Light Activation Switch

Yut_Man

I have tried the solar panel idea, seems very simple. Couldnt get it to work though. not enough power produced from the panels. If you have a cheap source of panels then its sound. I tried tieing a few panels from broken solar lights up. Im not giving up though. just need a cheap panel.

energysavingexp

Yut_Man wrote: »

I have tried the solar panel idea, seems very simple. Couldnt get it to work though. not enough power produced from the panels. If you have a cheap source of panels then its sound. I tried tieing a few panels from broken solar lights up. Im not giving up though. just need a cheap panel.

what are you connecting it to?

have you tried an ssr they work some work from 3v to 32v little current
required:beer:

digitaltoast

albyota wrote: »

I too have this set up, using a light dependent diode and a relay and via a 16 Amp contactor supplying the immersion heater, (average 1kW - 1.9kW (3kWp system) from the PV, the rest from the grid,) took a bit of setting up to get the light / shade level correct. I am also using a battery charger during the day 9am to 4pm to charge / top up a 110Ah leisure battery, then feed the battery through a PSW inverter to run the house lights in the evening, oh and I also programme the air source heat pump to come on at midday for an hour to boost the hot water cylinder.

C'mon, it's a couple of months later - you can tell us all now: you were pulling our leg, right? (Please, PLEASE tell me you were joking?!).

If not, I would genuinely be interested in seeing your spreadsheet of full up-front costs, and projected and actual savings.

larkim

I suspect the answer is that its not all about the money saved - there are plenty of people who just want to reduce their reliance on carbon based fuels, and aren't just interested in the money saving options.

Matt

whasup

larkim wrote: »

I suspect the answer is that its not all about the money saved - there are plenty of people who just want to reduce their reliance on carbon based fuels, and aren't just interested in the money saving options.

Matt

I suspect not. In a similar thread a while ago I suggested making a list of all the things you might do to reduce energy usage and tackling the most efficient ones first - on the basis that trying to eek a couple of extra watts out of a solar PV system would be low on the list. Unfortunately solar blindness kicked in and the suggestion was treated with a fair dose of disdain. So carbon (or energy or money) saving didn't appear to be the priority.

Brian99_2

Yut_Man wrote: »

I have tried the solar panel idea, seems very simple. Couldnt get it to work though. not enough power produced from the panels. If you have a cheap source of panels then its sound. I tried tieing a few panels from broken solar lights up. Im not giving up though. just need a cheap panel.

My solution: Just bought a 12v 1.5 watt panel from Maplin at £9.99
http://www.maplin.co.uk/solar-powered-12v-1.5w-battery-trickle-charger-98358

Also bought a 6v relay with 240v contacts, Maplin £4
http://www.maplin.co.uk/6-and-12v-8a-miniature-relays-2525

The relay switches beautifully today with winter sunshine.

Goes on about 3 volts ( 30 milliamps)

Will arrange variable resistor to control the sensitivity.
(Or simply cover part of the panel)

This could switch an immersion heater on, (prob 1 kW) when generation is decent. :j

Yut_Man

got a simular solar panel myself from maplins. bit big but it works. pity the sun has been a bit grim lately.

Brian99_2

Done a trial, having the panel and 6v relay switching a small kettle (240 v, 800 watt) and it worked fine.

Beware though, the relay is "maximum 8 amps resistive" Any more would damage it.

I think a bigger one is advisable.

Kernel_Sanders

grahamc2003 wrote: »

A simple bit of Boolean maths solves the problem. A dusktodawn switch is basically a NOT switch. While two wrongs don't make a right, two NOTs do make an equal.

So you get two dusktodawn switches, the first to operate a bulb (on at night, off in the day), and a second sensing the bulb. The output of the second one would be on in daylight and off at night, or dawntodusk.

Not sure this is the most elegant or efficient solution though.

I do like that solution!
However, all the dusk to dawn switches I have seen (in supermarkets) have a current restriction of less than 1 amp, or they state 'not suitable for heaters'.

John_Pierpoint

When I bought one of those floodlights (DW got excited about them) about 20 years ago that somehow knew when it was dark and then sensed infra red - it came with a 500 watt halogen light.
I repalced this with a 350 watt one and used the spare capacity to put bulk head lights round the other 3 sides of the house.

[It is an expensive PIA though if left on standby, as we have lots of wandering wildlife etc. that create false positives and heat the night sky. Tend to just use it on a two way (garage & back door) manual switch, these days.]