My 1st mod - Doubt about driver

Hi BLF!
I have a Brennenstuhl LuxPrimera 140 flashlight, a 24€ light bought long before knowing BLF or other lights!
It is a 3 mode light (H-L-Strobe), outputs about 100-150 lumens (according to manufacturer) and it is powered by 3AAA batteries! It is a thrower and has a narrow but nice CW beam!

Some time ago I started to use it with a 18650 battery flat top, the only kind that fits the light. And…I think I may have overcharged it with this battery, maybe a driver component got burnt, once the light doesn’t work anymore.

I was already thinking about using the host to make my first (simple) mod, but now I’ll definitely have to do it to make it work again.
My aims are to use it fully with a 18650 battery, with more brightness and other interface modes. But here start the doubts…

These are the flashlight’s:
Driver (17mm diameter) : http://imgur.com/xkQqKNj
Pill (yeah, this is weird…): http://imgur.com/3XiDA9A
Emitter (16mm diameter): http://imgur.com/sh9zVY6

To mod it, I think I cannot use a driver with spring or something below it, ’cause otherwise the battery won’t fit. The distance between the driver and the tailswitch is somehow short.

This way I need your advice in order to decide what driver can be used in here. I searched the Convoy Store and found this https://tinyurl.com/y9rrmpls.
1 - Do you think this would be a good driver for this pill? Can you recommend me another one or a better one, please?

2 - Also: I was thinking about putting a XML2 T6-3B or a XML2 U2-1A in a 16mm plate (also from Convoy Store). Do you think these would be good (if using the above mentioned driver)?

3 – I have some concerns with the tailswitch. As it was supposed to be used with 3AAA batteries, does it run the risk to get burnt/damaged with the use of 18650?

I appreciate your help in this!
Please note that this is will be my *first mod *and that *I don’t have *technical expertise on these things.

Thank you in advance!! :+1: :wink:

By no mean a 18650 , that has 4.2 volts , could damage a flashlight built for 3X AAA batteries ( 4.5 volts ). Looking at your driver picture , I'll guess that a flat top 18650 has very close to "0" chances to work .., but , if you want to make the changes you suggested , I think is possible.., the driver will give about 1400-1500 mA , the pill seems to have a shelf , so , go for it !!!. At this current , (1.5 A) , almost any tail switch will do the job , you don't have to change it ... Good luck !

Hi cera@1967!

Thanks for your comment and help!
I thought that the battery could have damaged the driver, but you’re right, it can take higher voltage so this wasn’t the problem for sure… :person_facepalming:
I already dismantled it:
Driver: Imgur: The magic of the Internet
LED: Imgur: The magic of the Internet
Pill (bottom): Imgur: The magic of the Internet
Pill (head): Imgur: The magic of the Internet

After dismantling it (the plate was really glued, I couldn’t take it out without destroying it and the LED…maybe because I’m new on these things :person_facepalming: ) I saw that the bottom of the pill has a small gap to insert the driver.
If I can enlarge it and make it go deeper, maybe I can insert a driver with a spring and with more chips!

BUT, if that doesn’t work and if I had to put a driver without spring, do you think that using a small/thin magnet (on the driver or on top of the battery) may work?
I saw some people talking about using magnets on batteries but I don’t know if there are specific magnets for that, or if it brings any “danger” to the light!

If none of those work, I may have to put a new tailswitch with shorter spring…

Thank you once again and sorry for the newbie questions here :innocent:
Best regards!

Looks like an XR-E emitter. Standard 1.4A driver should keep it happy, unless you want/need modes, in which case you’ll have to remove 7135s from a NANJG driver (eg, 104C).

Try https://www.fasttech.com/product/1127404-3v5v-4-amc7135-led-flashlight-driver-circuit-gener .

Hi Lightbringer!
Thanks for you comment!
I didn’t know Fasttech shipped worldwide, so I never considered see their products! :person_facepalming:
Thanks! I’ll take a look at the store from now on!

I’d like to have some modes on the light, at least 3 (L-M-H). If I manage to dig in the pill a little more, I’ll be able to use other drivers (even the biscotti, to be configurable).
If not, I guess I’ll have to chose one like that you linked! Thanks for the suggestion!

