SF M6 - IMR-M6 lamp question and batteries

Hello everyone.
Just wondering about two things:
1) Can you use the LF IMR-M6 lamp with 3 normal AW17670 batteries or you really have to use the IMR batteries? Is there just a lower performance or the bulb doesn't work?
2) Can you use a standard 17670 charger to charge up IMR17670 cells?

thanks!

Yes on both counts.

However, as you suspect, the performance will not be quite as good if you don't use IMR cells. the IMR-M6 is designed to take the full voltage of IMR cells, which will not sag under load. With ordinary 17670s, the voltage will sag by >1.5V, so the bulb will not give its full output.

IMR cells are charged exactly the same as regular Li-Ion cells.

DM51 said:

Yes on both counts.

However, as you suspect, the performance will not be quite as good if you don't use IMR cells. the IMR-M6 is designed to take the full voltage of IMR cells, which will not sag under load. With ordinary 17670s, the voltage will sag by >1.5V, so the bulb will not give its full output.

IMR cells are charged exactly the same as regular Li-Ion cells.

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+1

What he said.

+1, except that IMR17670s don't exist yet, so the discussion is purely academic anyway.

DM51 said:

IMR cells are charged exactly the same as regular Li-Ion cells.

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Do they stop charging at 4.2V on all chargers? I thought that you need a charger that stops charging the cells at a safe level and does not continue to charge past that point.

They usually settle back down to ~4.1V after coming off the charger. I use a Pila IBC or Hyperion EOS 5i for mine. They don't go past 4.2V.

IMR 18650's in a FM Megallenium body would be perfect for that lamp.

Lithium Ion AW 18650-26 cells in a Megallenium would likewise work a little bit better than 17670 cells due to less sag.

cernobila said:

I thought that you need a charger that stops charging the cells at a safe level and does not continue to charge past that point.

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You actually need that for ALL lithium-based rechargeables.

cernobila said:

Do they stop charging at 4.2V on all chargers?

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Charge termination is controlled by the charger. It is not a good idea to rely on the Li-Ion protection circuit to open up, as (a) it may not and (b) the cell will already sustain some damage by the time the Li-Ion protection circuit opens. The Li-Ion protection circuit is a failsafe only, for preventing nasty explosions, not so much for looking after the cells.

That, I assume, is why Fifty-One Deutschmarks says "IMR cells are charged exactly the same as regular Li-Ion cells."

lctorana said:

Charge termination is controlled by the charger.

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I thought that some chargers rely on the protection circuits on the cells to stop charging and therefore would continue to charge unprotected cells to higher level.

cernobila said:

I thought that some chargers rely on the protection circuits on the cells to stop charging and therefore would continue to charge unprotected cells to higher level.

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Yes, absolutely correct.

And that's always a bad thing.

So, going back to my original point........with IMR cells you have to be more selective in what charger is used. Not just any charger but one that does not rely on the protection circuit to stop overcharging.....With quality protected cells the choice of chargers is greater......Having said that, I now only use the Pila IBC model for all my Li-Ion cells.

Yes you have to be selective of the charger you use. The charger needs to cut off at 4.2 volts or less, since the IMR batteries do not have any built in protection.
I had an experience with using a Wolf Eyes tailcap charger that charges 3 batteries in the flashlight, and I was charging Ultrafire unprotected batteries which charged up to 4.59 volts when the charger light turned green. Yes I got rid of the batteries.

cernobila said:

So, going back to my original point........with IMR cells you have to be more selective in what charger is used. Not just any charger but one that does not rely on the protection circuit to stop overcharging.....With quality protected cells the choice of chargers is greater......Having said that, I now only use the Pila IBC model for all my Li-Ion cells.

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So I could use 6xIMR16340 to perfectly power the IMR-M6 bulb... right?

troller_cpf said:

So I could use 6xIMR16340 to perfectly power the IMR-M6 bulb... right?

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Yes, definitely. That was exactly what the manufacturer had in mind when they designed the IMR-M6.

but that will limit runtime to 20 minutes MAX....

Timmo.

325addict said:

but that will limit runtime to 20 minutes MAX....

Timmo.

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That's a lot of runtime given the output/throw. To be honest, I've never had a real need to run such beast for more than 5 minutes straight.

You'll probably find that the HO-M6R is the better choice on 3x17670 LiCo cells in the long term since it won't wear out the cells as quickly. Yes the IMR-M6 will work on 3 standard 17670s, but I'm not sure if the 30% gain in output (barely noticeable to the eye), is worth a ~30% drop in run-time and the increased rate of wear on the cells.

-Eric

I run my IMR M6 bulb in a KT-1 turbo head on a 9P with 3 IMR 16340s haha. Talk about bright and compact, it is the ultimate wow light.

And what if I run a WA1185 with 6 IMR16340?

troller_cpf said:

And what if I run a WA1185 with 6 IMR16340?

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