Solar-powered garden lights indoors?

[JohnW2]

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

It's been a lot more than 3 hours most days. However, if it can do it once (one day), I don'y see why it shouldn't do it every day, so I'm not sure why you appear surprised that it's been doing it for two weeks?

If one guesses that the LEDs are using 5-10 mA, I suppose that (forgetting losses and other inefficiencies) a fully charged battery could keep them going for 4-8 hours, and if we assume maybe 16 hours reasonable daylight (at present), it would (again, ignoring losses etc.) require less than 3 mA continuous charging each day from the solar panel.

 

[ericmark]

Interesting, I have solar panels on the house, and an inverter which connects them to a 3.2 kWh battery, I have not tried turning power off as an experiment, but when a HV fault in the street gave us a 5-hour plus power cut they worked well.

What I don't know, is what will happen once the battery goes flat? Will the inverter restart once the sun comes up, the battery will normally discharge to 10%, and with no grid to 4% the question is would the 4% keep the inverter live, so it can fire up again when the sun comes up. Think it will likely last the night.

But the output is so weather dependent. Today for example. does not matter how much, it is how it has varied, so in summer the battery is charged overnight, then at 5 am it stops charging, and we get a dip before the sun moved around as panels are South West facing, then it starts to discharge as the evening starts. with luck, lasts until the off-peak charging starts. But in winter we did not have the smart meter, so there was no off-peak charging, so back in January there were very few days when the battery could have been fully charged, about 2/3 of the days did we get 3.2 kWh in the day, but last month some days we got 10 times the batteries' capacity. the only way the solar really works in the winter, is that the inverter and battery allow us to use off-peak to recharge the battery. One poor day, it may continue to work, but we tend to get a run of poor days.

I tried to use a solar charger in my caravan when in storage, it failed, in part due to the radio, if disconnected it went into demo mode, so would not allow the battery to recharge.

But I have an interaction problem, when some outside lights are inhibited due to others working. Maybe better to show the year. Green is solar production, and you can see how little we got in the winter months. Do not scale change 0–600 and then 0–1000. I know your panels are much smaller, but I have a display for mine, so easy to see how much it changes through the year.

 

[Munroast]

I invested £1.50 in a diddy "solar garden light" from PoundLand. It has a coupleof little LEDs, a tiny 'solar panel' (about 30mm squatre) and an equally tiny battery (1.2V 40 mAh).

yes many of these lights run off these 1.2v rechargeable batteries and need very small amounts of power.

you can bypass the batteries with either a bigger battery or what I done a plug in transformer. Get a "buck step down"

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(Load regulation: 0 0.5%. IN-IN + input Positive Input Negative. Could not boost). Output current 3A (max). Output ripple <30mV. Positive output OUT + OUT-output negative. Power Supplies. YOU MIGHT ALSO LIKEVIEW ALL OUR PRODUCTS.

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then you could for instance wire it all up to a car battery with the buck set to reduce the 12v 1.2v (or may be 2.4v if there is a pair in series)
I have mine wired up to a plug in 5v transformer and it delivers the 1.2v to the lights and these run all winter (probably been going 5 years now) they seem very reliable.

 

[SUNRAY]

It's been a lot more than 3 hours most days. However, if it can do it once (one day), I don'y see why it shouldn't do it every day, so I'm not sure why you appear surprised that it's been doing it for two weeks?

If one guesses that the LEDs are using 5-10 mA, I suppose that (forgetting losses and other inefficiencies) a fully charged battery could keep them going for 4-8 hours, and if we assume maybe 16 hours reasonable daylight (at present), it would (again, ignoring losses etc.) require less than 3 mA continuous charging each day from the solar panel.

Mrs Sunray and her brother must have purchased 50 various solar lights between them and quite frankly I've found they have all rapidly lost performance to the point we've given up with them. We have some here which were presents and we haven't bothered getting out of their boxes for a year or 3:

Some of the early bollards we had I converted to 12V with 2 or 3W G4's (until the plastic deteriorated) when the solar failed

 

[JohnW2]

What I don't know, is what will happen once the battery goes flat? Will the inverter restart once the sun comes up,

That presumably depends entirely on the design of the inverter and/or any 'systems' controlling it ...

... if one constructs a very basic inverter, it will spring to life and produce output immediately an appropriate voltage is applied to its input - so that ought to happen "when the sun comes up".

