Help with 3C/4C Mag85?

[adirondackdestroyer]

Is there any information on building a 4C Mag85? I already have a reflector and lens, and will buy some potted 1185 bulbs from the BST forum, what I need to know is if there are any PVC tubes to go around the batteries for sale , or any extenders (for the 3C) to make the cells fit.

I did a search but couldn't find any threads on a 3C or 4C version since the search feature would only search for Mag85. If anyone has either a 3C/4C Mag85 please tell me a little about it. Any info is appreciated. Thanks

 

[mdocod]

for the 4C, simple use a piece of pipe whose outer diameter will fit inside the mag body, and whose inside diameter is about 18.5mm or slightly larger. use 3 of AWs protected 18650 cells. Bend the tip of the tail-cap spring over so it makes contact with the cell without cutting into the shrink-wrap.

there are some larger cells, like 26650 size that you might look into for the 4C mod, they are overkill but it's an option.

 

[RichS]

Is there any information on building a 4C Mag85? I already have a reflector and lens, and will buy some potted 1185 bulbs from the BST forum, what I need to know is if there are any PVC tubes to go around the batteries for sale , or any extenders (for the 3C) to make the cells fit.

I did a search but couldn't find any threads on a 3C or 4C version since the search feature would only search for Mag85. If anyone has either a 3C/4C Mag85 please tell me a little about it. Any info is appreciated. Thanks

I bought 3/4" electrical PVC conduit (gray tubing). This tube was a little thicker than the white pluming PVC, and the 18650s fit a little more snug in it. my host is a 3D, so the PVC tube has some slack in the battery tube. I just wrapped each end with duck tape to make it nice and snug. Now I'm just waiting on my reflector from Kai, and bi-pin adapter from FM to arrive so I can finish this thing and see some real light........
.....and waiting......

 

[DonShock]

I'm assuming you are planning on using three 18650 cells. I did one of those and used the grey 3/4" electrical conduit also. I split it down the middle along one side and then ran sandpaper along the slit until it was just the right size to slide in the Mag4C smoothly. I have since switched to AW's C cells and cut down the Mag4C to fit the length.

I still have the tube I made for mine. PM me your address and I'll send it to you.

 

[jimjones3630]

Have you thought about 3 A123 cells in your 4 C? They fit, when the cardboard sleeve is removed and wrapped in 1ml thich kapton tape, each cell it 2300mah, 3.6v fresh charge, 3.3v nominal. 3xA123= 10.8v fresh charge and the 1185, the ones I've used did not flash.
jim

 

[adirondackdestroyer]

For those of you who had a 4C Mag85 and ran it with three 18650 cells, how often did you experience an instaflash? How long did you rest your cells after charging them?
I think this could be an awesome setup, but I want to make sure everything will work out before I buy the 4C Mag and the bulbs.

 

[DonShock]

I've never had a flash. But I never really light em up fresh off the charger. If the batteries are low I just grab another light while they are charging. When they are doneand get put back in the light, it almost always sits for a while before being needed again. With several lights, self discharge is more of an issue for me than problems fresh off the charger.

 

[jimjones3630]

Self discharge is always a problem. All batteries do self discharge, lithium just do it at slower rate.
jim

 

[Spypro]

I made a Mag85 using 3 x AW's 18650 and it is working very well and I'm getting 11.1v at the bulb. It is really bright.

 

[RichS]

For those of you who had a 4C Mag85 and ran it with three 18650 cells, how often did you experience an instaflash? How long did you rest your cells after charging them?
I think this could be an awesome setup, but I want to make sure everything will work out before I buy the 4C Mag and the bulbs.

Someone else here who is using 3 AW 18650s PM'd me and said he does not let his cells rest at all before using in his 3D Mag85 build, and has never had an instaflash. However, he did not do any restistance mods either, which helps reduce the risk of this happening.

From everything I've read, resting li-ion cells doesn't do any good because they are so slow to discharge. In my experience, I have tested 18650's that I have put in lights fully charged and not used in weeks, and still tested above 4.0 volts. Even Eneloops discharge at a very low rate - only 15% after a year.

 

[Spypro]

The AW's 18650 I use are used fresh, out of the charger.
I measured the voltage at the bulb's pins and I get 11.1v.
I've done the tailcap mod to lower the resistance.
I also use the AW soft start switch and I ProGolded all contacts.
I never had instaflashes.
This setup is really good I would go for it.

If you want to use the 4C body like I've done you will have to the a PVC pipe (3/4 inch) because the 18650's are thinner than the body. Some people had to cut the spring of the tailcal to have less force applied on the batteries.

 

[mdocod]

there seems to be a lot of confusion about "resting" cells.

A good *new condition* quality Li-Ion cell should come off the charger at 4.20V and stay there for days or even weeks before any noteworthy change takes place. The ONLY reason that a Li-Ion cell might potentially have a higher chance of instaflashing a bulb fresh off a charger is that it's temperature might be slightly elevated. For batteries, increased temperature [within reason] usually results in the cell holding a higher voltage into a load. (I'd speculate that it has something to do with the compounds that store the energy being in a more "excited state"). So when dealing with Li-Ion, the only reason you might ever leave "resting" time is to let the cells come back down to room temperature before using them. If you were to charge the cells in a refrigerator so that they were at or below room temperature when they came off the charger, there would be no advantage to letting the cells rest at all.

