Lumens Factory H0-M4A with AW Batts

max52

Newly Enlightened
Joined
Oct 21, 2003
Messages
187
I have the HO-M4A for my M4. I E-mailed Lumens Factory to confirm that I could use the M4 with 3 AW batteries and a dummy. They responded that they have demonstated compatibility with that configuration and that it would void any warranty. Can anyone think of any reason that 3 R123as and a dummy will not work?
 
I have the HO-M4A for my M4. I E-mailed Lumens Factory to confirm that I could use the M4 with 3 AW batteries and a dummy. They responded that they have demonstated compatibility with that configuration and that it would void any warranty. Can anyone think of any reason that 3 R123as and a dummy will not work?


according to its specs....
HO-M4A draws about 2.15A

R123's arent designed for such high current draws

instead, i would use 2x AW protected 17670's and use either:
LF EO-M3T (for throw)
SF MN16 (high output lamp, for flood)
.
 
HO-M4:
9.2V 2.15A

RCR123: 3.7V, ~550mAH, 2C maximum safe continuous discharge. (that's 1.1A for most RCR123s).

If you look at Silverfox's discharge graphs for RCR123s, you'll see that most RCR123s will start off ~3.5-3.7V into a ~2A load. This means you would be hitting a 9.2V bulb with ~10.5V-11.1V on a fresh charge.

Overdriving lamps reduces bulb life on a logarithmic scale, to the power of about 12. The 20 hour rated HO-M4 becomes about a 4 hour lamp on RCR123s, anything that re-rates to less than ~10 hours is usually in insta-flash and premature failure territory.

So there is a whole bunch of things wrong with the configuration: Running the cells twice as hard as they are designed for would wear them out quickly, increasing the risk of a vent-with-flame, runtime would be about 5-10 minutes, lamp would be very likely to fail prematurely. not worth it IMO, just buy the right stuff. 17670s and a M3T bulb.
 
Correct me if I´m wrong but the HO-M4A is 12 volt.

I have been using it for awhile in my M3T with 3 of AW´s RCR123. There hasn´t been any problems yet.
 
Correct me if I´m wrong but the HO-M4A is 12 volt.

I have been using it for awhile in my M3T with 3 of AW´s RCR123. There hasn´t been any problems yet.

Ok, your wrong (sorry but you asked...:nana::
http://www.lumensfactory.com/m_series_specification.htm

9.2V, 2.15A.

And 2.15 amps is drawing way too much for RCR123s, and using three is asking for even more trouble due to the likely hood of getting cell imbalance.

I wouldn't be relying on 'yet' as a reference in this case.

In an M3, a really great set up is 2x17500s (bigger cells, can handle more current safely - longer run time) and one of the M3 Lamps. It's a win/win situation.
 
Lumens factory are giving you correct numbers!

The rated voltage of any lamp is nominal. You can stick any number of different voltages through it, from under driving it to verging on making it go :poof:.

It is listed as a 12v lamp because it is designed to run in the M4, so nominally it is a 12v lamp (4 x 3v CR1232s).

However....battery manufacturers take the voltage sag when under load into account when designing their bulbs to get the best performance from them.

Under the 2.15a load from this lamp, the voltage from 4xCR123s will sag quite a bit (apparently to about 9.2V!), LF have obviously determined that they can use a 9.2v lamp that draws 2.15a with 4xcr123s, because under that load the cells are putting out about that voltage. LF lamp may well be driven quite hard, but this is what makes it nice and white.

The fact that 3x RCR123s (about 12.3v to 12.6v off the charger) doesn't make it go :poof: is also evidence of the voltage sag when under load. And not good evidence either! That the 12.3v is sagging sufficiently not to instaflash the lamp indicates the cells are being driven awfully hard. Either that or it's an indication that one of the cells is stuffed, which is a possibility and even more worrying.
 
have a look at silverfoxes discharge tests on CR123s, you'll see that at ~2A, CR123s deliver about 2.3V each, which means a 9.2V design voltage is perfect.
 

Latest posts

Top