BMW rechargeable torch project, driver, led and battery reccomendations

Flashlight Modding and DIY Parts
1

Hi, new on here, had a search on google about these torches, but only one thread from 2005 came up. Looking for some advice on a project i am about to do, which is upgrade the rechargable torch from an older bmw e46, this is a fairly standard item on the older models.

The batteries had gone on both of mine, 2x varta v250h cells, and needed replaced. Two batteries were £15 and i looked at bulb upgrades for the e10 incandescent bulb. I found the following e10 bulb which looked promising.
http://www.ebay.co.uk/itm/1X-LED-1W-…0AAOSwyKxXhFVI
I then realised the batteries were 2.4v, and the minimum voltage for these was 3v, so I am guessing they wouldnt work. Also the bulbs had a positive earth, so i would need to modify the circuit to make them work. I then found a similar bulb with swiching polarity, and a minimum 1 volt neededed
http://www.ebay.co.uk/itm/NICELITE-LED-LIGHT-BULBS-BICYCLE-CYCLE-LAMPS-FLASHLIGHTS-TORCHES-MAGLITE-CREE-/252527200107?var=&hash=item3acbcb476b:m:mgDUxO72a7 Xke2B2ocxo8CA
These looked promising, but the project was going to cost me £40 for the 2, which made me think i could build something better for cheaper, with a little help!

What i am after is a torch that will fit/charge in the standard case, but with a li-ion battery, as bright as possible, with a runtime of say 30 mins or less, something to check on car engines at night briefly etc, not an often used torch. Happy to solder glue and modify away!

Here is a pic to explain what I am working with:

The two pins take the 12-14v from the car, and the circuit converts the power to charge the 2.4v battery pack. there is not a huge amount of room, as i have shown an AAA battery to scale. My knowledge of cars is far greater than that of electrics/leds, so some advice on components would be great! I do enjoy a little project. The dimensions of the space i have to play with are about 40 mm x 30mm, and about 17mm depth in the unit, now i have gutted most of the useable space.

After a long research on batteries the best solution due to size concerns would be a li-ion battery, a single 16340 battery, (cr123a) or a 15270 (CR2) will fit and give me some room for conversion and charging circuitury, which i have gone ahead and bought. I have bought a step down converter from the cars voltage, and also a li-ion charging circuit, I hope these will be suitable….

Step down voltage converter, i will remove the usb connector to make it smaller
http://www.ebay.co.uk/itm/322036308117?\_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Li-ion charging circuit
http://www.ebay.co.uk/itm/2PCS-Brilliant-5V-Mini-USB-1A-TP4056-Lithium-Battery-Charging-Charger-Module-/172354745809?\_trksid=p2047675.l2557&ssPageName=STRK%3AMEBIDX%3AIT&nma=true&si=cY8pSIPZaUIeeQfH8I6aZ5UqLWg%253D&orig_cvip=true&rt=nc

What i would like is a suggestion on batteries, after reading about protected ones, there seems to be a lot of rubbish out there, if someone could point me to a good source for 16340/15270, for the uk or from china that would be appreciated. Looking at led’s and drivers, I have become a bit lost, cree xml or xml-2 seem good, or x5, and drivers are endless. I am not bothered about mode switching, i would prefer just an on to full power or off driver, so i can utilize the standard bmw power switch. I have tried to calculate runtimes and got confused, and also i have concerns about heat after reading but am unsure if i will need a heatsink dependant on the bulb/driver, as i don’t think i will have room for one.

So in summary a suggestion of led, driver and battery source would be great, thanks!

2

Right i have had a look at drivers, batteries, and a look at led’s, but there are sp many cree leds’s.

