Solar panels 260w each

[1 Cup]

Hi upgraded my panels only and been on roof a month or so but only ever got P Max at 58volts 341 wats most 400 ish Watts at 24v insires It adds up at the end of day to elegant. 1kw or more.

Can my controller handle 520 Watts victron 100 30 ?.

 

[wildebus]

The 100/30 has a maximum output of 440W on a 12V system. If you were hitting 440W or thereabouts, then I would say that is the limiting factor. But if you are not ever seeing any more than 400W, then the 100/30 is not limiting anything.

With a total of 520W of panel, I would expect you really should have seen it maxing out to the limit of the controller (i.e. 440W peak) many times.

For example, my own Controller is limited to 290W (a 100/20), but the panels are a total of only 270W, so I expect to occasionally get to or close to 270W (the best the Panel + Controller could achieve).
Looking at the history, this week has been poor weather but last week was much nicer and I was hitting the peaks I would expect

solar history by David, on Flickr
(I am actually just exceeding the rated power occasionally even).

 

[exwindsurfer]

.I had to change my Controller to 100/50 when I put 590watts of solar up.

 

[Fisherman]

The 100/30 has a maximum output of 440W on a 12V system. If you were hitting 440W or thereabouts, then I would say that is the limiting factor. But if you are not ever seeing any more than 400W, then the 100/30 is not limiting anything.

With a total of 520W of panel, I would expect you really should have seen it maxing out to the limit of the controller (i.e. 440W peak) many times.

For example, my own Controller is limited to 290W (a 100/20), but the panels are a total of only 270W, so I expect to occasionally get to or close to 270W (the best the Panel + Controller could achieve).
Looking at the history, this week has been poor weather but last week was much nicer and I was hitting the peaks I would expect

solar history by David, on Flickr
(I am actually just exceeding the rated power occasionally even).

David great answer, but what's the point of fitting two 260W solar panels then using a 30 amp controller.
Is it you will rarely get anywhere near the max 520W, but you will average more solar harvesting.
My wee brain is hurting right now

 

[1 Cup]

OK so 440watts maxed out. Is that what my pics shows as my voltage went from 12.35v to 00.01v

 

[wildebus]

My wee brain is hurting right now.David great answer, but what's the point of fitting two 260W solar panels then using a 30 amp controller.
Is it you will rarely get anywhere near the max 520W, but you will average more solar harvesting.
My wee brain is hurting right now

You are right in thinking that you are potentially loosing nearly 100W of harvesting, but that is only at the peak harvest time around noonish. The harvest before and after that time will be lower and so you will further away from the peak and the extra power capability of the controller may not be needed.
The theoretical harvesting (so full sun, no cloud, no shadows) follows a very obvious "Bell Curve". I found on-line a real life Bell curve someone posted. He actually said "took 5 months to get a proper Bell Curve" (so without the noise caused by shadows, clouds etc.)
I took his graph and added the effect at the top that you would get by using an undersized Solar Controller

SOLAR Bell by David, on Flickr
The top part which is lighter blue is the pattern you will harvest with the 'right' controller on a ideal day, but if the controller is too small, the output is truncated, so you get a flat line for a period of time. (hope that makes sense?).
But that Bell Curve is rarely seen, especially in the UK, as is any extended peak harvesting. Below is one of the best curves I could find on my system ...

Solar Harvest by David, on Flickr
You can see the basic Bell Curve shape but with lots of dips and a poorish start to the day. You may also notice that although my controller is a 20A model, the output here never gets even to 15A - so if I were getting this every day, I could have fitted a smaller Victron 75/15 (220W Max) controller instead of the 100/20 (290W) controller and not lost anything.

End of the day, it is a matter of balance of capability and cost. I had a 100/30 on my last van and had 400W of solar. I added another 60W (so 460W on a 440W controller) but never considered upgrading to avoid the very occasional and short lived 20W loss. Having 520W of panels on a 440W Controller is a trickier call.
Also... it is important to know what happens if the power in is exceeded? On the Victrons, they don't care and simply truncate the excess current, but another make of controller may object a little more 'terminally'.

