Hi,
This is my system:
1. Inverter Schneider 4048
2. Midnite Classic 150
3. (6) LG Mono X Plus 360W solar panel
4. Rolls Battery 375AH C20 rate
I would like to know wich PV arrays suits my needs. According to your manual page 8-9 a 90v PV input is best for maximum power transfer to the batteries. Is this the best configurations for your charge controllers?
I understood that having more input voltage was more convenient and more efficent. Understanding this would help configure my panels in the best way possible, either 3 series or 2 series connection. Thank You.
Hi Jrosado..,
Generally with a Classic 150 on a 48 V Flooded Lead Acid (FLA) battery (and we cannot tell this), STC String Vmps of 85 - 90-ish volts is ideal. If your batteries are FLAs, then, strings of two PVs (even if they have 72 Cells) will often not have a string voltage that is high enough to fully charge/EQ the battery.
Relatively lower string voltages to the Classic, will increase its charge efficiency a bit, as long as this voltage is high enough to fully charge the battery, and/or allow an EQ voltage that is high enough, if the system uses FLA batteries.
We also do not know the exact model of PVs, but at that 360 Watt power level, they could be 60, or 72 cell PVs. Some modern 72 Cell PVs in strings of three can have an almost too-high string Vmp/Voc for a Classic 150.
Please use the Classic String Sizer, here:
http://www.midnitesolar.com/sizingTool/index.php
Even more info on your exact batteries and PVs would help us give better advice ...
Thanks, Vic
Thank You for your answer. Yes, my PV are 360w 72 cells. My batteries are flooded lead acid 375ah at 48v. Im checking the logs in my midnite, and my PV input voltage is around 85 to 90v due to the 2 series connection i currently have in my pv array. Is this enough for my battery bank ? I could increase to 3 serie connection to have around 140V Open circuit.( LG Mono X Plus). I have read the manual and the classic comes with a “hyper voc†function. I guess you are familiar with. I suppose to protect the charge controller and my batteries in case the voltage increases. What do you think is best ? Stick with my current array or having more input voltage is better for FLA batteries ?
Hi Jrosado,
OK, just to try to have the exact data on your PVs and battery, two questions:
1. What is the exact model number of your PVs ?? This is on the label on the back of each PV.
2. What is the exact model number of your Surrette batteries ?? This is on the label on the side of the batteries.
It is important to know in accurate detail what your system IS composed of. Otherwise you could make decisions that might not work well with the actual components of your system.
Thanks, Vic
As i already said. My panels are LG Mono X Plus 360w model. A quick search on google and it will show you the data sheet. My batteries are the Rolls S6 L16 375ah model a total of 8 for a 48V system.
Should I stick with the 2 series connection or increase it to 3 series connection ?
P.S. i have 6 panels and thinking to buy more for a situation with shadows in my house. Which connection will be best? This will determine if i have to buy 3 more panels or 4.
Quote from: Jrosado99 on August 06, 2020, 02:59:22 PM
As i already said. My panels are LG Mono X Plus 360w model. A quick search on google and it will show you the data sheet. My batteries are the Rolls S6 L16 375ah model a total of 8 for a 48V system.
Should I stick with the 2 series connection or increase it to 3 series connection ?
P.S. i have 6 panels and thinking to buy more for a situation with shadows in my house. Which connection will be best? This will determine if i have to buy 3 more panels or 4.
If you take the data from those panels and put them in this calculator it will give you a lot of information on best setup for the Classic .
http://www.midnitesolar.com/sizingTool/index.php
Larry
Quote from: Jrosado99 on August 06, 2020, 02:59:22 PM
As i already said. My panels are LG Mono X Plus 360w model. A quick search on google and it will show you the data sheet ... "
Yes, indeed, you did.
Had wanted to ask a couple more questions about your environment outside, and inside, where the batteries and Classic are located. But trying to get these answers is not needed, as, has been noted twice before, YOU can run the data from your PV spec sheet, environment, and come up with some guidance from the results of the Classic String Sizing Tool.
As shown in the following Link, there are several LG PVs that are available:
https://www.solarelectricsupply.com/solar-panels/lg-solar-modules
Just wanted a confirmation of your PV module model number before running that data through the String Sizer that is Linked, above.
You mentioned that your LG PVs are 72 cells.
With a Classic 150, your exact PVs seem to place your system near two different sides of the operating envelope -- strings of two PVs appear to have a bit too low a string Vmp, and strings of three PVs may well have a bit too high string Vmp, and perhaps too high a string Voc (Vin to the Classic 150). The outdoor Max and Min temperatures have an effect on the decision of string configuration
When you run the string Sizer, please use a reasonable maximum and minimum outdoor temperature for the location of the system. Having you run this data through the String Sizer, will keep us from needing to ask you what is this temperature range, etc.
Sorry to have been too demanding for "exact data". Good Luck. Vic
No need to sorry Sir. Thank You for your time and your Answer. I will definitely check this... i live at PR and temperatures can be very high some times.
Am short on time, right now. But is you could tell us the lowest and highest outdoor temperatures for the system location, I could run the Classic String Sizer. And post the results here, probably later today.
