Solar power now: The Ikea Sunnan lamp

Yes, I've been a bit of an Ikea fan recently. It is kinda nice to be immersed in new furniture, decorative stuff and lights from Ikea because there is such a huge variety! Makes me wanna buy a house and fill it with interesting and functional products and furniture. I think the thing that makes me want to visit Ikea time and time again is because their products range caters to those with deep pockets to customers who are struggling with the high cost of living in Singapore. Naturally, the cheaper products are not always very well high quality, but they can be rather cheap. Some of the time, the cheapness really comes from how the product is designed and packaged. One example was a table lamp I saw which was on sale for $5.90. What the hell, it is cheaper than a Big Mac meal! Oh my oh my, it was tough to resist picking up every little interesting product I saw.

I wanted a small directional lamp for my table so that I can light up my table. My ceiling lights are really bright and it is kind of wasteful to light up my entire room when I'm only at my table. So, I looked at several of their flexible-neck lamps that uses LEDs. Damn, it turned out that most of them produces a far amount of heat. I suspect that the entire step-down transformer is housed in the head of the lamp since LEDs do not produce much heat. Moreover it was quite a let down since they were not as bright as my torchlight it was producing more heat than my torchlight!

So, I came across this small work lamp that uses a solar and rechargeable batteries, the Sunnan lamp. It too has a flexi-neck. Most of the time, solar based products are rubbish - the entire product becomes useless when the rechargable batteries die. Not this one though. The design allows you to swap dying batteries.

Whats more, the designers figured that it would be strange to put the entire lamp in the sun to charge, so they made a removable module with the solar panel and batteries in it so that it can be sufficiently charged in the sun.  The only problem is that the batteries will get pretty warm when left under the sun. This will potentially shorten the lifespan of the batteries. Currently, I'm thinking lengthening the wires to the solar panel so that I can place it outside my window permanently to let it charge my batteries rather than having to remove the module every time.

The lamp is rated at 20,000hours so I probably won't ever have to change it. Even if I do, it is to upgrade it to a newer, more efficient bulb in the future. The batteries however, will probably need to be changed every 1.5years. I'm not sure how long the solar panel will last though.The circuity is also very simple, if anything fails, it is possible to run to sim lim tower to get a replacement.

I don't think it can replace a normal lamp if you are intending to use it to light up a table for writing an essay. But increasingly, we are using solely using laptops for work and play and this lamp is sufficient for lighting up the keyboard and for doing simple stuff. I can imagine using this for lighting up outdoor tasks such as BBQing.

Edit:

I tried charging the battery pack a few times and it worked splendidly. The solar panels may take quite a while to charge up the battery but it does get the job done. Simplicity is good.

The solar module opened up to reveal the outdated BYD brand 3x 1200mAh NiMh batteries. I really doubt the batteries can take the abuse from being heated up under the sun. The really simple circuit board holds a diode and a fuse. I'm not sure if a fuse is so necessary but it will probably prevent a short circuit should a careless person touch both leads together. The diode is to prevent blackflow of current into the solar panel. Thoughful and simple.

When it comes to electrical components, the less there are, the more efficient the entire product is. The lean circuitry of this lamp does without many other components that it can live without. Thing such as:

1) a voltage regulator to maintain the brightness of the lamp throughout the entire battery capacity.

2) Overcharge protection to prevent stuffing too much sun energy into the batteries. After all, the battery module is likely to be unattended when left outside to the sun.

What I would recommend is to check the individual voltages of the batteries once in a while for uneven charging. If any uneven voltage is spotted, charge them up on a charger that charges each cell individually (most chargers do that already). This will minimize the chance of over draining a single cell and damaging it in the process.

Project: An automatic drawer light

Now, I could have simply used an automatic DIODER drawer light to light up my little drawer. But I didn't like it that it switches on only for a short 12 seconds. I want it to stay lighted up as long as the drawer is open. So, I thought that it might be better to make my own. It shouldn't be too difficult right?

My ingredients are:
White LED strip
A reed switch
8x AA batteries and holder.
Some black sticky tape to match my table.

I bought a 10m white LED strip from dealextreme. It was quite a good deal considering that they are $15 per meter if bought locally. These were really bright! It is bright enough to be my night light and it can be really discrete since they are so thin!

This is my little power source. My LED strip is more for automotive use and takes in 12v. So, 8x 1.5V AA batteries are required. I measured the power consumption and found that it would take 13hours to fully drain these batteries. I could use rechargeable batteries to save cost in the long run but I also risk damaging my rechargeable batteries should I run them down completely. The circuit is simple and hence, there is no protection circuit. These cheap and cheerful IKEA alkaline batteries cost $2.50 for a pack of 10. They are not as good as other branded alkaline batteries, but these are really value for money.


This is my hidden "normally closed" reed switch hidden under the sliding tray of my drawer. The other piece is stuck to the drawer door where the two parts will be separated when I open the drawer which then closes the circuit :)


The LEDs and their wires are hidden from plain view using black tape. See how bright my drawer is compared to the rest of my room? Having bright light shining on my drawer makes it easier to take things from it.