 

[wildebus]

OK so 440watts maxed out. Is that what my pics shows as my voltage went from 12.35v to 00.01v

The other important factor is how much charge can your battery take/need? If there is nowhere for the power to go, the power won't be harvested so if your batteries are in a pretty high state of charge, then you cannot really tell how well your solar setup is performing - or at least CAN perform. IN your screenshots, a lot of the days you are are hitting absorption and float, so your batteries are full. If they got to that level before say 11AM, the time for potential peak solar is a time when the power is not needed.
If you were to look at my history, you may notice my best peak harvesting is on days when the controller stays in Bulk as it needs the recharge power.

To test your setup, you need either a flatter battery, or create a high battery load for the solar to try and replenish. On a nice sunny cloudless day around noon time, put on your (electric) kettle and see what the solar controller is doing then

 

[Fisherman]

You are right in thinking that you are potentially loosing nearly 100W of harvesting, but that is only at the peak harvest time around noonish. The harvest before and after that time will be lower and so you will further away from the peak and the extra power capability of the controller may not be needed.
The theoretical harvesting (so full sun, no cloud, no shadows) follows a very obvious "Bell Curve". I found on-line a real life Bell curve someone posted. He actually said "took 5 months to get a proper Bell Curve" (so without the noise caused by shadows, clouds etc.)
I took his graph and added the effect at the top that you would get by using an undersized Solar Controller

SOLAR Bell by David, on Flickr
The top part which is lighter blue is the pattern you will harvest with the 'right' controller on a ideal day, but if the controller is too small, the output is truncated, so you get a flat line for a period of time. (hope that makes sense?).
But that Bell Curve is rarely seen, especially in the UK, as is any extended peak harvesting. Below is one of the best curves I could find on my system ...

Solar Harvest by David, on Flickr
You can see the basic Bell Curve shape but with lots of dips and a poorish start to the day. You may also notice that although my controller is a 20A model, the output here never gets even to 15A - so if I were getting this every day, I could have fitted a smaller Victron 75/15 (220W Max) controller instead of the 100/20 (290W) controller and not lost anything.

End of the day, it is a matter of balance of capability and cost. I had a 100/30 on my last van and had 400W of solar. I added another 60W (so 460W on a 440W controller) but never considered upgrading to avoid the very occasional and short lived 20W loss. Having 520W of panels on a 440W Controller is a trickier call.
Also... it is important to know what happens if the power in is exceeded? On the Victrons, they don't care and simply truncate the excess current, but another make of controller may object a little more 'terminally'.

Your last sentence answered my main concern David , what would happen if you exceeded max capacity. I take it running your controller to the max won’t damage it in any way. Thanks David.

 

[Nabsim]

You can fit a second controller when you add the second panel, depends what makes financial sense. Obviously you would need to double up cables for second panel though if using a second controller

 

[1 Cup]

Thanks the victron can handle the extra 80watts like you said by noon batteries fully charged most days.
Unless I leave 3000k invertor on as I did 6am Monday till 5pm Sunday. Ouch

But the invertor now buzzes in stand by ?

 

[trevskoda]

Thanks the victron can handle the extra 80watts like you said by noon batteries fully charged most days.
Unless I leave 3000k invertor on as I did 6am Monday till 5pm Sunday. Ouch

But the invertor now buzzes in stand by ?

My fridge one goes into a sleep mode until the fridge kicks in.

 

[1 Cup]

I need the extra box screen for the invertor as it is as it came and stayed in default mode ?. Looking for a good cheap option. That screen is how much and will it come with long lead as its ( invertor) is 5m from switch board .

