Mag C switch at high current?

[Hack On Wheels]

Hi all,

I've mainly dabbled with LED lights so far, but I'd like to make a few nice Incan Mag mods as you just can't beat the warmer tints and the high CRI for outdoors. I'm trying to stick with the Mag C hosts as I don't find the larger diameter of the Mag Ds very comfortable to hold.

Most of the info I've found has been relevant to the Mag Ds though; so it leaves me with some questions about the Mag C, specifically about its switch. I understand that the Mag D switches don't tend to last long when run at 10+ amps, but I haven't found anything mentioning the Mag C switches at similar high currents.

I'm planning to make an (obligatory) ROP setup, but I'd like to make a bit of a Mag C monster as well. I guess the starting point would be to install a KIU high temp socket. I'll be resistance modding the tail spring and all, but that will leave some contact resistance. I'll use deoxit where applicable, but I'm still concerned about melting the switch.

I've read up on MOSFETs a bit, would it be worth trying to fit a MOSFET setup into the switch housing? I'd certainly have more research to do if that is the case.

Anyway, this post has gotten long, but if anyone has any advice, relevant experience, or knows some good threads that I should check then please post. Any help is appreciated, thanks!

-HOW

 

[Billy Ram]

I don't see folks running much more than a 1185 in a C-mag but I would think with proper heat sinking the switch could handle the FM1909. The problem running IMRs in a C-mag is the body needs to be bored out a bit the accept the larger diameter IMRs and you'll need a deep tail cap or extension. So most just use a D-mag and a piece of 1" PVC pipe for a battery sleave and 3xIMRs for the FM1909 or 4xIMRs for the m*g623.
I have found the D-mag switch can handle arround 5.5a. ok but high voltage and 10+a. will soon burn out the thin contacts. A soft start switch would be easier on every thing running something like the m*g623 or m*g458.
I'm like you and don't care for the D-mag body for running IMRs so mine are made using the FM 3x26500 and 4x26500 bodys. I didn't see much point in being aggravated with trying to fit IMRs in a C-mag when FM has been kind enough to provide special bodys just for IMRs.
Billy

 

[divechief]

I started with the obligatory 2C ROP for a work light. (I work aboard ships as a marine engineer) it was an impressive light, but when making a round if I flashed the polished aluminum deck plates, I was blinded. I decided to take it up a notch and make something useful for work, (and for a mine is bigger than yours thing for all the guys showing up with 2X 124 Power led lights)

I am not a great machinist, but I can get by and I have access to a lathe so boring the light was no problem. I added a AW soft start switch and with two IMR 26500's no tail cap or spring mods were required. I picked up the 5 mega bi focal reflector, had to drill it out a bit to accomidate the Philips 5761 bulb and I love it!

If I give the batteries a full charge and turn it to high the bulb lasts maybe a second. If I run it for a few minutes on low or medium (or pull the batteries off the charger at under 4 volts) it's not an issue. it is a great work light and I have seen things in dark places on my boat that I have never seen before. I still carry a 4 sevens quark AA with a 14500 battery for when I have to inspect things up close (or turn it into a headlight with the prisim) but we all need more than one tool.

so, the build list was

2C M*G light
access to lathe
5761 bulb
5 mega bi focal reflector
boroflot lens
AW soft start switch
2 X IMR 26500 batteries

(already had the below charger)
ultrafire LI battery charger
two "C" battery holders (radio shack)
4 alligator clips to solder to above
2 wooden dowels (2AA size with conducters on each ind to clip alligator clips for charging)

Tail cap amp reading predicts about 20 minute run time on high, maybe 1 hour on low. I monitor the batteries and charge when convenient.

I have gotten a lot from these forums, hope this gives a little back
Dave

 

[Hack On Wheels]

I don't see folks running much more than a 1185 in a C-mag but I would think with proper heat sinking the switch could handle the FM1909. The problem running IMRs in a C-mag is the body needs to be bored out a bit the accept the larger diameter IMRs and you'll need a deep tail cap or extension. So most just use a D-mag and a piece of 1" PVC pipe for a battery sleave and 3xIMRs for the FM1909 or 4xIMRs for the m*g623.
I have found the D-mag switch can handle arround 5.5a. ok but high voltage and 10+a. will soon burn out the thin contacts. A soft start switch would be easier on every thing running something like the m*g623 or m*g458.
I'm like you and don't care for the D-mag body for running IMRs so mine are made using the FM 3x26500 and 4x26500 bodys. I didn't see much point in being aggravated with trying to fit IMRs in a C-mag when FM has been kind enough to provide special bodys just for IMRs.
Billy

Yeah, C Mags tend to get a bit neglected, so to speak. I'm hoping to find some older models that won't need boring. I'd like to do something along the lines of a Mag 623, but keeping it on a fairly tight budget. A soft-start switch and all would be great, but perhaps I'll get one later on if I think whatever setup I end up with could benefit from that. I'm open to playing with MOSFETs and NTCs to save the switch and to soft-start the bulb, respectively.

