rin67630
Solar Enthusiast
Welcome to the reality of >50° latitude's solar, brother!Sorry, missed your reply earlier when I replied to others who’d posted after you.
Thanks for your tips. I’ve already experienced a run of heavily overcast days and was dismayed by how little the panel produced - its what lead me to order a second identical 160W panel to run in parallel, but even so I’m quite sure there will be plenty of days thru the winter when I run out of power and need to switch on a mains powered battery charger.
The purpose of my solar exploits has been something of a moving target. I suppose where I’m at right now is that it will reduce our mains power bills as I transition as many household devices from inefficient “wall wart” PSUs to running direct from solar DC.
The initial aspiration when I first began looking into solar was “how do I run my house ventilation fan on solar power, can I just stick a 20W panel straight on the top of it and have a battery local to the fan”. I decided that wasn’t viable and it would be better to get a larger 160W panel to charge a car battery to run the fan plus whatever other devices the available power would stretch to.
So what started as “small solar panel connected direct to one device” turned into ”bigger panel charging a car battery” and that has now evolved into two solar panels, an MPPT controller and a 100A LiFePO4 battery. The costs seem to go ever upwards once you get sucked into this solar panel lark!
You will quickly discover that you will permanently get either too much, or too less energy.
Your 300W panels will just produce 15W for a couple of hours during the winter, not even enough to run a decent internet router.
In the summertime, you will get so much energy that your 100Ah battery will be filled at 11'clock and your SCC will throttle down for the rest of the day...
So optimizing busbars is pretty vain:
-during the wintertime, the panels will have a so much high internal resistance and feed so few amps, that the leads do no really matter,
-during the summertime you will have too much energy anyway, so losses don't matter again.
Of course, you have sunny days in winter as well, and they are a game changer.
Frequently only an hour or two in the morning or in the evening, so it is important to have at least one panel oriented correctly to harvest that opportunity.
I would place the two panels at 60° oriented SSE/SSW wired in parallel and be sure that they have a Schottky diode in SERIES. (most panels are sold with a reverse Schottky diode in parallel, intended to wiring panels in series.