Victron SCC tracking limitations?

[ricardocello]

You both have got me thinking now, however Im going to be adding more strings down the road. I haven't checked the chart yet to see what ga I need with my new found limitations on the SCCs. Will probably be adding another 450/200 down the road also and reconfigure my strings to best output. Will still probably be close to 7 string.

With higher string voltages (> 250v), multiple runs of smaller wire tend to make more sense.

With lower string voltages (< 250v), bigger wire is a better match for the charge controllers.
I regularly run 33A @ 165V into my MPPT 250/100 (and get the full 100A out).
Can’t do that with the 450/100.

It is a tradeoff between future expansion plans, voltage drop, and best match to the solar charge controllers.
And the number of trackers you need. I’ve got shading to deal with, so I like the parallel strings.

 

[ADK Homer]

Yeah thank god I dont have any shading, would be a disaster for me running that many panels in parallel groups for my distance. I think 2 450/200s make the most sense for me now and for future expansion. Just gonna kill the wallet.

 

[ADK Homer]

Now I gotta figure out ground mount(s) Lotta sand in my field so at least digging will be easy.

 

[sunsurfer]

Would be very nice if Victron didn't have those wattage limitations.

I am not sure what you mean as far as wattage limitations, can you explain?

 

[1201]

I had recommended ac coupling in another thread but op didn't hear me.

You would only need one 11.4 kw grid tie inverter at about $1600 and you get 4 600v mppts, 97.5% efficiency, and far better daytime efficiency(about 90% for your victron quattros vs 97.5% for the grid tie inverter.

Reasons why to choose DC and/or AC coupled solar in Off-grid Power Systems [Victron Energy]

www.victronenergy.com

 

[1201]

.

 

[ADK Homer]

I am not sure what you mean as far as wattage limitations, can you explain?

Tracker limits. I can put 16k into one unit, but only 11520k usable output.

 

[ADK Homer]

I had recommended ac coupling in another thread but op didn't hear me.

You would only need one 11.4 kw grid tie inverter at about $1600 and you get 4 600v mppts, 97.5% efficiency, and far better daytime efficiency(about 90% for your victron quattros vs 97.5% for the grid tie inverter.

Reasons why to choose DC and/or AC coupled solar in Off-grid Power Systems [Victron Energy]

www.victronenergy.com

Yeah I said before the goal is to be grid free. The Quattros have two A/C inputs, which I will be using for a short time upon setup.
Are you insinuating running an AC coupled AOI in lieu of SCCs, while keeping the Quattros?

 

[sunsurfer]

Tracker limits. I can put 16k into one unit, but only 11520k usable output.

So you want to over panel beyond 16K? That is interesting.

 

[ADK Homer]

So you want to over panel beyond 16K? That is interesting.

Negative. 4k limit per tracker x 4 trackers on the 450/200. Should be 16000k, however the unit has output limit of 11520k. I need to soak up enough sun to power 4 Quattros and charge my batteries. So plain and simple, losing 4500k output per scc...sucks for me! But, it is what it is, if you wanna play the game.

 

[Rocketman]

Thinking of wire in the ground…

I am looking at a place that would need solar and really long runs of wire. The wire is very expensive. I found two wires that were of interest to me. Both aluminum direct bury. A 2-2-4 and a 2-2-2-2. Use the #4 as the ground wire. Then with both cables in the ground you have three strings available. So go with the 250/100 mppt. Probably 5s3p or 4s4p. (Voltage drop 4 to 6%).

See if that’s overall cheaper than two runs per 450/100. (Because each tracker on the 450/100 needs it’s own wire run).

 

[ADK Homer]

Thinking of wire in the ground…

I am looking at a place that would need solar and really long runs of wire. The wire is very expensive. I found two wires that were of interest to me. Both aluminum direct bury. A 2-2-4 and a 2-2-2-2. Use the #4 as the ground wire. Then with both cables in the ground you have three strings available. So go with the 250/100 mppt. Probably 5s3p or 4s4p. (Voltage drop 4 to 6%).

See if that’s overall cheaper than two runs per 450/100. (Because each tracker on the 450/100 needs it’s own wire run).

Hopefully that works for you. What kind of price/ft you getting on that alum. For me I would need sewer pipe conduit to run that much aluminum lol. I'll have around 60 panels and 8 strings, around 400ft

 

[1201]

Yeah I said before the goal is to be grid free. The Quattros have two A/C inputs, which I will be using for a short time upon setup.
Are you insinuating running an AC coupled AOI in lieu of SCCs, while keeping the Quattros?

