Can overheating a driver do this...??

[Sprinkles]

I soldered a driver into a pill last night, thankfully this was an experimental build with a small "cheap-o" light. No fire, smoke, etc. But I did notice that the driver doesn't seem to function like intended. It seems that the modes are now not spaced correctly.

Here's the specs given for the ShiningBeam 0.8-1.7v driver: 900ma, 200ma, and 25ma.

Here's what I'm getting: 500ma, 320ma, and (I can't remember low, but it's NOT 25ma - probably more like 100ma).

If the driver is functioning "properly" but it's not giving the right output, can that actually be a product of overheating?? I would think that the driver would be toasted, maybe missing a mode or not change or something if that were the case.

(Maybe I just got a faulty driver???)


Thanks!

 

[Sprinkles]

Really....nothing?

 

[georges80]

There's so many things that could go wrong that it's unlikely anyone can answer your question with a yes/no response.

I can easily envisage overheating (especially if soldering etc) damaging a variety of various components. Could be a feedback/sense resistor that has been damaged, shorted, dropped off etc. Less likely that one of the active devices have been damaged, since that would likely have more catastrophic consequences (but still possible).

It could even be something simple like the type of flux in your solder, some are partially conductive and can affect the current sensing/regulating circuits. I recommend folk to always use NO-CLEAN solder/flux unless they have the equipment to wash/clean/dry a board after soldering.

Could also have been a faulty driver - who knows at this point...

cheers,
george.

 

[KillingTime]

It's possible, if you've damaged a surface mount component on the other side by using excessive heat.

Did you test the driver before you placed it all together?

If not, then I'd try de-soldering it for inspection. Try with different Vf leds and battery voltages (within spec). Check for solder shorts.

 

[Justin Case]

As George stated, there are too many variables to be able to say yes or no with any degree of useful confidence.

A major issue is that these cheap Chinese drivers often don't conform to the stated specs, even if they aren't overheated from soldering. Thus, if the OP didn't test the driver before vs after, IMO it is basically impossible to know if the driver is behaving the way it would have prior to getting heated up or if it did get damaged in some way.

 

[Sprinkles]

What's a recommended way to test the driver before install? I have another one just like it and I'd check it before use.....

Thanks.

 

[Justin Case]

I meant testing before you potentially overheated the driver. Clearly, you have to hook it up in some fashion to test the driver, which most likely means soldering various hookup wire connections. If the installation step that possibly overheated the driver was soldering the ground connection between the driver and the pill, then you can test the driver before final installation into the pill. It's probably useful to test the driver for function before final buttoning up anyway.

 

[bshanahan14rulz]

can using 4 or 5 0.7V diodes be used to simulate the LED, and a 1-ohm high-power resistor for to measure the Amps? He says he has another new driver of the same model.

 

[65535]

What kind of meter are you using if it's a PWM driver, most meters will get false readings.

 

[Sprinkles]

I don't think I'm getting false readings. Here are some comparison pics for the light.... (all the images using same fixed settings - aperture/shutter/WB etc...)



Fenix E01

Fenix P2D Q5 (turbo)

unmodded (mx AAA) light (measured @ 490mA)

moddeded with Dereelight xr-e R2 (lhigh)

moddeded with Dereelight xr-e R2 (med)

moddeded with Dereelight xr-e R2 (low)

 

[MikeAusC]

How are you measuring the current - in such low-voltage applications, inserting a small amount of resistance will reduce the current.

You need to measure the battery voltage while the LED is on. Any drop in battery voltage means you wonlt get the rated voltage. The specs may mean you only get the rated current at 1.7 volts !!!

 

[Sprinkles]

...why would the low mode output be higher than the stated amount then? Specifically, I can understand the drop in mA, but I can't understand why the low mode wouldn't actually be an EVEN lower mA reading than the driver spec'd.

