parallel connection for 3x123 into Mag 2C?

I like the Mag 2C platform in terms of dimensions etc, and have a Mag 2-cell LED upgrade bulb that generally produces the amount and quality of light I want. Next step is to try Kryloning the OEM reflector.

But the application for this flashlight is as a general purpose car light. I've tried using rechargables in the car but remembering to recharge etc is too much hassle. Alkalines are convenient and cheap but worriesome about peeing and not handling the heat/cold well.

I've read posts here about the 3x123 mod, but as I understand it the three 123s are in series which would produce 9 vdc? If they were in parallel I would think they would produce 3 vdc with a really long runtime, and drive the Mag 2-cell LED bulb properly. 9v LED bulbs are in short supply AFAIK, and I'm kinda trying to do this on the cheap as this is a flashlight I don't use much.

Is there a 3x123 holder that will connect them in parallel?

thanx

My guess is you would have to do your own fabrication for 3 CR123s in parallel.

RE: running this setup in a 2c MagLED platform- I think you need to consider the mAh output of 3 CR123 in parallel vs. the mAh of 2 cells in series.

If my math is correct:

Alkaline C batt 7800 mAh. 2 alkaline C batteries in series = 3v @ 7800mAh
Litium CR123 battery 1400 mAh. 3 lithium CR123 in parallel = 3v @ 4200mAh

It looks like a substantial runtime downgrade associated with this modification.

The lithiums will handle the cold better, but isn't a huge issue in most applications. If you live in a severe cold area, I would suggest trying a CR123 flashlight solution, as opposed to a magmod. I think streamlight has a LED option for the TL3. There are plenty of fine 2 cell CR123 LED lights as well.

The biggest issue for me is the leaking associated with alkalines stored in a vehicle. I deal with this by changing the batteries out annually. If it is still an issue, you can go to a shorter battery swap cycle.

I love my new custom MagLED 2C (black HAIII coating w/sputtered reflector) and plan on mounting it in my new Ford Escape. I'll back it up with a minimag/NiteIze upgrade w/lithium AA or an Inova X5T w 2 CR123s.

Cheers, TR

pizzaman said:

If my math is correct:

Alkaline C batt 7800 mAh. 2 alkaline C batteries in series = 3v @ 7800mAh
Litium CR123 battery 1400 mAh. 3 lithium CR123 in parallel = 3v @ 4200mAh

It looks like a substantial runtime downgrade associated with this modification.

Click to expand...

My impression, based on no science or math whatsoever, is that much more of the capacity of lithiums is available than is the case with alkalines, at least for high current applications. Maybe with regulated LEDs, more of the juice can be effectively sucked out of alkalines?

After reading about all the CR123 explosions on this site, I'd be very nervous about connecting them in parallel. If one is a bit stronger or weaker than the others, you'll have one battery trying to charge the others. Normally it's a minor problem, but with these batteries you might have an explosive failure.

Why not just go with a light that's meant to take 1xCR123?

What about two CR123 along with a dummy battery and a Mag 4 cell LED. Then you can use the Mag 2 cell LED for a house light.

pdq123 said:

Is there a 3x123 holder that will connect them in parallel?
thanx

Click to expand...

WARNING -> DO NOT DO THIS!!

If you connect primary lithium batteries in parallel, whichever one has the most charge will attempt to instantaneously dump all of the excess charge into the others. You risk at least overheating your batteries, or at worst an explosion! If you were to protect each of them by using a series diode (anode to positive) then you are wasting energy but it will be safe.

With rechargable batteries NiMH, NiCD, or Lead-Acid, you can connect them in parallel since the charge will equalize. Don't ever do it with primaries.

Ah, hadn't thought about the cell-cell current path. Yeah, that doesn't sound too good.

The 2x123 w/ 4-cell LED bulb isn't a bad idea, aside from not being able to back-convert to plain C cells if I'm out in the middle of nowhere. I suppose I could keep the original cheapie incandescent bulb in my toolbag.

It would be nice if Mag comes out with a 6-cell version of their LED bulb, that at least would dovetail in with the 3x123 mod.

I really like the mag 2C form factor also. I have the 2cell led just like you very nice.
the idea above about the 4cell led and a dummy cell sounds like a must have. But for more fun ( I don't know that I would leave it in my car) try...
The 2C ROP
you can get I think all of this at Lighthound.com
-pelican 3854 bulbs (2pack)
you get a 24watt bulb and 10 watt bulb in the two pack
-get a dsd charger And batt's
--the 10 watt bulb will run with 2x18500 with stock reflector and lens
you will only need a battery spacer and to colapse the spring
--The 24watt bulb needs the 2x18650 short burts ok with stock reflector
long runs you will need to buy the metal reflector and glass lens.
the 2x18650 setup you will have to put batt's down to the tail cap
you will only have 3mm for a spring or alluminum foil oh yea you will
have to grind out the anodizing.
Awsome set ups for the price
oops just realized I'm led forum sorry to be advising ican

pdq123 said:

The 2x123 w/ 4-cell LED bulb isn't a bad idea, aside from not being able to back-convert to plain C cells if I'm out in the middle of nowhere.