Here is what i found for batteries, i am going to go for a 16340 as they seem to offer more choise, are any of these any good?
Fasttech seems a good source for components…
https://www.fasttech.com/products/0/10000481/1156500-trustfire-protected-16340-3-7v-880mah
https://www.fasttech.com/products/0/10000487/1055500-ultrafire-16340-36v-1000mah-protected-rechargeable
Not sure whether these cheaper batteies are worthwhile…
http://www.ebay.co.uk/itm/3-7V-1200mAh-16340-Li-ion-Rechargeable-Battery-Flashlight-K7-/221879948435?hash=item33a9135493:g:mvgAAOSwWnFV8DVg
https://www.aliexpress.com/item/Guaranteed-100-UNITEK-1000mAH-1000mAH-CR123A-123A-16340-Rechargeable-3-7V-Li-ion-Battery-For-Flashlight/32277444670.html?spm=2114.30010308.3.333.gbMgg8&ws_ab_test=searchweb0_0,searchweb201602_3_10056_10065_10068_10055_10054_10069_10059_418_10073_10017_10071_10070_10060_10061_10052_10062_10053_10050_10051,searchweb201603_1&btsid=95cc1f14-5752-4c5a-aba6-ff2199e5a7ed
https://www.aliexpress.com/item/2pcs-CR123A-16340-123A-CR123-3-7V-2300mAh-GTL-Rechargeable-Battery-for-Aircraft/32716709199.html?spm=2114.30010308.3.395.GQxrY2&ws_ab_test=searchweb0_0,searchweb201602_3_10056_10065_10068_10055_10054_10069_10059_418_10073_10017_10071_10070_10060_10061_10052_10062_10053_10050_10051,searchweb201603_1&btsid=95cc1f14-5752-4c5a-aba6-ff2199e5a7ed
https://www.aliexpress.com/item/2pcs-lot-100-Original-TrustFire-CR123A-Battery-Li-ion-3V-1400mAh-Non-rechargeable-Battery-Flashlight-Battery/32697318186.html?spm=2114.30010308.3.225.VqYU4x&ws_ab_test=searchweb0_0,searchweb201602_3_10056_10065_10068_10055_10054_10069_10059_418_10073_10017_10071_10070_10060_10061_10052_10062_10053_10050_10051,searchweb201603_1&btsid=206e0f4b-c2c0-4c33-8287-fe95df8d4765

For drivers i founs some single mode drivers, which i wanted, the first two are 700ma, then a 1050ma, and a 1400ma, i am guessing the more current will allow me a brighter led? Any other specs i should compare?
https://www.fasttech.com/products/1612/10001535/3647200-700ma-1-mode-led-driver-circuit-board-for
https://www.fasttech.com/products/1612/10001751/1127408-3v5v-2-amc7135-led-flashlight-driver-circuit-gener
https://www.fasttech.com/products/1612/10001751/1127406-3v5v-3-amc7135-led-flashlight-driver-circuit-gener
https://www.fasttech.com/products/1612/10001751/1127404-3v5v-4-amc7135-led-flashlight-driver-circuit-gener
I was wondering whether i needed a driver if i was running a single cell 3.7v 16340, but i guess it will just provide a stable output for the led.

Led’s, i have looked at many cree leds, xm-l, xm-l2 xp-g, xp-g2, XR-E Q5,XT-E Q5-7B, and other, but i am unsure of what i should go for, any help would be great, thanks.

3

This is a fun project. I have one of these but never think to use it.

I question if using lithium batteries in this light would be a good idea for something permanently installed in a car. They get pretty hot!

4

+1

And welcome to BLF!

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Thanks sciencetists, I am more of a car orientated tinkerer, than a flashllight modder, hence coming on here for a little help hopefully! I have being doing a fair amount of reading, and read about lithium batteries in cars, but living in scotland the ambient temps never get high here! I did read a thread on here that discusses the concern of lithium batteries in a car and I didnt feel it was a bad idea, I am open to suggestions on this build though, and can deviate from what i have bought so far!

I am sure you know that they are pretty unuseful lights in standard state! I will post up what i have done, rightly or wringly in the end, just looking for someone to impart a little knowledge for the project to me, as I can’t seem to find a great education on drivers and led’s here, it seems to be suggestions of products for people with certain brand torches, and not coming from any knowledge in this area I am a little uncertain!

6

THanks for the welcome the miller!

7

This is a complicated mod, to do for the first time.

I can answer a couple of questions, though.

For starters, one thing you need to do with the charging board is make sure it is charging correctly. Is it cutting off at the proper voltage? Is current right? Etc.

If you have a 700 mah battery, it will last about an hour with an led/driver using 700ma, which is 0.7A. 1400ma/1.4A would give about 0.5 hour, 350ma/0.35A gives about 2 hrs.

I wouldn’t want to run over an A through a 4056 board, especially with a 700 mah 16340. 0.5A or less better, imo. Check specs on board and battery.

