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Thread: Maglite Mini 2AA Mod Questions

  1. #1

    Default Maglite Mini 2AA Mod Questions

    Hello everyone! This is my first post here and I am excited to get into the swing of things. I sure hope this is going in the right place.

    After picking up a couple lights I've become emboldened to try a bit of modding. And ambitiously enough I'm going to attempt an incandescent Maglite Mini mod.
    Mostly just for fun, and because the host is lying around.
    I've done a lot of scouring around here in past posts and it seems like:

    • There don't seem to be any parts lists
    • Most interest in Maglite mods dwindled away in the early-mid 2000s?

    I've got a bit of background in the electrical know-how as well as a Hakko 888D. This is hopefully just a sanity check and fishing for advice.

    So, originally, I was thinking to keep the light engine all in the head but I couldn't really think of a good way to keep things in place so I've shifted gears to a possibly more consistent battery-tube build.

    So without further ado, here is what I am thinking:

    Part Detail Cost
    Reflector McR-18 Reflector $17
    Glass 20mm AR $2.45
    Heatsink OFC Copper Heatsink $28
    Driver 14mm FET? $11.45
    Emitter XHP50.2 on 10mm sinkpad $12
    Switch Kroll Tailcap $4
    Power 2x14500 protected 750 mah cells $16
    Thermal Compound Arctic Silver or similar $6
    Total --- ~$97

















    I think I have it mostly sorted out but the driver in particular I'm unsure about. Can an XHP50.2 handle that?

    The heatsink came from this post and seems like a good solution for the "pill retention problem"
    And here is the build process from that same thread:


  2. #2

    Default Re: Maglite Mini 2AA Mod Questions

    Excited to see what becomes of this. I've got several old mini mags that I would like to mod.

  3. #3

    Default Re: Maglite Mini 2AA Mod Questions

    :

    John 3:16

  4. #4
    Flashaholic pc_light's Avatar
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    Default Re: Maglite Mini 2AA Mod Questions

    Welcome to CPF Reziarfg, that's going to be some hot-rod.

    If you haven't planned to already you'll need to include an isolating/insulating LED spacer, I only mention it because it's not listed on your bill of materials. Between the aluminum McR and the short lead distances of the 10mm mcpcb you'll probably need one.

    The batteries you've choosen will probably self-limit the current going through your mod, because with high-drain batteries I could see the Kroll switch getting overwhelmed.

    My last AA mini-mag mod was nothing so ambitious just XP-L driven 1A with a NiteIze tailswitch added recently. It's still running great though.

    Looking forward to seeing the results.
    "may you live light and phosphor" - Mr. Spark

  5. #5

    Default Re: Maglite Mini 2AA Mod Questions

    Quote Originally Posted by pc_light View Post
    My last AA mini-mag mod was nothing so ambitious just XP-L driven 1A with a NiteIze tailswitch added recently. It's still running great though.
    How do you like that tail switch? It was one of the first I came across and I almost went for that one instead. But some report it's a bit mushy.

    My biggest fear to be honest is that the LED won't handle the 8.4V from the FET driver very well. But I can't find a buck driver in 14mm.

  6. #6
    Flashaholic pc_light's Avatar
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    Default Re: Maglite Mini 2AA Mod Questions

    The Niteize switch works fine but it is also probably not able to take high current. Despite the unusual shape the Kroll is fine, my comment only pertains to your mod powered with 2xhigh drain cells, shouldn't be a problem as is.

    Hmm, forgot about possible over-voltage with emitter. Battery sag and the innate resistance (including the switch) might reduce enough to be ok. It could also be that Mtn somehow reduces the voltage (divider?) as part of the Zener mod in order to protect the MCU as well, you would need to ask Richard at Mtn.

    I know this completely changes your hot-rod-mod but there is a recently released 3V XHP50.2 that is receiving good reviews. Running 2x1.7V cells or a single 4.2V cell with dummy spacer might be an option.
    Last edited by pc_light; 04-05-2019 at 09:22 AM.
    "may you live light and phosphor" - Mr. Spark

  7. #7
    Flashaholic* Icarus's Avatar
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    Default Re: Maglite Mini 2AA Mod Questions

    I like your attempt to mod the MiniMag (I've done several myself) but none of the switches I'm aware off will be up to the job for this mod. In best case they can withstand 1.5A. I would avoid the Kroll switch because it's unreliable even at low currents.