I saw a picture of your FM lights that you posted recently, those sure are beauties! I'd love to have one of those, but I don't think it's likely at the present time. Thanks for the suggestions.

 

[Hack On Wheels]

I started with the obligatory 2C ROP for a work light. (I work aboard ships as a marine engineer) it was an impressive light, but when making a round if I flashed the polished aluminum deck plates, I was blinded. I decided to take it up a notch and make something useful for work, (and for a mine is bigger than yours thing for all the guys showing up with 2X 124 Power led lights)

I am not a great machinist, but I can get by and I have access to a lathe so boring the light was no problem. I added a AW soft start switch and with two IMR 26500's no tail cap or spring mods were required. I picked up the 5 mega bi focal reflector, had to drill it out a bit to accomidate the Philips 5761 bulb and I love it!

If I give the batteries a full charge and turn it to high the bulb lasts maybe a second. If I run it for a few minutes on low or medium (or pull the batteries off the charger at under 4 volts) it's not an issue. it is a great work light and I have seen things in dark places on my boat that I have never seen before. I still carry a 4 sevens quark AA with a 14500 battery for when I have to inspect things up close (or turn it into a headlight with the prisim) but we all need more than one tool.

I have gotten a lot from these forums, hope this gives a little back
Dave

Thanks for the reply!

I'm curious as to which battery setup you used for the ROP? The 5761 setup sounds quite nice. For the moment I'm planning on not doing any boring though, so I won't be fitting any IMR26500 in my 2C. I've already got a 2C Mag with a Mag C Tower and metal reflector for the host; I might splurge for a bi-focal reflector if FM has any left. I'll probably just see about fitting a couple of 18650s in there as I have a bunch of those already.

An AW softstart would be nice, I got to try out one of those in an M6 this week... pretty slick setup! Maybe in the future, but I'm looking to do a "homebrew" (i.e. an NTC) setup if I need softstart for any lights.

 

[LumenHound]

The Mag C body switch is more robust electrically than the D body switch.
You won't have any trouble with it handling the 4 amps or so the ROP HI bulb draws.
Give it a good cleaning and use Deoxit Gold or Progold on the contacts.

 

[Hack On Wheels]

The Mag C body switch is more robust electrically than the D body switch.
You won't have any trouble with it handling the 4 amps or so the ROP HI bulb draws.
Give it a good cleaning and use Deoxit Gold or Progold on the contacts.

I'm glad to hear that about it! I suspected the C switch might be a bit better from what I saw pulling both a C and a D switch apart recently, but I never had any real justification for that "hunch".

I'm certainly not worried about the ~4A of the ROP Hi and I am planning to give it a good cleaning before using it. However, the big question for me is what will happen under the ~10A of a 623 setup. Any thoughts?

 

[LumenHound]

I've only pushed a C switch to 6 amps so I have no personal experience as to how it would handle 10 amps but if I had to push one I'd make sure the contact area was lightly coated with Pro Gold/Deoxit Gold in order to minimize the possibility of arcing and heat build up. Adding a NTC will certainly help to reduce any arcing on start-up.

If I were to go this route I would pull the switch out of service after say 25 or so 10 amp switching cycles and examine the contacts closely for signs of trouble before putting it back in service for the long haul.
Slightly time consuming pulling the switch back out but well worth the peace of mind you gain by knowing that it's been checked.

Personally, I don't think you'll have a problem with a NTCed C switch and it's greater contact area over the D model as long as your Pro Golded contacts are in excellent condition to begin with.

 

[divechief]

I also built the ROP with 26500's, I got the parts when I was on vacation and did not have lathe access so I wrapped sandpaper around a wooden dowel and sanded it down, It was a bit of a pain, took a few hours and it buggered the tail cap threads up a bit, but it did work.

Overall, a few minutes with a boring bar was much more satisfactory.

Dave

Thanks for the reply!

I'm curious as to which battery setup you used for the ROP? The 5761 setup sounds quite nice. For the moment I'm planning on not doing any boring though, so I won't be fitting any IMR26500 in my 2C. /QUOTE]

 

[Hack On Wheels]

Personally, I don't think you'll have a problem with a NTCed C switch and it's greater contact area over the D model as long as your Pro Golded contacts are in excellent condition to begin with.

Lumenhound, thanks for the reply! I will clean and de-oxit gold the switch regardless, and it's certainly good to know that an NTC would help prevent/reduce arcing in the switch. However, I think I'll still look into the MOSFETs first and try and get that to fit and work. Just using an inline NTC will be my back-up plan. If all else fails, I'll try that and see how my luck is!

divechief, good to hear more support for the boring bar solution. What type of boring bar did you use? I might do that for one of my 2C Mags if I ever decide I want to fit IMR cells in them.