The There Are No Stupid Questions Thread

If you don’t need an electrical connection between pill and driver (e. g. if the tube is pressing directly onto the driver when screwed in) you could also glue the driver to the pill with a small amount of Arctic Alumina or similar. Two tiny drops of glue at opposite positions is often sufficient.

The pill is aluminum and I couldn’t even get the solder to stick even with lots of flux. Even feels like a lower quality aluminum. I may try the wire filler as you suggested.

Electrical connection is required but glue might be my only option.

Thanks guys.

I have an 20700 protected cell from an Acebeam L30. It doesn’t fit in any of my chargers including the MC3000. Which charger can handle a cell this long?

Here is a question that I can’t find an answer to.
Immediately after a rechargeable Li-ion cell is manufactured, what is its voltage?
Is it zero?
Is it perhaps around 3.7v? If it is then charging it to 4.2V would be in a sense over volting it.
How could it be zero when first manufactured? If it is then they would have to have been charged to about 3.7 when shipped. If they are, then why is it that first initial 0V state not damaging to the cell?
I personally think they are manufactured at 3.7V and shipped. (no charging after manufacture)
Also, I have witnessed 10 year old NOS ( new old stock) cells resting those 10 years at 3.7V charging up and performing almost as good as new. Another question would be if a brand new cell was charged to 4.2V, then discharged to 3.7V and put aside for 10 years. Would it still charge up and perform as new , just as a NOS cell does?

I have done this a few times.

Can lithium ion batteries be stored together safely as long as only one positive and negative end are touching? ie: two 18350 batteries in a single 18650 case.


They will if people give them a reason like they have with laser pointers. It is important to follow common sense and etiquette when using our high power lights. All it will take is a few idiots blinding traffic, messing with police and rescue, or children losing their vision from staring into extreme light sources to get the ball rolling on legislation.

I just checked the dutch regulation for bicycle lighting and was quite surprised that no output limit was set. I do think that it will be added at some point.

Thanks for all the non-stupid answers guys. I have another non-stupid question. Can I “bulk out” a hollow pill with a slurry of copper wire bristles and solder blobs, heated with a butane torch? I dunno if I am explaining it well. My plan is to cut some strands of wire into little ~2mm bristles, cut ~500mm of solder into rice sized grains and cast the mixture into my hollow pill. Has anyone tried it? This is to increase thermal mass for the Ultrafire C8 mentioned earlier in the thread… Thanks again!

I think you must first ask yourself if filling up a hollow pil is going to give you a measureable performance gain. Using a standard 1.6mm copper DTP board on top of a hollow pill, if the connection to the edge is well done, will give you pretty good performance already, perhaps over 4A you start noticing a gain of filling up the pill.

some where i saw a blf host diy. I thought it was banggood but can’t seem to find it now it my also have been a sofrin host does anyone know what i’m referring too. thanks

What’s the trick to soldering emitter leads to the emitter board?

I did my first three driver swaps and soldered the leads to the original emitter boards (to aluminium, one copper) without a problem, but now that I’m trying to put a new emitter in my L2 I just can’t melt the solder on the pads.

I have a 30W temperature controlled soldering iron. Do I need more power?

It is about three things, more of each is better:
*power (but 30W with a quality tip is enough for most emitter board joints)
*contact surface (the pointy end of a small tip is not going to do it, a bit further down the tip where it widens is much better, or use a flat-end tip)
*a clean tip loaded with some fresh solder for a good thermal bridge (oxide layers are excellent thermal insulators)

… and one more thing:
I don’t know if you are trying to solder to an already mounted MCPCB - if yes, it does what it is expected to do - leading the heat away. Lift the MCPCB a bit. If there are screws - loosen them before.

Thanks djozz and Flashy Mike.

I think the tip might be the issue - it’s a small conical tip and there isn’t enough room to use the side, and it is looking a bit oxidised.

I’ll try some tip tinner and working with a blob of solder on the end. If I still can’t get it to work I might get a cheap 40W it on and flatten the tip.

How are babies made?

Can a HF 9-led 3-AAA giveaway light be modified in any useful way economically?

I got one just like that!

I bought it at the Darth Mall.