Best regards!

You might be able to put a little solder blob on the driver, right in the middle of the pad where the spring normally goes, and use a flat top 18650 that way.

If the solder wants to spread out too much, soldering a tiny bit of stripped solid core wire where you want the blob should create the necessary bump.

If you have space for one spring, but not two, I’d put the spring on the driver and the solder blob on the tailswitch PCB. That way, if you drop the light, the spring will protect the driver from being “hammered” by the bouncing cell. The tailswitch end is usually easier to repair, as long as it has a screw-in retaining ring and not a push-fit, glued or soldered arrangement.

Hi Phlogiston!
Hum, nice idea! I never thought about that, but it makes sense! Soldering a small blob may work in this case! No spring and no magnet, just the solder!
Thank you for the idea!! :+1:

I’ve sanded a bit in the inside of the pill, just to create more inner space for the driver (about 17mm diameter).
I’m chosing what to buy now…and it may take a while to arrive and to get back to the project… :person_facepalming:
I guess I’ll go for one like Lightbringer indicated (with one or more modes, without spring, adding the solder blob), and another like biscotti (several modes to configurate, with spring, if I manage to get it inside the pill).

Anyone has an idea if this is a good driver? It is an option as well…

Thanks once again for your comment and idea!! :wink:

You’re very welcome, I’m glad it helped :slight_smile:

If the spring on the Biscotti driver is a problem, you might be able to unsolder it from the driver board and replace it with the solder blob.

A word of advice about soldering on or near driver boards: try to be as quick as possible with the soldering iron and give the board time to cool down between steps. If you get the board really hot, there’s a risk that the solder on the surface mount components will melt, and then they’ll fall off.

Similar considerations apply to tailswitch boards. There have been one or two cases here on BLF where someone has melted a tailswitch whilst soldering a replacement spring or soldering a bypass wire to the existing spring…

I know the feeling :slight_smile:

Hi again Phlogiston!

Hum…I think I won’t adventure myself unsoldering the spring and soldering a blob on the biscotti .
I don’t have much experience on soldering, and doing that on board may ruin it.
Still, thanks for the tip as it is a good option in case I wanna try to adventure on it :smiley:

Also, thanks for the advice about the “timing” when soldering! That one I can’t forget in any case, otherwise I will damage the board and other components! Being a newbie on this is only good because we have lots to learn :wink:

Yeah, and time waiting for this to come from far far away seems like eternity, but there’s the place where most of us can find these things. The problem sometimes is to assess quality, but…we have to try them :wink:

Once again, thanks for the help and the information given!

Best regards!! :+1:

Although I've chosen my driver (biscotti) and led (XML2 U2-1A in 16mm and 20mm plates) for my first mods in 2 similar 18650 lights, I'm looking for other 2 drivers for other 2 mods I intend to do!

I want a driver to use in a 9 led flashlight host (similar to the one on this thread https://budgetlightforum.com/t/-/20256), but instead of using a mule, I would use:

  • reflector + glass lens or a TIR optical lens;
  • aluminium or copper pill (22mm but compatible with 17mm drivers);
  • 18350 or a 18500 battery (depending on the space left inside);
  • tailclick switch;
  • eventual pocket clip (the Convoy S2+ fits well);
  • LED with NW tint (XML2 T6-3B) .

I'd like to have a driver always starting on the lowest mode (no memory), with no strobe.

My major concern here would be the drain in use of the battery and the heat in the host (its aluminium is not that thick...).

Would a biscotti driver be good for this as well? If so, how many 7135 chips would be good?

Or what other options could you suggest me please?

The other one would be for a 1xAA / 14500 Li-ion battery flashlight. Same characteristics here:

  • 17mm diameter driver
  • always starting on lowest mode (with 3 or 4 modes)
  • no strobe (or hidden)

I've read some threads in the forum and searched for a while, but to take a lower voltage from a AA battery or a higher from a 14500 Li-ion and not being a 3 mode (H - L/M - Strobe) it seems that there are not many options.

Would you recommend me one, please?

Thank you very much! Regards!!