A NIMH cell on the other hand, actually comes off the charger at a much higher voltage than it typically settles to within about 1-24 hours. A WARM NIMH cell will come off the charger reading ~1.45+V (depending on the charge rate used to charge the cell). When removed from the charger, it will slowly settle to somewhere around 1.35+/-V. When the cell is fresh off the charger, it has a lot of potential to deliver a higher voltage into a load than a rested cell. This can cause instaflashing.

 

[jimjones3630]

Mdocod,

Do you find a difference now-days between Li-Io and Li-Po? At some time in the past IO charged to 4.1v and Po to 4.2v IIRC.
jim

there seems to be a lot of confusion about "resting" cells.

A good *new condition* quality Li-Ion cell should come off the charger at 4.20V and stay there for days or even weeks before any noteworthy change takes place. The ONLY reason that a Li-Ion cell might potentially have a higher chance of instaflashing a bulb fresh off a charger is that it's temperature might be slightly elevated. For batteries, increased temperature [within reason] usually results in the cell holding a higher voltage into a load. (I'd speculate that it has something to do with the compounds that store the energy being in a more "excited state"). So when dealing with Li-Ion, the only reason you might ever leave "resting" time is to let the cells come back down to room temperature before using them. If you were to charge the cells in a refrigerator so that they were at or below room temperature when they came off the charger, there would be no advantage to letting the cells rest at all.

A NIMH cell on the other hand, actually comes off the charger at a much higher voltage than it typically settles to within about 1-24 hours. A WARM NIMH cell will come off the charger reading ~1.45+V (depending on the charge rate used to charge the cell). When removed from the charger, it will slowly settle to somewhere around 1.35+/-V. When the cell is fresh off the charger, it has a lot of potential to deliver a higher voltage into a load than a rested cell. This can cause instaflashing.

 

[adirondackdestroyer]

Ordered the bulbs, a 4C Mag, and the cells from AW today. Now the waiting begins. I'll post some pics of the light compared to my 2C ROP Low when everything arrives.

 

[mdocod]

Do you find a difference now-days between Li-Io and Li-Po? At some time in the past IO charged to 4.1v and Po to 4.2v IIRC.

not sure I entirely understand the question, but for years Lithium Cobalt oxide cells were charged to 4.1V because it was as high as they could be charged and still deliver good cycle life. As various advancements to the technology and manufacture process were made, 4.2V became achievable while still maintaining high cycle life (500+ theoretical cycles). You might check with Tom (Silverfox) for a more in depth explanation. I know he has posted on that in the past.

 

[jimjones3630]

my charger has li-io and li-op charging programs. Li-io program charges to 4.1v and Li-Op charges to 4.2v. My question stems froms mention of li charging to 4.2v. That I have not heard of before. That's all.

The difference it makes I've read is if charging to 4.2v a battery designed to charge to 4.1v this will shorten it cycle life.

Among RC groups over charging newer cell chemistry like A123 and Emoli 26700 cells is discussed as acceptable loss given 1500 recharging life cycles some manufactures claim.

jim

not sure I entirely understand the question, but for years Lithium Cobalt oxide cells were charged to 4.1V because it was as high as they could be charged and still deliver good cycle life. As various advancements to the technology and manufacture process were made, 4.2V became achievable while still maintaining high cycle life (500+ theoretical cycles). You might check with Tom (Silverfox) for a more in depth explanation. I know he has posted on that in the past.

 

[adirondackdestroyer]

Just wanted to thank all of you for your help. My bulbs arrived yesterday and I charged up some 18650's I already had, and WOW this thing is bright! I'm getting a little over 1,000 lumens out the front when the cells are perfectly fresh. Unreal output!

If anyone is planning on making one of these for yourself, you definitely need to cut the spring. I cut 3 whole rings off just to be safe. The amount of pressure on the cells when the spring isn't cut is way to high. It's kinda difficult to even screw the tailcap on. After I cut the spring it works much better and I'm not worried about damaging the cells either.

Thanks again to everyone! :twothumbs

 

[kman]

Just seen this topic... and I have a 4C Mag lying around.... Quick questions.... Is the reflector and lense size the same for a 4C head as it is for 3D head? and if not, what size is it and where can I order it?

Thanks alot

 

[RickB]

Just seen this topic... and I have a 4C Mag lying around.... Quick questions.... Is the reflector and lense size the same for a 4C head as it is for 3D head? and if not, what size is it and where can I order it?

Thanks alot

kman,

Yes, the reflector and lens are the same and interchangeable between the "D" and "C" Mags. The bezel (the part that holds the lens and screws to the head) is also the same. The head itself is not the same, having a different shape to fit the different diameters of the "D" and "C" bodies.

-Rick