Small solar panel system

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Killter

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Hi all,

Although I'm pretty handy about the house I have no idea about electrics.

I am thinking about a solar panel system to supply energy to two average sized oil filled portable radiators, which I gather are 1500W. Nothing else to be run off the battery.

Can anybody tell me what wattage panel and battery I would need for this in a very sunny area.

Thank you!
 
Panels are 400 watts so four panels 1600W, but they are not perfectly efficient so maybe 5 panels.

But the panels only work when the sun shines, while it can sometimes be sunny and cold, in general sunny weather is not the time you will want heat.
 
Solar panel ratings indicate their maximum potential output under ideal conditions. Think south of Spain, ideal conditions rarely exist in Ireland, and pretty much never exist when you want to power heaters.

In this part of the work a 300W panel on a south facing roof with a 40 degree pitch will produce ~260kWh over the course of a full year. That's just 0.7kWh a day on average, enough to run a 3kW load for 15 minutes a day.

That will be concentrated in the summer. Expect winter output to be as little as 20% of the output you'd get in summer.
 
@Killter will this be a grid tied system? Or off grid?
If it's grid tied, don't bother with the battery, the feed in tariff makes the battery redundant and unable to ever pay for itself.
If it's off grid, obviously it needs a battery. There's a great YouTube channel https://www.youtube.com/c/WillProwse and on it somewhere he covers how to calculate the size of battery and panel that you need (for off grid).
 
Leo said:
Solar panel ratings indicate their maximum potential output under ideal conditions. Think south of Spain, ideal conditions rarely exist in Ireland, and pretty much never exist when you want to power heaters.

In this part of the work a 300W panel on a south facing roof with a 40 degree pitch will produce ~260kWh over the course of a full year. That's just 0.7kWh a day on average, enough to run a 3kW load for 15 minutes a day.

That will be concentrated in the summer. Expect winter output to be as little as 20% of the output you'd get in summer.
Click to expand...
It really just does not sound at all viable to me.
 
Hi Everyone - thank you very much for getting back to me. It is actually for the south of Spain, south facing. The idea would be use a battery, off grid, to charge up during the day and run the heater at night.

Cremegg - thanks - I didnt realise it was a direct division. Judging by this it might not look so feasible - four large panels to run a radiator....not great.

So when you see solar panel kits with battery, inverter, panel etc. for sale for a couple of hundred Euros...what are these for? Charging a phone? Powering a lamp?

Thanks again guys.
 
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Killter said:
So when you see solar panel kits with battery, inverter panel etc. for sale for a couple of hundred Euros...what are these for? Charging a phone? Powering a lamp?
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They're for reducing overall consumption. The 3kW you're proposing is a very heavy load when you consider the average house here has a total electricity consumption in the order of 11.5kWh a day.
 
Whoa there! It is Definitely 100% possible to do this! If you get a big enough battery and enough panels you can 100% run that load.
The only question is how expensive is it going to be and then is it worth the cost.
You can only answer that by doing the math.
 
Example of the maths, I'm just pulling these figures out of the air but this is how to approach it
Each heater needs to run for 3hours a day =6 hours x 1.5KW = 9KWh
Want to be able to run heater for 2 days with no sun. Implies 18KWh Battery
Need to supply average 12 KWh per day during winter
In Spain in winter, need 10KWp Panels to supply average of 12 KWh per day

As I said figures are made up but you get the idea. Again check out that YouTuber, he know his stuff.
 
Killter said:
So when you see solar panel kits with battery, inverter, panel etc. for sale for a couple of hundred Euros...what are these for? Charging a phone? Powering a lamp?
Click to expand...
Caravan, motorhome, running some lights in a remote shed...
 
I haven't used them but these guys do kits

Electric Solar Panel Kits - Solartricity

Solartricity is a wholesaler supplier of Solar PV Panels for your home and business. These are the electric solar panel kits for an on roof mounting, plain tile roof. Slate and other roof systems require slightly different roof hooks and flashing.
solartricity.ie solartricity.ie
 
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