 

[Geek]

David great answer, but what's the point of fitting two 260W solar panels then using a 30 amp controller.
Is it you will rarely get anywhere near the max 520W, but you will average more solar harvesting.
My wee brain is hurting right now

I can't speak for David, but if I fitted more panels than the controller could handle, this is why I'd do it:

In Summer the insolation is high. You get an average of five hours of full sun which ought to be more than enough. You don't need the full output of the panels, and indeed you won't be able to use it once the batteries are full.

In winter, you only get an average of one hour of full sun each day, and it's delivered at a low angle so the panels will miss a lot of it. As a result, it is unlikely to be enough power for many people, so you need another power source in winter.

At some point in the Spring and the Autumn there will be a point when there is just enough power from the solar panels to meet your daily needs. Adding more panels to the roof moves those dates further towards winter, giving a longer self-sufficient season.

The extra panels will increase the output when they're running below rated capacity, so the controller won't limit operations when it matters.

 

[wildebus]

I can't speak for David, but if I fitted more panels than the controller could handle, this is why I'd do it:

I would have the same thoughts. Right now my solar array is to small to be keeping up with my demands, although I would be ok IF if the controller was able to be running at its maximum (but it is limited to what the array is sending it).
When (if?!) it stops raining for more than a few hours, I will be going on the roof to see what I can in-fill with small panels to up the array size. However, even though by doing that that I will have an array larger than the current max rating of the controller, I don't intend to upgrade the controller as the amount of time it will be at the maximum is quite small, especially in Winter, but even in Summer, and the cost of a new controller when I have one already in place that is good enough 99% of the time is not worth paying. (Of course, if it was a substantial increase in the Array size, it becomes more of a consideration).

But .... when building a NEW setup, it makes sense to match the controller to the array to take advantage of every bit of power you can (again, cost is a consideration. If I was fitting a 300W array say, I may well still buy a 100/20 Victron as that goes up to 290W, just 10W short, and the next step is a much larger - and pricier - 440W unit, and most of that capability will ALWAYS be wasted)

In Summer the insolation is high. You get an average of five hours of full sun which ought to be more than enough. You don't need the full output of the panels, and indeed you won't be able to use it once the batteries are full.

In winter, you only get an average of one hour of full sun each day, and it's delivered at a low angle so the panels will miss a lot of it. As a result, it is unlikely to be enough power for many people, so you need another power source in winter.

At some point in the Spring and the Autumn there will be a point when there is just enough power from the solar panels to meet your daily needs. Adding more panels to the roof moves those dates further towards winter, giving a longer self-sufficient season.

The extra panels will increase the output when they're running below rated capacity, so the controller won't limit operations when it matters.

The one thing which is an absolute MUST is to understand what happens if you exceed the rated power, voltage and/or current capabilities of your solar controller.
If we take a Victron MPPT controller, and my own 100/20 for a specific model:
PV Voltage - Victron say you must never exceed the rated input voltage. The "100" in this case is the PV (solar) Panel total voltage. I believe that if you do, the controller is not damaged, just shuts down until voltage drops, but don't take my word for it, just do not exceed it!
Output Current - the "20" in this case is the output current (the input current will ALWAYS be smaller) and is the maximum the controller will output, if there is more potential current that the rated value, any excess is chopped off.
Wattage - the Victron solar controller is not power limited. The quoted wattage is just a mathematical number of the maximum current x the output voltage, so will vary depending on what the battery is at (this is why if the same controller is used on a 24V battery system instead of 12V, the rated power doubles).

The above is true for the Victron MPPT Solar Controllers. Other brands of solar controllers may and will act in different ways, especially on the way they handle over-voltage inputs (the Ablemail MPPT just won't go above 32V but has protection so no damage occurs. The Redarc MPPT blows up and is irrepairable). Some solar controllers could fail/break if the permitted power is exceeded.
Know your controller before you 'overload' it. And check for yourself the Victron ones as well, don't just trust what some bloke on a forum says!

 

[1 Cup]

All good as above. I thought it was 100 volts my panels volts are 67 - 75 volts max . The 30 is amps mines 24 amps at max.

