This update will prevent the failure from occurring.
How should I update my firmware?For systems on the VRM Portal; you can use the new remote firmware update feature.

For details, see the VRM Remote Firmware Update manual.
Using VictronConnect to do the update
Standalone Solar Chargers can be updated with VictronConnect; the recently released version 5.1 will automatically update all solar chargers to v1.37. Here’s a video for that and documentation is available here.

Article courtesy of Matthijs Vader of Victron Energy 

Recently announced at METS the Octo GX is a Venus-device and a member of the GX Product Family, which consists of the Color Control GX, Venus GX, Octo GX and the CANvu GX.
The new Octo GX is the best fit for installations that have many MPPT Solar Charge Controllers, as it has 10 VE.Direct ports.
The GX Product FamilyAt a glance details can be seen in the image below. For further information see the GX Product Family page.

Octo GXThe Octo GX is DIN-rail mountable, so it’s compatible with existing industry standard control boards. It has many interfaces, allowing control and monitoring of over a dozen Victron components simultaneously. Also and very handy for ESS systems – it has a built-in RS485 port.
Octo GX applications include large integrated commercial or industrial electrical systems where you may have a control room with many VE.Direct MPPT’, Multiplus Inverter/Chargers and CANBus devices.
Further information can be found on the Octo GX product page.

Article courtesy of John Rushworth from Victron Energy