M*g11 M*g85 on 2 or 3 li-ion?

[Lumencraft (Matt)]

I was wandering if anyone is currently running a m*g11 on 2 li-ions? I have a m*g74 (7.2v bulb) that I have tested at 8.4v so I orederd 2 D cell li-ions for it. But I am a little conserned that wa1111 being 6v may because of the over voltage from fully charged li-ions.

Aslo same question for m*g85 does anyone have one running on 3li-ion direct drive? If not will a 12v resistor be enough. If you have this setup feel free to add pics. or any instructions you think may be helpful.

Thanks in advance.

 

[choppers]

I am running a Mag85 off of 3 AW 17670 3.7v Cells.....I call it a "Mini Mag85"...It is a 1D size mag...

 

[Chongker]

Li-ion batteries, although they show ~4.2V when fresh off the charger and on an open circuit, don't actually function at this voltage. When you put a load on them, they will (as with almost all batteries) sag in voltage from the load. Depending on how much they are stressed, this may be down to ~3.6-3.7V, so the bulb will never actually see the full 8.4V of two li-ion cells.

Running the WA1111 will mean you're just driving the bulb to ~7.2V, which it should handle fine. Running the m*g74 means you are driving it at speck, and not pushing it at all probably. A 1185 should be able to take 3 li-ions as well, the only thing you have to watch out for is to not pop in the cells hot off the charger and let them rest for at least a few hours beforehand.

 

[Evil Twin]

I run a Mag85 off of 3 AW C Li-ions, and a FiveMega Mag11 off of 2 of AW's C Li-ions. Never flashed a bulb on either, even hot off the charger. :thumbsup:

 

[iapyx]

Better = 2x li-ion + Philips 5761 bulb = brighter than a m@g85 with 3x li-ion.

Northern Lights did do a lot of research about this setup. Here's a Northern Lights quote:
5761 Vbat=7.2 Vbulb=7.04 bulb lumens=1336 torch lumens=854

Let me look up a link for you. brb

here are some nice links:
Maglite LED and incan mods and drop-ins, Overview
http://www.candlepowerforums.com/vb/showthread.php?t=193434
And a NL thread:
http://www.candlepowerforums.com/vb/showthread.php?t=145224

iapyx

 

[DM51]

Better = 2x li-ion + Philips 5761 bulb = brighter than a m@g85 with 3x li-ion.

Northern Lights did do a lot of research about this setup. Here's a Northern Lights quote:
5761 Vbat=7.2 Vbulb=7.04 bulb lumens=1336 torch lumens=854

The 5761 needs 'C' Li-Ions to power it - it draws 5.5A, which is too much for 18650s and far too much for 17670s.

The 5761 and WA 1185 are very similar in output. The 1185 is a more efficient bulb, IMO.

 

[Lumencraft (Matt)]

Wow good solid info you guys. I think since I have 2D cell li-ions on the way I may look into that 5761 bulb as well. I realy appriciate the help and the new (to me) Ideas about other bulbs and sutch.

One more question. I followed some of the links provided for research and found this link. http://www.light-edge.com/
but it doesnt seem to be working, I was wandering if this is still in business? The quote I saw said there were several good parts for m*g mod there, like reflector, always looking for another reflector source

 

[gchand]

I have had problems running my Mag-85 on 3 of Emillion's original unprotected Li-ion D-cells. The extra capacity of the D-cells seems to result in a higher operating voltage as opposed to 3 of AW's protected Li-ion C-cells, which many CPF members have reported to work OK. On the one bulb that survived for awhile, the output was incredible, but it failed quickly, as did a couple of subsequent victims. I now have my Mag-85 running on 9 Eneloop AA's, and it works quite well, although it is not as bright as the original 1185 on the 3 D-cells.

George

 

[choppers]

In addition to my Mini Mag85 running 3 of AW's 17670's, I am also running one with 3 of AW's "C" li-ion cells. I have never had a problem flashing a bulb with either of these setups...even hot off the charger...as far as I am aware Li-ion cells hold their charge unlike the NiMH cells which dont retain their charge over time...

As I said in another post....I have many of the high powered incans and the Mag85 continues to be one of my favorite light!!!

 

[Flipside]

A 1185 should be able to take 3 li-ions as well, the only thing you have to watch out for is to not pop in the cells hot off the charger and let them rest for at least a few hours beforehand.

