Hey guys, I’m just getting into this flashlight thing and would like to build my first custom flashlights over the next few months. I have a 4D incan. Maglite host that I’d like to convert to a XM-L2 that can still run on alkaline/nimh (either 4 D batteries or 8 AAs in carriers).
I would like to use the Nanjg 105C if possible because it is readily available with 2.8 amp output and a great selection of modes. FT 105C Link
The obvious issue is that the 105C is only rated for 3-4.5 volts… I am assuming that the batteries will sag down from 6V under load but will it be enough?
Will this work without burning up the driver? If not, what is a good multi-mode driver that can put out ~2.8 amps and work with 4 alkaline/nimh?
Thanks for the suggestions!
P.S. I also have a 3D maglite… I’m thinking about 9A driven SST-90 w/ 3x 26650 . . . is this a crazy idea or should I go multi XM-L?
I have used 4 Nimh’s with a amc7135 driver without issues. But the 4 Nimh D cells where quite old tired cells so the voltage sag was high. I have read comments of a few other people that have run 4 D Nimh’s with a amc7135 driver without problems. I have also read where several people have had problems with running 4 D Nimh’s. This could be that the batteries they where using did not have a lot of voltage sag, so the amc7135’s had a much greater heat load to get rid of. With 4 D Nimhs it may depend on if the cells are new and how well they handle a 2.8 amp load as to whether they will work or not. Most quality Nimh D cells are not going to have a lot of voltage sag at 2.8 amps and may not work without heat issues. With 3 Nimh’s the issue doesn’t exist as far as I know (never heard of any problems) and should work fine.
4 D alkaline cells I have never tried. 3 D alkaline cells will work fine but at a reduced current level. The alkaline cells cant push more than about 2 amps out because of the internal resistance even if DD. There just not made to push heavy currents. 4 D alkaline cells may work for this reason but I have never tried it. Maybe something you will have to try for yourself. I would be interested in the results if you do.
As for your sst-90 build you might look into a MT-G2 with a couple of li-ions and maybe find a suitable driver here. I would at least weigh the options.
Aren't alkaline Ds around 1.62-1.65 fresh out of the pack? That could be too much for a 105C... and only 3 isn't quite enough. The 105C can handle "6 volts" if it's 6v from something like 2x CR123As, that same voltage from much much MUCH stronger cells might cause issues.
It's the voltage the cells can maintain under load that matters, and I don't know an easy way to work out what that will be on paper as there's a lot of variability between all these parts. For instance a combo that might burn up on the bench test with good solid connections everywhere might be fine installed in a flashlight with the built-in resistance of all the various threads and springs and whatnot.
edit: Yes I ignored the NiMh issue... 3 good ones will do 4 amps to a single XML in direct drive, and the voltage range nearly duplicates a single LiIon, so driver selection is easy-peasy. As long as the chosen driver's output is less than what the cells do in DD it will be regulated, and even the low voltage protection should work nice for 3xNiMh (3v = 1v each cell). I would not like to see what happens with 4xNiMh, not if they're as strong as the Tenergy Ds I have for my Maglites...
Hi comfychair,
I know you can use a single 12v A23 battery directly connected to a 5mm led and it will work fine from the internal resistance (limits the current) of the 8 individual button cells inside. I thought that 4 D alkalines may fall under the same priciples as the A23 with a 5mm led. But I’am not sure, never tried it.
I have seen to many post where people where having problems using 4 D Nimh’s. It probably depends on the cell voltage sag more than anything. Mine has always been fine but I would not consider my cells new or of high quality. New name brand quality cells will probably give you a problem with the voltage sag graphs I have seen. They don’t sag much under a 3 amp load.
Interesting. I just checked with alkalines. I don't have 4 fresh cells, I picked 4 that were close to the same voltage, 1.43-1.49v each.
2D alkaline:
2.98v open circuit
2.80v loaded
.31a
3D:
4.40v open circuit
3.17v loaded
1.90a
4D:
5.80v open circuit
3.34v loaded
3.15a (falls rapidly)
Don't forget that brand new cells starting at 1.60v each or more will likely give a lot more current in the 4D setup, and only a little more in the 2D setup.
NO, I am not going to test 4x NiMh Ds. :p
A viable option might be a 4D host, running 4 alkalines or 3 NiMh+spacer.
One more thing I forgot to mention, a typical D alkaline should have around 15000mah. But that’s at very low level current drain. Draining a D alkaline under a heavy load may reduce its capacity to the point of being not very economical. Even at 1 amp discharge capacity is about half. I hate to link it but I don’t know of another place where it was tested.
