Plonkster and Don, may I ask you a technical question?

You have told me the difference between the Phoenix and the Multiplus inverters which was extremely useful to me.  However what about the range of Easysolar?  These have MPPT included, plus a lot of other things that apparently makes it far easier to install.  Is it a new range?

https://www.victronenergy.com/upload/documents/Datasheet-EasySolar-with-Color-Control-EN.pdf

I have chosen this one above - the 3kW, not the 5kW.  It is the smallest of the 48V and it may be just the job for me.  I would need to be able to charge the batteries from Eskom, from my Generator AND from solar panels.  Can it manage all that?  I am coming around to the panels and I have a really good place to put 2 only.  If I used Sunpower 327w panels that would be a lot better than nothing wouldn't it?  To create a string of about 8 is going to mean defacing a roof with an imported shingle tile and I don't want to do that.

@Richwost, I am not up to speed with Victron equipment, @plonkster, will be able to give you much better advice. If I look at the data sheet, I can make a few comments that is about it: 

Will it be able to handle your load - Yes. It seems the unit has 5 outputs. 1 for heavy loads, like an aircon or something. It is rated at 16 amps, so not really suitable for a stove or geyser. That outlet is only available when you Eskom is available. Then there are 2 x 16 amp outlets for plugs and 2 x 10 amp outlets for lights. This would be ideal if you had a farm house that has never had power before and you would like to power up the house, as it comes with a small "built in" DB Box. Where you have an existing DB Box, all those would be a bit of a waste, as you require all the power on 1 outlet to feed your existing DB Box. I don't see the Generator connection and automatic transfer switch which you actually require. 

It will work, but it is not really designed and setup for your application.  

2 hours ago, Richwost said:

 To create a string of about 8 is going to mean defacing a roof with an imported shingle tile and I don't want to do that.

It does not have to go on the roof mine is a ground mounted array. You do however deface the garden but I have found a place near the house but not too intrusive. You could add a carport or gazebo-like structure if there is nowhere on the ground you can go with the array.

Atheist to agnostic and now a born again!  

1 hour ago, Richwost said:

You have told me the difference between the Phoenix and the Multiplus inverters which was extremely useful to me.  However what about the range of Easysolar?  These have MPPT included, plus a lot of other things that apparently makes it far easier to install.  Is it a new range?

The easysolar is a multiplus with an mppt included, plus a few breakers. It's an all-in-one thing. The larger models come with a CCGX too. It's really just packaging. You save a bit on cabling perhaps, it may or may not be cheaper than the separate components... it's the same stuff on the inside. It's not new, I think they introduced it in 2014.

Just want to say something about the two outputs on the Multi: It seems like a strange feature to have if it disconnects when the grid goes down. The reason it has this is because of the hybrid features. These inverters are often used in RVs or on boats/yachts. The power point provided in the harbour/caravan park might not be able to power all your equipment (especially if you have a really nice yacht), so the Multiplus can then provide the difference (on either output 1 or 2). Also, when in ESS mode without a grid meter, it can feed surplus solar to devices on output 2. If the power goes out, it disconnects output 2. I cannot remember if it is possible to switch output 2 using the inverter's programmable stack. I'll have to find out.

Second item, you already have a generator with a transfer switch (an "auto" feature that starts the generator). Obviously you don't want the generator to start immediately when the grid goes out. You want it to start if the grid is out AND the batteries are getting low. If there is a manual start option on the generator (I suspect there will be), you can use one of the relays in the inverter to start the generator when the conditions call for it. You won't be able to stop the generator unless you use a quattro (because the inverter won't know the difference, it needs two inputs so it knows when the grid is back).

The final complication comes with managing the incoming solar. When there is no solar, the setup is relatively straight forward. The multi uses grid/diesel power if available (to power loads and charge the batteries) and drops to battery otherwise. When adding solar it becomes more interesting. Now you only want it to go to grid if the batteries are low. So you'll need at least a BMV too.

It depends how much automation you want. If you want seamless automatic generator starting and stopping when the grid is out and the batteries go low, you need to look at the quattro. The inverter will then replace the transfer switch that came with the generator.

2 hours ago, Chris Hobson said:

It does not have to go on the roof mine is a ground mounted array. You do however deface the garden but I have found a place near the house but not too intrusive. You could add a carport or gazebo-like structure if there is nowhere on the ground you can go with the array.

