8 x 415Wp panels. How to proceed?

[missingegg]

But then let's get into specifics.

I know by now that the MPPT chargers from victron only need a surcharge of 5 volts, over the battery array voltage, to trigger the battery charging. Once triggered a surcharge of 1 volt is enough to keep it going.

However. Their maximum range is only 250/70 if I am well informed. meaning a max input of 250 volts and a max charge of 70 amps.

This does not seem to cover my use case when all 8 or maybe better all 16(I am still considering getting extra panels) are being fully blasted on by the sun. We do have some sun here from time to time and when it happens I don't want to have things melting, or catching fire, in my technical room.

Victron equipment is highly regarded, but I don't think they make a charge controller that meets your needs. I'd recommend searching for a 600V charge controller, which would enable you to have an 8S string without burning out the controller when the sun is out. I think that there are 1000V MPPT controllers available as well, but I've never needed to research this. I'd recommend searching the forum for advice about high voltage systems, or start a new thread specifically asking for high voltage charge controller recommendations. I suspect it's possible to find a controller that would support a 16S string of panels.

One note though: 600V current is not something you want to learn about through trial and error. A mistake could lead to your heirs having to hold an estate sale with a lot of solar gear. If you go down this path, I'd very strongly recommend hiring an electrician to help out.

 

[missingegg]

choices choices.

So could I make 2 x 24V Lifepo4 arrays and then hook up the 8 panels.
Or should I dig a little deeper and get another 8 panels and then hook them up to a single 48V array?

Options options, I am rather confused.

As you says, lots of choices to be made. In your position, I'd try to see if I can specify a 24V system. The wires will need to be bigger, but I assume you'll have short distances between the charge controller, batteries, and inverter. They key question is how much power you might want the inverter to produce, and can you find 24V inverters that meet your needs. Having 3 phase instead of single phase power may make this easier, as I think it's common to have a separate inverter for each of the three phases, and a somewhat smaller output per phase from a 24V system would still produce plenty of power for most people's needs. But you'll need to seek advice elsewhere about 3 phase inverters, as I know little about that.

 

[DJSmiley]

Victron also has higher voltage products, their regular MPPTs are 100, 150 or 250V.
This works out perfect for most setups.

For local/ongrid storage or bigger setup I always go for a 48V setup. That allows much thinner wires and saves money on the controllers.

With a victron 250V/70A controller at a 48V battery bank you can connect up to approx 4kW of panels without problems. 5 panels with a Voc of approx 40V in series, adding in the 10-15% higher voltage during winter, is still within the 250V limit of the controllers.

So with 20 panels and a 5S2P configuration, and 2 controllers, you're good to go. I'm currently building a similar setup, with 2 MPPT's (1 for 10 panels facing west, 10 panels facing east). Having a separate MPPT for each orientation will give more efficency compared to a single MPPT with strings facing in different directions.

If you need to go above 250V, Victron has also the MPPT RS series, up to 450V.

Or you can use a non-victron controller and connect it in parallel to the output of the multiplus if it does support frequency shifting and is in line with the multiplusses power capabilities

AC-coupling and the Factor 1.0 rule [Victron Energy]

www.victronenergy.com

 

[SamDeleted]

No brother, I am from the wrong side of the pond and here in the NL we have 3 phase as a standard for new constructions starting as far back as 2006 if I am not mistaken.

Why on earth would you lot be on 3 phase ... Are you lot all just stoned ?

 

[missingegg]

Why on earth would you lot be on 3 phase ... Are you lot all just stoned ?

No need to be offensive about it. 3 phase power has a lot of advantages. It may not provide a big benefit for traditional residential power needs, but it's the most common form of power from grid scale generation around the world.

 

[missingegg]

Victron also has higher voltage products, their regular MPPTs are 100, 150 or 250V.
This works out perfect for most setups.

For local/ongrid storage or bigger setup I always go for a 48V setup. That allows much thinner wires and saves money on the controllers.