  8. #8
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    Default Re: Maglite Mini 2AA Mod Questions

    I did a mule xhp50 mod for a little while. Used two IMR 14500s but the fet drivers werenít out yet so I had a few 7135 chips added though I donít remember how many. It got hot and fast but was pretty cool.

  9. #9

    Default Re: Maglite Mini 2AA Mod Questions

    Quote Originally Posted by Icarus View Post
    In best case they can withstand 1.5A. I would avoid the Kroll switch because it's unreliable even at low currents.
    Hmm. I didn't know that. Is there an alternative? The build process for that ofc heatsink says a switch is required and shows a kroll one I believe. What are the alternatives if leaving it twisty doesn't suffice?

    EDIT: Looks like the requirement for a tail switch is due to this mod defeating the twisty power-on configuration of the original light. Now I have to find a tailcap that can support a 2S 8.4V light? I don't even know where to start with that.
    Last edited by Reziarfg; 04-05-2019 at 06:09 PM.

  10. #10
    Flashaholic* Icarus's Avatar
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    Default Re: Maglite Mini 2AA Mod Questions

    As far as I know there isn't a high current tailcap switch for the MiniMag AA readily available. I'm using a switch like this one but it's also only for use with low current mods. For high current mods you should put the driver in the head and switch the light on/off by turning the head down/up. The driver should then make contact with the top of the body (negative contact) and the top of the battery (positive contact).

    The heatsink you are using is ok but then you need a tailcap switch to turn the light on/off and since there isn't a high current switch readily available you will be limited to a low current mod or have to make your own switch which I think has no one done before.

  11. #11
    Flashaholic* Icarus's Avatar
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    Default Re: Maglite Mini 2AA Mod Questions

    FYI the switch in my link can be found on ebay. Unfortunately they are only available in black. They are the best alternative for the Kroll switch. Nite Ize is selling an upgrade kit for the MiniMag AA which also contains a tailcap switch. However this switch is not as good as the one in my link.
    Last edited by Icarus; 04-06-2019 at 04:27 AM.

  12. #12

    Default Re: Maglite Mini 2AA Mod Questions

    The Nite Ize clicky is glitchy. Sometimes it doesn't work proper even on a stock minimag. Flickering or finicky turn on have been my experience.

    Agreed the most reliable would be cut/restore the circuit at the front end.
    John 3:16

  13. #13

    Default Re: Maglite Mini 2AA Mod Questions

    Quote Originally Posted by Icarus View Post

    The heatsink you are using is ok but then you need a tailcap switch to turn the light on/off and since there isn't a high current switch readily available
    Thanks for the insight. Looks like I may have to fall back on a lower current build. Unless, is it possible to use the tail switch with a simple spring bypass? Would that be all I'd need to do?
    What bothers me is it's so hard to do the math for these. I don't know what current it can or needs to handle.

    EDIT: Also if the batteries are protected and shut down at 3A would that be a problem? What stops the LED from pulling more than that?
    Last edited by Reziarfg; 04-06-2019 at 01:45 PM.

  14. #14
    Flashaholic* Icarus's Avatar
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    Default Re: Maglite Mini 2AA Mod Questions

    Quote Originally Posted by Reziarfg View Post
    Thanks for the insight. Looks like I may have to fall back on a lower current build. Unless, is it possible to use the tail switch with a simple spring bypass? Would that be all I'd need to do?
    What bothers me is it's so hard to do the math for these. I don't know what current it can or needs to handle.

    EDIT: Also if the batteries are protected and shut down at 3A would that be a problem? What stops the LED from pulling more than that?
    I couldnít find which Vf your LED has but since you are using 2 li-ion cells in series I assume you choose the 6V version. Then the driver probably has the Zener mod and the 6V LVP?

    The spring bypass for the switch will help but time will tell if this is enough for the switch to survive. All depends on the current that goes through it. The XHP50.2 @ 6V is rated for 3A max but since you are using protected cells the protection circuit might kick in earlier. Try it, it needed you can still use high drain IMR cells.