So that why I haven't changed controller 100/30 plus its another £300..00

My vans all electric and solar tilts both sides for winter time. As expected dave we planed for 700watts on roof.

Thanks for help guys.

 

[wildebus]

All good as above. I thought it was 100 volts my panels volts are 67 - 75 volts max . The 30 is amps mines 24 amps at max.

So that why I haven't changed controller 100/30 plus its another £300..00

My vans all electric and solar tilts both sides for winter time. As expected dave we planed for 700watts on roof.

Thanks for help guys.

The 24A you are talking about is the INPUT Current. Once the Input (PV) voltage is converted to the Output (Battery) Voltage, the Output current increases.
Below is a datasheet of various Victron Panels (could use any brand, but the table is nice to use). I've highlighted the 305W panel.

Victron Panels by David, on Flickr

The two key bits of info are boxed in black - the Max Panel Voltage and the Max Panel Current. multiply one by the other and you get the Max Wattage (so 32.5V x 9.38A = 305W (on a 12V system)).
The INPUT current is 9.38A. If that panel is harvesting at full power on a battery that is currently taking power at 14.5V, that 32.5V gets converted to 14.5V. The beauty of the MPPT controllers is that is doesn't just chop off that extra voltage, it converts it into extra current instead..
So if the INPUT numbers are 32.5V and 9.38A, the OUTPUT numbers become 14.5V and 21.02A - so you are putting not 9.38A into the battery but 21A in.

If you then got a pair of these panels - you would either connect in Series (double the Input Voltage) OR in Parallel (double the Input Current).
SO with two panels, you are putting in a max of either (in series) 65V and 9.38A (=610W); OR (in parallel) 32.5V and 18.76A (=610W).
Same result, just different way to connect. But whichever you use, the OUTPUT Voltage is still 14.5V, however, the OUTPUT Current is now 42A.
So if you have a 100/30 Controller, yes, both the Input Voltage and Input Currents are below the 100 and 30 respectively, but the 30 is always the output current and not the Input current, and that 42A gets limited to 30A output and anything above is ignored. (if it were the input values, then the 100/30 controller would be a 3000W controller (100 x 30) and not a 440W Controller (14.5 x 30)).

The 100/30 controller would not be suitable for a 700W PV array unless you originally planned on a 24V Leisure Battery system. On a 24V system, the 100/30 is good for upto 880W.


(PS. Numbers above I am ignoring any power losses on cables, controller, etc. We are assuming 100% efficiency )

 

[1 Cup]

Mines 12v is that 24v then ? So why 100 /30 victron aye. When away I'll take more photo for data.

 

[wildebus]

Mines 12v is that 24v then ? So why 100 /30 victron aye. When away I'll take more photo for data.

if you are running a 12V battery system, then a 100/30 controller is too small for a 700W array.

 

[wildebus]

Mines 12v is that 24v then ? So why 100 /30 victron aye. When away I'll take more photo for data.

You must have had some specific plan for the solar in mind originally which you have later changed?

We had a telephone conversation a couple of years ago, and then I sent you a message afterwards saying:
"The Victron SmartSolar 75/15, suitable for upto 220W, I can do for £xxx.
The Victron Smartsolar 100/30, good for upto 440W would be £xxx.

I think following our conversation, starting off with the 100/30 would make sense as you could switch it to the new larger array and get the smaller 75/15 for that - or get another 100/30 to keep them matched.
Cheers"

I don't remember the detail of what was discussed, and without that, it's impossible to say why we talked about those two controllers (especially the 75/15), but obviously there must have been a reason.
As you can see from the above, I told you the power rating of the 100/30 Controller, which you went on to buy ....

 

[1 Cup]

Your right dave we started small to expand to 700watts 2020. At that time I had 280w. 2x100w 1 x80w over 3 panels. New 2023 260w x2 so will up rate controller before Christmas. I see a 100 50 for £250 ish on ebay. This month. It was £ 300 in.2020.