Solar-powered garden lights indoors?

[JohnW2]

Reading the beginningof this ... I thought I was going to see some useful suggestions, however all I see is the products or components of products sold in poundshops.

Same here - and none of the products suggested by him are anything like 'meaty enough' for my purpose (as well as all being 'ridiculously cheap')

I think John has been making it abundantly clear he is expecting to use a bigger solar panel and bigger battery, in some way, to achieve the required goal

I though I had, as well, but I'm not convinced that everyone has read, and understood, what I've been writing!

 

[JohnW2]

That is my attitude towards them - simply not worth the bother. I leave the lights entirely to Avril, and try not to get involved.

As I've said, these products designed for garden use are ridiculously cheap and cannot be expected to last very long when 'exposed to the elements'. However, they are so cheap that (if one wants them for a garden), one can simply regard them as 'disposable'.

I'm using them only as an ultra-cheap products fro determining what can be achieved with solar cells illuminated though a window - I certain;t would not use such products for a 'definitive' solution.

 

[ebee]

those who conduct research which yields results which are not 'positive' often struggle in their attempts to share that information with those to whom it might be of interest

Agreed

 

[ebee]

So my suspicion is it is a little "suck it and see" experiment with enough of these cheap items to get a comparison, of sorts, of what is achievable in lots of differing inside locations as to the useful sunlight, therefore energy, that might be soaked up in various conditions.
Once you get a "feel" for it then the next step might be how to best utilise more expensive set ups and see if they compare (or hopefully exceed) in most expectations.
That might just give you one parameter to any likely final solution(s).

The next step might be timers controlling switch on/off sequences to give the illusion of a suggestion of home inhabited.

Power draw could be minimised by using CMOS switching electronics but greater protection might well be needed too.

Once you got all the swings and roundabouts sorted then it might lead to possibilities in ultimate design(s).

 

[JohnW2]

... those who conduct research which yields results which are not 'positive' often struggle in their attempts to share that information with those to whom it might be of interest

Agreed

Indeed - it's usually called "publication bias". In fields I work in, things have improved consdierably over the decades, but are still far fromperfect. One of the positive developments is that there are a now a good few 'open access' repositories for results of research - so that researchers are no longer anything like as much at the mercy of what journals and journal editions feel inclined to publish.

Kind Regards, John

 

[JohnW2]

So my suspicion is it is a little "suck it and see" experiment with enough of these cheap items to get a comparison, of sorts, of what is achievable in lots of differing inside locations as to the useful sunlight, therefore energy, that might be soaked up in various conditions.
Once you get a "feel" for it then the next step might be how to best utilise more expensive set ups and see if they compare (or hopefully exceed) in most expectations. ... That might just give you one parameter to any likely final solution(s).

As I've implied, I think I can probably now bypass a lot of those 'little experiments'. Despite the fears (of myself and others) I have satisfied myself that even a tiny solar panel can generate a 'useful' amount of electricity when illuminated through a window, so I think I can probably now move up to a much larger solar panel and see what it can generate 'through a window' (particularly as days shorten) - and that will not really require me to initially bother about 'storing' the electricity; I can move on to considering that once I have discovered how much electricity I might reasonably have 'to store'.

The next step might be timers controlling switch on/off sequences to give the illusion of a suggestion of home inhabited... Power draw could be minimised by using CMOS switching electronics but greater protection might well be needed too. ... Once you got all the swings and roundabouts sorted then it might lead to possibilities in ultimate design(s).

indeed - but all that is even further 'down the line'!

Kind Regards, John

 

[SUNRAY]

Diodes in the charge circuit, were always a no, no.

Why?
FWIW I have dealt with some substantial 'additional battery' charging and the only way I'd ever contemplate a professional installation (including ambulances with a number of 200AH batteries) is using series diodes with a proper controller and battery voltage sensing. My choice has always been Adverk and using appropriate alternators/regulators and if the 2nd etc battery is in the trailer, proper connectors too.

W/L controlled relays and later the voltage controlled relays, always worked fine for me.

And I've repaired loads of failed WL controlled relays and the circuits.

the secret was one of installing an adequate size of cable, to overcome the volts drop along the length. Not many installing such cables, understand volts drop, or take account of it.

There is a lot of difference between a professional installation and what others do.

 

[SUNRAY]

Is it not apparent that the only reason I've been 'playing' with these ridiculously cheap toys is to get an initial feeling as regards the viability of generating a useful amount of solar energy with an indoor ('through window') solar panel

Yes it is clear to me.
My comments based on experience with cheap solar lights;

Corr 2 weeks and still doing 3 hours a day, you must have picked up a good one!

is the performance of them drops off extrememly rapidly, noticably within a couple of weeks. Initially I assumed it was crap batteries (mostly AA or AAA) and replacing them appeared to solve the problem but it seems to be the panels are the weak link.
We have a couple in the garden at the moment since May and getting any noticable light out of them is now rare. I've not tried them indoors to compare but these

have been shaking their hips for years so that may be worthy of note... Oh and also worthy of note: the closed curtains behind them at lunchtime

 

[JohnW2]

Yes it is clear to me.

I'm pleased to hear that at least some people understood me

is the performance of them drops off extrememly rapidly, noticably within a couple of weeks. Initially I assumed it was crap batteries (mostly AA or AAA) and replacing them appeared to solve the problem but it seems to be the panels are the weak link.

