Will 6 D cells run an MT-G2 direct drive?

[Chicken_Drumstick]

I know you can run the MT-G2 direct drive on 2 x li-ion (8.4v).

But how about doing the same on a Mag 6D? 6 x 1.5 = 9v will this be too much?

I could swap in some AA Eneloops instead, so 6 x 1.2 = 7.2v?

Any ideas on if it’s worth trying any of these, although I’m not keen to fry one of these expensive emitters.

Ta.

[M4D_M4X]

interesting question…

subscribed!

[DavidEF]

You may get by with 6 x 1.5v D cells, because of voltage sag. I don’t know what the exact voltage sag will be, but I think with any alkalines it will be substantial. In fact, if 2 x 4.2v Li-Ion works, then surely 6 x 1.5v D cells cannot be too much.

[Chicken_Drumstick]

My only issue is thinking resting and nominal voltage.

As 2 x li-ion is 8.4v resting, but only 7.4v nominal.

I haven’t put a D cell on a DMM for ages, but I think a fresh resting voltage is more like 1.65v or something. 9.9v for 6.

Think I’ll try it on 12 AA Eneloops 2P6S and see how it does for starters. I can compare amp draw and lux readings vs 2 x li-ion. Will have to wait a few weeks for the emitter though.

[djozz]

You just will not get the amps out of an alkaline cell to kill an MT-G2, remember you need more than 16A ! So what will it deliver? Perhaps 3 or 4 if you are lucky?

NiMh is the same story, they have very high amp capability but also a lower voltage. When fully charged, 6x1.32V=almost 8V, and even without any voltage sag you stay within 16A, more likely it will be between 4A and 6A.

[DavidEF]

A couple of (almost) related reads that may give a bit of insight into alkalines:

question about using 1.2v nimh AA instead of officially stated 1.5v AA alkline - Post #1 from Boaz says this:

@Boaz

Lumens are usually higher on a nimh  because of less internal resistance of a nimh vs an alkaline .When loaded an alkalines voltage sags pretty hard as well …Nimh batteries almost always charge up to over 1.4 volts anyway …mine settle down to mid 1.375??? after sitting a bit 

eneloops or nimhs almost always win the output race

alkalines  just suck

NANJG 105C w/ 4 D Batteries (~6V) - Post #6 from comfychair:

@comfychair

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.

[power911]

I’m not sure if I’m hijacking but…

MT-G2 6v running direct off lantern 6v sounds like a fun upgrade to old incan 6v lantern flashlights

[hank]

I long ago had some M@g lights — 4, 5, and 6-cell — built long ago with four Luxeons, direct drive — they were ok with alkalines, but overheated fast with NiMH Ds

[Bigchelis]

I got an MTG2 mounted on copper directly thanks to venturebloods heatsink sales….Mine was Direct Drive with copper to LED bonding so, maybe that helped.

Anyhow in my 6D Mag with 6 Tenergy NiMH D cells it did work great as expected.

I than added an extension and ran 7 Tenergy NiMH D cells and saw like 9A at tailcap if I recall correctly. Worked great too and the tint was pure white bliss.

bigC