Or build a solar carport

6 hours ago, Richwost said:

 If I used Sunpower 327w panels that would be a lot better than nothing wouldn't it?

Richwost, you have asked this a few times without an answer. First of all, 2 panels will not work. Let me show you why not. When you look at the data sheet of an inverter, have a look at the PV voltages. Below is an example of the Infini V Series. That tells you your max. PV array voltage and the MPPT operating voltage.

Then at the same time have a look at your solar panel data sheet. See example below: The open circuit voltage is when the panels are having a sun tan without any load. You have a high voltage, but no current flowing. Once the solar kicks in that voltage would drop to anything from 80 - 100 volts, depending on your load. The higher the amps goes on your panels, the lower the voltage will drop.

Looking at the solar panel chart, the operating voltage is say 37 volts. If you only have 2 panels, the operating voltage will only be 74 volts, which is very close to the minimum operating voltage. Once the panels take load they would probably fall below the minimum operating voltage and your will inverter will disconnected your solar panels. Same thing with clouds, they move in front of the sun, the panel voltage takes a nose dive and you end up with about 10 - 20% of your normal solar production. You will end up with nothing. 

Therefore looking at the max PV array open circuit voltage, you would need at least 3 solar panels in series = 3 x 45.8 = 137.4 Volts - Less than the 145 max open circuit voltage. The operating voltage at maximum power = 3 x 36.4 Volts = 109.2 volts - the operating range on the inverter is 60 - 115 volts. Well within the range and close to the max of 115 where you want to be. 

If you want to add more panels, then you add them in parallel. The voltage stays the same. Then you start looking at the max PV amps the inverter can handle. That will determine how many strings in parallel you can install. 

So how many panels do you add? Your inverter dictates the minimum and maximum panels it can handle. Then you determine your need and hopefully it fits in between what the inverter can handle and your needs. I would say enough to at least charge your batteries and some extra panels to cater for your load to run on free/solar power during the day. Well that is my view in any case. This can get very technical if you start looking at losses in inefficiencies. Angle tilt of panels, facing north or north west or north east, etc.

I thought I would just share that with you so you get a better understanding of what to look for when you start looking at installing solar panels.  

6 minutes ago, Don said:

Richwost, you have asked this a few times without an answer. First of all, 2 panels will not work. Let me show you why not. When you look at the data sheet of an inverter, have a look at the PV voltages. Below is an example of the Infini V Series. That tells you your max. PV array voltage and the MPPT operating voltage.

Then at the same time have a look at your solar panel data sheet. See example below: The open circuit voltage is when the panels are having a sun tan without any load. You have a high voltage, but no current flowing. Once the solar kicks in that voltage would drop to anything from 80 - 100 volts, depending on your load. The higher the amps goes on your panels, the lower the voltage will drop.

Looking at the solar panel chart, the operating voltage is say 37 volts. If you only have 2 panels, the operating voltage will only be 74 volts, which is very close to the minimum operating voltage. Once the panels take load they would probably fall below the minimum operating voltage and your will inverter will disconnected your solar panels. Same thing with clouds, they move in front of the sun, the panel voltage takes a nose dive and you end up with about 10 - 20% of your normal solar production. You will end up with nothing. 

Therefore looking at the max PV array open circuit voltage, you would need at least 3 solar panels in series = 3 x 45.8 = 137.4 Volts - Less than the 145 max open circuit voltage. The operating voltage at maximum power = 3 x 36.4 Volts = 109.2 volts - the operating range on the inverter is 60 - 115 volts. Well within the range and close to the max of 115 where you want to be. 

If you want to add more panels, then you add them in parallel. The voltage stays the same. 

So how many panels do you add? I would say enough to at least charge your batteries and some extra panels to cater for your load to run on free/solar power during the day. Well that is my view in any case. This can get very technical if you start looking at losses in inefficiencies. Angle tilt of panels, facing north or north west or north east, etc.

I thought I would just share that with you so you get a better understanding of what to look for when you start looking at installing solar panels.  

