Tec40 w/ KPR103 & Alkalines?

Just curious - everyone talks about using a Tec40 w/ a KPR103 and NiMH. I use my Tec40 (and most of my lights) outdoors away from sources of power, so NiMH doesn't help me.

Will Alkaline batteries be able to generate enough current for the KPR103? What happens when you run one w/ Alkaline cells?

In the end, my real questions is: Is it possible to get more light from a tec40 than irs native bulb if you want to use Alkaline cells?

camisdad,

To simply answers your question first,
1) YES, the alkalines will be able to supply enough current.
2) YES, the Tec 40 w/KPR103 running with Alkalines will produce more light than the "native"bulb.

Now, the details and reasoning.....
The main reason for the CPF members advising you to use NiMH cells rather than alkalines is NOT because of current. It is because of voltage.
You are using a bulb design to be driven by 3.6V (KPR103). But when you are overdriving it with 4 cells, you get a higher voltage, and thus a "overdriven light".
Because NiMH rechargeable cells have a nominal voltage rating of 1.2~1.25V (Although right after recharging they can be as high as 1.47V), the resulting voltage from the 4cells would be ~4.8V.
When using Alkalines to overdrive it, however, the voltage becomes much higher. The alkalines have a nominal voltage rating of ~1.5V, so 4 cells will result in a voltage close to 6V.
The higher the "overdriving voltage", the bigger likelyhood of blowing the bulb.

This is why the CPF members recommend using rechargeable cells rather than alkalines.

HOWEVER, from my experience (experiments?), I have been successful using alkaline cells with my Tec40 w/KPR103. I haven't blown a bulb yet.
I've tried various voltages and various types of bulbs (even the XPR103), and to my surprise, the krypton filled bulbs seem to handle "overdriving" best.

On a different light, I once blew a xenon filled bulb as soon as I turned the light on (due to too high a voltage), but the same voltage failed to blow a krypton bulb. The krypton bulb did finally blow after about an hour of service, but it was clear that the krypton bulb seemed to handle the high voltage much better than the xenon.

Alan from Hong Kong had similar results from his experiments as well.

Good luck.

I own a few Tec40's, and they come with HMP20 4.8V .5A lamps. I've gone the route of bulb changes / battery types (my worklight is nimh, my "home if you need it light is alkaline"). Although some combinations do give better light output, IMHO PT did their homework with the lamp they selected as "stock". If you can live with a little less than the maximum output possible, use the stock lamp with any battery type you want, including nicd's. (still have fun playing around, though)

Note: HMP20: 500ma @ 4.8V
KPR103 800ma @ 3.6V
runtime?

The NiMH will deliver higher rates of total power quickly than the Alkalines (hence the success of NiMH in digital camera applications where alkalines just get eaten up).

So...it isn't just about finding a bulb that is closer to the nominal 4.8v of the 4 NiMH AAs. It is also about delivering the amps necessary to create a bright light.

I do agree though that Princeton Tec seems to have done their homework and the stock bulb is a very good balance of brightness and longevity. Although, the Princeton Tec retailer in our area (an outfitter store) charges $7 for the bulb...so obtaining it locally can be a little pricey.

Originally posted by camisdad:
I use my Tec40...away from ...power, so NiMH doesn't help me.

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<font size="2" face="Verdana, Arial">This needn't be a reason not to use NiMH. In a really bright (high amperage) light, NiMH should give similar run time to Alkalines. So...on an extended hike/camp you might need 2 sets of batteries...or perhaps 3. Unless you are pitching the spent alkalines into nature along the trail (hmmm...I hope not), you will be packing them back to civilzation. So...if you are doing that, why not take several sets of freshly charged NiMHs and simply recharge them upon return?

I really hate the thought of filling up our landfills (or our trails) with spent alkalines. NiMHs can be recharged 500-1000 times, also giving you much lower costs over time for battery power.

I posted about a somewhat value buy in a Rayovac 'Prodigy' 4AA light.

I run it with Lithium AAs and a KPR103. I haven't run the crap out of it, but it is WAY bright, and hasn't blown up the bulb yet though I turn it on at least twice a day just to wonder at the brightness of it!

I plan to have a TEC 40 pretty soon and will try the same combo (though may go kpr113 for longevity).

Edited to add: Oh and Lithiums rule! But I refuse to spend around $2 EACH for batteries. I shall almost certainly run Alkys for the most part.

Originally posted by camisdad:
...7 day trip ...NiMH lose about 2% charge per day

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<font size="2" face="Verdana, Arial">Hmmm. Yes, after a 7 day outing, your fresh NiMHs would be down to about 86% of their original charge. Although, maybe that would still be a substantial enough amount of energy for your needs.

