Solar Panel Project for a £1.75 LED light. Advice?

FrankFalcon

Hi all

This is just for fun and not really important but I hope I can learn something along the way. So, some of you may have seen the bargain last week on HUKD which was the ‘Relax’ light from Argos. It was £1.25 so I got one. It is the word ‘relax’ that is lit up and powered by 3 batteries at 1.5V each (total 4.5V). For the price it is a bargain and I’d love to modify it so I can put it up in our garden Gazebo in summer. By modify I mean I’d like to do away with the battery pack and connect the wires to a solar source. Now, I’m sure it must be achievable because I’ve seen solar garden lights in Poundland, B&M, Home Bargains etc starting from as little as £1. Indeed, last year the missus picked up something similar last year for a couple of quid. It is a spike that pushes into the ground that has a small solar sensor on top. The spike is connected to a chain of about 50 very tiny White LED’s, similar to Christmas tree lights but much smaller lights. When it goes dark these tiny lights illuminate and stay on for most of the dark night. For a couple of quid it is a bargain. So, in the interests of learning something and of course going one better than the wife I’d like to get hold of a solar panel that will take power in the day and power my ‘relax’ light at dark. I assume these things are VERY cheap? My plan is that I buy a gadget that is Solar powered and uses 4.5v and use the solar bit to connect it to my ‘relax’ light instead of the battery pack. Is it actually as simple as this or are there any other electrical factors that need to be taken into account. ?

fwor

The thing that you (probably) won't be able to know for sure when buying the LED solar gadget is exactly what's inside it, and hence what voltage it runs at. It seems very common for the typical "spike" lamp to have a 5.5V (nominal) solar panel - which should work Ok for you - but there are others that operate at a different voltage. It's also fairly common now to use a small Lithium Polymer battery instead of the older style of 1.5V NiMh battery arrays, and they will typically have a voltage of 3.7V, so the internal circuitry will be a slightly different design in those.

It's also true that Chinese manufacturing largely involves cutting back everything so that it isn't quite good enough - and as a result the battery capacity is almost always too small and too low quality to last any length of time. The amount of power that your "Relax" display takes compared to what the gadget was originally design to drive will be a factor in how long it will illuminate for. But worth a try - why not?

FrankFalcon

Thanks fwor...Any suggestions on where/what I should buy here as in Solar Panel?