Click to expand...

It sounds good to me, too. Another possibility is to put in 3x123 and a 5-cell hotwire bulb. I did that for a glovebox light, and I've been very happy with it.

pdq123 said:

I suppose I could keep the original cheapie incandescent bulb in my toolbag.

Click to expand...

Or, you caould just put it in the tailcap?

pdq123 said:

It would be nice if Mag comes out with a 6-cell version of their LED bulb, that at least would dovetail in with the 3x123 mod.

Click to expand...

That would be great. Are they still selling enough of those 5 and 6 cell lights to keep producing them? I suspect that the decision not to make the LED dropins for the big lights may be connected to small sales.

pdq123 said:

The 2x123 w/ 4-cell LED bulb isn't a bad idea, aside from not being able to back-convert to plain C cells if I'm out in the middle of nowhere. I suppose I could keep the original cheapie incandescent bulb in my toolbag.

Click to expand...

If you kept a Nite Ize Led In the tail cap it would work with what ever battery configuration you come up with.

Use a Schottky diode at each battery and tie off at the opposite ends of diode. This will prevent a backflow from capacity difference.

|--[ ]+ --|>|--|
|--[ ]+ --|>|--|-----
|--[ ]+ --|>|--|

DON'T use regular diodes as they have 0.5-0.6v voltage drop. Schottky is around 0.1-0.2v.

nota bene on changing batteries periodically; for we nortemaericanos who live in Daylight Savings territories, the changeover dates in the spring and autumn are great reminders for changing batteries in your smoke alarms, checking the gauge on your fire extinguishers, changing the oil in your cars, etc.

nelstomlinson said:

It sounds good to me, too. Another possibility is to put in 3x123 and a 5-cell hotwire bulb. I did that for a glovebox light, and I've been very happy with it.

Click to expand...

My current thinking (bad pun, I know) is that if I need a real photon cannon in my autos, its better to go with a big 12v spotlight of some sort and use the big honkin' battery up front that comes with its own charger. If the car's battery is out I mainly need a cellphone to call for a tow! I figure a Mag w/ LED for general use is adequate, plus my Princeton Tec Impact LED as a backup and for extended repairs.

nelstomlinson said:

Or, you caould just put it in the tailcap?

Click to expand...

I figure I'd forget, and end up with trying to run a 3v LED bulb off of 2x123, or a 6v bulb driven by two alkalines. What I could do is to keep a two-pack of C alkalines in my toolbox and tape the original 3v incandescent bulb to it.

nelstomlinson said:

That would be great. Are they still selling enough of those 5 and 6 cell lights to keep producing them? I suspect that the decision not to make the LED dropins for the big lights may be connected to small sales.

Click to expand...

I thought the 5- and 6-cell clubs were really rare, but in surfing this and other boards they may not be as rare as I thought. But if Mag doesn't scratch that itch, eventually somebody else will. The Mag 3W bulbs are going to turbocharge the industry I think.

Mikeg23 said:

If you kept a Nite Ize Led In the tail cap it would work with what ever battery configuration you come up with.

Click to expand...

That there is a good idea. The Nite Ize may not perform well enough for primary use, but it sure seems to make sense as a backup bulb.

Handlobraesing said:

DON'T use regular diodes as they have 0.5-0.6v voltage drop. Schottky is around 0.1-0.2v.

Click to expand...

Never heard of a Schottky before, but that's quite a difference! That does imply that my idea is do-able, if a good 123 holder were available and moddable.

Handlobraesing said:

Use a Schottky diode at each battery and tie off at the opposite ends of diode. This will prevent a backflow from capacity difference.

|--[ ]+ --|>|--|
|--[ ]+ --|>|--|-----
|--[ ]+ --|>|--|

DON'T use regular diodes as they have 0.5-0.6v voltage drop. Schottky is around 0.1-0.2v.

Click to expand...

Many schottky diodes have a 0.5V drop, not all but many.

One of the more common schottky diodes is the 1N5817.
At 0.1A going thru it, you are looking at 0.32V, but with higher currents many flashaholics are using, say 1A, you will be looking at 0.55V across it.
Figure 9 will show you the leakage currents found in a schottky diode, which, with a fully charged cell, and even 25C, exceed the drain caused by a uC in sleep mode, where folks complain about even 50uA of leakage. In this case, you are looking at over 500uA of leakage current:
http://www.onsemi.com/pub/Collateral/1N5817-D.PDF

The additional big problem with schottky diodes and their reverse leakage, it rises with temperature.

You could do 3x123 with an EverLED (1.5-9V) or a 5-cell Mag-Num Star.