Li-ion isn’t a leave-it-charging-and-forget-about-it proposition. NIMH much better for this. Ideally monitor the charging, and pull off at 100%. It sounds like youd be charging it all the time, and that’s not a real good idea with li-ion.

If your inexpensive parts fail and overcharge the battery, you might lose your car to fire, with possible injury to yourself.

I bought the BLF-348, and there’s a nice AAA light on ShenZhen Convoy site. I might just use those.

8

Thanks for taking the time to read and reply to my thread mike. Yes it is my first attempt at a flashlight mod, and not having any experience with this scene, makes it a little overwhelming, but I am determined to create something! Thanks for the suggestion of the BLF-348, however I would like to keep the light as a standard bmw part, as it has it own charging cradle in the glovebox, and i would like it to look standard, just with a little more lumens so I can use it! The reason i started was the standard torch had a woeful output, and the batteries were gone and not cheap to replace, having to cut the case open to get to them led me to think of an upgrade!

I haven’t received or hence tested the li-ion charging circuitry i purchased, but it may be defunct if i switch to ni-mh as suggested. I did have a breif look at ni-mh, but the voltage was looking like 1.2-1.6v, i thought the li-ion would be better at a higher voltage if it provided longer runtimes, and the li-ion seemed to come in much better packaging sizes for my project.

Thanks for the education on li-ion as a leave it charging option. The car will only charge the unit whilst the engine is running, as this is a secong car it may only get a couple of hours charge time per week, but yes i have yet to investigate the charging circuitry to see if it does charge continually once the engine is on.

Thanks for the info about the runtimes too, this is exactly what i was looking for. I would be tempted to head towards the upper end of the scale, 1400ma with about a 30 min runtime, as this would provide as bright as possible for 30 mins, which was my requirement. You suggested less than an amp would be better, 0.5A or less would be best due to the 4056 charging board. Forgive my poor knowledge of flashlights and electronics, but as the 4056 board is part of the charging side of the circuit, I am unsure why it would be seeing a 1a load (with a 1a driver), i would have thought the current would be drawn to the led driver side of the circuit. Here is a rough diagram of what i was planning to build….

12-14V input Step down to 5v=4056 charger=16340 batteryled driver===led

Thanks again for your input, any suggestions on alternative components would be great, I was just sort of going with what i thought would work, and fit!

9

I have an E36 and don’t have the original light only the charging slot in the glovebox. I walked through this BMW light question too and came to the original light is pretty expensive and has not much light at all. To mod it will be cost more higher so I bought an Ultrafire SK68 AA battery light when it’s on sale for 2,5$ and drop it in the glovebox with a NiMh rechargable battery in it. I like original factory extras and gadgets but in my opinion this doesn’t worth the effort.

10

Thanks zozz, I did have a look but there were no answers to modifying this light. I expect the mod cost will be around the cost of replacing the original batteries, and bulb for an led substitute, as stated above. I did have the light to begin with, which can be quite costly, so that is not part of my cost consideration. The overall cost for me I imagine will be about the same as re-newing the torch, hence why i want to upgrade it instead. I want an OEM bmw torch, not a substitiute, I am willing to take the time and effort and cost, just needing some reccomendations on battery, if it is or is not a single li-ion 16340, and a suitable single mode driver and emitter.

11

a quick google search, brought up this thread The Glove Box Flashlight | BimmerFest BMW Forum

which although not an upgrade, does have some usefull info and pics that may help

looks like the guts are interchangeable between models which may be handy as a new oem one on ebay is about £20, or the newer batteries are less then £5

for an easy upgrade, chuck in a new 250mAh battery and change the lamp out to one of the better 5mm white leds, should be an improvement over the original

if you want a brighter led youll need at least some sort of heatsink, the plastic housing wont help much but you could replace the negative connection strip with some copper and solder the led to that, you wont be able to push too much current but would be doable.

most of the cree leds put out a similar amount of light at low currents, so it mostly depends on which one has the lowest Vf and if you want to use an optic.

a single 7135 chip would give you 350mA which with an xml should give 150 ish lumens, heat should be tolerable as well

12

Truth be told, i am trying to talk you out of it, but You’re welcome, Glad to help you understand li ion better. The 4056 is a 1A board, if you put more than 1A into it, at 5V, you risk burning up the board.

