Battery and Bulb Selections for Regulated Hotwires

[Alan B]

Much of the available information for Battery and Bulb selection for Hotwires is based on direct drive, possibly with a current limiting thermistor.

In this thread I would like to explore the somewhat different setups that make sense when a Programmable Hotwire Regulator is added to the light. This is important since the bulb voltage can be precisely controlled and the battery voltage need be only higher than bulb voltage. Another important change is the soft start and how that allows a higher current to be drawn from many protected cells without tripping their overcurrent protection during startup. Together these features change the combinations that are practical and useful.

Really there are three parameters involved in these recipes. Besides the battery and bulb there is the physical package. Solutions are really tuned for the particular battery space. Perhaps the output of this discussion can be a list of useful recipes for regulated hotwires. I will put this list into a subsequent posting below in this thread.

Optimal choices are when the battery voltage is greater than bulb voltage, but not by too large a factor. Regulation works best when the PWM duty cycle is greater than 50%, and this occurs when the battery to bulb voltage ratio is less than 1.4:1. Direct drive compatible solutions are also somewhat sub-optimal since the duty cycle reaches 100% and the system falls out of regulation at the highest level.

Note that these regulators are presently in final development and testing. See the separate threads on the design and status of these projects listed below.


-- Alan

Links

Hotwire Regulator FAQ
http://www.candlepowerforums.com/vb/showpost.php?p=2805117&postcount=160

Alan B's D M@g Drop-In Programmable Hotwire Regulated Driver:
http://www.candlepowerforums.com/vb/showthread.php?t=218506

wquiles SF-M6 Programmable Hotwire Regulated Battery Pack:
http://www.candlepowerforums.com/vb/...d.php?t=215806

JimmyM's D-M@g Programmable Hotwire Regulator:
http://www.candlepowerforums.com/vb/...d.php?t=216160

LuxLuthor's Destructive Bulb Testing Data:
http://www.candlepowerforums.com/vb/showthread.php?t=179748

LuxLuthor's Most Powerful M@glite Mods List:
http://www.candlepowerforums.com/vb/showthread.php?t=177171

Sources

Litho's Bulbs:
http://www.cpfmarketplace.com/mp/showthread.php?t=181713

FiveMega's Battery Holders, Bulb Sockets, Reflectors, Bulbs and Hosts:
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[Alan B]

Regulated Hotwire Configurations Recipe List

M@g 1D

will these even work due to the high current?? LiMN available?
3x17670 Li-Ion, WA1111, short runtime, requires tri-bore
3x17670 Li-Ion, WA1185, short runtime, requires tri-bore
3x17670 Li-Ion, WA1164, short runtime, requires tri-bore

M@g 2D

2x3AA NiMH, 2x18650, 2xC-Li-Ion, 2xD-Li-Ion - about 7.2V - WA1111, Philips 5761
2x4AA (requires boring) - about 9.6V - WA1164, WA1185
2x18650,C LiMN

M@g 3D

3x3AA, WA1185, 1:1 ratio, not much regulation at full output
3x3AA, WA1164, a bit more output than the 1185, lower voltage gives more regulated time
3xC/D Li-Ion, WA1185, 1.03:1 ratio, long runtime, not much regulation at full output
3xC/C Li-Ion, WA1164, nice output and regulation
3x4AA, WA1185, excellent 1.33:1 ratio, requires boring, good regulation

M@g 4D

4x3AA, WA1185, excellent 1.33:1 ratio, no boring
4x4AA, WA1185, 1.78:1 ratio, quadbore required
4xC/D Li-Ion, WA1185, 1.56:1, long runtime, no boring reqd

M@g 5D

M@g 6D

Elephant and Colossus short?

4x18650 Li-Ion, ...?

SF M6

3x..