Just to try to make sure that we have the correct data sheet your the PVs that you are using,
Is the model number of your LG PVs: 360S2W-A5 ??
Here is a link to that data sheet:
https://www.lgenergy.com.au/uploads/download_files/d95acb53f1726da69196a3f3d3e9d1859dda1ff5.pdf
It makes no sense running the incorrect data through the SIzer, and perhaps drawing incorrect conclusions ... Thanks
More later, Vic
In the intirim,
Did run the Classic String Sizer, three strings of two, and two strings of three, each Attached below. Guessed at your max and min outdoor temperatures. Having correct info on temperatures is very important.
Really seems, that strings of two PVs (if I used the correct model on LGs) has too low string Vmp. Strings of three will reduce the Classic efficiency a bie (and increase its heating), but is probably OK, if your lowest temperatures are not too low.
Later, Vic
Lowest outdoor temperature 18C, highest outdoor temperature around 31-33C. Here I attach the link to the data sheet i use for my panels.
https://www.lg.com/global/business/download/resources/solar/MonoX%20Plus%2072cells.pdf
Thank You for your time.
Hi Jrosado..,
Thanks for the Link to your PV data. That appears to be the data used in the String Sizer.
Thanks, too, for the temperature range. My guess was 3C for the lowest, and 36C as the highest, so, you appear to be OK there. With strings of three, the Classic is projected to begin using Hyper Voc (where it rests, until the PVs warm above that temperature. But it appears that your temps will not get that low.
It does seem that strings of three PV will be best in your environment. Strings of two would work much of the time, but with strings of three, the Classic will have more range to find the MPP that will produce the most power at that time.
f
More later. Good Luck with the WX. Vic
This is de PDF generated from the sizing tool. What can you tell me about both configurations? One is with the 2S5P configuration and the other one is 3S3P configuration.
Hi Jrosado..,
Thanks for running the Classic Sizer for your proposed configurations.
I still believe that the 2S5P configuration (really just as the 2S3P), would result in a too low string Vmp for hot days, and when trying to EQ your FLA batteries (especially when the batteries are cool, on a warm day).
The rule of thumb for most any MPPT CC, is noted in the following footnote taken from one of your Sizer runs:
"NOTE: Generally speaking you'll want to use the Classic 150 or 200 as they are less expensive and will handle more power. With MPPT controllers the
higher the input voltage the less efficient they are. This is not a large value but it will add up to a little more heat in the controller and a point or two less
in efficiency. BUT you also have to be careful not to have the input voltage to low. Most all MPPT controllers will want to see a minimum of 130% of the
actual high battery voltage. So if we have a 48v battery and it has an Equalize voltage if 62.3 volts than we would multiply that by 130% and we would
need a minimum of 81 volts on the input on the hottest day of the year in order to have enough headroom for the MPPT to work"
Two of your PVs in series will NOT comply with this advice. It is good that your system is in a very moderate climate -- not too hot, and never cold. In many locations with cool/cold temperatures, these PVs have a bit too high Vmp and Vocs to run well on a Classic 150, with FLAs.
Would suggest that you need strings of three, even though you will have a bit less apparent power from nine PV vs ten.
All my opinion. Does the above make some sense to you? Thanks, Vic
Thank for your answer. I read that note in the sizing tool and still got confused. Yes, they recomend a lower voltage for optimum perfomance but my PV voltage wil not be close enought at high temperatures. I guess i am in a difficult spot situation. However, i checked my CC and the PV input voltage is at 77VDC with a load of 800~ish Watts. i think i should change my conf. for a 3S connection. Even i loss a little bit in efficient.
Can I connect 2 different solar panels of 370w also 72 cells with one Lg 360w in series? They are both Mono panels. The reason because i coulndt find my current panels in my location. I know this is not ideal, but i need those extra panels.
Hi Jrosado..,
You could try to find some 60 Cell PVs, and perhaps make series strings of two of your existing LGs and one of the new ones. This would reduce your string voltage a bit, and perhaps make a slight improvement in the efficiency of the Classic.
In general, the current that each of these new strings would be limited to the current of the PV with the lowest Imp. If there was a significant difference in the Imp specs, this would cause the PVs with the highest rated Imp to be more lightly loaded, and result in the Vmp of those PVs to increase somewhat ... gets a bit complicated, and is probably not worth trying too hard to play that game.
The standard rules of thumb for adding PVs in parallel with existing PVs is, that ideally the STC Vmps should ideally be within 5%, and not more than 10% different, maximum. And for adding PVs in series in with other PVs in a string, that ideally the STC Imps be within 5%, and not different by more than 10% maximum. So if you could find some 340 - 380-ish watt PVs, you can compare the STC Imps if you were adding those in series in strings with the LGs, or compare the STC Vmps if you were adding the new PVs in parallel.
Since you are trying to combat Shading issues, my may be thinking of placing the new PVs in a somewhat different location. In this case, the exact matching of Vmps may not be quite as critical, compared to a situation where you were just looking to have more power at an existing array location ... and so on.
Enough for now, good luck in finding some more PVs that are close enough for your needs. Please let us know how you are doing, thanks, Vic
Thanks Vic,
Yes, i have work to do. I will be updating