This charges the battery at about 1A, or less, depending on the A you put in. I need to check, but my 750 ma phone usb charger is about 750ma charge, i think. I wouldn’t want to charge a 700 mAh battery at 1A, although others probably disagree. I’d want charge current to be 500mah/0.5 A, or preferably less. Probably can go up to 700 mAh charge current, the capacity of the battery, easily, though. Check specs.

Charging too fast is dangerous.

A 1400 mAh current from the battery to the led/driver is quite bright.

From what I understand, NiMH is MUCH less likely to start a fire. And you can trickle charge them for long periods. But not li-ion. A few hours a week is too much. I could be wrong, but I think most people on here wouldn’t leave a 4056 on a lithium ion battery in their glovebox, and depend on it to cut off properly. I wouldn’t.

2.4V is 2 AA or AAA, IMO, if you have enough room. Not sure if this is enough to run an led, but it may be.

The sipik 68 clone is a good idea. I almost edited my post above to say that. Most are single mode, supposed to be 30 min runtime AA. I consider them very bright.

13

Thanks bertie, i have googled on bmw threads, but nothing on what i am wanting to do, i was unable to find a cheap source for the replacement batteries, hence the modifications. I have gutted the case, so wont be going back to standard. I used to use a lot of 5mm leds, i have 5 and 10mm here, but the output was still pretty unuseable. I could have tripled up, but still a more modern led is what i want, with a much higher output.

I still have the switch mechanism, so the copper idea is a good idea. I do have a few heatsinks from other projects, i might be able to cut down one from a 3w star emitter, but space is so limited it might be of no useful size.

Thanks for the onfo on the cree emitters, i might try pushing a higher current if i can get a heatsink of sorts installed, i doubt i will manage to fit an optic in too.

If i were to go for a 2x or even a 3x 7135 chip, i guess 700ma, or 1050ma respectively, would heat be a major issue on a runtime of up to 30 mins?

14

Thanks mike, i re-read your post and understood you were talking about pulling 1a through the charging side, not the output side. I did read the specs on the li-ion charger, and by swapping a single resistor, i can drop the current down. It is rated at 1a, and the voltage converter at 3a, but if i did drop the charging circuitry down to 0.5a, it would be a lot safer, now i have read a little more into current!

My only issue with nimh, is these are the only cells i have ever had issue with, in the form of drill batteries shorting, and i ended up with a fairly large explosion as the cells decide to go off one by one. My experience of li-ion has been much better, but that is only personal experience! The issue with nimh also is the unavailability of different sized forms of battery, i have spent a long time on the wiki page of battery sizes, and i may just manage to fit a single aaa battery in the casing, if i rip out the existing circuit board from the connection pins as shown in the pic below. I think 2 would be a struggle if i keep the original switch circuit., their length is the main issue. A thread i read on here about using li-ion in cars and trickle charging, suggested that there are many devices besides phones doing the same, like sat nav units in cars. However my guess is that the charging circuit on these in not a 4056.

Thanks again for the help, and for my understanding, I know you are keen to put me off due to possible risks, but i am keen to persevere! As safely as i possibly can, well if I can make it fit! Thanks again for the sipik88 idea, it would be a good alternative, but it isn’t in a bmw casing that fits the car!


15

I would like to get some drivers/leds ordered for this, i was looking at the following driver with 3x 7135 chips, and check the heat.
https://www.fasttech.com/products/1612/10001751/1127406-3v5v-3-amc7135-led-flashlight-driver-circuit-gener
It specifies 1050ma output current, and Works with Cree R5 T4 T5 T6 U2 MCE, and other similar LEDs.

The led selection is the issue for me, i was going to go with cree due to the availabilty, and some coming on a 16mm board. Apart from the colour temperature, and max lumens, i can’t seem to see what to go for, or tell the difference between them. An xm-l2 as below has a huge lumen max figure, and a 10w power consumption. Would this be a waste on a 1050ma driver?
https://www.fasttech.com/products/1609/10003889/1425001
My calculations would mean P=IV for the driver, so 1.05 x 3.7 = 3.9w, so the driver can output that maximum, and a 10w led would be a waste? Or am I getting these led’s all wrong?

Would something like this be more suitable? XP-G2 S2-2B, 1500ma max, 5w?
https://www.fasttech.com/products/0/10001905/1682204-cree-xp-g2-s2-2b-458lm-5700-6000k-led-emitter

I am guessing both would be as bright as each other as the driver would set the current, with the xm-l2 giving a lot more possibility to be driven harder.

