Lithium Vs. Ni-MH Batteries (AA)

Lithium weigh a little less and have almost twice the capacity, but you can't recharge them

http://www.led-resource.com/2011/10/introducing-energizer-ultimate-lithium-runtime-tests/

Dave

Thanks Dave, that's what I was looking for.

Is lithium really twice the capacity? It seems like good NiMH AA batteries are around 2000-2700 mAh capacity, while lithium AA's are around 3000 mAh. So 20-50% more capacity unless I'm missing something.

Regardless, lithiums are clearly the higher performing battery but I use NiMH because it's much cheaper and easier on the planet than tossing batteries every couple trips.

It's about half. Depends on how you measure it.

That link said run time is 40 hours/low/NiMh, 60 hours/low/Lithium

But the voltage of lithium is a little more, so low lithium is probably a little brighter than low NiMh – I think that was un-regulated

and 5 hours/high/NiMh, 10 hours/high/Lithium – those are regulated so maybe the same brightness?

If you calculate capacity/weight, lithiums are more than twice as good

Dan, the one factor that you are missing is the voltage. A lithium primary battery tends to run around 1.7V open circuit. A NiMH rechargeable tends to run around 1.25V open circuit. For some devices, that voltage won't make any difference. For others, it makes a big difference. So, the capacity in mAh is only part of the output picture, and you might need to look at total watt-hours. Lithiums have an impressively flat output curve, and that is good for lots of devices. Unfortunately, that means that when they go to hell at the end of life, they really go to hell quickly.

–B.G.–

The mAh ratings vary with the discharge rate of the battery. Lithium batteries are much better than Alkaline or NiMH batteries at high current discharge rates. At very low current discharge rates there is not much difference.

of course if yr constantly using it for long duration night activities over and over again, then you generally want a rechargeable battery …

;)