camelot-forum.co.uk

Krill wrote: ↑Fri Mar 08, 2024 10:19 am I'm doing a bit of work planning to complete my solar pergola, and I've come to the conclusion that I need to use solar panels roughly 2.2m by 1.1m in size to maximise the area covered. I will be using them in portrait orientation and they need to be half cut cells because of the shade thrown by the house.

I've checked a couple of sites (Bimble, its, midsummer, cityplumving) and they seem to be quite rare: there are a few 575w panels available but they are pricy. Are there other retailers which are decent, or should I be looking a different types of retailers due to looking for commercial sized panels?

Secondly I'm toying with using a hybrid inverter (which requires a sparky to hook up which I'm averse to), or just going with a simple dc/dc charging a la Victron. Given that I'm using 3 US5000 and normally the max charging current would not be an issue and I can easily limit the max AC charging current. I'm unsure though how the dc/dc chargers would communicate: is the usual process just setting a lower max voltage on the chargers that lack communication?

I'm not in a rush with this, very good chance I don't get to do any of this expansion this year. Longer term I would hope to expand the battery stack but that's a separate step.

Any advice greatly appreciated.

Stinsy wrote: ↑Fri Mar 08, 2024 11:37 am Additionally these jumbo panels tend to have higher current ratings than most consumer inverters can make use of. This isn’t harmful (the reverse polarity protection might not function) you just won’t get the full power the panel is capable of.

robl wrote: ↑Fri Mar 08, 2024 12:54 pm

Stinsy wrote: ↑Fri Mar 08, 2024 11:37 am Additionally these jumbo panels tend to have higher current ratings than most consumer inverters can make use of. This isn’t harmful (the reverse polarity protection might not function) you just won’t get the full power the panel is capable of.

Are you sure about that? Inverters tend to have a maximum MPPT current which it's ok to exceed (you just loose power), and a higher maximum short circuit current which I don't think you should exceed:


https://www.sma-sunny.com/en/inverters- ... onception/

Krill wrote: ↑Fri Mar 08, 2024 3:00 pm I'm never going to claim I'm au fait with the rules around inverters, capacity, and everything else going on, so apologies if this comes across as naive.

I've used the Victron MPPT calculator and when I plug in the numbers for the 555W JA panel nowty suggested it shows that most SmartSolar chargers from 250/60 and up can easily take eight panels (4s2p), but the lower end charge controlers (250/60 that are limited to 60A) are capped, but the higher rated ones (250/100) would probably be a better fit. And this would be cheaper than using two separate charge controllers for each string.

So here's the questios: Assume the panels are set up, two horizontal rows of four panels. 15% angle to the horizontal. Shade will come from the house roof which is directly in front and flat for 80% of the year (the other 20% the sun rises and sets behind the house in summer). The shade will always creap up from the bottom in a straight line, hence the desire for half cell panels. For the 80% of the year that the roof is the main shading object, there are no problems from trees or other objects.

If the array is set up as a two strings of four panels, and the bottom row starts to decrease in output as the shade rises in the evening, but the top row is unshaded, what happens to the charge controller in terms of power output?