  15. #15
    Flashaholic* Icarus's Avatar
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    Default Re: Maglite Mini 2AA Mod Questions

    Quote Originally Posted by Reziarfg View Post
    EDIT: Also if the batteries are protected and shut down at 3A would that be a problem? What stops the LED from pulling more than that?
    Ths software in the driver limits the current (by PWM).

  16. #16

    Default Re: Maglite Mini 2AA Mod Questions

    Quote Originally Posted by Icarus View Post
    I couldnít find which Vf your LED has but since you are using 2 li-ion cells in series I assume you choose the 6V version. Then the driver probably has the Zener mod and the 6V LVP?

    The spring bypass for the switch will help but time will tell if this is enough for the switch to survive. All depends on the current that goes through it. The XHP50.2 @ 6V is rated for 3A max but since you are using protected cells the protection circuit might kick in earlier. Try it, it needed you can still use high drain IMR cells.
    Thank you. You've been super helpful.
    To be honest I got impatient and just bought both the protected cells that should do well up to 3A and another set of unprotected IMR 6.5A cells.
    At worst this will just be an excuse to pull the trigger on a 14500 Zebralight or something.

  17. #17

    Default Re: Maglite Mini 2AA Mod Questions

    @Reziarfg
    Glad I found this thread. Were you the guy who bought one of those OFC heatsinks?

    Anyway your proposed MagAA setup poses a problem. Why? Because the MagAA is supposed to be of a simple, everyday setup which doesn't require complicated battery setup. In other words, you want to stick to 2xAA instead of 2x3.7V (2x14500) whenever permitted.

    Also for such a MagAA mod you want to limit the drive current to up to 1A, or less -- depending on your preference in output or runtime. And the overall heatsinking is also a problem since this is to be a makeshift LED setup but not a native one. The OFC sink does help a bit, but still the MagAA host is a relatively small one so overrunning the light module would still render the host to be quite warm (if not hot) -- especially if you drive the LED at more than 1A.

    Here are my proposed components:
    Optic: a shallow (ie. short) reflector or colliminator optic is needed. Otherwise, with the head assy it won't be able to screw down completely onto the body, due to lack of threads. And lack of threads means the head would wiggle very badly.

    As for the choice of McR18, you'll need to shorten it from both sides to cap the total height to less than 10mm;

    Lens: 20mm is too narrow. For the MagAA chassis you'll need 22.5-22.61mm in diameter. Thickness will need to be around 1mm, or no more than 1.5mm. Too thick of the lens and youj'll have problem screweing in the bezel ring effectively;

    Driver: Sandwich Shoppe 0.55" driver for sure, especially the Nexgen boost drivers. My personal choice would be NG1000. Anything below 917mA would yield a very low output IMO;

    LED: XHP50/2?? No freaking way! It's going to be VERY hot and is thus not suitable for MagAA use, even with the right battery combo. For such LED usage you'll need a Mag C/D mod setup which is a completely different story. For MagAA usage you want to stick to Cree XPG2/3 or even Nichia 319a/b. A ~8mm MCPCB is needed for these emitters.

    Also you'll need an emitter with the right Vf. XPG2/3 and 319a/b have low Vfs of around 3V at 1000mA, suitable for most 2xAA combos (NimH, L91 single-use Lithium etc.)

    Thermal cpd: You need thermal epoxy (a+b). Everything needs to be stuck together for the heatsinking system to take effect. Just thermal paste (Arctic Silver 5, Ceramique 2) is not enough.

    Hope that helps...
    Last edited by yazkaz; 04-10-2019 at 06:57 AM.

  18. #18

    Default Re: Maglite Mini 2AA Mod Questions

    Oh boy there's a lot to unpack here.
    Firstly, thanks so much yazkaz. Yes that was me!

    And yes I've conceded that I won't be able to put together a ridiculous hot-rod as I had hoped initially.

    For the McR-18 reflector I noticed it was a bit too long when I purchased it which is fine. I'll take care of that with a bit of filing.

    What I ended up going with is actually a Nichia 219C D240 on a 10mm sinkpad. I'm hoping I didn't make a mistake here since you indicate 8mm. Is it going to be impossible for this one to fit? 10mm seems to be the smallest available sinkpad I could find.

    I'm wondering if I made a mistake with the driver though since I did see the .55" sandwich shoppe one but ended up going for a 14mm (.55") FET from mtn-electronics. I think it'll be compatible? No zener mod, so the voltage input should be right.

