Series vs Parallel multiple 18650 flashlights? Safety?

If a short flashlight (soda can style) takes 3 18650s...

But if you pop in only 2 18650s and it still works (i haven't tried popping in only 1) does that mean the battery circuit is built in parallel?

If yes, is this a safer configuration compared a lengthier (nightstick style) flashlight accepting 2 18650's back to back? (i'm presuming this would have to be a circuit built in series)

Any thoughts?

If yes, is this a safer configuration compared a lengthier (nightstick style) flashlight accepting 2 18650's back to back? (i'm presuming this would have to be a circuit built in series)

Click to expand...

Yeah, that sounds right. Conventional wisdom says parallel is pretty much safer than the same number of batteries in series.

I've got a light (Noctigon M43) that takes 1, 2, 3, or all 4 batteries. I always run it with 4 because turbo mode drains them like crazy.

But if you pop in only 2 18650s and it still works (i haven't tried popping in only 1) does that mean the battery circuit is built in parallel?

Click to expand...

Yeah, that sounds right.

Blind said:

If a short flashlight (soda can style) takes 3 18650s...

But if you pop in only 2 18650s and it still works (i haven't tried popping in only 1) does that mean the battery circuit is built in parallel?

Click to expand...

Most likely it is a parallel circuit.
Although I believe that, it is possible to create a series of two and a series of three that the driver can support the different voltages.

If yes, is this a safer configuration compared a lengthier (nightstick style) flashlight accepting 2 18650's back to back? (i'm presuming this would have to be a circuit built in series)

Any thoughts?

Click to expand...

Yes IMO parallel are safer. I'd suggest that you look through this section of the forum. Most of the problems reported here are multi-cell RCR123 lights. Those lights are in series. That doesn't mean that other batteries never have problems, even some single cell cel-phone batteries have failed.