Bulb Info Summary (Voltages used in above ratios):

WA1111
WA1185 10.8V xA 1200 lumens
WA1164
Philips 5761

 

[LuxLuthor]

Alan,

There is not really a 'set' way to pick the proper combinations that you are looking to do, but having regulation gives a lot more options. It is actually a fairly complex set of choices, and I'm not even sure there is an ideal way to go about picking what's best.

FiveMega created a superb variety of bulb & battery combinations, often picking mag length, battery choice, holder, boring, etc. of how he wanted to make a setup for 1 or 2 bulb choices.

Each bulb has its optimal voltage if overdriven, and the higher the current, the shorter the run time. The smaller the Mag length, the less battery options are available. Maybe I'll start with some ways to sort this out for people. There are others who will always just want a "set package" where someone decides it all and they buy it.

• 1) How much light do you want? Let's start with (bulb) lumens, even though the accuracy of that term is rarely understood or represented accurately. I'm also not dwelling on the bulb/filament color/quality, or reflector features which can have a huge impact.

• 2) How long do you want the run time?

• 3) What size light do you have? FiveMega put out quad-bore, tri-bore, unbored 1D, 1.5D, 1.75D, 2D, 2.5D, etc etc that all give different battey combinations. Others did a more diffuse bore (not grooves) which can also work.

• 4) In terms of batteries, the required bulb current can limit your choices, unless you get into parallel setups.

For example, in NiMH cells a 1D/1.5D can have 4s or 2s2p of 4 x AA's. Then 3s of 4/5A. 6s or 9s of 2/3A.

In Li-Ion: 4 x 14500, 4 x 14670, 3 x 17500, 3 x 17670
​

To some degree, there is a limitation on available (affordable) Mag hosts that are bored and with battery holders.

I could probably give a couple of ideal setups for various Mag lengths. For example, even at lesser total lumens, I prefer the 1166 over the 1185 because of bulb/filament quality/color...and less amps. I also like the 1164 with its lower voltage than 1185. FiveMega put out about 8 runs of his 700L 1.5 D using 1331 bulb & 3s 17670 which is another medium output choice.

 

[Alan B]

The goal here is just to find some of the "nice" setups. There are so many possibilities. I could write a program to generate them all, and perhaps I will do that sometime, but there are probably a few "best" setups that really take advantage of the size, batteries, bulb and regulator that are worth cataloging.

I took the first article regulator SN001 that LuxLuthor tested and reconfigured it for a 2D 8xAA NiMh driving a WA1164. This is a very nice 2D package, but it does require a special battery holder and a boring operation to make it fit.

So what are the nice regulated 2D Hotwire setups? Perhaps a pair of unprotected KD 2D Li-Ion cells into a 5761? Or perhaps a pair of LiMN cells? 18650 or C or ?? Two A123M1 LiFe cells should fit but is there a bulb low enough in voltage to make that purr?? One can go to battery holders and boring but that raises the cost a lot and wastes volume in the battery compartment.

I do have some KD unprotected Li-Ion D cells. Those should be good for a 2D. Again, what is the best bulb?

Let's explore the space a bit and seek out the 'gems'.

 

[Jay T]

I do have some KD unprotected Li-Ion D cells. Those should be good for a 2D. Again, what is the best bulb?

Let's explore the space a bit and seek out the 'gems'.

May I suggest the 64275. With an axial filiment this bulb produces a very pretty beam. Using an AW softstart + 2 KD LI-Ions I have killed too many of these bulbs, a good canidate for regulation.

 

[Alan B]

May I suggest the 64275. With an axial filiment this bulb produces a very pretty beam. Using an AW softstart + 2 KD LI-Ions I have killed too many of these bulbs, a good canidate for regulation.

Very interesting suggestion. 6+ amps! Is that a bit high for the unprotected KD Li-Ion's? Getting into LiMn territory? What's the best battery that fits into 2D? Was there a new 26650 LiMn recently??

 

[SR.GRINGO]

Another combo that could offer many options Alan's regulator, Mag 3D with 4 of AW's IMR26500. This could make a wow light, as well as a long runner.