Yes you would simply be using the grid tie inverter for the mppts. You wouldn't be connected to the grid at all

 

[ADK Homer]

Yes you would simply be using the grid tie inverter for the mppts. You wouldn't be connected to the grid at all

Quick question, can an AOI as your talking about, be configured to act as just a pass through of PV and then inverted at the Quattros.
Either way I would still need 2 AIOs, for all the strings and redundancy if one were to go down. I would also need 2 Vic 450/200s, which are 96% efficient, as are the Quattros.
From that stand point, going all Victron would only be a few hundred dollars more for SCC purposes, with higher quality and less chance of failure, Imo.

 

[yabert]

From that stand point, going all Victron would only be a few hundred dollars more for SCC purposes, with higher quality and less chance of failure, Imo.

Why not 2 systems?
1-Lower cost/high quality Victron 250/100 + Victron inverter of your choice.
2-AIO with multiple MPPT

That way you have Victron reliability for a part of the system and high power capability a low cost for the other part of the system.

 

[1201]

Quick question, can an AOI as your talking about, be configured to act as just a pass through of PV and then inverted at the Quattros.

The grid tie inverter(not aio) has already converted the DC to ac at 97% efficiency, taking the load off your victrons during the day.

Either way I would still need 2 AIOs, for all the strings and redundancy if one were to go down.

You only need one. You can buy two if you want but you only need one.

I would also need 2 Vic 450/200s, which are 96% efficient, as are the Quattros.

The quattros are about 90% efficient on average, not 96%

From that stand point, going all Victron would only be a few hundred dollars more for SCC purposes, with higher quality and less chance of failure, Imo.

It would only be a few hundred dollars more but you have higher losses in your DC lines, poor daytime efficiency, and shortened lifespan on your quattro's since they have to work 24/7

Grid tie inverters also generally last longer than 10 years

 

[sunshine_eggo]

The grid tie inverter(not aio) has already converted the DC to ac at 97% efficiency, taking the load off your victrons during the day.

But when AC coupled and charging with AC from the PV inverter through Quattro charger, it's only about 85%.

The quattros are about 90% efficient on average, not 96%

Yep. The peak efficiency is at 25-30% rated capacity.

 

[1201]

But when AC coupled and charging with AC from the PV inverter through Quattro charger, it's only about 85%.

That's correct. Might even be lower than that but the lower wire losses and higher daytime efficiency should more than make up for that,in most cases

 

[ADK Homer]

The grid tie inverter(not aio) has already converted the DC to ac at 97% efficiency, taking the load off your victrons during the day.


You only need one. You can buy two if you want but you only need one.


The quattros are about 90% efficient on average, not 96%

It would only be a few hundred dollars more but you have higher losses in your DC lines, poor daytime efficiency, and shortened lifespan on your quattro's since they have to work 24/7

Grid tie inverters also generally last longer than 10 years

Sounds nice, but the other problem is I would need several AIOs to get the output I need, hence the 4 Quattros 10k. Didn't realize the efficiency would be that low on Victron vs other AIOs.

 

[ADK Homer]

Why not 2 systems?
1-Lower cost/high quality Victron 250/100 + Victron inverter of your choice.
2-AIO with multiple MPPT

That way you have Victron reliability for a part of the system and high power capability a low cost for the other part of the system.

Have seriously considered two different separate systems, as I had numerous subpanels spread throughout different areas.

 

[1201]

Sounds nice, but the other problem is I would need several AIOs to get the output I need, hence the 4 Quattros 10k. Didn't realize the efficiency would be that low on Victron vs other AIOs.

They won't replace your quattros. You'll still need those. All they do is serve as the PV input for the system. The grid tie inverter replaces the 450/200

 

[ADK Homer]

They won't replace your quattros. You'll still need those. All they do is serve as the PV input for the system. The grid tie inverter replaces the 450/200

Yeah I realize that, but I will have approx 8 strings when finished. Around 30kw at max, solar incoming. One AIO is not going to cut it for PV input or out. If Im spending the money to buy several AIOs and incorporate them into the system, why build a victron.

 

[Brucey]

Yeah I realize that, but I will have approx 8 strings when finished. Around 30kw at max, solar incoming. One AIO is not going to cut it for PV input or out. If Im spending the money to buy several AIOs and incorporate them into the system, why build a victron.

So you'll be running two 450/200s? Or more?

 

[ADK Homer]

So you'll be running two 450/200s? Or more?

Yeah 2 450/200s will be maxed out and over-paneled very slightly, which is fine I believe.

 

[Brucey]

Yeah 2 450/200s will be maxed out and over-paneled very slightly, which is fine I believe.

Oh they can be overpanelled like crazy I had nearly 15kw of panels on my 450/100 at one point earlier this year, 10s2p on each tracker with 370 and 375W bifacials.

You mentioned 30kW peaks and you'll be maxed out at about 24kW but not too shabby.