Fully Regulated 4AA Incan Mod * Pics added *

I Just finished installing one of Willie Hunt's LVR3C voltage regulators in my Craftsman 4AA Tool Light (virtual clone to the Dorcy Boss 4AA). Installation was actually rather easy. I'll post pics & details eventually if anyone else is interested.

I wanted to use a better quality host for this regulator, but I haven't found a suitable donor yet. This modification is reversible, so I might move it to a better light in the future. This will do for now, as I am anxious to learn exactly how well the LVR3C's features will work for my needs.

I had my unit programmed for 3.8 volt output for use with the Carley #816 halogen (potted in a PR base). Driven at that level, the lamp is re-rated to about 82 lumens output.

I chose the Carley #816 lamp due to it's high lumen-per-watt ratio compared to all other lamps I could get info on in the voltage/current ratings needed for this application.

I haven't yet started a controlled run time test, but I would expect about 2-hours+45-minutes of FULL BRIGHTNESS based on my calculations using good 1800mAh NiMH's.

I also want to mention that Willie claims >99% efficiency for the LVR - and I have absolutely no reason to doubt that figure. That's pretty amazing IMO, especially when compared to other circuits I've looked into.

I chose this setup because I wanted a AA-cell light that didn't care whether I used NiMH's, Alkalines, or lithiums; the lumen output will remain EXACTLY the same - only the run times will differ.

Now, just a few notes on my first impressions using this light...

The soft start ramp-up takes between 1.5 to 2 seconds to full brightness (at least w/NiMH's). This should virtually eliminate filament stress during startup, and extend lamp life.

Following the normally-absent slow startup, the next thing I noticed was how white the light output actually is. Very white compared to other lamps/lights (non-LED) that I have. So far, so good...

Willie's LVR also has a low battery warning feature which is activated when the battery voltage aproaches the programmed output voltage, and appears as a slight (70%?) dimming at a bout a 1 Hz rate. I haven't reached that point yet (gee - how long has it been on?). As the battery voltage is further reduced, the LVR should go into an extended dim-run mode to extend useable run time as much as possible.

With NiMH's, the low battery warning is the point where I should prepare to change batteries, as I don't want to risk damaging them due to cell reversal. With other chemistries (throw-away's), the LVR should literally "suck them dry".

At any rate, I really like the thing so far, and will fully explore all of its useful features as my time permits.

Time to take out the trash...(Wait a minute - I'll need a light for that...)

Later - John

Yes, please post pictures etc. inquiring minds want to know. I'm surprised no one else has modded an incandescent since it is a simpler mod to do in general. I've done some many years ago using monolithic adjustable buck converters. I guess that makes me an old timer in the mod arena. Now there are much better parts to choose from in the likes of Linear, Maxim, and National.

CM

Looking foward to the pics

This is very interesting. I'm not a modder but I've always thought a regulated 4xAA incandescent
had real potential. What do you think the smallest practical host for this could be, a UK 4AA for example? What about space and heat?

If someone could build me a similar reliable mod I'd be willing to pay "appropriately".

Brightnorm

Brightnorm,

This thing is really pretty cool so far - I've only had it operational for a couple of days now. The work thing keeps gettin' in my way of doing some run time testing and pics, ect.

You can check out the LVR3C on Willie's site - very informative and shows pics, too. Search the forum and you'll find a link to his site.

The LVR3C is .5" x .8" by approximately .2" thick, and has three solder pad connections. there are many connection options for the switch (board has a momentary SMD switch as well that allows direct connection to the battery).

My Craftsman 4AA Tool Light is (for now) a test mule. I'm still looking for a better light with enough room to add regulator. I was actually thinking (maybe) about the LEDcorp "our Best Auminum" 'cuz I think it takes 4AA and a PR-based bulb.

Gotta go now - We'll pick up on this laier (I hope).

Thanks - John

BN,

Forgot to ask earlier - doesn't the UK 4AA use a lamp module or LA? I don't have one, so I'm not sure if there's room enough in there, or whether a suitable lamp could be substituted. If there's room, you'd still need to fit a lamp assembly (or lamp) that would be run well on about 3.6 to 4 volts for use on 4AA (NiMH's at least). If memory serves, Willie states that alkalines can be drained to about .8-.9 volts per cell to get most of their energy, so I suppose it's possible to to run a lamp as low as 3-3.6 volts for alks if you found a suitable lamp.

