Lithiums e2 start out with a voltage of about 1.82v (1.7 rated.) Alkalines start out at about 1.61 volts. (1.5 rated). Fresh nimh start about about 1.4 after charging (1.2 rated)
So e2's are only more powerful than alks ONLY until the voltage drops down below 1.61. Probably for most lasers it will be about 10-15 minutes.
Off course liths have a longer run time, but I don't know if they are worth 2-4 times the cost of a regular alkaline. I guess its up to you.
Unless you are burning or bursting, you probably would not know the difference. Certainly I see no need for them in less than 55 mw lasers. However , if you have a borderline burner, the e2's might put it over the top for you!
One advantage lithiums do have is that they work much better in colder weather (below 0 C or 32 F)
What I think we really need is specs on how much amperage batteries will put out in a certain time period. The more amperage (flow rate) put out by the baterry / minute seems more inmportant to me than the starting voltage, but I may be wrong. I have seem some fast drain rechargable batteries on the market, I think from Amondotech.com or maybe batterystation.com.
I saw an ad today in a magazine about a new battery Panosonic that is rated at 1.7v . Wonder what that is all about? I will have to check the add again or look on their website.
Meanwhile, Menards had a flyer for 8 free aaa or AA alks with $10 purchase so I picked the AAA's up today. They were Panasonic Alkaline Plus.
I am waiting on 2 lasers from AtlasNova. Purchased the CPF high spec (30+ mw)greenie special and the 635 pointer. My first 2 purchases. My wife bought the greenie for my birthday and I sprung for the 635. Hope I get something near 40mw. Hope to get them by Saturday.
There are still some of the CPF specials available in chrome for $79 plus shipping.
Neo