I'm sure that YMMV, but my FM85 had an instaflash on batteries that were charged to 4.200V, and then rested for three (3) DAYS. When I got to a place where I could check their voltage a few days later they clocked in @ 4.185 +/- 0.002V.

Damn good cells, those AW's: they lost ~0.02V after 7 days. I did check them off the charger (BC-6) and they all clocked in at 4.200 +/- a few hundreths.

So, given this experience, I'll only be charging the Li-Ions from AW to 4.000V in the future. It should prolong the life of the cell, as well as keep the bulb healthy beyond a $5.00, 1 second flash...

 

[LuxLuthor]

As everyone has already said well, but I'll add a couple of minor tips.

Chongker - Absolutely right about voltage dropping under load. To see the capability of a particular brand/size you need to find a run-time plot test where a cell is discharged at a particular Amp rate. An example of this is the curve from AW's C Protected Li-Ion that he sent me (i.e. green line shows how well the voltage holds up at 4.5 Amps draw rate)

However, Li-Ion cells should not drop voltage by waiting "hot off the charger" as you see with NiMH. If you are seeing a drop, either your charger is ending the cycle prematurely, or your cells are aging (Li-Ion start losing capacity several years after manufactured), or have been damaged.

One of the most important issues to remind everyone about when looking at a particular battery/voltage setup is the amount of resistance that is in your setup. A stock Maglite using FiveMega battery holder, gold bipin bulb holder can have a lot of added resistance that effectively blunts the voltage delivered to the bulb.

So one setup that Choppers uses with 3 x Li-Ions can have high resistance (protecting the bulb from flashing--but with side effect of lowering the potential overdrive brightness); while some other 3 x Li-Ion setup can have lower resistance and flash the very same same bulb.

 

[Lumencraft (Matt)]

I have orderd a 2D protected li-ion pack from kd that I am going to do some testing with. This week already I have flashed 2 bulbs that by ALL rights should NOT have flashed. The one I flashed this evening was wa1185 running on 3x 3aa to D converters (the electrolumen ones) after the batteries reseted for at least 6 hours. What was realy wierd was it was not an insta poof. The light ran for a couple of miunutes befor it blew. I think maybe I bought cheap batteries and they are the trouble. I have Kodak 2500mah digital camera batteries and thats the second bulb I have lost useing them in a configuration that mathmaticaly should have been fine.

Also I was still wandering if this link is just broke of if this company is out of business? http://www.light-edge.com/

 

[choppers]

Also I was still wandering if this link is just broke of if this company is out of business? http://www.light-edge.com/

Dont think the link is broken...the website has looked like that for sometime now...

 

[EvilPaul2112]

I run a M@G85 with 3 AW"C" cells and all the resistance fixes I could perform with no problems at all. I prefer to use Litho's potted lamps as opposed to the bi-pin lamps. I like that stability of the potted lamp and the ease of field replacement. I have never had a problem with insta-flashes...(I did have a lamp explode on me once when it was installed without cleaning it though).

 

[litho123]

One more question. I followed some of the links provided for research and found this link. http://www.light-edge.com/
but it doesnt seem to be working, I was wandering if this is still in business? The quote I saw said there were several good parts for m*g mod there, like reflector, always looking for another reflector source

Ronnie @ light-edge.com and I collaborated on purchasing reflectors a few years ago. Due to personal things, he has dropped out of circulation.

= = = =

You're right about your setup:
- (3) Electrolumens holders (more resistance)
- rested cells (6 hours)
- Kodak 2500 cells (a fair amount of voltage sag)
I doubt these things contributed to your blown bulbs.

Ditto on what EvilPaul2112 said... ...(I did have a lamp explode on me once when it was installed without cleaning it though).

If the bulb is running a minute or two before it fails, I would suspect that the bulb wasn't cleaned properly. Any oils from your fingers will collect heat and cause a real short life for your bulb.

My rule of thumb is "Whenever the head comes off, the bulb gets wiped before the head goes back on." I adhere to this rule whether or not I touched the bulb.

 

[M.S]

I think I should start cleaning my bulbs with alcohol... I just burned 1185 that I installed yesterday. I don't think it was instaflash, it burned for few seconds before failing after I installed fresh c-lions from charger. I had maybe 10 minutes on that bulb...