With a victron 250V/70A controller at a 48V battery bank you can connect up to approx 4kW of panels without problems. 5 panels with a Voc of approx 40V in series, adding in the 10-15% higher voltage during winter, is still within the 250V limit of the controllers.

So with 20 panels and a 5S2P configuration, and 2 controllers, you're good to go. I'm currently building a similar setup, with 2 MPPT's (1 for 10 panels facing west, 10 panels facing east). Having a separate MPPT for each orientation will give more efficency compared to a single MPPT with strings facing in different directions.

If you need to go above 250V, Victron has also the MPPT RS series, up to 450V.

Or you can use a non-victron controller and connect it in parallel to the output of the multiplus if it does support frequency shifting and is in line with the multiplusses power capabilities

AC-coupling and the Factor 1.0 rule [Victron Energy]

www.victronenergy.com

For the OP's panels in an 8S configuration, the charge controller would need to support at least 300V. The 250V and lower charge controllers thus wouldn't be workable. But I hadn't been aware that Victron had a 450V charge controller, and I'd assume that would work just fine.

 

[SamDeleted]

No need to be offensive about it. 3 phase power has a lot of advantages. It may not provide a big benefit for traditional residential power needs, but it's the most common form of power from grid scale generation around the world.

Not being offensive, just my British sense of humour.

 

[DJSmiley]

Why on earth would you lot be on 3 phase ... Are you lot all just stoned ?

Yeah, save a lot of expensive copper to run your grow lights when using 3-phase
Just run a 3-phase wire to the growshed and install a subpanel.

anyway, as said, here in NL its now common to get 3x25A. This used to be 1x40A in the past. If you want to have anything different, you pay additional fees, up to 3x25 or 1x40 is the same base tariff for a grid connection.
(some very small connections excluded)

This makes it slightly tougher to make a hybrid setup, since you have to move everything to a single (25A) phase, or invest in 3-phase inverters.
It does have some advantages as well: If the grid is overloaded on a single phase, you might be able to still backfeed to the grid using solar on another phase. And for EV charging 11kW is pretty common, most EV owners with a driveway have their own 11kW charger.

 

[brandnewb]

OK, no more messing about this time around.

I am willing to go for it, the deep pockets, if it seems functiona and at all reasonable. I mean I do not dine in a 3 star reastaurant every night just because I can. No dining there is just not value for money. It's something we'd all like to try once in a life time. and once we have it might even be disappointing.

So I think the best way forward is to get both a victron multiplus II and a growat MOD 7000TL3-XH.

Then the power supply to my loads should be covered.

I am thinking like this;
Victron seems to never be meant for economical solutions for 3 phase dwellings. As far as I have been able to gather Victron is more boat related.
Victron on the other hand has a reparation of being good... but expensive.

Well, Victron has it fair share of issues so it seems after I have scanned through the community forum there. Sometimes even with no actual satisfying resolve.

However Victron Multiplus does seem to do what I'd like. A 20ms switch from on grid to battery when the grid goes off.

They even promote it as being able for my servers to NOT notice!!!

So to have all my crucial stuff on this inverter is comforting.

Then for the 3 phase aspect then nothing beats a growat
well, I just said it but I am not sure I mean that yet.

At least it is relativly affordable and if it can only do what I want from it.

Regarding the panels I have. Maybe stop trying to skimm on costs and go for a 250 mppt variant (victron).
But on paper those 8 x panels will do more than that. argggg why is it that there is nothing open source yet that is configurable to one's use case

 

[SamDeleted]

OK, no more messing about this time around.

I am willing to go for it, the deep pockets, if it seems functiona and at all reasonable

If you're really going for it think about redundancy, it doesn't have to be massive but little bits and bobs separate from your big system can be life savers.

When the power goes out, and your big sod off ££££ Victron breaks down ( cause they do everything does ) if you have no back ups , boom you're sat in the dark just like everyone else

 

[SamDeleted]

I'd recommend searching for a 600V charge controller, which would enable you to have an 8S string without burning out the controller when the sun is out

TriStar MPPT 600V - Morningstar Corporation

TriStar MPPT 600V, Morningstar Corporation, Solar, Charge Controller, Maximum Power Point Tracking, High Voltage

www.morningstarcorp.com

 

[brandnewb]

If you're really going for it think about redundancy

yes indeed, that is why I was opting for both a voctron and growat inverter.

is there something I am missing there?

