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Thread: 3x123 kpr112 runtime?

  1. #1

    Default 3x123 kpr112 runtime?

    Anyone have measurements of the runtime of a kpr112 on 3x123's to 50% brightness? Or total runtime until you normally change the batteries?

  2. #2
    Flashaholic* milkyspit's Avatar
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    Default Re: 3x123 kpr112 runtime?

    MTFD17, please don't read this as sarcastic or negative in any way, as that's not the intent. But based on my experience with this combo, the bulb may well blow before the batteries are dead. That's what's happened with mine, and I've spoken with at least one other CPFer who had a similar experience. Those bulbs can blow after as little as 30 minutes to an hour of runtime. On the other hand, they're cheaper to replace than the batteries themselves! So no big deal I guess.
    [img]/ubbthreads/images/graemlins/icon3.gif[/img]

    If you were to remove the tailcap of the light and measure current flow using a DMM, you could reach a rough estimate on battery life by dividing 1300 by the mA of current flow. Those 123 cells can handle high rates of discharge, so the rated capacity (typically 1300mA) should give you a good mathematical basis for the overall runtime of the light.

  3. #3

    Default Re: 3x123 kpr112 runtime?

    I've got to echo what Scott said. The bulb is severely stressed. I've had bulbs that lasted over 35 minutes in total runtime but others blow right away. Runtime would be the least of my concerns with this setup because while it is fun, it is ultimately not reliable. It pays to have a bag of KPR112s around.

    Wilkey

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    Flashaholic* EvilLithiumMan's Avatar
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    Default Re: 3x123 kpr112 runtime?

    MTFD17,

    I've lost five bulbs so far, but I am not using 3x123, running two 18650 Li-Ion cells instead. I did manage to get 90 minutes of run time on the last bulb, as I discharged the pack to 8.0 volts first. I measured 750ma current at that level.

    You may want to try a kpr118, which is 7.2v @ 600ma. (RS 272-1164) I've tested a couple of hours with one and haven't blown it yet. Not quite as over driven or bright as the kpr112, but still very bright none the less.

    On a semi-related note, another thread mentioned the 2, 3 & 4 cell xenon bulbs by Maglite. I picked up a 3 cell one at Home Depot yesterday and compared it to the xpr103 3.6v 800ma bulb from Radio Shack running on a single 18650 Li-Ion cell. Wow, it is quite a bit whiter % brighter. So much so in fact, that I returned to HD this morning and bought two of each type @ $3 ea. (I'll need something to do over the long T-Day weekend. May as well vaporize some tungsten).

  5. #5

    Default Re: 3x123 kpr112 runtime?

    ELM,
    You discharged the 2x18650 to 8V prior to feeding the KPR112? too bad the HD's out here suck. They don't ususally stock the Mag Xenons.
    Wilkey


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    Flashaholic* milkyspit's Avatar
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    Default Re: 3x123 kpr112 runtime?

    All, I know this is going a little off topic, but last week just for giggles I bought a KPR113 bulb at Walmart and stuck it in an el cheapo 2D flashlight, then used 6AA in a pair of Elektrolumens' infamous 3-to-D adapters to drive it. Bright bright BRIGHT! [img]/ubbthreads/images/graemlins/cool.gif[/img] So far the bulb hasn't blown, but I haven't used it for all that long yet. Still, this might be an alternate bulb to try.

    Come to think of it, maybe those 3-to-D adapters could be put ot good use with a KPR112 bulb, because the resistance introduced by those adapters could help pull voltage to the bulb just a bit back from the edge, and maybe the bulb wouldn't blow so quickly. [img]/ubbthreads/images/graemlins/thinking.gif[/img]

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    Default Re: 3x123 kpr112 runtime?

    milkeyspit,
    The KPR112 with two 3toDs isn't that great. I've been using various 6 volt bulbs (because I get them free). The PR13 does pretty good and 6 volt halogen are about the same. These aren't in the same class as 3x123 & KPR112. The 3D with three 3toDs & KPR118 is better than 3x123 & KPR112. If you try other bulbs please keep us posted.
    The KPR112 with 7 alkaline & 2 dummy cells is about equal to the 3x123 & KPR112 (maybe a little dimmer). The KPR112 with 8 alkaline & 1 dummy cell is a little brighter and quite a bit whiter than the KPR112 driven by 3x123.

  8. #8

    Default Re: 3x123 kpr112 runtime?

    Mine registers 0.80A, so the battery runtime should be over an hour. However, the bulb lasts much less than that.

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    Flashaholic* kz1000s1's Avatar
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    Default Re: 3x123 kpr112 runtime?

    I've been building the KPR112 3x123 mags and Energizer lights for over a year and have yet to blow a bulb (Radio Shack). web page There was one that failed, but there was nothing visibly wrong with it, so something must have seperated internally. Maybe one reason for not having a problem is that I don't use these lights for extended running or runtime tests. This was mostly with Surefire batteries and a few DP's. If you need a supply of these bulbs, RS gives you a discount if you buy 12 or more.