 

[JohnW2]

yes many of these lights run off these 1.2v rechargeable batteries and need very small amounts of power. ... you can bypass the batteries with either a bigger battery or what I done a plug in transformer. Get a "buck step down"

I think you have probably missed what I'm trying to achieve. The 'limiting factor' in the product I'm experimenting with is the tiny size of the solar panel - so nothing would be gained by having a larger battery, and nor is there any need to 'transform' the voltage.

.... then you could for instance wire it all up to a car battery with the buck set to reduce the 12v 1.2v (or may be 2.4v if there is a pair in series)

I don't need anything as large as a car battery, since I only need a very small handful of Ah each day and, to be able to run continuously, the battery will, on average, only have to be charged by that amount each day

I have mine wired up to a plug in 5v transformer and it delivers the 1.2v to the lights and these run all winter (probably been going 5 years now) they seem very reliable.

I'm not sure what youy are saying here. What is it that is "wired up to a plug-in 5V transformer", and what is that transformer plugged into? As I explained at the start, my system needs to be able to work from solar-generated electricity alone (with no mains electricity available).

 

[FrodoOne]

I invested £1.50 in a diddy "solar garden light" from PoundLand. It has a coupleof little LEDs, a tiny 'solar panel' (about 30mm squatre) and an equally tiny battery (1.2V 40 mAh).

Manufacturers put in the smallest capacity battery that they can get away with.
If it is AAA, you can obtain batteries with much higher capacities - up to 3000 mAh claimed.
I suggest that you obtain at least one cell of higher capacity and test with that installed.

 

[JohnW2]

Mrs Sunray and her brother must have purchased 50 various solar lights between them and quite frankly I've found they have all rapidly lost performance to the point we've given up with them. We have some here which were presents and we haven't bothered getting out of their boxes for a year or 3:

A lot of these things sold for garden use are ridiculously cheap, so I wouldn't expect them to last very long at all when 'exposed to the elements' - although I might hope that they would probably last a lot longer if used 'indoors'.

However, I'm obviously only using one of those cheapo products for a 'proof of concept' experiment (the concept of using a solar panel 'through a window'). If I can satisfy myself that it is a viable concept, I will use a battery of at least a few Ah capacity, together with a solar panel large enough to more-or-less fully charge the battery (from 'flat') with a day's worth of daylight.

 

[JohnW2]

Manufacturers put in the smallest capacity battery that they can get away with.

... and/or the biggest that makes sense in relation to the charging ability of the solar panel.

If it is AAA, you can obtain batteries with much higher capacities - up to 3000 mAh claimed.

It's not AAA - it's a tiny Ni-MH 'button cell' - but, even if a higher capacity (higher than 40 mAh) one were available in that format, I doubt that the tiny solar panel would be able to charge it within the number of hours of daylight in a day, even in summer

As I've recently written, if I can satisfy myself that the concept is viable, my definitive system will use a batter of at least a few Ah ('a few thousand' mAh) capacity (assuming I stick with 1.2V - more generally 'at least a few Wh capacity'), with a solar panel of correspondingly appropriate size.

 

[FrodoOne]

I suggest that you should stop "playing" with items from "Pound Shops" and investigate something like
https://www.aliexpress.com/item/1005005461679721.html?spm=a2g0o.cart.0.0.74f138daeRGVlF&mp=1
Note that, while the input is (nominally) 2 V, the output is 3 V - using one (or more) 1.2 V Ni-MH Cell(s).

The "output" of these can be one of 8 "modes", one of which is "continuous".

Then there are "packs" such as these - https://www.aliexpress.com/item/1005006860936703.html?spm=a2g0o.detail.pcDetailTopMoreOtherSeller.2.6c54o6bzo6bzDv&gps-id=pcDetailTopMoreOtherSeller&scm=1007.40050.354490.0&scm_id=1007.40050.354490.0&scm-url=1007.40050.354490.0&pvid=cb9cd2b1-030c-4970-b198-ec8c09fc07e0&_t=gps-idcDetailTopMoreOtherSeller,scm-url:1007.40050.354490.0,pvid:cb9cd2b1-030c-4970-b198-ec8c09fc07e0,tpp_buckets:668#2846#8109#1935&isseo=y&pdp_npi=4@dis!AUD!39.20!17.25!!!189.56!83.41!@2101c5a417211963059317173ef79d!12000040513252124!rec!AU!3729617017!&utparam-url=scenecDetailTopMoreOtherSeller|query_from:
to which you could add more Cells (in parallel) (https://www.aliexpress.com/w/wholes...g0o.productlist.auto_suggest.1.15fb73b5qi6gpx )
and
more "Panels" - such as https://www.aliexpress.com/item/100...order_list.order_list_main.139.18651802eCJGqQ

There are COB LED "Filaments", such as
https://www.aliexpress.com/item/100...order_list.order_list_main.279.2e151802a1nSWG
which could be used in place of any 3 V "String".
However, these items are quite brittle and must be handled with great care (experience !)
The smallest is rated at 55 mA 3V and you would need to experiment with a suitable series "limiting" resistor.