Did I mention that the 4AA Tool Light has an interchangeable lamp holder with the Rayovac 4AA Rubber Lite? I can easily switch my regulated lampholder from the wider flood beam of the Craftsman to the tight beam of the Rayovac. Throws amazingly far if the lamp is properly centered and focused in the reflector. The Carley spacer rings help for that.

Later - John

Here are some picks of the lamp holder with LVR added...













...and a few construction notes...

The negative lamp contact (side of lamp base) had to be isolated from the negative battery contact, and connected to the LVR as follows:

The rivet was removed, and the holes in the base and contacts were enlarged for a #6-32 nylon screw.

The negative lamp contact was then removed from the bottom of the lampholder base and placed on TOP of the lampholder base. The flange end of the bulb contact had to be shortened slightly so as not to extend beyond the top of the lampholder sleeve.

The battery negative spring and battery indicator contact were then re-attached to the bottom of the lampholder base with the nylon screw, and the bulb contact was secured on the top side with a brass #6-32 nut. The nylon screw is what isolates battery(-) from bulb(-).

The brass nut had to be trimmed on the side nearest the lampholder sleeve to provide clearance for the reflector sleeve.

The LVR bulb(-) lead was secured to the lamp contact under the nut.

The battery(+) and battery(-) leads from the LVR were soldered to the existing battery indicator contacts of the lampholder.

While the LVR has many connection options, it should be noted that the bulb and LVR utilize a POSITIVE(+) common, and so the bulb(-) is the output of the LVR.

The configuration for this Craftsman light essentially has the power switch in series between the battery and the LVR. Battery(+) connects to the LVR and bulb's bottom contact, and Battery(-) connects only to the LVR. Output from the LVR to the bulb is Bulb(-).

As I said before, this rig is just a test mule so hot-melt glue was used to secure the LVR leads to the lampholder base. This works OK for temporarily securing the LVR in place via the wires if a suitable guage wire size is used. I think I used #20 or #22.

If anyone has any suggestions for a better quality light that can accept a lamp rated for around 3.6 volts @ .8-1.0 amps, and might have room for this circuit, I'd love to get some suggestions.

Thanks to all - John

Great job!!!

Did you buy the Carley #816 halogen already potted in the PR base or you did it yourself?
Where do you buy the Carley bulbs from?

Thanks in advance - HGB

Anyone? I'm still looking for a better 4AA host for the LVR...

HGB,

Thanks! I had Carley pot the lamps along with several others.

You can check out their lamp selections on the web site -

www.carleylamps.com

You can also get their phone number from the site. You'll want to talk to Patty (Patricia) Taylor (a recent new-comer to CPF!) and tell her what you want. She's been really super to deal with!

Be advised, there's no minimum order, but you'll be charged for the lamp, plus a relatively small amount per lamp for potting, plus a bit for shipping, and also 2.5% if you pay via credit card. I declined on the additional marking charge since the lamps come separated in little ziplocks that are marked - then use a sharpie and mark 'em yourself.

This all worked out to something close to $8/lamp. A little pricey (I know) but they are better than the hoards of cheap krypton lamps I've bought only to find that they often produced really crappy beams. Mine appear to be very white in color compared to other commonly available lamps I've tried.

I suggest you buy at least 2 or 3 of the lamps you want, because there may be some variation in filament alignment, or even potting alignment, so if you use them in a light that's really sensitive to that, then pick the best of the lot and use the others as backup.

Don't forget to ask for the spacer shims (you normally get 5 w/ every Xenon Star for flashlights), so there should be no charge for them. [Patty, correct me if I'm wrong about this.] They do help to optimize your beam in many cases.

In lieu of potting, you could order the #912 PR-based socket adapter and order the lamp as just a 2-pin and plug it into the adapter. I think the adapter is less than $4, but don't try it with lamps over 1.2 amps. The #816 draws about .8 amps.

Hope this helps - John

Illuminated,

Thanks a lot for your time and the priceless data that only comes from experience.

By any chance, did you try the Carley Xenon Star #713 (3.8V - 0.84A ~ 3.2W) with your setup?

I'm inclined to get Carley Xenon Star bulbs, because of the hard glass envelope and the precision centering of the filaments.

I know the charts show higher efficiency for the #816 => 6 CP for 2.9W --- and a lower one for #713 => 4.3 CP for 3.2W.
But is that accurate? Is the #816 really a 39.5% brighter with less consumption?

Sometimes numbers don't represent accurately real life perceptions.

Thanks again --- HGB

HGB,

Glad to share my info with anyone. That's what makes CPF so valuable to me (the willingness of others to share that which I have not yet discovered or learned).