Don, 2x 327W panels will work fine with that MPPT range. Vmp of 2 panels => 60V

A BlueSolar MPPT needs 5V above battery to start charging, and thereafter 1V above battery. So if the panel makes 60V or more (and given that Voc is more than Vmp), two panels will work. Won't be optimal, but it will work. Two 72-cell panels should make around 76V at Vmp, which is more than sufficient for a BlueSolar to start charging. On a bad day with "half a sun" of insolation, the Vmp will be around 60V which is barely enough, but will be sufficient for a float charge :-)

How much more? Between 58 and 62 Volts my inverters get confused and don't know if they want to connect the pv or disconnect them. I don't argue they they wont work. As soon as they take load, the voltage would probably drop below 60 Volts. 

 

My panels stand at about 128 volts with no load. At full load it drops down to probably 80 Volts, can't remember.

Just now, Don said:

How much more? Between 58 and 62 Volts my inverters get confused and don't know if they want to connect the pv or disconnect them. I don't argue they they wont work. As soon as they take load, the voltage would probably drop below 60 Volts. 

 

I don't know which inverter of panels you have, but in this case Richworst asked about 327W Sunpower panels which have 64.9Voc and 54Vmpp. 2x panels' Voc = 129V, so he won't be able to use 3x panels in series in any case. 

4 minutes ago, Don said:

Between 58 and 62 Volts my inverters get confused

They aren't all created equal :-)

3 minutes ago, Don said:

My panels stand at about 128 volts with no load. At full load it drops down to probably 80 Volts, can't remember.

That seems rather hectic. As a rule of thumb, 0.6V per cell open circuit, 0.5V per cell at Vmp. 60-cell panels are popular with the Axperts (because 3-wide it is in the optimum band), so 36Voc and 30Vmp, so open circuit it should be at 108V dropping down to 90V at load. Two 60-cell panels will be insufficient, for any 48V setup.

10 minutes ago, plonkster said:

Vmp will be around 60V which is barely enough, but will be sufficient for a float charge

Exactly. Will 2 panels work - Yes. Will they be efficient - No. Do you only install 2 panels - No.

Now we are arguing if 2 panels will work or not. That is not the point I am trying to make. 

Just now, Don said:

Now we are arguing if 2 panels will work or not. That is not the point. 

He's already got two. They are "free" for all practical purposes. I say go for it...

I say don't waste your time, get one more.

4 minutes ago, plonkster said:

He's already got two. They are "free" for all practical purposes.

I have a beetle without an engine. You can have it for free and push it around, lol. 

2 minutes ago, Don said:

I say don't waste your time, get one more.

If Silver is right and the Voc is 54V, two is the maximum.

I have 72-cell Canandian Solar panels, 45V Voc, 135V if you have three. So it will work for SOME panels but not for others. I think it will work just fine.

Just now, Don said:

Exactly. Will 2 panels work - Yes. Will they be efficient - No. Do you only install 2 panels - No.

Now we are arguing if 2 panels will work or not. That is not the point I am trying to make. 

Don, did you look at the exact panels the OP referred to?

The  Sunpower 327W panels have 64.9Voc and 54Vmpp, more than sufficient for minimum MPPT. A 3rd panel  will probably blow the MPPT!

And, using 255W and 265W solar panels, I have personally done many 2x / 4x / 6x or 8x panel installations using Axpert 5KVA inverters - worked perfectly well every time. 
 

1 minute ago, plonkster said:

If Silver is right and the Voc is 54V

If that is per panel, then yes, it will work. Will be 108 Volts in series which is fine. I don't have the spec sheet of those panels.

Just now, SilverNodashi said:

Don, did you look at the exact panels the OP referred to?

No, I am referring to the spec sheet I posted. I post a spec sheet you guys talk about another spec sheet I don't have. Very confusing.

5 minutes ago, SilverNodashi said:

unpower 327W panels have 64.9Voc and 54Vmpp, more than sufficient for minimum MPPT. A 3rd panel  will probably blow the MPPT!

I agree with you Silver. I posted some examples for the guy to get a better understanding of what to look for when buying inverters and panels. 

I am talking of what I posted and you guys are talking of what some other panel can do. We are not singing of the same hymn sheet here.  

1 minute ago, Don said:

Very confusing.

 Jip, stick to the panel the OP refers to otherwise it gets confusing. 

When I saw Sunpower 327w I thought lekker man. Go for it. Awesome.

Not once have I looked back from my 310w which are 36.3 and 45.35v - it gets a pain to match them to controllers but dang, once you have the hang of it, you can fly with them, literally.

Sunpower 327w are top of the range panels.