    I have AA NimH in case I need to, but I was hoping to actually get away with a 1x14500 and x1AA dummy though I don't know if that would work. Hoping it does.

    I also had ordered RTV black silicone sealant which I'd heard was suitable for these sorts of things. Correct me if I'm wrong.

    Looks like I may have to purchase a larger diameter lens though. Thanks for that



    As a sidenote, I did still pick up an XHP50.2 which I may try to configure into a mule fully enclosed in the head with a larger chunk of copper in a completely separate mini maglite.

  19. #19

    Default Re: Maglite Mini 2AA Mod Questions

    Quote Originally Posted by Reziarfg View Post
    Oh boy there's a lot to unpack here.
    Firstly, thanks so much yazkaz. Yes that was me!

    And yes I've conceded that I won't be able to put together a ridiculous hot-rod as I had hoped initially.

    For the McR-18 reflector I noticed it was a bit too long when I purchased it which is fine. I'll take care of that with a bit of filing.

    What I ended up going with is actually a Nichia 219C D240 on a 10mm sinkpad. I'm hoping I didn't make a mistake here since you indicate 8mm. Is it going to be impossible for this one to fit? 10mm seems to be the smallest available sinkpad I could find.

    I'm wondering if I made a mistake with the driver though since I did see the .55" sandwich shoppe one but ended up going for a 14mm (.55") FET from mtn-electronics. I think it'll be compatible? No zener mod, so the voltage input should be right.

    I have AA NimH in case I need to, but I was hoping to actually get away with a 1x14500 and x1AA dummy though I don't know if that would work. Hoping it does.

    I also had ordered RTV black silicone sealant which I'd heard was suitable for these sorts of things. Correct me if I'm wrong.

    Looks like I may have to purchase a larger diameter lens though. Thanks for that



    As a sidenote, I did still pick up an XHP50.2 which I may try to configure into a mule fully enclosed in the head with a larger chunk of copper in a completely separate mini maglite.
    I'll try to keep it short here.

    McR18 -- Precision machining is needed, but another issue is how to do the machining effectively such that no metallic dust would get into the reflector's parabolic surface, or risk permanent damage to it. I've been there before so I'd rather stick to my Khatod optics;

    Battery -- if you want to use 1x14500 with dummy contact spacer then you'll need the GD1000 buck/boost driver. With the NG1000, your LED's Vf is probably too low such that the driver may exceed the +0.7V overvoltage tolerance too easily, thus destroying it;

    Driver -- No comment on anything beyond the SS. But the SS drivers have detailed specs listed so you'll have a good idea what they can achieve, and vice versa;

    LED -- Definitely no XHP50/2. AFAIK it's Vf is actually around 6V (can someone here confirm?). And underdriving an LED means you're not utilizing the LED efficiently;

    Sinkpad -- You'll have to measure the diameter of the collar on the copper hearsink. An MCPCB at less than the measured diameter should do. Do remember that the light module is to be transferable from one host to another, so it needs to be readily removable.

    So I may not be all correct regarding the above, if I ever make a mistake please correct me. Thx...

  20. #20

    Default Re: Maglite Mini 2AA Mod Questions

    Thanks again, yazkaz.
    I am definitely NOT planning on putting the XHP50.2 into there. I am aware it is a 6V LED and was planning on a 2S 14500 build but I'll have to find something suitable to put it in. I take your experience on this very seriously and of course will not attempt such a thing. Since you've discouraged it so strongly.

    Looks like I'll need to be picking up an NG1000 at Sandwich Shoppe after all.

    I hope this is the right one. It would be nice to use a single 14500 with a spacer if possible though. I was having a hard time figuring out the GD Buck/Boost at SS though. Can I just choose the blank and put in two 0.10 resistors for 1A output? I think that's all that's necessary. It looks like that would allow either 2AA or 1x14500 and the spacer which would be a very nice option to have.

    Thanks again so much for the insight. I know I am being very ambitious for a first build here.

