This is about the panel wiring, it's 40v selv. Mfr says minimum fuse 20A for a 10A panel. Why fit a fuse that can never blow? Mfr says 4mm^2 cable for a 10A panel. Why? Which standards apply to the selv wiring, part of which will be outdoors? Would screwing ss fixing to the ali frames cause corrosion? Is there a good reason to use the twist pole connectors already on the panel?
Because manufacturer does not know how many panels you are going to fit and what different combinations of series or parallel panels are to be configured. If shorted the 20A fused will blow to protect the panel.
and. Cable sizes are related to voltage drop. If you've only got 40v even a
1 volt drop is 2.5% of the total. Thicker cable will have less of a voltage drop.
Probably linked, not 100% familiar but normally fuse is to protect cable from fire. So if cable can take 20A then you can put in a 20amp fuse.
then they have no business dictating fuse rating.
no, Ishort is 10A on the equator. A 20A fuse is entirely useless afaik
Yes. It also depends on length. Specifying only one half of what's relevant seems odd.
1mm cable does 10A no problem. The advised 4mm does way more. F20A can never protect against fire if it can never blow. Maybe it's in case of power feedback.
1mm cable will drop 0.46v per metre at a 10A current. It's only a quarter of that for 4mm cable
This discussion left me wondering what happens when your battery, no matter how large, gets fully charged. Where does the output from the cells go? Assumedly they still generate power, but probably fluctuating due to the weather etc. It would be nice to think modern tech could use this to in some way direct feed appliances. Brian
I know you can change things to your own preference but isnt the standard config to send solar power to the home appliances first, then any excess to the battery then any excess to the grid?
I dont know what happens to the generated power if there is a grid outage as the inverters should be configured to stop sending out to the grid if its down.
Um ITYM '1/16 of that' if it's the *diameter* you are talking about... If its the AREA you need to say 'sq. mm'. But I do accept that the trade absolutely uses mm everywhere where it means 'sq mm'
I put some standard T and E on my LV spots between the transformer and the lamps. At 4A and three meters the lights were noticeably dimmer. The upside is the same bulbs are still in there 20 years later :-)
Why? you can get far more money by generating power for the grid than it will cost you to get it *from* the grid. Viz the Spanish 'solar farms' that were running diesel generators to generate 'solar energy' to make more money than the diesel cost.
They got caught out when they forgot to turn them off at sunset...
The EU is so f****ng wonderful isn't it?
Indeed they do, and that is a huge problem because they stop sending if the grid frequency even DROPS.
So e,g, if a windfarm loses power because the wind is too strong, as has happened, and the grid frequency falls, *every f****ng piece of renewable energy and interconnectors will disconnected itself*
And the grid will separate itself into sections and blackout some areas. THAT is why they are adding batteries. Not to store sunlight after dark but to keep the grid frequency up under overload until they can get a CCGT set or hydro installation up from cold. or whatever
Its' called a *f****ng* smart grid, innit.
>
Export to the "grid"
The panels just go open circuit once the battery charger/inverter doesn't demand power. If the system is grid connected the excess power can be exported up to a maximum allowed by the distribution network operator,5.68kW in my case, it can pay in excess of 15p/kWh depending on the time.
The fuse protects the battery if a short happens between the panels and battery
Not (AFAIK) in the UK.
I am with Octopus on a dual rate tariff. My overnight rate is around 16p (per kWh). Daytime rate is around 36p. Export rate is variable but is typically between 7-12p. Sometimes it will go slightly over the night time rate (usually between 16:00-19:00) where I could export from the batteries and make a couple of pence but that needs to be balanced against the risk of the batteries running out before the night time period and being charged at the daytime rate for any electricity that we use.
There were a few times last winter when the export rate went up to around £1.70. When this happens its quite clear that dumping everything from the battery (purchased at 20p then) back to the grid is a good idea (which I did) and then buying it back at the daytime rate (which was 44p then). I think that happened about half a dozen times.
I have solar panels and batteries. On low solar days I charge the batteries from the grid on the over night rate
LOL
If you are on old FIT rates, maybe
Present SEG export rates are *much* worse, as low as 2p from some
Good. That probably means the end of the whole 'renewable energy' boondoggle
Worse than that, many in the trade, especially those educating the 'learners', constantly refer to things like "2.5 millimetre squared" instead of "2.5 square millimetres".
2.5 millimetres squared is a perefectly valid measure, however it means 2.5mm x 2.5mm or 6.25 sq mm. A useful way of referring to something that is actually square.
Octopus Agile Outgoing is about 8 to 20p currently: (scroll down to the bottom)
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