Try not to apply anything to the reflector if you're going to use the LED module. You shouldn't need to, the LED module produces a pretty smooth spot already, and anything that you apply to the reflector will just diminish the output from the LED module.

Try changing the alkalines at regular intervals (once every 6 months/1 year or when depleted.) Any battery is capable of leaking; if your overly concerned about it, another alternative (guaranteed safer) is to store the batteries with the flashlight in the car and only insert them when needed.

First of all, 2 C batteries cost less than a decent quality CR123, (yes, I know there are Chinese house brands for $1), and 3 CR123 batteries in parallel are almost 1/2 the capacity of a C alkaline battery. Take into account that a 2C Mag only costs about $15 to replace (if the batteries corrode and you aren't able to get the tailcap off, you can still remove the LED module from the other end.) Insofar as the sensitivity to heat/cold, that would depend a lot on your level of usage and how you might be impacted by heat or cold (assuming that you're probably going to use the heater inside of the passenger compartment if it gets cold.)

pdq123 said:

Next step is to try Kryloning the OEM reflector.

Alkalines are convenient and cheap but worriesome about peeing and not handling the heat/cold well.


Is there a 3x123 holder that will connect them in parallel?

thanx

Click to expand...

jburgett said:

WARNING -> DO NOT DO THIS!!

If you connect primary lithium batteries in parallel, whichever one has the most charge will attempt to instantaneously dump all of the excess charge into the others. You risk at least overheating your batteries, or at worst an explosion! If you were to protect each of them by using a series diode (anode to positive) then you are wasting energy but it will be safe.

With rechargable batteries NiMH, NiCD, or Lead-Acid, you can connect them in parallel since the charge will equalize. Don't ever do it with primaries.

Click to expand...

What about the Surefire M6? The stock cell carrier connects six CR123A cells in a series/parallel configuration. I've never heard of a M6 exploding on its owner.

Ty_Bower said:

What about the Surefire M6? The stock cell carrier connects six CR123A cells in a series/parallel configuration. I've never heard of a M6 exploding on its owner.

Click to expand...

Ty,

Can you use an meter to determine how they are wired, or if there is a protection diode used? The holder may actually be wiring them in series or using diodes. Pages 7 and 9 of the downloadable PDF manual show that they all are loaded into the battery carrier pointing the same way, and "looks like" a series/parallel configuration.

Perhaps the easiest way to tell is to load the carrier with cells, and measure the resulting voltage. You can also try placing one cell in the top and bottom row of each column, and checking the voltage.

For the price of the Surefire M6, it is worth the extra expense to set up the holder such that all cells are inserted the same way.

Cheers!
Jim

Brighteyez said:

Try not to apply anything to the reflector if you're going to use the LED module. You shouldn't need to, the LED module produces a pretty smooth spot already, and anything that you apply to the reflector will just diminish the output from the LED module.

Click to expand...

Not so much looking for better spot performance, but OK spot performance and good flood performance. In backyard testing I've decided that I'll give up a little throw for a better flood*. And I plan on doing the reflector in my nightstand light anyway, so I have a full can of Krylon with no other use for it. New reflectors are cheap anyway.

On the issue of diodes and switches, is it possible that the smart way to do it is to use a 3-pole switch and locate the diodes between switch and bulb rather than between battery and switch? I guess that would take the diodes out of circuit when the light isn't on. Increases electromechanical complexity though.

* I've compared my Maglights with Mag LED bulbs against my Surefire 6P with and without its beamshaper.

jburgett said:

Ty,

Can you use an meter to determine how they are wired, or if there is a protection diode used?

Click to expand...

I'd love to, but someone is going to have to send me their M6. I don't have one of my own.

I do know that the MN20 and MN21 assemblies used in the M6 are 9 volt lamps. I've also heard that people have run lower amperage lamps in the M6 (namely the N2 lamp) by only installing three cells into the carrier. That tells me the M6 cell carrier is two paralleled sets of three cells in series. Is that 3S2P, or 2P3S? And does it have some kind of diode in it? I dunno.

Where is Size15's? He can answer this for us...

NewBie said:

Many schottky diodes have a 0.5V drop, not all but many.

One of the more common schottky diodes is the 1N5817.
At 0.1A going thru it, you are looking at 0.32V, but with higher currents many flashaholics are using, say 1A, you will be looking at 0.55V across it.
Figure 9 will show you the leakage currents found in a schottky diode, which, with a fully charged cell, and even 25C, exceed the drain caused by a uC in sleep mode, where folks complain about even 50uA of leakage. In this case, you are looking at over 500uA of leakage current:
http://www.onsemi.com/pub/Collateral/1N5817-D.PDF

The additional big problem with schottky diodes and their reverse leakage, it rises with temperature.

Click to expand...

ha. you're right. I get around 0.1v at testing current on a DMM, but apparently not the same under real load.