Green Building Forum - Solar Inverter Tue, 14 Apr 2026 09:23:25 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 Solar Inverter https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15796&Focus=269312#Comment_269312 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15796&Focus=269312#Comment_269312 Wed, 11 Jul 2018 18:59:46 +0100 tony
As I see it if there were 6kW of panels in winter they would only generate 2 kW a lot of the time]]> Solar Inverter https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15796&Focus=269313#Comment_269313 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15796&Focus=269313#Comment_269313 Wed, 11 Jul 2018 23:05:50 +0100 bxman Have 2 3kW inverters matched to 3kW of panels and combine both strings onto a single inverter in winter would be my advise .

https://www.google.co.uk/search?q=solar+inverter+power+curve&safe=active&hl=en-GB&tbm=isch&source=iu&ictx=1&fir=PwD4ytLcQ75XqM%253A%252CaRfTb54TZj1DVM%252C_&usg=__pdJSeO-cbGsT3ViYF7uI0qDqD5s%3D&sa=X&ved=0ahUKEwi-1J76hpjcAhWqB8AKHQ3QB3cQ9QEILzAC#imgrc=PwD4ytLcQ75XqM:]]> Solar Inverter https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15796&Focus=269315#Comment_269315 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15796&Focus=269315#Comment_269315 Thu, 12 Jul 2018 07:35:31 +0100 tony Solar Inverter https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15796&Focus=269318#Comment_269318 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15796&Focus=269318#Comment_269318 Thu, 12 Jul 2018 09:19:50 +0100 fostertom Solar Inverter https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15796&Focus=269325#Comment_269325 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15796&Focus=269325#Comment_269325 Thu, 12 Jul 2018 12:15:29 +0100 barney
This rises quickly so typically at about 10% load, the invertor is about 85% efficient

At 15% load, the invertor is about 95% efficient

Peak efficiency is around 30% loaded - say around 97% efficient

It will tail off steadily towards full load where is should be about 90% efficient

The invertor efficiency is = Power ac/Power dc

Power ac = AC Power out

Power dc = DC Power in

dc power is also a function of panel dc voltage

Depending on the scale of the system, that gross mismatch between Panel capacity and invertor capacity could be a significant chunk of energy lost

Regards

Barney]]> Solar Inverter https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15796&Focus=269327#Comment_269327 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15796&Focus=269327#Comment_269327 Thu, 12 Jul 2018 13:22:27 +0100 fostertom
What about
Posted By: fostertomThat winter-summer switching- is it OK with your certification?
]]> Solar Inverter https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15796&Focus=269328#Comment_269328 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15796&Focus=269328#Comment_269328 Thu, 12 Jul 2018 14:09:57 +0100 barney
In terms of designing up a simple DC switching panel so you can put low winter output of all panels onto a smaller invertor and back again to two or more invertors for high summer output is entirely feasible - but not without challenges. Switching DC is a bit of a bugger to avoid lots of contact arcing and potentially a bit risky due to welded contacts without DC compatible equipment

Keep in mind that at the end of the day, it gets dark - so there is a period at the start and end of each day where you are at the low efficiency point anyway.

It should be easy to analyse the effects when initially selecting the panels and the invertor so that you end up with the best mix of panel size and grouping to invertor size contrasted from summer to winter - I bet it's rarely done however, in most cases, I think the owner just sucks it up.

As I mentioned, you have to be really underloaded to get down to a poor efficiency point - in the vast majority of cases it's rarely less than 80% so is anyone really bothered ?

There is probably a greater impact in fixing the orientation and angle of tilt on the average system

Regards

Barney]]> Solar Inverter https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15796&Focus=269356#Comment_269356 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15796&Focus=269356#Comment_269356 Sat, 14 Jul 2018 11:12:59 +0100 jamesingram Solar Inverter https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15796&Focus=269357#Comment_269357 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15796&Focus=269357#Comment_269357 Sat, 14 Jul 2018 11:14:15 +0100 jamesingram http://stringtool.power-one.com/]]>