    To me this a magic combination that yields results that are better than anyone would expect. It also has the whitest beam of any incandescent I have. I've also tried 4x123 with the KPR118 and it wasn't as bright or white. Also an MR-16 20W lamp and 4x123 and still not as good.

  10. #10
    Flashaholic* Zeppert's Avatar
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    Default Re: 3x123 kpr112 runtime?

    I agree with MilkySpit... The bulb blows before the batteries run out. But keep an extra bulb or 20 [img]/ubbthreads/images/graemlins/wink.gif[/img] on you and you'll have a bright far, far, far throwing little torch.

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    Default Re: 3x123 kpr112 runtime?

    My local Radio shack rarely has the KPR-112 in stock. In three trips to the store, over the course of about 6 weeks, i've only managed to score two bulbs.

  12. #12

    Default Re: 3x123 kpr112 runtime?

    Hmm... My minimal experience so far:

    3x123 KPR112:
    First bulb went poof after ~25 minutes.
    Second bulb still alive (so far) with about the same usage...

    8xAA(cheapo alkalines) KPR112:
    Ran a touch brighter that the 123 combo.
    Unfortunately, one of the cells leaked after about 10 minutes of use. Tore it down. Cleaned it. put it back together with
    8 E2 lithiums.

    8xAA(E2 lithiums) KPR112:
    POOF! (Pretty much expected that.)

    8xAA(E2 lithiums) KPR118:
    POOF! (Not that surprised, but I though it might work okay.)

    6xAA(E2 lithiums) KPR118:
    Pretty nice but not as bright as the 3x123 or 8xAA(alkaline) so I took the KPR118 out and put in a KPR112

    6xAA(E2 lithiums) KPR112:
    Sweet! Maybe a touch brighter than the 3x123.
    Hmmm... bulb went poof after ~20 minutes so I put the KPR118 back in. I haven't used it much but it's still alive.


    On to 20W sylvania/osram 12V MR16 spots...
    (OT but I might as well put the info here while I'm typing.)

    12xAA(E2 lithiums) 20W MR16:
    Nice even pattern. Not a hot white spot like the KPR112 but very usable. I only ran it for a few minutes... so no runtimes.

    7x123 20W MR16:
    A bit brighter than 12xAA. SWEET little package when put 4C Mag.

    14xAA(E2 lithiums) 20W MR16:
    Nice! Brighter than the 7x123!

    Final MR16 Notes:
    After ~20 minutes use on the 7x123 and ~15 minutes on the 14xAA the 14xAA is quite a bit brighter. Heat doesn't seem to be a issue. Pin receptacles are potted with JB-Weld in previously poofed RS PR bulb bases.

    YMMV Enjoy!

  13. #13
    Flashaholic* kz1000s1's Avatar
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    Default Re: 3x123 kpr112 runtime?

    Radio Shacks never have many KPR112's in stock. Just have them order some for you.

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    Default Re: 3x123 kpr112 runtime?

    drumgod,
    What are you using for D to AA converters? I'm using 3toDs and the KPR118 works great with 9 alkaline AAs. My 3toDs are not moddded to reduce resistance. The KPR112 with 7AAs and 2 dummy cells is about equal to 3x123 with the KPR112, and 8 AAs are a little brighter, and 9 AAs flash a KPR112.
    All AAs were new Rayovac alkaline.

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    Default Re: 3x123 kpr112 runtime?

    I had the same problems getting bulbs, so I get them on line. If you buy $25 worth shipping is free. Get KPR112s here
    http://www.radioshack.com/product.as...%5Fid=272-1163

  16. #16

    Default Re: 3x123 kpr112 runtime?

    My radio shack offered to order a 20x microscope and have it mailed home at no extra charge. This is, no doubt, RS policy.
    So ask them to order a bunch of 112's for you and mail them to your house.

    BTW I'm still lookin for the 20x handheld lighted microscope.
    The RS warehouse didn't have any .... sheesh
    Tom

  17. #17

    Default Re: 3x123 kpr112 runtime?

    wow,
    Nice work drumgod. Meticulous, voluminous and photon-worthy. That 14xAA lith has got to be an expensive setup. The best price I've found is $7 for 4.
    Wilkey

  18. #18

    Default Re: 3x123 kpr112 runtime?

    Hoghead,
    I have been using a pair of *severely* lightened 8xAA adapters from Radio Shack. (As seen here on CPF. Sorry, I don't have the link handy or remember who gets the credit.) I set them up so that there is a small hole in the negative contact, lined up with the negative contact of the last pair of AAs. So, 6xAA in 2xD space if I put a small nut & screw through the hole, 8xAA without. They're not pretty but they're cheap and have been working well so far. I occasionally get large amounts of AAs for free, so I thought it might be nice to set up a few of my experiments to use them.