Go down to about the 7th graph.
Thanks for all of the comments and suggestions! I really appreciate it. I’m going to do some more MT-G2 reading now for the other build.
Any good sources for C size dummy cells / spacers?
I guess I will order some dummy cells/spacers and first try three cells, measure voltage/amperage then if it looks reasonable try and add the fourth and see what happens.
The nimh/alkaline build is going to my father as a Christmas present this year (better not to get into LiIon).
The other build (2 or 3 26650) is going to be for me
Am I correct in my assumption that schedule 40 1” PVC will work as a spacer so that I can use 26650 cells in a D body?
(1.315” OD, 1.049” ID)
(33.401 mm OD, 26.65 mm ID)
The simplest solution to your problem is switch hosts. Do the xml in the 3D and the SST90 in the 4D. Both will work great with 7135 based drivers and NIMH cells
My understanding was to forget about alkalines with a nanjg driver (or at least with 3 cells). Seems the best setup is direct drive for alkalines. That said, I built a 3C XP-G Mag that my coworkers ran on 3AA's (alkaline AA's in a C cell adaptor). No idea on runtime, but I expect it ran longer on NiMh's. Oh, it was running a 1.4A Nanjg 3 mode driver.
Nope. Just measured a piece of sch40 1" @ 26.15mm I.D. I then measured width on a protected 26650 TF Flame and an INR 26650 King Kong (unprotected). The TF was smallest @ 26.38mm wide. I then test fit to make sure it would not go in. Maybe you could ream out the PVC a hair wider to accommodate. I can post photos tomorrow.
The last mag I built was for a present to my father also. I knew he didn’t know much about rechargeable Nimh’s and knew he probably would never spend the coins to get them. I used a xml u2 on one of my heat sinks with a 2800ma amc7135 driver and a rebel reflector. With 3D alkaline it had a tail cap draw of a little over 2 amps. So the driver was really not needed. But I thought maybe one day me or him one might decide to splurge on some good Nimh D’s to throw at it. So its fully ready when that happens. It’s still pretty impressive with alkaline’s just not as much as it could be.
I use to build a lot of 2D mags with 18650 conversions. What I did was walk in my local lowes and head to the pluming section with my Maglite in hand and a 18650. I went through several adapters and extensions and what not until I found the right combination that worked. You might have better luck if you walk in lowes with battery and mag in hand and try some of the stuff to see what might work best. The pieces I found almost made a perfect fit for both battery and mag tube. I had to cut to the right length but ended up with no battery rattle. It took 3 pieces and cost me around 4 or 5 bucks I think.
I still have a picture of what I used. Not the same as what you will need but maybe they have something else similar.
007, thanks for the info! What did you end up using for your pill/heatsink? Aside from turning down a big chunk of aluminum (which really shouldn’t be necessary for a single XML @ 3 amps or less) what are my options? The biggest pills I’m finding are 30mm, and the ID of the tube is around 34mm on my D Maglite. If really necessary I could have my friend turn me down something nice out of a solid chunk of aluminum but he would also have to ship it to me since I’m away at school right now.
You will need a decent heat sink, they do get quite warm when driven at 3 amps. I turn down mine myself from aluminum bar stock.
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Comfychair has had some great ideas with making heat sinks for magites with a drill press.
Here are my photos from last night checking my 26650's against a 1" schedule 40 PVC pipe:
Inside Diameter of 1" PVC = 26.15mm
Protected TF Flame 26650, measured at widest point (at protection strip) @ 26.38mm:
Unprotected King Kong INR 26650 @ 26.32mm
Test-fitting the TF Flame into the 1" PVC pipe (won't go):
Also,as far as a Mag heatsink goes, it's not a great solution, but you can use this 52mm complete XM-L drop-in module from DX. You won't have much contact to the Mag tube at all, but it's ok if you don't run it long on high. I put one in a 2D Mag running on (2) 18650's and it worked out well (my first real flashlight mod). I don't use it often. Note the driver says 5.8v min. (no idea how accurate that is) so you probably won't be able to use (4) alkalines or NiMh cells with it. You could replace the driver (it's 26mm I believe, but I've used a similar module and rigged a 17mm driver into it). I looked for the bare version of this drop-in (just heatsink & reflector) but I don't see it. The bare one I used (this one made for a P7) I only used the "heatsink" in my 3C Mag. With some filing work the heatsink will press-fit into the Mag C tube. I then used a Mag LED reflector with its cam cut off (reflector purchased from www.zbattery.com).