I'm eager to share my findings or ideas with anyone interested (and willing to endure my long-winded posts).

Answer to your question:

No, I didn't try the #713, sorry. I did, however, get lots of good info from the Welch-Allyn site on re-rating a lamp's performance when operated at a slightly different voltage than its design voltage.

WWW.walamps.com (I think)

Check out their site, and poke around until you find the info on "Electrical Characteristics". I downloaded this PDF for reference.

As far as efficiency goes, once you calculate a lamp's output in lumens at the voltage and current you'll be running, you can divide the lumens output by the electrical watts consumed, and you'll get a number generally between about 13 to 28 or so. A higher number is more efficient, but also generally means that lamp life will probably be shorter.

BTW, remember to convert the lamp's CP to Lumens: CP x 4pi = Lumens

I know I ran all the numbers on the #713 vs the #816 and I don't have the figures in front of me now, but I'm certain I chose the #816 for it's efficiency at the voltage/power levels I needed.

At 3.8 volts, the lamp life for the #816 would be reduced from 20 (I think) to about 15 or so, but I figure the LVR3C's soft start feature will bump that back up a bit. Only time (and testing) will tell.

I haven't had time to do a controlled run test yet, but I'm betting that I'll get close to 2.5 hours or more continuous on NiMH's. I'll also be testing alkalines as well.

Interestingly enough, Willie himself mentioned in an email that 1800mAh NiMH don't generally do so well in applications driving loads in excess of 1 watt per cell, and said that the 1600 mAh NiMH actually had better run times based on his testing. Since I have both, I intend to find out first-hand.

Willie also mentioned that for loads greater than 1 watt per cell, I might get better run times using 1200 mAh NiCads.

This brings me to asking another question of anyone patient enough to read through this rather lengthy post (sorry folks...) ----

Since the LVR is essentially a constant-power regulator, at least until the low battery warning flash kicks in, wouldn't this be an ideal setup to use for testing the capacity of rechargeable cells?

The curent drawn from the batteries would increase as the battery voltage under load drops during discharge. If output power from the regulator is known, the battery capacity (at a given load) could be calculated based on the continuous run time measured until a minimum usable voltage level was observed.

A suitable resistor could even be substituted for the lamp to make the testing more consistent.

Seems right to me - I wonder what some of our more experienced members think about the idea of using this as a constant-load battery tester. Commentary respectfully requested.

Thanks - John

Can you post beam pics along with another flashlight for reference? at let`s say 20-30 ft, how white is the Carley beam? SF White?

What do you think about the Xenon/led/CCFT I wrote about in another thread?, BTW how long did you have to wait for the regulator to arrive?

Thnx!
Alex

AlexGT,

I have to leave town on business for 1 week - I'll try some beamshots afterwards, but not yet sure how to set borrowed HP315 camera up manually for meaningful comparison.

I've seen pics and description of the Xenon/led/ccft you mention, but I haven't considered getting one yet as I have many lights now and many "irons in the fire".

I don't have a Surefire yet (I know -the shame of it...ttt) to compare, but I can say that my #816 is whiter in color temp than the new Mag Xenon 4-cell and other commonly available Xenons an Kryptons (not overdriven by 1 extra cell).

While I could use a higher wattage 3-cell lamp with this LVR such as the Carley #805 (1.6 amps), the AA NiMH's output voltage sags considerably under higher loads, so I'd need a different battery/light config to run 4 C's, D's, etc.

Willie initially misplaced my order, so it took awhile to get my unit. Once I emailed him to inquire about delivery, the mistake was realized and I got the unit within days. I have no qualms whatsoever about it - Willie was very good about answering email questions and making suggestions regarding best application for the LVR. I intend to purchase several more units.

I would suggest you email him with info on lamp type, battery config, etc., to determine optimum voltage needed. Then email him again indicating that you have sent payment for your purchase.

I had sent PayPal, and perhaps did not clearly notify him that payment was sent. The wife's name appeared on his statement, and he probably did not know who/what it was for. Again, I don't hold the mistake against him - it was resolved quickly without hassle.

I encourage anyone to get one of his LVR's and try it - they have many features and possibilities for creating a very cool incandescent.

Althouh larger and more expensive, Willie also offers LVR's that can handle higher voltages and huge wattage lamps for some serious lights, and you can even get them programmed for depth of low batt warning flash, reduced power level settings other than the standard 87%/75%/67%,etc. Low battery cut-off for rechargeables can also be programmed.

Have to go dig my way out of the driveway now...Later - John