More Panels in Series for More EarlyProduction

[chrisski]

Do you really see earlier production by putting panels in series to exceed the charging threshold? I don't, but I'd like to hear your experiences.

I thought I was getting a bit of watts doing this, but I’m not. For example panels set up 3S for a potential 66 volts to squeeze more watts early in the morning while charging a 24 volt battery. I estimate by going with 3S instead of the bare minimum 2S to get the early production I produce less than 10 watt hours extra.



My Array:

3S3P
Panels 100 watts
VOC: 22
VMP: 19

Time	Total Watts 3S3P	Producing if 2S
7:14	2	No
7:36	24	Marginal
8:07	461	Yes

I did this on December 1st in the Northern Hemisphere so about three weeks prior to the shortest day of the year.

This is my 3S3P setup at 7:14 with 35 volts making 2 watts. (11.6 Volts Per Panel; 22.6 volts per 2 panels Below Charge threshold for a 24 volt system; 1P3S am only producing .7 watts for a 6 kWh daily requirement)

This is my 3S3P setup at 7:36 with 44 volts making 24 watts. (14.6 Volts Per Panel; 29.2 volts per 2 panels; Marginally at charge threshold 2S for a 24 volt system, but only 8 watts with 1P3s so 16 watts if 1P2S; 3S3P I am only producing 24 watts for a 6 kWh daily requirement)

This is my 3S3P setup at 8:07 with 58 volts making 461 watts. (19.3 Volts Per Panel; 38.6 volts per 2 panels; Above charge threshold 2S for a 24 volt system, 461 watts with 3s3P so 102.4 watts if 1P2S; 3S3P finally producing 461 watts for a 6 kWh daily requirement)


Wish I had graphing software for this. Also, the 30 amp SCC is slightly overpaneled but will produce 840 watts when maxed out and on a sunny day will reach this by 10 am.

 

[saen]

Try with simple experiment, point tree of panels 35 degree on east from south direction.
Test tree left south pointed.

Fill your location in profile, it will be more easy to others.

 

[12VoltInstalls]

Wish I had graphing software for this

Your information is very empirical and scientific. I don’t have that kind of data, just experience doing it.
I’m not surprised with the low Watt variance.

For my circumstances I do believe I get some earlier charging input with series panels by exceeding charging threshold, and my gut tells me that the biggest difference is probably on overcast days.

Either way the “real wattage difference” isn’t that great I don’t think, but getting some charge in overcast conditions does occur imho. However, that’s seat of the pants.

The biggest difference for me was series panels facing SW- I don’t think the wattage difference is that great with that, either, but what it did do was maintain full charge closer to sunset.

When I was only a few batteries and 600W 3S2P it made a noticeable difference with overnights. I even switched around a couple times over a three week period of sunny weather and duplicated my observations.
But I don’t have the great data that you show.

So holding full charge later in the day does seem to be the ‘big’ difference but again that isn’t driving a lot of watts, it’s just grabbing more optimal watts later in the day. And as you know, earlier and later in the day the energy available from the sun is way less.

In my quite small system and ~60W fridge at that time it made a noticeable difference- but “20W” for a 60W load when I wasn’t home is 33% whereas 20W for your circumstances might only be 5% (or perhaps less?).

I hope that’s good food for thought, and merry christmas, man.