 

[SamDeleted]

yes indeed, that is why I was opting for both a voctron and growat inverter.

is there something I am missing there?

Oh growat AND Victron , I thought you said 'or' , great idea

 

[DJSmiley]

The Tristar supports Modbus, as does the Victron Cerbo, so you might be able to integrate the readings into the Cerbo and/or VRM.

Another option might be using a regular grid-connected inverter. You can connect it on the grid side and with net metering you can configure the Victron ESS to use any surplus PV power for charging the batteries (thus no backfeeding into the grid as long as the batteries are not full)

If the inverter supports frequency shifting, and is matched with the Victron's capacity, you can connect it to the output of the MP as well. This also allows you to still use the PV while the grid is down. (A direct grid-tied PV has to shutdown if the grid fails thus you only have battery power).
Using frequency shifting and the inverter at the output allows you to still harvest/use PV and not (fully) depend on your batteries.

However, the PV to DC is the more effective way, but depending on whats already installed might be the more expensive route.

Personally I would consider rewring the panels. The Tristar is pretty expensive (1200 euro if I google correct), where as a Victron 250/70 is 'only' 800-900. And it's easier to integrate due to its VE.CAN

 

[OzSolar]

Personally I would consider rewring the panels. The Tristar is pretty expensive (1200 euro if I google correct), where as a Victron 250/70 is 'only' 800-900. And it's easier to integrate due to its VE.CAN

Nice summary.

I'm going round and round with this right decision right now. I already have the 48v battery bank and the solar panels. I just picked up 10 x 535w bifacials that I couldn't refuse the price on. I already have ~ 17 kW of PV so this is just a "for fun" project integrating modules into a patio roof. That Victron 250/XX VE. Can is the leading contender and I can find it for ~$750 USD or a bit less.

 

[DJSmiley]

The VE.CAN with a Cerbo is great, and allows you to do nice things when you have a Cerbo or Color Control
Note: there now is a Cerbo-S, which is a fully functional Cerbo, but it only lacks the tank sensor inputs and BMS.can. If you don't need any of those it saves another $100 or so.
The color control is cheaper, but it lacks some connections, and has a lower resolution (And less memory) compared to a Cerbo. But for basic functions its still sufficient.

I'm a fan of the Cerbo units, since they also provide remote access using victronconnect on your phone through their VRM, and allows remote monitoring of the setup. And with the addition of eg Ruvi tags you have temperature monitoring as well, and can apply actions based on it. And with the relay ports you can also enable/disable things eg run a water heater on excess solar, or disable water heather if the SOC is below a certain threshold.

The 150V MPPT is even cheaper, but it does require more strings (3 panels in series usually max).

 

[brandnewb]

However, the PV to DC is the more effective way, but depending on whats already installed might be the more expensive route.

I have 11 x 3 phase microinverters APsystems YC1000
with 4 x 275 WP panels on each totaling 44 panels.

They tend to beak often those microinverters and getting things replaced used to be very difficult and tedious until I threatened going public on facebook.

It would be great if that system can be configured to not go dark when the grid goes out. I will look into this frequency shifting thingy. it does have a lot of things one can configure.

and on an overcast day like this nothing is really happening with those panels. This is what I would like to change with the new setup.

 

[littleharbor2]

Can you find one more panel and simply go 3s3p, use a 150 Voc. controller and put an end to this lunacy?

 

[brandnewb]

I do not dare to when using a 150/35 victron mppt. because I have been warned that we need to take into account the 10% extra Voc that can incur on cold days. I have been warned twice already.

So that would mean 167.2 Voc. now if the victron MPPT can deal with that and just limits it to 150 then I am game

 

[brandnewb]

and also what you call lunacy I call doing ones homework.