As for the charge time, possibly a Ray-O-Vac 1 hr charger would reduce the burden on the charge time before your trip. In the long run, rechargeables will definitely help you save costs.

One compromise we've used is to start out with fresh NiMH and take alkalines for the extra spares. That way if we need them, we've got spares with good shelf life but at least the initial burst of energy comes from rechargeables.

Every little bit helps!

Good luck with your family outings (a great activity for families IMHO)!

And that 2% loss everyday is Not a linear one.

Thanks very much everyone.

I would have thought that when alkaline cells are asked to deliver high current across a small resistive charge their actual voltage would be much lower than nominal - since the nominal discharge voltage for battery measurements is typically 10mA. I guess I need to start reading alkaline battery spec sheets in detail... Thanks to all!

PS - NiMH in storage for 6 weeks (between 2 outings) means about 0.98^40= about 40% charge.

With some chargers and some cells you can sometimes get a 'false charge', where the charger kicks out way before the cell is charged. That's fun because you usually don't notice until your using it.

I use NiMh in my handheld radios, but for emergencies, I've always got several sets of Alks in the trunk.

At wally world, is the KPR103 available? I mostly see rayovac bulbs, rated at "3C cells" or whatever combination.

Note - Ray-o-vac 1 hour charger - good charge but runs hot and may damage batteries (see here). I would recommend the 4000N from Ripvan100.com.

Best - Michel

Hi ikendu - my wife, little boy and I go on extended biking and backpacking trips in the wilderness areas of CA. We carry 4-5 lights of different ilks and uses plus spares. We do a lot of night activities - therefore light use. I do have a couple of packs of NiMH for the digital camera. Given our consumption, the flashlights together on a 7 day trip would compel me to carry $200+ worth of NiMH (including spares). So I use Alkalines for that. This is also the reason why I try to use only AAs and AAAs - so as to simplify and lighten the amount of spares I need.

In addition, NiMH lose about 2% charge per day of storage. You have to recharge all your NimH packs before you leave, which is very time consuming if you have many of them - impossible for me as I have a 80-hour week job. So, altogether, using NiMH for lighting does not work well for me.

And, btw, we don't dump our batteries on the trail any more than you do. What we pack in we pack out.

Originally posted by camisdad:
...In the end, my real questions is: Is it possible to get more light from a tec40 than irs native bulb if you want to use Alkaline cells?

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<font size="2" face="Verdana, Arial">camisdad,

I don't go on such extended hikes as you and your family, but when I did runtime/brightness tests comparing the Tek 40, UKE Mini Q40, Stealthlite 4AA and Streamlight 4AA incandescent, along with the UKE 2L, (all with stock lamps) I found that the Mini Q40 was clearly the best performer in terms of both runtime and brightness, as well as the smallest and lightest. Granted, lithiums are ridiculously expensive. NTL, they give me 5 hours of light in the Q40. Four of those hours were surprisingly bright, the next 1/2hr was still highly functional, while the last 1/2 hr was distinctly dimmer but still enough to light your way. I take at least one or two battery changes, a spare lamp assembly and a Lightwave 3000 or Tek 1400 for my large LED light. I take other lights also, but the Mini Q40 and either of those big LED lights is a very useful combo.

Also, my (don't laugh please) CMG Reactor (I lucked out with a good one) which I believe is direct drive and thrives on lithiums will supply bright light for a surprisingly long time. I've mentioned this before, but in Brock's great chart, he shows that the Inova X5 (direct drive) lost only 7% of initial brightness after three hours and only (if I remember correctly) 13% after 4 hours, and this is a light that is highly overdriven.

Back to the Reactor: I did a VERY informal overnight test of it and the Streamlight 4AA LED. Sorry for lack of figures, but when I came down the next morning the Streamlight was barely shining while the Reactor was still producing a fairly bright functional light. Frankly I was surprised, and I will give it a structured test at some point. When I tested it out in the country on a very dark moon-obscured night it was quite good; not as good as my 1400, but considering the size/weight differential between the two lights I was impressed.

I'm sure you know this, but just to remind you if you're taking any lithium 123 lights, they are very cost effective using split 223's, which is not a very popular practice here because it's a bit of a pain, but you will get remarkable savings.

Brightnorm

Originally posted by Albany Tom:

At wally world, is the KPR103 available? I mostly see rayovac bulbs, rated at "3C cells" or whatever combination.

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<font size="2" face="Verdana, Arial">Yes, if you look closely at the "3D Cell" blister pack, you'll see that the pack labeled 2-K3 contains two KPR103 bulbs...about 80 cents each.