Apologies if these are silly questions, i can’t seem to find a noobs guide to this!

16

You can alter the 4056 board for lower current. The part is very small, though, and Im not very good at soldering. So I just try to limit current in. I suppose you might get heat, dropping 1A to 0.25A, anyway.

You seem to be getting the leds pretty well.

The smaller xp-g2 might give a more focused beam? I’m not an expert, but I don’t think it would make much difference, xml2 vs. Xpg2. Smaller leds often used in throwers, with a reflector, for a focused beam.

But you might not want a “thrower” under a car hood, and I’m not sure what difference it’d make on the light, Xpg2 vs. Xml2, if you dont have a reflector.

I think 3A should kill a 4056 fast. 1A is the listed max, and even then HKJ used a heatsink.

Remember that you have contacts on the back of the board, and don’t just put a metal heatsink on it, or you can get a short on the board.

Here’s a link to a 4056 thread, where HKJ tested it :

But, it’s a cheap Chinese charger. You have to test it. The microcontroller could have been programmed poorly, for instance. Is it cutting off properly?

I probably wouldn’t worry about a heatsink too much on a 16mm board at about an A. I’ve been told you can go to 6A on a hollow pill sk68. Although even those have some ability to wick heat out to the body. I guess the plastic body might need a heatsink for 30 min.?

I might start with a driver with modes, and use a less bright mode, if it is too hot.

17

Several lumens vs. A graphs:

18

Several lumens vs. A graphs:

The xml2 is a bit brighter at 1A in these tests.

19

Thanks mike, once again! Yes i had already read the thread on the 4056 board, and adding some 0603 resistors to the shopping list. I have soldered some very small surface mount leds before, in car brake lights and instrument panels, so willing to have a go! Might need a new smaller tip for the iron though. I am not really thinking heat would be an issue as such a small resistor is used and it is under the manufacturers guidelines to change the resistor.

Thanks for the info on the led’s, I guess i would prefer a wider beam, but doubt i will be chaniging the beam with optics anyway. I was just concerned about current ratings, but think i have grasped it, and from what i can see there is little difference between other factors. I guess the current will dictate brightness mainly, not the bulb, unless it is overpowered!

Yeah the issue with the heatsink will be there last, once i can see how i can package the components safely without shorting, a big heatsink will just cause issues, i was thinking along the lines of a copper plate inder the bulb. Am i correct in thinking the driver does not need a heatsink, only the bulb, or does the driver get hot? i will see how warm things get once i get something ordered. The case will not be much use for the heat so i will see how it goes. I doubt i can change mode very easily with the standard switch, my thoughts are if it gets too hot i could remove one of the 7135 chips to lower the current.

“I think 3A should kill a 4056 fast. 1A is the listed max, and even then HKJ used a heatsink.”
This is my last concern, I thought the 4056 would be cooler if i drop down the charge current? The other part you mention is 3A should kill the 4056 quickly. I am not the most electronically minded person, but it was my understanding that the step down charger would supply 5v at up to 3A. My thoughts on current were that the device requesting the load will regulate how much of that 3A it needs, and if the 4056 is supplying a resitored down say 300ma, it will only pull that from the 5v step down charger, rather than the charger forcing 3A into the board, if you follow? So would the 5v step down transformer not be safe to run the 4056?

20

You’re welcome! Another thing you might consider is putting the led and driver in one of these and putting it in there :

https://m.fasttech.com/products/1616/10002799/1208600-driver-pillar-w-emitter-slot-for-flashlight-diy

Or P60 drop in is smaller, and it’s easy to remove reflector.

I’m really not sure how the step down charger works, if it just provides what is used you might be ok. Never used those, if it just provides up to 3A, I need to get one. I probably should try one, and see what it does. I wouldn’t leave a 4056 on in the glove box, though. But a car charger could be handy :slight_smile:

Sounds like you are in good shape on changing the resistor! So that’s good.

I might get a cheap 5-pack of Xpg2’s. Only $7-8, in 2800-3500K, and if you blow some, you already have extras, and don’t have to wait for shipping from China. Looks like the xml2 is a bit brighter, though. I think another reason that lights have Xpg2’s is cost, certainly cheaper now.