Reef Discussion

[MagicJ]

Wow is right Scuba Rich they are bloody tiny!
I like the sound of the 1000mA drivers.
If the drivers handle 1 - 14 LEDs, how many drivers will the power supply handle MagicJ?

The LDD-1000 has a wide input voltage of 9-56v DC and a corresponding output voltage of 2 – 52v DC so you can size the Power Supply to suit you requirements – the supply needs to also meet the power (wattage) and current (amps) requirements of your led strings.
The ELN 60-48P which we are familiar with, operates at 48v DC, 60 watts and up to 1.3 amps (variable).
For this discussion, I will assume that a typical led will run at 1amp; have a forward voltage of 3.5 volts and thus require 3.5 watts.
Normally, the supplied voltage will be the limiting factor to the number of led’s that can be run in a serial string i.e. 48 / 3.5 = 13.7 rounded down to 13 led’s to allow some overhead for the supply.
In this example the total power requirement = 13 x 3.5w = 45.5 watts which is well below the rated 60w for this driver.
So, using the LDD driver the equation is pretty much the same – to drive 13 led’s at 1 amp you will require a Power Supply rated at 48v, 45.5 watts and 1 amp. But, to run 5 LDD’s it will need to be rated at 48v, 228 watts and 5 amps – a suitable supply might be the Meanwell SP 240W, 48v, 5.0a supply from here http://www.power-supplies-australia.com.au/single-enclosed-psu/sp-240.
But, you might want to only run 6 led’s per driver i.e. around 22v, 21 watts and 1 amp – for 5 you will want 22v, 105w and 5 amps – something like this http://www.power-supplies-australia.com.au/single-enclosed-psu/s-150.
One final example using the Meanwell SP-750-48 (48V / 15.7A) :
This will effectively drive 15 of the 1amp HDD drivers, with each driver hooked up to a string of 13 leds i.e. a total of 195 leds.
It is just a matter of working out your requirements and matching a Power Supply to fit.
One thing to note is that the price of the supply will increase as the wattage increases, and whilst the HDD series will accept up to 56v DC, the 48V supply seems to be the most cost effective option.
I will discuss the cost effectiveness of these drivers in the next post.

 

[MagicJ]

They are a tidy little unit MagicJ very similar in operation to the sure electronics driver I use. Just built to handle more LEDs, mine will only technically do 6 but I know they can do 8 - 10. With a max input voltage of 35v.

How do they work out cost wise when you add in the power supply also?

Cant wait to see how they turn out!

I have struggled to find any ELN 60-48P drivers for sale in Australia – Cutter has the D series for $50 but not the P series. Rapidled (US site) currently have the P driver for $35 so for comparison purposes I will use this price and ignore postage costs.
For the first example I will use a typical build of 60 leds.
This will require 5 ELN drivers @ $35 = $175.
OR
5 x HDD drivers @ $9 = $45
SP-240-48 (48V / 5.0A) - Model 7 = $85.80
i.e. a total cost of $131 or 25% cheaper.
But, cheaper supply’s are available from China via eBay – a similar supply will cost around $46 delivered which represents a total saving of almost 50% compared to the ELN alternative.
Another benefit is the ability to upgrade in the future – if you provide some overhead when selecting the power supply i.e. purchase a 500w supply when you might only require a 300w supply (the additional cost will not be great) – then it will only cost an additional $9 to add an extra string compared to $35+ to buy another ELN driver.
I also think these are a good alternative for small builds i.e. 20 led’s. With the ELN drivers you are limited to only 2 strings which makes adjusting different colour led’s difficult, if not impossible.
2 x ELN 60-48P @ $35 = $70
OR
5 x HDD drivers @ $9 = $45 (assuming 4 led’s per driver)
SP-75-15 (15V / 5.0A) - Model 6 = $55.00
i.e. a total cost of $100 but you have 5 channels to dim compared to 2.
But, a build like this could be powered by a laptop power supply such as this 15v 6a 90w – available via eBay for $10 delivered. A total cost of $65 with the ability to add another string if required.

In summary, using these drivers would work out cheaper, and considerably cheaper in most situations, and provide much greater flexibility than using the ELN driver series. Their relatively small size also makes it easier to build the drivers into the hood.

 

[Synodontis]

You never cease to amaze me at times MagicJ lol.
Now I, looking for two or three SP-750-48's

 

[VaultBoy]

MagicJ Thanks. I though as much!

They seem like a really good production version of the cheap drivers I have used... They can drive a few extra LEDs and have a higher input voltage.

I look forward to seeing the completed product.

 

[MagicJ]

You never cease to amaze me at times MagicJ lol.

That's what I think when I see the pictures of your tank :p

 

[MagicJ]

Hey MagicJ, my programming is coming along nicely with everything working so far except one odd thing: when I display a bitmap image, everything is shifted one pixel to the left and the left-most column of pixels appears on the right.
For some images it isn't obvious unless you look really close, but on small icons or graphics it is.

I checked the example programs in the UTFT library, which appeared to display correctly, but a close examination shows that the mainly white edge of the pictures disguises the effect. Its made more obvious if you edit, say, the top left pixel to something contrasting.
Not sure if it its something specific to the display I'm using.

Hi Brekel

This is the reply from Henning in relation to this issue

I have notice the issue with the image converter on two (and only two)images, but I have not been able to figure out why it happens. When I saved the image in another file format it converted it correctly, so I assume that there are some bugs in the .Net module that loads and saves images.

So, any workarounds that you have devised i.e. moving the right hand column of pixels to the left hand side before saving, will need to continue.

Cheers