colours and temperatures (mainly)

[AilSnail]

Here is my preliminary results with (mainly) BB400, two R2H(HD) and three Q4H(LD). The testing was done with two fresh D alkalines. The stars were superglued to an aluminium box, while the regulators were hanging in free air.

First, the colours. All three LD's have similar brightness and are rather green. One of the HD's is a bit less green, and the second has a nice violet shade of white.
This was rather surprising, since I was under the impression that the lower number should be more green.
The LD's had a much lower Vf (~3.14-3.17) than the HDs (~3.70-3.86) @~400mA.

I tried the other boards briefly, but 500, 700 and 750 started making noises so I quickly shut them down. All the boards (including MM+ adj with a bit bruised inductor) got too hot to hold for more than a couple of seconds. I could barely feel the heat on the stars.
I had a voltage drop of 0.02-0.05V from the various regulators to the stars(+). This seems a bit much, perhaps this could account for most of the heat? I will try to use shorter wires (they are ~15cm from Vout to ground), perhaps thicker ones, get rid of switches and see if the boards fare better. The measurements were done with a cheap digital multimeter, but it was at least fairly consistent with itself. There might be a voltage drop on the ground path as well, but it would at least be a bit smaller, I think.
So long.

 

[AilSnail]

I think I found the reason for the heat. The atteries were down to 1.6V under load. I installed 2x2 batteries of another brand, and they had 2.7V under load. The odd thing is, the Matrix led, which I always considered to be white with a slight bluish nuance, now looks green compared to the nicest r2h. Gotta get more of these. Edit: the BB500 still get just hot enough to hurt at 2.6V in (Vf~3.8). The greenish r2h gets much nicer with more power.

 

[PeterB]

Why is the VF of the R HD's so high? I would expect a maximum of 3.27V and maybe an increase of 50mV due to the 50mA overdrive for the BB400.

 

[AilSnail]

Dunno. The code on the stars is R2HW 0007692 1803LXHLMW1D.

The dynamic resistance of LSs is reported (by Doug_S) to vary very much from one LS to another.

 

[dat2zip]

That's too high a Vf for a H ranked LED. Lemme go check...

OK, I measured some with a constant current of 350mA and most of the ones I just spot checked rang in around 3.2V and a few were quite high. Very random on which ones were high. Ones right to it were low.

Looks like some of these are mismarked as they are definitely not H ranked LEDs.

Well, personally if the H rank is wrong and the bin rank of 2 is more like 3, I'll take the mislabeling since a whiter LED is in our favor.

Wayne

 

[dat2zip]

The Badboy IC is almost always hot under normal conditions. The Madmax IC runs warm most of the time.

Under low Vin conditions the IC is asked to do more work and thus increases the power it dissipates.

The IC under max load will be pulling close to 0.5W in that little package. It's always recommended to apply some forced air on the converter boards if running them in free space and always thermally pot them or heatsink them when you use them.

It's manditory to heat sink the Badboy converters when driving a 5W design.

 

[AilSnail]

I have tested them with different batteries, the ~3.70(this one is a bit off due to memory) and 3.86 Vf were with BB400. I need to do more testing with BB500 and maybe 700 to extrapolate the Vf at 350mA. What currents should I expect from the boards?
The colours of the two are very different.