 

[Alan B]

Another combo that could offer many options Alan's regulator, Mag 3D with 4 of AW's IMR26500. This could make a wow light, as well as a long runner.

Excellent suggestion. How much space is there in a 3D with those? How about three in a 2D???

 

[Timaxe]

Lithium (well, actually all) direct drive solutions provided a good indicator of low battery levels - ie when to stop using the light. You lose that with a regulator, so more care will be required with the battery and bulb combinations. This is more important with Lithium chemistries than NiMh, etc., especially with higher cell costs and the protection circuits most have to prevent various run-away conditions.

You definitely don't want the V_in to exceed V_bulb by more than 1.4. This would correspond to the voltages of a Lithium cell: 4.2v Fully Charged, 3.0v Completely Discharged.

Something closer to a 1.25-1.30 ratio may be better - towards the end it'll fall out of regulation and quickly dim telling you to stop using it. But it may take a while for people to recognize this condition. So perhaps for the lithiums recommending something around a 1.25 ratio could be better as it'll fall out of regulation by 3.35v and there is still enough left in the battery to dim the light down with the cells reaching 3.2v or lower in say (guessing here) 30 seconds or so.

Fortunately there isn't much on there that does this with the Lithium suggestions so far (just add a note for the 4D/C sized lithium hosts). But it can be food for thought when coming up with combinations - at least until something can be programmed into the driver to safely turn off the light because the battery combination is known.

(I realize a big issue is the user interface and limited board space - I've worked with AVRs for a year mainly with automotive interfaces and signalling applications and have followed parts of your project so the hardware/software solutions for this aren't foreign to me. I may track down your parts and build a large-ish bench model to play with on a power supply )

 

[Alan B]

Good considerations. One thing to also add is that with the regulator the light may spend a lot of time set to a lower level and will not fall out of regulation at all.

The present software watches the battery voltage and when it drops below the specified minimum it "blinks", turning the light off for a couple tenths of a second, and when it turns the light back on the output bulb voltage is lowered to 3/4 of what it was, which is about half the power. If the battery cannot sustain this lighter load it will blink again until the battery does sustain the load, or the bulb voltage drops below the minimum specified voltage and the regulator turns off.

In actual use the light blinks from high power to a lower power and continues to work for a time, then repeats to a lower setting, finally going off. I got quite a lot of experience with this during the past weekend when I recommissioned the SN001 back from LuxLuthor's review into my 8xAA NiMh WA1164 2D M@g. The batteries were weak, I believe a couple of the cells are damaged, and it worked fine at medium levels but at full power lasted only a short time, then falling into the drop-back mode. It worked quite nicely, repeatedly turning on and dropping to a useful midrange value. You could get a very useful amount of runtime at moderate output even with this damaged pack. The range on this light is quite amazing, from a few lumens at 2.0 volts to around 1500 lumens at the 9 volt level. Fairly impressive for a 2D.

By the way, I have a bare regulator test board and many of the parts that I didn't build up, exactly what you might do for the bench. I should sell it to help pay for all the development and tools.

 

[SR.GRINGO]

Excellent suggestion. How much space is there in a 3D with those? How about three in a 2D???

Asked AW the same question the only magic Mag is the 3d. Lots of options here.

64430
1185
FM's Carley 43(we need another group buy)
5761
64623

 

[Alan B]

Asked AW the same question the only magic Mag is the 3d. Lots of options here.

64430
1185
FM's Carley 43(we need another group buy)
5761
64623

Great suggestions. I'll have to add those to the list in the earlier post.

Today I received several M@g D extensions from FM. I combined the 34mm with the 6D and six A123M1 cells plus a KD Golden spring. Looks like a good fit though I think I need to turn an aluminum follower to make good connection with the button on the A123M1. Remember that these cells go backwards due to their reverse case polarity - so the button is toward the tailcap.

So we are a bit closer to a regulated 6D A123M1 test setup. I need some more Kiu sockets... PM me if you have any I can obtain...