Upgrade options

Chris_5339762

Hi there, just a scenario thats cropped up. There has been discussion about an additional battery or an inverter for our solar and I really don't know which one to suggest.

We have the following -

• 3kW inverter, gives us 3.3kW in reality.
• 8 panels, upgraded to 11, with a 12th put in for free (long story)
• 5kW Huawei battery
• Absolute maximum panel power of just over 5.5kW (3.3kW inverted + 2.5kW to battery)
• Old solar array for water heating
• Eddi

So we are limited by the inverter, clearly. It can only ever generate 3.3kW of power, or export 3.3kW. Frustratingly, we ended up with a 3kW inverter as the systems was originally 8 panels, but then a second roof was filled and we have 8 on one string, 4 on the second. A 6kW inverter was not thought of, or offered to us, at install. Annoying, in hindsight.

Needless to say the company won't take back the 3kW and give us a 6kW! Donedeal was the solution given.

Recently there has been a query about upgrading. My father wants to upgrade the inverter to a 6kW and get rid of the 3kW - he does not like the inverter maxing out at 3.3kW during the summer and extra energy just dissipating as heat - says it'll reduce panel life.. The electrician suggested a second battery. I suggest nothing, as it'd be impossible to claw the additional money back. The company does NOT want to put a second 3.3kW (2.7 to max out at 6) inverter in parallel.

During the summer, we use about 4kW overnight - the battery lasts until 3 or 4am. So a second battery would not be used much in the summer - but would help in the winter.

So which is the most cost effective? I can't make a call on this one. Any thoughts?

• Buy a 6kW inverter and sell the 3kW inverter somehow.
• Buy a second 3kW inverter and get the company to parallel them, or one string each.
• Buy a second 5kW battery
• Do nothing at all - the upgrade will never make its money back.

Any ideas? I can't decide, all are expensive.

slave1

Just note, technically a 6kW inverter is outside a NC6, the fact you already have a legacy NC6 (esbN allowed up to 6kW on a concessionary basis a few years back) may allow you to upgrade, not sure…will depend when you got your current NC6

graememk

All depends on how much it is to swap out the inverter, but will be for a 5kW one due to NC6 regulations.

What wattage are the panels? If they are 350 w the max output is 4.2kW.. then it's unlikely to be beneficial to swap out.

When over sized and inverter is at its maximum, the power in solar just isn't generated. There is no waste heat or damage to the panels.

paulbok

Is there scope to add additional panels at some stage?

Chris_5339762

There is scope for two sets of new panels but neither are likely in the near future.

• Replace the old solar hot water when that eventually fails with 4x solar panels
• Westerly facing panels on the garage roof would would really only be effective on summer evenings

Thanks for the heads-up on the NC6 and inverter size, rest assured we'd only go for the absolute maximum allowed there.

I think the panels are Jinko 450w ones. Even if waste heat or damage isn't happening, he's still paranoid about heat in the summer reducing panel life. His own idea - 15 year guarantee, but summer heat would reduce a 25 year likely life down to 20…. This forward planning from a gentleman who is 79!!!

graememk

https://www.boards.ie/discussion/comment/123774636#Comment_123774636

Ah of they are 450 there will be a bit more clipping.

But that will not reduce the lifespan of them. It's not how panels work. The power just isn't generated. So its lost as in not generated not that it's burned off in heat.

And they are designed for much hotter climates than what we get here!

Chris_5339762

In the end the decision was taken out of my hands as retired father decided what to do!

He's decided to get a new 5kW inverter, and is also getting an extra 5kW battery.

Expensive, and I know we will likely never get a return on this, but the hobby aspect is worth something to him and he did said he'll either sell the 3kW or use it to have an offline system or something like that. His thinking is along the lines of increasing energy prices or blackouts in the future. We're not entirely in agreement on this upgrade, but look, why not go for it.