    All,
    The Radio Shacks around me seem to be really slow at re-ordering. There are 3 within about 20 minutes of my house/office. Each location had 2 of each KPR bulb. I bought all (6) of the KPR112s and a pair of the KPR118s.
    I was in the first RS I hit yesterday, and in about a month they have not re-stocked the the 2xKPR112s or the 1x8xAA holder. Oh well, they really do have a pretty good ordering system. I used to get AAAAs from them regularly... and I use the ads they send me to start my grill! [img]/ubbthreads/images/graemlins/mad.gif[/img] <-- That's not mad... It's FIRE [img]/ubbthreads/images/graemlins/wink.gif[/img]

    EDIT:
    Ginseng,
    Thank you for the kind words. Voluminous... Yes, I've been accused of that before. Meticulous? Well, lets just say I use my DMM more for trouble shooting than planning. [img]/ubbthreads/images/graemlins/frown.gif[/img] Yeah, the E2s are $$ but a couple boxes of them fell into my lap. I figure, "smoke 'em if you got 'em". I'd hate to feed it "out of pocket" though [img]/ubbthreads/images/graemlins/broke.gif[/img]

  19. #19
    Flashaholic* EvilLithiumMan's Avatar
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    Default Re: 3x123 kpr112 runtime?

    Ginseng,

    I may have 'solved' my problem with flashing kpr112 bulbs through the highly inefficient method of adding a 1N4001 diode to the Li-Ion pack. It provides a .6 volt drop, a little more than I need, but should allow the kpr112 to have a reasonable life span. The throw from this combo is impressive, considering the costs involved.

    Darn, it just dawned on me that I have some 1N5817 Schottky diodes. Their forward drop is only .2 of a volt; one or two of those may be the best compromise of lumens vs. life.

  20. #20
    *Flashaholic* Icebreak's Avatar
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    Default Re: 3x123 kpr112 runtime?

    [ QUOTE ]
    milkyspit said:
    Come to think of it, maybe those 3-to-D adapters could be put ot good use with a KPR112 bulb, because the resistance introduced by those adapters could help pull voltage to the bulb just a bit back from the edge, and maybe the bulb wouldn't blow so quickly. [img]/ubbthreads/images/graemlins/thinking.gif[/img]


    [/ QUOTE ]

    I think you may be right. It seems ineffecient but (unless someone corrects me)I don't think there is much energy loss.

    [ QUOTE ]
    Hoghead said:
    I'm using 3toDs and the KPR118 works great with 9 alkaline AAs. My 3toDs are not moddded to reduce resistance.

    [/ QUOTE ]

    I did the same thing. I found it to be brighter than any KPR112 combo I tried. More importantly, the hotspot is twice as big. I suppose it is time to order some more 3toDs. I’m going to have to break down and attempt a “Hot Wire Guys” modification for the incoming super bulbs. I want to keep these unmodded 3toDs because I like this bright and cheap to run combination.

    The PITN to me was re-aligning the bulb to get the filament perfectly centered. Took me 6 tries this time and I’m sure it was mostly luck. If the filament isn’t centered the beam is wacked.

  21. #21

    Default Re: 3x123 kpr112 runtime?

    ELM,
    You're speaking Greek to this chemical engineer but I'm glad it's working [img]/ubbthreads/images/graemlins/wink.gif[/img] I'm going to go the regulated route for better control. That and someone else can build my controller to suit the exact voltage needs. I bet it costs more than a diode or shottky though.

    Icey,
    You've got to try the ultimate bulb alignment tool/method. I can't take credit for it but I can pass it on. If you have a donor Mag from which you've removed the switch body, take the bulb attachment collar and the heavy tubular piece it screws into. Unscrew tha collar as if you were going to put a bulb in but put it in upside down so the PR base is sticking out where the bulb capsule normally should be. Now look down the other end of the metal tube and you'll see the filament. Just rotate the tube and observe which way the filament wobbles to. Grab the base gently with a pair of pliers and bend the base in the other direction. Repeat until perfect. You have centered the filament by adjusting the flange. While the capsule may still look way out of whack, the filament will be dead center.

    Wilkey

  22. #22
    *Flashaholic* Icebreak's Avatar
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    Default Re: 3x123 kpr112 runtime?

    I love a simple solution. Thanks, Wilkey. [img]/ubbthreads/images/graemlins/thumbsup.gif[/img]

  23. #23
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    Default Re: 3x123 kpr112 runtime?

    just for the record, I used a Mag 4cell Xenon bulb with 3-to-Ds and it was nice and white. It was bright but I can't say since I've never had a KPR112 mod. Tried 3x123 with the MagXenon, it was hella bright but zapped instantly. Today I got a hold of some RS 112s. Wish I had that MagXenon to compare them to. txs

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