I can understand that the light, given this driver, could indeed be more accurate to spec if the V of the battery closer matched the top end of the driver's limits. I installed a rechargable nimh and it was brighter....but still not accurate.

If there's resistance at work here (as I'm sure there is), then the 25mA low would actually be LOWER....so it still doesn't fit the argument.

The real question of the thread isn't so much what the mA is. It's can the mA setting actually CHANGE if I've overheated the driver.

 

[Packhorse]

There's so many things that could go wrong that it's unlikely anyone can answer your question with a yes/no response.

I disagree




YES!!!!

 

[Essexman]

I don't have an answer to you question.

But I I'm very pleased to see your getting 500mA from 1AA, I might have to order some of those drivers for a play.

The design of driver I think your playing with has some history on CPF, do a search for RV7 1AA driver, ring any bells anyone?

 

[Sprinkles]

i don't think this driver is "old" on CPF. According to SB, it's a newer driver, so I don't think it's seen much review here.

(It's actually an AAA light.)
​

 

[Essexman]

i don't think this driver is "old" on CPF. According to SB, it's a newer driver, so I don't think it's seen much review here.​

(It's actually an AAA light.)​

Correct the SB driver is new, but the type of driver design has been shown here on CPF and was made by a member called RV7, see HERE
There is also a driver for sale on DX which is alike but not the same.

IF you are using am AAA that might be why your output is lower that expected. That design of driver draws a lot of current to boost the power up to a full 900mA. I don't think a AAA will be able to cope with the current draw.

 

[Sprinkles]

I was thinking about that too.

But that still leaves the question unanswered..... I'm actually kind of satisfied with the output on high this little AAA light is giving! It's actually pretty bright despite not getting the 900mA. The part that most bothers me is that it's not getting the LOW it should be. Heck, if I'm not able to get the 900mA. that's ok. But I REALLY want that 25mA on low....that would be really nice.

Anyway, question still remains:
Can overheating a driver cause the current output to change levels?
(ie. go from 900mA to 550mA or 25mA up to 100mA)

 

[georges80]

Anyway, question still remains:
Can overheating a driver cause the current output to change levels?
(ie. go from 900mA to 550mA or 25mA up to 100mA)

You have read the responses to this thread, yes? The answers have been provided

You never answered how HOT you got the driver - answer that with a specific degree C and for how many seconds and maybe someone can give you a specific answer to your question.... i.e. what I wrote in the first response to this thread still stands. You aren't going to get a guaranteed correct answer to your question given all the unknowns.

I design LED drivers for a living and I'm not exactly incompetent when it comes to how they work and how they can be damaged, and I certainly can't give you a guaranteed correct answer without knowing the specifics of how you soldered it, what type of solder/flux you used, how hot you got it, whether any components where shorted, shifted, solder blobs fell on the board, whether the board was faulty to start with etc... Again, there are too many unknowns and I don't drink tea so can't check the tea leaves either

What I can guarantee to a pretty high percentage is that drivers made in the far east are untested. their specs can be subject to change and heat is the enemy of electronics...

cheers,
george.

 

[jarekdadej]

I think:
1. 900mA to 500mA drop - battery can't supply more then 500mA
2.200mA to 320 spike - 200mA to the LED 120mA driver efficiency and resistance losses.
3. 25mA to 100mA - 25mA to the LED 75mA driver efficiency and resistance losses.

And if you take to account efficiency in #1 you are going to have lesser efficiency than in #2 so that is why you don't see a big difference in modes #1 and #2. That is my guess but someone correct me if I am wrong.

 

[HarryN]

Perhaps this can help.

How do you think it is that a company can sell a driver for less than anyone else can even buy the parts, even if purchased in quite high volumes?

Answer - they buy off -spec material and use devices outside of their intended current, voltage, or temperature range.

Why does georges80 (taskled) above have so few complaints with his drivers?

Answer: Because he doesn't do that stuff with his drivers.

Honestly, there are driver features I wish he offered, but the ones I have work.