  21. #21

    Default Re: Maglite Mini 2AA Mod Questions

    Quote Originally Posted by Reziarfg View Post
    Thanks again, yazkaz.
    I am definitely NOT planning on putting the XHP50.2 into there. I am aware it is a 6V LED and was planning on a 2S 14500 build but I'll have to find something suitable to put it in. I take your experience on this very seriously and of course will not attempt such a thing. Since you've discouraged it so strongly.

    Looks like I'll need to be picking up an NG1000 at Sandwich Shoppe after all.

    I hope this is the right one. It would be nice to use a single 14500 with a spacer if possible though. I was having a hard time figuring out the GD Buck/Boost at SS though. Can I just choose the blank and put in two 0.10 resistors for 1A output? I think that's all that's necessary. It looks like that would allow either 2AA or 1x14500 and the spacer which would be a very nice option to have.

    Thanks again so much for the insight. I know I am being very ambitious for a first build here.
    If you have a strong desire to use 1x14500 then definitely go for the GD1000. Currently the SS is out of the 1000 so you'll have to configure one from the GD blank board, which is more expensive than the standalone GD1000 when listed. Perhaps you can contact the SS to express interest in the GD1000, so that they can put up a few for you?

    Of course you can use ordinary 2xAA with the GD, but output will be a bit less (even with 2xL91 Lithium AA). In other words, the system may not run as efficiently as with one single 3.7V.

    If however you want to squeeze as much juice as possible from the AAs then the NG1000 is no escape. I have two MagAAs run on this driver and it simply feels great -- no worry about LiIons when out in the fields.

  22. #22

    Default Re: Maglite Mini 2AA Mod Questions

    Hmm,
    So I've received all the parts and wired them up but got no output to the LED. I'm not sure if I've made a mistake or if there's an issue with the buck/boost converter from sandwich shoppe.

    Soldering two battery holders to the LED directly with two NiMH AA in series (2.4V) lights up the LED as expected.

    I wired up the converter (GD1000 buck/boost see pic below) J5 to LED+ pad and J6 to the LED- pad then VIN is a short soldered wire going to the grounding screw in the heat sink.
    I get continuity between the heatsink and positive battery terminal on the obverse of the converter board. When i attempt to touch the positive battery end to the terminal on the other side of the board and the negative side (still 2.4V) to the heat sink, I get no output.
    Have I missed something?

    Thanks all.


  23. #23

    Default Re: Maglite Mini 2AA Mod Questions

    Quote Originally Posted by Reziarfg View Post
    Hmm,
    So I've received all the parts and wired them up but got no output to the LED. I'm not sure if I've made a mistake or if there's an issue with the buck/boost converter from sandwich shoppe.

    Soldering two battery holders to the LED directly with two NiMH AA in series (2.4V) lights up the LED as expected.

    I wired up the converter (GD1000 buck/boost see pic below) J5 to LED+ pad and J6 to the LED- pad then VIN is a short soldered wire going to the grounding screw in the heat sink.
    I get continuity between the heatsink and positive battery terminal on the obverse of the converter board. When i attempt to touch the positive battery end to the terminal on the other side of the board and the negative side (still 2.4V) to the heat sink, I get no output.
    Have I missed something?
    I think you've got one connection wrong: The VIn should be empty. Instead, the second J6 should be used for GND.
    FYI the J5 and J6 terminals are in pairs (ie. two J5 holes, two J6 holes).
    In other words,
    J5 #1 -- LED+
    J6 #1 -- LED-
    J6 #2 -- GND (connect to heatsink)
    VIn -- empty

    BTW the SS boards require extra care, and that one simple mistake could kill the board. Also for testing, it's absolutely necessary to apply a load to it. Failure to do so and your board will be instantly wasted.

  24. #24

    Default Re: Maglite Mini 2AA Mod Questions

    Thank you again Yazkaz. You should charge an hourly rate.

    I was aware that there is no open load protection for this board so all testing was with the LED in circuit (soldered, to ensure constant connectivity).
    It looks like my mistake was definitely the wiring then. The way you laid it out makes a lot more sense as it puts the GD1000 in a more obvious parallel circuit with the LED.

    I accept that my mis-wiring could have toasted this board though I hope not. I will re-wire and test as indicated.

    EDIT: Anyone know if it matters which J6 is used for the grounding screw? Generally buck/boost converters have "in" and "out" contacts that are specific.
    Last edited by Reziarfg; 05-18-2019 at 07:11 PM.

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