Ive found that batteries at around 1.4 to 1.5 volts gives the optimum brightness to heat related issues. Fresh lithiums are noticably less bright that partially drained coppertops. Dont ask me why but My opto 178mw pen likes batteries at around 1.4 volts or less. Trust me Lithiums are not your friend on this setup
sbdwag
Totally agree. Lithiums for one reason or another don't work well with this laser. Just grab some rechargeables (which gives plenty brightness) and call it a day. Not to mention you won't have to worry about possible long term damage.
BATTERY FACTS
Can NiMH batteries be substituted for alkaline batteries even though they are only 1.2 volts?
Yes, for most high drain electronic applications NiMH batteries are ideal substitutes and you needn't worry about the apparent voltage differences. Even though alkaline batteries are rated at a nominal 1.5 volts, they only deliver 1.5 volts when they are fully charged. As they begin to discharge the voltage of alkaline batteries continuously drops. In fact, over the course of their discharge, alkaline batteries actually average about 1.2 volts. That's very close to the 1.2 volts of a NiMH battery. The main difference is that an alkaline battery starts at 1.5 volts and gradually drops to less than 1.0 volts. NiMH batteries stay at about 1.2 volts for most of their discharge cycle.
There are a couple of cases where their actual voltage difference may be important to you. In the case of a device like a radio, where a higher voltage can mean a stronger signal, a fresh alkaline battery may be more desirable - but more expensive - than a rechargeable NiMH battery. This is also true for a flashlight, which will be brighter with the initial higher voltage of alkaline cells. This minor difference may not be important to you and is probably offset by the much lower cost of operating NiMH batteries. And keep in mind that the alkaline battery only has a higher voltage when it is fully charged. Once it gets to 50% capacity or less, it will be delivering a lower voltage than a NiMH battery.
The one time when the voltage difference of the two is important would be in the case of a device that checks the voltage of a battery to estimate the amount of charge left on the battery. Because the voltage of an alkaline battery drops at a very predictable rate it's possible to estimate the amount of capacity left in an alkaline battery based solely on its voltage. (1.5 volts - fully charged, 1.25 volts - 50% charged, 1.0 volts - almost fully discharged). But a NiMH (or NiCd) battery stays at about 1.2 volts until it is nearly completely discharged. This makes it almost impossible to know the amount of capacity left based on its voltage alone. When a device that's using NiMH batteries indicates the battery is low, it's time to change the batteries now!
really
