Solar PV Hints, Tips & Troubleshooting

Another reason not to like Solis. At least you can easily upgrade or downgrade Sofar firmware from MicroSD cards

Hi folks, Just had a 8.4kw array installed with a 6k Solis invertor. 20 Panels which are Tiger Neo 420 watt on 3 orientations E W and S

The East and South have 12 panels (6 and 6) on a string and have 12 Tigo optimisers on them. while the west has 8 panels. I've a few noob questions about the generation through out the day.

I thought i would be maxing out the invertor around the lunch time mark but I only just just tipped 5.8 once

I've attached the graphs, but I'm confused why my west string is showing a voltage early in the morning when I would of expected it to only get going around midday? I'm based in Sligo, which had some clear sun over the weekend, again I'm still very green to this stuff so just wondering if this can all this be explained away with "relax, its still only march" :) NB time is in UTC

The panels will have a relatively stable voltage through the day, but it's the current which will change as the day progresses. Your power is voltage x current. if you pull up the chart on the current, you'll see that the amps on your west string will be pretty low early in the morning.

Give it another month, mid/end of April and you will be clipping that inverter. The sun's slant angle is improving a lot now and when it's facing more "end on" to your panels, you'll be maxing that out.

Top tip: With the hour going forward, "solar noon" when the sun is highest over your house in sligo is about 1:40pm every day and not "high noon" as most people expect. :-)

Don't confuse voltage with current. Expect the expected voltage, but with very low current rates

Time is fast approaching to get a replacement PV system following the house fire earlier this year.

The original system was 14 panels at 5.18kWp on a SSE (140deg) roof + a 5kWh battery. During the dark months, generation stopped at about 14.00 hrs.

For the new system, I would like to put 5 extra panels facing WSW (230 deg) to take advantage of the afternoon sunlight. I contacted the original supplier to discuss and I was told that the inverter could handle up to 8 panels on each string so 8 panels on the main roof at 2.96kWp and 5 on the sub roof at 1.85kWp, total 4.81kWp.  This means I will have 0.37kWp less generating power from 1 less panel.

 What is the consensus of the cognoscenti on this board. Would it be better to stick with the original 14 panels facing SSE and suffer the shorter generation periods or go with the other idea of having 1 less panel but facing two directions and potentially generating for longer hours per day? I don't like the idea of having to use optimisers to increase the panel numbers.

I seem to remember discussion on the board about 'overloading' the inverter. Would it be possible to put 10 panels on one string of the inverter and use the second string to take the 5 new panels, even though the supplier says it can't be done?  The Ergocell inverter is rated at 6.5kW continuous PV input power.

Dave

I have already submitted an NC6 form when the original system was installed last year. The house fire early this year destroyed the solar system, so I will just be replacing the system. The ESB do not know that the system was destroyed.

I want to find out whether it would be better to spread the panels over two aspects but have a smaller system, or keep the larger system on a single aspect. In addition, I want to know whether my understanding that an inverter can be overloaded on the assumption that it will not be working at 100% efficiency is correct.

Dave

Look at the input per mppt on the specs of the inverter vs VOC of the proposed panels, to know the number per string. Never known less than 10 on a string tbh

But after that, I think that I would lean towards the 2 separates - with the 5 on WSW.

What you could do is parallel a WSW panel with an SSE one thereby adding a Sto the W string, but avoiding an optimizer. It's like adding a double sized (but same voltage) panel into the string.

has anyone else had an issue with Energia charging you for 30 mins at night rate ( 2 am to 2.30 ish ) when that should be EV rate ?

Is there an issue with them or a clock issue somewhere ? My Zappi and Inverter clocks book seem right

Thanks

What time is on your meter? That might be the problem

The time might be off on the meter though. Mine is 15 mins fast so night rate for me is 2345-0845

What do people do with their solar setup when they go on holidays? turn it all off ?

any tips for avoiding export? Battery and car both full. Need to look at a way of my leaf 30 only charging to 70% or something.