I certainly would have expected that the batteries would be more likley to fail early than the solar cells in these cheap toys. However, even f the latter also fail very early, gthat does not really matter to me, because mine have carried on working for long enough to demonstrate what they can achieve 'when they are working'!

 

[Harry Bloomfield]

Why?
FWIW I have dealt with some substantial 'additional battery' charging and the only way I'd ever contemplate a professional installation (including ambulances with a number of 200AH batteries) is using series diodes with a proper controller and battery voltage sensing. My choice has always been Adverk and using appropriate alternators/regulators and if the 2nd etc battery is in the trailer, proper connectors too.

Simply because - The usual installation is in a domestic type car, with a fixed 14.4 maximum output voltage, using an alternator. A dynamo system voltage would be even less. Deduct 0.7v from that, for the diode and there is little chance of there being enough voltage remaining, to usefully charge a battery, especially if that battery is located at the far end of a fairly small cable, even more so, if it includes a fridge.

Voltage sensing at the load/battery, nullifies all of that, of course..

 

[Munroast]

Thanks, if you feel that your suggestions were 'very much on target', as useful responses to my initial question (first posted last November, and repeated recently), then I would be very grateful if you could explain a little more clearly, and will be very interested to understand exactly what you were/are suggesting.

As I've said, in relation to what you previously wrote, transforming voltage wouldn't make any difference to the amount of solar-generated energy available, and nor do I understand what you meant by the suggested "plug-in 5V transformer", or what you were suggesting I could 'plug it into'.

aye, probably a bit beyond where you are. The idea of suggesting a Buck Step Down was to enable linking up any small LED outdoor type lights to most small DC supplies. I mentioned a 5v plug in transformer that I am using as 5v would be a typical voltage of many of the USB solar panel charges that are available at very reasonable prices, a 'step down transformer' would enable connection to the 1.2v (2.4v) mini outdoor lights that you are using. (may be create a small bank of the rechargeable 1.2v batteries arranged in parallel to store the solar enegy for longer use in the autumn - and may be a small wind turbine to charge them in the winter. Lots of interesting things can be done!

 

[JohnW2]

aye, probably a bit beyond where you are. The idea of suggesting a Buck Step Down was to enable linking up any small LED outdoor type lights to most small DC supplies.

Fair enough - but, as you may understand, there';s no reason why I need to (or would) use "LED outdoor-type lights", and certainly not 'lights' fed from a very low voltage (e.g. 1.2V) source.

I mentioned a 5v plug in transformer that I am using as 5v would be a typical voltage of many of the USB solar panel charges that are available at very reasonable prices, a 'step down transformer' would enable connection to the 1.2v (2.4v) mini outdoor lights ...

Fair enough. I certainly will use a much higher voltage than 1.2V - possibly 5V (as you say, facilitating the use of solar USB chargers), but possibly higher (e.g. 12V) - but, as above, I would not ned to down-transform that voltage (with associated losses/inefficiencies) in order to run very low-voltage lights. I would either use 'lamps' designed for the appropriate (higher) voltage) or, more likely simply use a string of the appropriate number of LED elements in series (quite possibly series-parallel) with some sort of current control..

hat you are using. (may be create a small bank of the rechargeable 1.2v batteries arranged in parallel to store the solar enegy for longer use in the autumn -

I could easily increase the storage capacity of the battery(ies) (at 1.2V or some higher voltage) but I don't think that would, per se, help the 'non-Summer' issue. I ideally want the lights to come on every night, which means that the limiting factor will be the amount of electriocity that can be generated (from solar or whatever) during the preceding parts of that one day - an increase in 'generating capacity' would be required to address that..

and may be a small wind turbine to charge them in the winter. Lots of interesting things can be done!

I have toyed with that idea, but as yet have given it little thought, since I have almost no experience of wind turbines and therefore have no idea what sort of set-up would be required to generate the required amount of electricity. However, this thought remains at the back of my mind, in case I need to give it more serious consideration in the future.

Kind Regards, John

 

[cdbe]

I sent my wife to The Range to buy some replacement batteries for our solar lights. The man laughed condescendingly and said "you don't need batteries, they're solar". Even when she found and showed them to him he just couldn't understand it.

 

[JohnW2]

I sent my wife to The Range to buy some replacement batteries for our solar lights. The man laughed condescendingly and said "you don't need batteries, they're solar". Even when she found and showed them to him he just couldn't understand it.

 

[FrodoOne]

Is it not apparent that the only reason I've been 'playing' with these ridiculously cheap toys is to get an initial feeling as regards the viability of generating a useful amount of solar energy with an indoor ('through window') solar panel - something which many thought was probably a non-starter when we discussed this last year.

I have now ascertained that, in roughly mid-summer, a 'useful' amount of solar energy can be generated even with a tiny indoor panel.

The next experiment will involve a much larger solar panel. probably with a much higher voltage output, to enable me to determine how much solar energy I can reasonably generate, particularly as the days become shorter. Armed with that information, I will eventually hopefully design a definitive system, with a solar panel of adequate size, and with a battery of appropriate capacity feeding appropriate light sources, probably with some sort of 'control system.

OK.
I was trying to be helpful in "designing" a small "system" which could be expanded - using more "panels" and more/larger capacity Cells

while the input is (nominally) 2 V, the output is 3 V - using one (or more) 1.2 V Ni-MH Cell(s).