26650 to 4xAAA adapter.

[AaronT]

Does anyone have any experience with similar devices to this?
Or swapping between 26650s and AAAs with the same diode/driver combo?

 

[Sta]

Usually that will not work. 26650s are usually between 3.7 and 4.2 volts whereas 4xAAA is 6V. What are you trying to use this for?

 

[AaronT]

Considering a build based on a host that uses 26650s, It sounds like I could get more power using 8 AAAs.

 

[diachi]

Considering a build based on a host that uses 26650s, It sounds like I could get more power using 8 AAAs.

You'll be able to pull way more current out of a lithium if that's what you're going for - and they are way higher capacity than Alkaline batteries too. Especially given the physical size difference of AAA vs 26650s.

8x AAAs isn't a whole lot more voltage than two unprotected Lithium cells in series either - ~12V for the AAAs vs ~8.4V for the Li-Ion. I'd just go with two Li-Ion cells - unless you need 12V for some reason.

 

[Pman]

It's interesting that that converter exists but it's also kind of odd. If you take 4 normal AAA cells at 1.6V you get 6.4V compared to a fully charged 4.2V. I suppose that's fine if you are going to get voltage sag or whatever it is you are driving can handle the voltage but generally the point of adapters like these are to get away with subpar instead of investing in the proper.

 

[AaronT]

Thanks for the info guys.

 

[Benm]

Usually that will not work. 26650s are usually between 3.7 and 4.2 volts whereas 4xAAA is 6V. What are you trying to use this for?

Well, that 1.5 volts for a AAA is the open cell voltage for an alkaline cell. Under a bit of load that could sag to 1 to 1.2 volts each so it would not the be that far from the original 26650 lithium.

If you were to use it with nimh cells the nominal voltage would be 4.8 volts, perhaps a bit lower with serious load.

I guess this could work with boost converters for diodes that operate at 5 volts forwards or so, but it would not last very long compared to the proper lithium cell. It would also risk fyring the laser off fresh cells as most boost regulators cannot really reduce voltage from input to output, apart from the voltage drop across the schottky diode and ohmic resistance of the inductor.