Unless a "delivery charge" is indicated, delivery for multiple items in one "order" from this source is usually the equivalent of only €2
Delivery time is usually 10 Days - or less.

 

[Munroast]

I think you have probably missed what I'm trying to achieve. The 'limiting factor' in the product I'm experimenting with is the tiny size of the solar panel - so nothing would be gained by having a larger battery, and nor is there any need to 'transform' the voltage.

I don't need anything as large as a car battery, since I only need a very small handful of Ah each day and, to be able to run continuously, the battery will, on average, only have to be charged by that amount each day

I'm not sure what youy are saying here. What is it that is "wired up to a plug-in 5V transformer", and what is that transformer plugged into? As I explained at the start, my system needs to be able to work from solar-generated electricity alone (with no mains electricity available).

well beg my pudding for trying to help, but in fairness and going back to your opening post of the thread

Hi, does anyone know how well (if at all!) 'solar-powered garden lights' (lights on continuously during hours of darkness, not PIR-controlled) would get charged if sited indoors, close to a window?

I ask because I am considering ways of achieving some nocturnal lighting (for 'security') in a house which is sometimes unoccupied for appreciable periods with the whole electrical installation switched off.

Kind Regards, John

my suggestions were very much on target

 

[SUNRAY]

I suggest that you should stop "playing" with items from "Pound Shops" and investigate something like
https://www.aliexpress.com/item/1005005461679721.html?spm=a2g0o.cart.0.0.74f138daeRGVlF&mp=1
Note that, while the input is (nominally) 2 V, the output is 3 V - using one (or more) 1.2 V Ni-MH Cell(s).

The "output" of these can be one of 8 "modes", one of which is "continuous".

Then there are "packs" such as these - https://www.aliexpress.com/item/1005006860936703.html?spm=a2g0o.detail.pcDetailTopMoreOtherSeller.2.6c54o6bzo6bzDv&gps-id=pcDetailTopMoreOtherSeller&scm=1007.40050.354490.0&scm_id=1007.40050.354490.0&scm-url=1007.40050.354490.0&pvid=cb9cd2b1-030c-4970-b198-ec8c09fc07e0&_t=gps-idcDetailTopMoreOtherSeller,scm-url:1007.40050.354490.0,pvid:cb9cd2b1-030c-4970-b198-ec8c09fc07e0,tpp_buckets:668#2846#8109#1935&isseo=y&pdp_npi=4@dis!AUD!39.20!17.25!!!189.56!83.41!@2101c5a417211963059317173ef79d!12000040513252124!rec!AU!3729617017!&utparam-url=scenecDetailTopMoreOtherSeller|query_from:
to which you could add more Cells (in parallel) (https://www.aliexpress.com/w/wholes...g0o.productlist.auto_suggest.1.15fb73b5qi6gpx )
and
more "Panels" - such as https://www.aliexpress.com/item/100...order_list.order_list_main.139.18651802eCJGqQ

There are COB LED "Filaments", such as
https://www.aliexpress.com/item/100...order_list.order_list_main.279.2e151802a1nSWG
which could be used in place of any 3 V "String".
However, these items are quite brittle and must be handled with great care (experience !)
The smallest is rated at 55 mA 3V and you would need to experiment with a suitable series "limiting" resistor.

Unless a "delivery charge" is indicated, delivery for multiple items in one "order" from this source is usually the equivalent of only €2
Delivery time is usually 10 Days - or less.

Reading the beginningof this

I suggest that you should stop "playing"

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

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

 

[Harry Bloomfield]

Mrs Sunray and her brother must have purchased 50 various solar lights between them and quite frankly I've found they have all rapidly lost performance to the point we've given up with them. We have some here which were presents and we haven't bothered getting out of their boxes for a year or 3:

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

 

[JohnW2]

I suggest that you should stop "playing" with items from "Pound Shops" ...

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.

 

[JohnW2]

well beg my pudding for trying to help, but in fairness and going back to your opening post of the thread ... my suggestions were very much on target

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'.